Here's what I've got:
(9) 285W SolarWorld PV's (three strings of three each wired into midnite combiner box)
Midnite Classic 150 Charge Controller with Whizbang Jr & 500a/50mv Shunt
MagnaSine MS4024 Inverter (4000W/24V)
(8 ) Trojan T105 Batteries wired in series/parallel (24V/450AH)
Here are the battery settings from Trojan:
EQ= 32.4
ABSORB= 29.6
FLOAT= 27.0
I'm currently getting anywhere from 8-10 kwh a day of sun and have estimated my daily usage to be about 4.5 kwh. The problem I'm having is that my batteries don't seem to be receiving a full charge, and even after the absorb stage is completed and it goes into float my battery AH or SOC continues to decrease when there is plenty of power still coming in to run everything directly off the pv's. Shouldn't my batteries remain at 100% SOC (if they are truly charged at 100%) until my pv's stop producing enough power to carry the loads? Or do I have to somehow hardwire the charge controller directly to my Inverter to run the loads directly off the pv's?
Here's what I've tried so far:
1. Calibrating the battery volts in the TWEAKS settings after letting them set for an hour or so without loads
2. Setting the CHARGETIME to 4 hours instead of 2 hours
3. Setting the ENDAMPS to 6.0v after watching yesterdays charge cycle
I have also noticed that sometimes it goes into FLOAT after the absorb charge and other times it goes into FLOAT MPPT. Whats the difference? There is no information in the manual about FLOAT MPPT. I also don't have a hygrometer just yet (apparently its a pretty handy tool for checking batteries) but I would think the Whizbang Jr and Shunt (yes they are properly installed) are supposed to accurately track the SOC/AH- at least that what I purchased them for. Am I wrong? We lost power the other night and the SOC was at least above 50% but the battery voltage was somewhere around 20v prompting me to start making the changes above the next day. I believe the Inverter shut the power off because of low voltage as it had to be reset. My batteries were at 76% when I got up this morning (I think the battery voltage was around 23.5v if I'm not mistaken) but after setting the ENDAMPS to 6.0v yesterday the absorb stage was so short that I completely missed it today, or it just went straight to FLOAT after the BULK MPPT stage completed. The pv's are bringing around 2000w right now and my battery bank is already down to 94% and counting. :( Batteries are currently at 26.5v and the Classic continues to remain in FLOAT mode.
Any help would be greatly appreciated as we are new to off-grid living- and loving it despite the difficulties!
With flooded lead acid batteries such as the t105 you should plan for a maximum 20 to 25% depth of discharge in the daily charge/discharge cycle. See the manufacturers specs on DoD,cycles and life expectancy.
It would appear your battery capacity is too small for your overnight loads
The floatmppt state means there is insufficient input power for the classic to maintain the batteries at the float voltage setting.
You are seeing the 8 to 10kwhr daily energy from the Classic display?
How is the 4.5kwhr load estimTed? What are the loads?
And just to be sure, the only connection to your battery -Ve is one side of the deltec shunt?
All other -Ve connections inc the inverter go to the other side of the shunt?
Dgd
Thanks for the quick response!
From everything I've read its best to keep the batteries above 50% for longer life (less discharge is of course better) and with a 24v x 450ah battery bank that gives me a total of 10.8kwh at 100% discharge. Half of that would be 5.4kwh or 50% depth of discharge. The 4.5 kwh should leave me somewhere around 6.3kwh or 262ah remaining. Am I calculating this right? However, that 4.5kwh figure is for a full day of use so if my batteries were at 100% SOC in the evening when the pv's stop producing enough wattage to carry the loads then we should have plenty of headroom. Case in point after making the changes yesterday my batteries were fully charged at around 6pm and 12 hours later they were at 76% SOC- which is completely acceptable. Also, the well pump doesn't kick on at night and the laptop and modem are unplugged to reduce the load. Today my batteries were fully charged at around 12:30pm but the SOC/AH has been decreasing even though there is more than enough current coming in from the pv's to carry the loads. It has been in FLOAT ever since and holding the batteries at 26.5v so I don't understand why the SOC/AH continues to decrease. My batteries are currently at 86% or 388ah and my obvious concern is that they won't make it until the next charge. I'm not sure if I should REBULK and top them off while there's still enough current coming in from the pv's or not because by doing so I decrease the life of the battery. Am I wrong to think my batteries should hold a full charge in FLOAT while the excess current from the pv's supply the load as it is available?
Yes, the 8-10kwh is calculated on the Classic. The 4.5 is an estimate based on my figures using a kill-a-watt meter; refrigerator, small freezer, jet well pump, laptop, modem, led lights, etc.
The Shunt is on the negative side of my inverter with the battery on one side and the loads on the other. Also, the wbj is pointed towards the battery side as its supposed to be.
For FLA batteries That should be above 80% for longer life NOT 50%
Taking your batteries on a daily cycle anywhere near 50% DoD will kill them fairly quickly.
The 76% SOC looks good but not that good as it's showing you don't really have any reserve for the bad weather days where power input is low.
The solution is either more fla batteries or change to more efficient types such as LiFePO4 where 80% DoD is possible
reset the classic to the 2 or 3 hours absorb timing you originally had so that you get the 100% SOC after the absorb cycle completes
When you see SOC reducing and the classic is in Float is that actually floatmppt?
Dgd
Interesting. I don't have the link handy but I read somewhere that 50% dod would give me 4-6 years out of the T105's. People who keep them at 80% or more have reported 8+ years out of them. I'll definitely have to do some more research on the matter and consider adding another string. I've only been using them for less than a month so it shouldn't be a problem.
So do you recommend that I change the charge time, reset the ENDAMPS to 0, and REBULK the batteries today? We only have a couple hours left to store the power...
The Classic is in FLOAT (not FLOAT MPPT) maintaining the 26.5v but my SOC/AH continues to reduce. That doesn't sound right, does it?
**EDIT**
We just had some overcast come in and the Classic dropped into FLOAT MPPT so we'll just have to make it on the 80% SOC that's displayed.
Can someone please tell me if the Classic is in FLOAT the batteries are to be kept at 26.5v and 100% SOC? Or is it normal for the SOC to decrease while the batteries are maintained at 26.5v?
Hi iy4h, Welcome to the Froum.
Just a few quick thoughts;
OK, End Amps is a current setting -- Amps. When you "set EA to 6 V", assume that you mean 6 Amps. Rebulk is in volts, and in the Advanced menu, it is right next to the EA set value, assume that you are really changing EA, and not ReBulk, which defaults to 8v, and might possibly be settable to 6 V. Know that you are not daft, but just checking.
And know that you have the WBjr and Shunt installed correctly, but, just make sure that you have set things to USE that Shunt current and not the Classic's output current.
That Hydrometer is much more than a handy gadget, it is THE ESSENTIAL TOOL for working with Flooded batteries. Get two or three of them, and test them all to see how well they agree. Use one, and set the others aside, in a safe place, waiting for the time that the one you are using breaks.
Make certain that you are using the Battery Temperature Sensor (BTS). Apply it to the side of the case on one of the batteries in the center of the pack. IMO, it is good to place a block of Styrofoam(R) over the BTS (1" - 2" thickness), and tape it down to the clean battery surface.
You will probably want to get a DC Clamp Ammeter. Sears has one for about $50-ish. Very handy for measuring how well the two strings of batteries are sharing charge and discharge currents.
The WBjr is a great device, and it counts Ah well. But, like any other battery monitoring device, it is only as good as the setup data entered into it, and, at best, it is a reasonable rough approximation of SOC of a battery. There are many factors which can impact actual remaining Ah, so constructing a good model for a battery is difficult. And even if the data entry exactly described the nature of your battery on any given day, the nature of a battery changes over a period of time, and depends upon exactly how it is charged and discharged, and so on.
Also, batteries need a reasonable number of cycles to build full Capacity, and perhaps your batteries are still settling in, although, after about one month of daily cycling, they probably have developed their full capacity.
It might be time for you to do an EQ, although, it would probably be best if you fully charge your batteries, measure the SG of EACH CELL, and log this data in your battery Log Book. Number each battery and each cell, like #1 A, B, C; 2 A, B, C, etc.
What is the battery Efficiency value that you have used, when setting up the Classic for the WBjr?
Thanks, Vic
Thanks for the reply Vic!
Yes, the ENDAMPS is set at 6 amps, not volts. It was a typo. That's the figure I came up with after carefully watching the batteries charge yesterday. I checked it every 10 minutes during the ABSORB time and it seemed to settle on 5.9A-6.0A. From what I've read its supposed to be 1-3% of the 450AH capacity so it certainly falls within that range. However, I've read conflicting reports about even setting the ENDAMPS so I don't know if its best to use it or not. Whats your opinion on the matter?
So, how do I know if the Classic is using the Shunt current as opposed to the Classics output current?
I'll be going into town tomorrow and won't come home without the Hydrometers. :)
The battery temperature sensor is set and working. Thanks for the tip about the styrofoam.
I don't have an Ammeter but will add that to my list. I was careful to make the battery cables the same length so hopefully that pays off.
I haven't attempted to do an EQ just yet but that may be in order once I can get the batteries fully charged. Also, a battery log book is an excellent idea! How often would you recommend checking them?
I set the battery efficiency for the T105 at 85% per the Trojan tech I spoke with the other day.
Quote from: inyour4head on June 26, 2016, 06:07:14 PM
Can someone please tell me if the Classic is in FLOAT the batteries are to be kept at 26.5v and 100% SOC? Or is it normal for the SOC to decrease while the batteries are maintained at 26.5v?
I have not seen this occur on any of my RE systems. If a load comes online during float then the Classic will increase it current output to cover the load and maintain float voltage (assuming there is sufficient PV input power) otherwise it will drop back to FLOATMPPT and put all PV power into the battery/loads.
It would be good to see your wiring circuit info, do you have a diagram of this? and maybe some photos of your setup - battery wiring, DC distribution box wiring etc..
dgd
That's what leads me to believe the batteries aren't fully charging. I have seen the Classic increase its current to cover the load in FLOAT before but at the same time the SOC/AH still decreases. Perhaps the wbj is reading the Classics output current as opposed to the shunt output current as Vic mentioned??
I don't have any diagrams or pictures on hand but I'll try to explain.
The pv's run into the combiner box and then to the corresponding Classic terminals. I also have a midnite surge protector in the combiner box wired per the instructions that came with it. The Classic runs into the battery bank from the other set of terminals. Battery positive and negative run from the battery box to the bottom lugs on the inverter. Positive and negative run from the inverter terminals to the house breaker box. The wbj cable is connected to the AUX2 terminal then proceeds to the Shunt on the inverter cable lugs as previously described- battery on one side load on the other. I also plan to add some breakers in the future so I don't have to run to the combiner box or battery box every time I need to disconnect power. Hindsight is always 20/20.
Quote from: inyour4head on June 26, 2016, 07:18:21 PM
The pv's run into the combiner box and then to the corresponding Classic terminals. I also have a midnite surge protector in the combiner box wired per the instructions that came with it. The Classic runs into the battery bank from the other set of terminals. Battery positive and negative run from the battery box to the bottom lugs on the inverter. Positive and negative run from the inverter terminals to the house breaker box. The wbj cable is connected to the AUX2 terminal then proceeds to the Shunt on the inverter cable lugs as previously described- battery on one side load on the other. I also plan to add some breakers in the future so I don't have to run to the combiner box or battery box every time I need to disconnect power. Hindsight is always 20/20.
Sorry, but the battery wiring needs explained more exactly
The +ve cable from the battery bank box goes to inverter +ve lug
The -ve cable from battery box ONLY goes to the one side of the shunt AND NOT TO THE INVERTER -ve lug
(You say above that it does!)
Then the other side of the shunt goes to the inverter -ve lug where all the other -ve connect to, such as the Classic -ve etc...
Is that what you have.
Please take a couple of photos as they will clarify
dgd
I would also strongly recommend you get a Midite Epanel or an MNDC box with 250A breaker for the inverter and 80A or 100A breaker for the Classic.
Both these boxes have space for the Deltec shunt/Wbjr and come with detailed wiring diagrams
dgd
Quote from: inyour4head on June 26, 2016, 07:18:21 PM
That's what leads me to believe the batteries aren't fully charging. I have seen the Classic increase its current to cover the load in FLOAT before but at the same time the SOC/AH still decreases. Perhaps the wbj is reading the Classics output current as opposed to the shunt output current as Vic mentioned??
I don't have any diagrams or pictures on hand but I'll try to explain.
The pv's run into the combiner box and then to the corresponding Classic terminals. I also have a midnite surge protector in the combiner box wired per the instructions that came with it. The Classic runs into the battery bank from the other set of terminals. Battery positive and negative run from the battery box to the bottom lugs on the inverter. Positive and negative run from the inverter terminals to the house breaker box. The wbj cable is connected to the AUX2 terminal then proceeds to the Shunt on the inverter cable lugs as previously described- battery on one side load on the other. I also plan to add some breakers in the future so I don't have to run to the combiner box or battery box every time I need to disconnect power. Hindsight is always 20/20.
Quickly,
There are two places where you will see "Shunt" on the Classic's MNGP display.
First one is in the Advanced menu, and is under the set value for EA, IIRC.
AND, there is another on the WBjr Status display ... about the fourth button-push on the Status pages. This is the display of the WBjr battery charge Amps, somewhere on that page, it should say Shunt.
If the WBjr has not been setup to use the Shunt, then those displays might say, " Classic ".
IIRC, Vic
Thanks for the info. I will definitely look into getting those breaker boxes.
As for my wiring perhaps I didn't explain very well. My +ve from the battery bank goes onto +ve inverter lug. The -ve from the battery bank goes onto one side of the shunt, and then the other side of the shunt goes onto the -ve lug on the inverter. My Classic does not connect to the inverter at all. The +pv and -pv from the combiner box goes onto the +pv and -pv terminals on the Classic. Then the second set of +ve and -ve terminals on the Classic go onto the +ve and -ve terminals on the battery bank. Does this sound correct?
I'll try to post a couple pictures when I have time.
Quote from: inyour4head on June 26, 2016, 06:52:17 PM
Thanks for the reply Vic!
Yes, the ENDAMPS is set at 6 amps, not volts. It was a typo. That's the figure I came up with after carefully watching the batteries charge yesterday. I checked it every 10 minutes during the ABSORB time and it seemed to settle on 5.9A-6.0A. From what I've read its supposed to be 1-3% of the 450AH capacity so it certainly falls within that range. However, I've read conflicting reports about even setting the ENDAMPS so I don't know if its best to use it or not. Whats your opinion on the matter?
So, how do I know if the Classic is using the Shunt current as opposed to the Classics output current?
I'll be going into town tomorrow and won't come home without the Hydrometers. :)
The battery temperature sensor is set and working. Thanks for the tip about the styrofoam.
I don't have an Ammeter but will add that to my list. I was careful to make the battery cables the same length so hopefully that pays off.
I haven't attempted to do an EQ just yet but that may be in order once I can get the batteries fully charged. Also, a battery log book is an excellent idea! How often would you recommend checking them?
I set the battery efficiency for the T105 at 85% per the Trojan tech I spoke with the other day.
Hi iy4h,
Yes, looks like you have set up the EA correctly for a start. Measuring SGs when the Classic goes to Float should confirm this EA value. Or allow you to change EA a bit to get a full-charge. I have ONLY used EA for over a decade on all systems that I deal with. In earlier days, used CC EA, without a Shunt, which can also work OK.
Very good that you are using the BTS.
IMO, a glass float/glass outer tube Hydrometer should be fine. Try to find ones that have real numbers on the float, and go from about 1.110, to 1.3XX. Colors on the float are OK, just as long as there are actual numbers for measured SG. Believe that the Trojans are typically 1.277-ish when fully-charged.
NAPA, or other good Auto Supply store should have perfectly adequate Hydros.
85% Efficiency is a fine place to start for Flooded (FLA) batteries.
Often one chooses one or two Pilot Cells. These are often cells that have the lowest SG in the bank. You can check this one or two cells as a quick survey of the approximate SG of the battery bank.
Initially, you will probably want to check SGs fairly often, every week or so, until your battery becomes fully-charged, and you feel it has become predictable.
Here is a Link to Surrette Battery's article on measuring SGs:
http://support.rollsbattery.com/support/solutions/articles/4347-measuring-specific-gravity
More Later, Vic
... "The +pv and -pv from the combiner box goes onto the +pv and -pv terminals on the Classic. Then the second set of +ve and -ve terminals on the Classic go onto the +ve and -ve terminals on the battery bank ..."
NO, really, the Negative from the Classic battery terminals should connect to the Negative side of the Shunt. This is the side of the Shunt where ALL of the negatives from everything that needs the battery Negative connection. The ONLY thing on the other side of the Shunt, is the connection directly to the battery Negative.
Vic
Vic,
I checked the Classic and the wbj seems to be set up correctly. However, I do not have the negative from the Classic connected to the negative on the shunt as previously stated. Could this possibly be the cause of my problems? I will make the change and see what happens. :)
Quote from: inyour4head on June 26, 2016, 08:02:17 PM
Then the second set of +ve and -ve terminals on the Classic go onto the +ve and -ve terminals on the battery bank. Does this sound correct?
I'll try to post a couple pictures when I have time.
No, that is not correct
The -ve from the Classic should go to the inverter -ve lug so that the ONLY -ve wire to the battery box is coming from the shunt.
The purpose of the shunt is to measure ALL current in and out of the battery. So its very important there is no other device connected to the battery -ve at the battery box
Fix this and your Classic will start reporting what is actually happening as now the SOC% figure is not accurate.
dgd
Okay I just took the negative from the second Classic -ve terminal and put it on the negative side of the Shunt. But am I supposed to run from the negative side of the shunt back to the negative on the battery bank?
I think we're making progress. :)
Sorry but I'm still not sure you are correct.
One side of the shunt ONLY has one cable connected to it and that cable goes to the battery box NEG.
On the other side of the shunt every other NEG from ALL devices, inverter, classic etc connect
If I uderstand correctly you have the other side of the shunt going to the inverter NEG lug which you are using as a NEG common connection point hence you connect the Classic NEG to that point.
You really need to take some pics and post them here so we can see what you wired to what.
dgd
The terminal on the left goes on the negative lug on the inverter. The two negatives on the right are from the negative on the battery bank and from the negative on the Classic.
ok, still wrong
That small black cable from the Classic should connect to the other side of the shunt so that the Classic -ve and the inverter -ve are on the same side of the shunt.
dgd
Quote from: dgd on June 26, 2016, 09:59:42 PM
ok, still wrong
That small black cable from the Classic should connect to the other side of the shunt so that the Classic -ve and the inverter -ve are on the same side of the shunt.
dgd
YES, absolutely correct.
The ONLY cable that belongs on one side of the Shunt is the battery Negative.
ALL other negative leads belong on the other side of the Shunt -- everything!!
Almost there. Vic
After re-reading the posts I see that I misunderstood things. The good thing is that if we aren't making mistakes, we aren't learning anything. ;D
I put the Classic negative on the other side so we should start getting more accurate readings now. I installed the wbj and shunt about a week ago so hopefully we didn't do any serious damage to the batteries during that time. I admit that we still have much to learn about living off-grid but its well worth it- we wouldn't have it any other way!
Have a good night and thanks for all of your help!!
One more thing; Do you think its possible my EA of 6.0 is not correct because the current wasn't being measured correctly? Should I just re-set it to zero and set the charge time to 4hrs and monitor the amps again tomorrow? Or just leave it as is? Thanks!
I would just go back to the default 2 hour timed Absorb the over a week or so observe when the Absorb Amps tails off about about 2 to 3% of capacity, ie around 15 amps for your bank.
If it never reaches that then repeat for 3 hour timed Absorb.
Once you have that Amp figure then perhaps move to that EA Absorb termination
dgd
Inyour4head,
I think I see your problem:
You state in the above post that Classic +ve and -ve go to battery +ve and -ve terminals.
If that is how you are wiring then the shunt will not see charge current.
To reiterate what others have said.......
There is only one connection to battery negative......-ve......that is the Deltec Shunt.......all negative returns fron inverter, charge controller, AND all loads must go to the Deltec Shunt........I.e......ALL the current going to or from the battery bank MUST go through the shunt for the Classic to read that shunt and read the real current through that shunt ....which will represent the real current flowing into or from that battery.
Please recheck your connections at the battery negative. If your Classic negative is connected to the battery side of the shunt....not the load side.....then the Classic will not see its own output current.
David
<EDIT>. Ok so I read only the first page before I wrote response, I see that others have also caught that error. That is the problem as Vic pointed out
After making the changes the Classic seems to be reading the wbj properly now. Thanks again for all your help!! ;D
We have some overcast today but we are confident that the batteries will be topped off in the next couple of days and then we should be good to go. 8)
Quote from: inyour4head on June 26, 2016, 10:36:12 PM
One more thing; Do you think its possible my EA of 6.0 is not correct because the current wasn't being measured correctly? Should I just re-set it to zero and set the charge time to 4hrs and monitor the amps again tomorrow? Or just leave it as is? Thanks!
iy4h,
YES, would watch the WBjr battery charge current with a fairly long Absorb time set, as you tired to do previously.
I have had very good luck with Shunt EA on the FLAs here. The main banks are approaching 11 years of age, and have needed to tweak Vabs and EA settings to keep the batteries happy, in the past 9 months, or so. But the initial settings had been stable for many years.
Using FLAs is so nice -- one can actually measure the SOC directly!
Have fun with the new system, Vic
They only sold the cheap hygrometers at the auto stores so I'll have to order a good one online. However, I checked the batteries with the one I picked up this evening and one bank measured approximately 1.3 but the other bank measured approximately 1.1 causing me some concern. According to Trojan the battery is charged at 1.227 give or take .007 or so. The SOC is currently at 63% and the battery voltage is at 23.7v. My well pump draws about 10 amps but when it kicked on this evening it wouldn't even pressurize the system so I'm not sure if the problem lies with the jet pump or the batteries, but the batteries are obviously suspect. Note: I just fired up the generator and the jet pump still wont come on (it sounds like its seizing up but its only a couple months old) so there must be a problem with the pump as well. Perhaps the low voltage caused it to fry (is that even possible?) or its just a cheap pump. Either way when it rains it pours around here... Speaking of rain it was an overcast day here and it did happen to rain so we didn't even bring in enough power to get to the absorb stage. It remained in bulk mppt the whole day but now that the wbj and shunt are installed correctly I did see the SOC/AH increase a small amount even as the loads were supplied so that's an improvement. :)
So, is it possible to bring both banks to the same charge by equalizing them? If so, anyone have any pointers on how to do so correctly? Do I just manually set the EQ at 1hr?
Or does it sound like that string of batteries is fried? They are still under warranty so if that's the case then hopefully we can exchange them with no problems.
Inyour4head,
I'm assuming the 1.1 and 1.3 readings are from your cheap hydrometer. If these are really 1.100 and 1.300 then you need to take corrective action now......don't delay! 1.100 is DEAD! I suggest that you isolate the two strings of batteries and charge that weak set up to 1.260 s.g. as read on a good hydrometer. Don't leave a set at that low of charge or you will have lead bricks! Also your voltage at rest is way too low......23.7 is pretty dead.......I do not take mine below 24.8.....
If you have a good multistage charger then use that to charge the weak set while running system on stronger set.
This raises a question.......you have a new system?....how did you get in this state this fast?
Ok the battery cabling for parallel strings are critical. What you need there is exactly equal lengths of cable to each battery set....NOT....connected to one set then jumper end to the other set...
Unequal battery cable lengths will create an easy path and a hard path for electrons to flow.
Think of running a race.....you have an oval track about 1/2 mile in length and you have an extra loop that is 1/4 mile in length. You can run the short 1/2 mile faster than you could run that 1/2 mile plus the extra 1/4 mile extra length. What are you going to do? Run the short course!
That is exactly what electrons do when the cables from controller and inverter are connected to one battery bank then jumpered to the other bank. Electrons are lazy....they will take the shortest path every time, leaving you with a dead bank.
There is a learning curve to this......
David
Quote from: inyour4head on June 27, 2016, 09:48:23 PM
They only sold the cheap hygrometers at the auto stores so I'll have to order a good one online. However, I checked the batteries with the one I picked up this evening and one bank measured about 1.3 but the other bank measured about 1.1 causing me some concern. The SOC is currently at 63% and the battery voltage is at 23.7v. My well pump draws about 10.5 amps when it kicks on and it wouldn't even pressurize the system when we tried to take showers so I'm not sure if the problem lies with the jet pump or the batteries, but the batteries are obviously suspect. I just fired up the generator and the jet pump still wont come on so there must be a problem with the pump as well. Perhaps the low voltage caused it to fry or its just a cheap pump? When it rains it pours around here... Speaking of rain it was an overcast day here and it did happen to rain so we didn't even bring in enough power to get to the absorb stage. It remained in bulk mppt the whole day but now that the wbj and shunt are installed correctly I did see the SOC/AH increase even as the loads were supplied so that's an improvement.
Does anyone have any suggestions? Is there any way to bring both banks to the same charge by equalizing them? If so, anyone have any pointers on how to do so correctly?
iy4h, Thanks for the update.
Think that you realize that the range in SG from 1.3 to 1.1 is huge. 1.100 SG is a dead battery. and 1.300 is "overcharged", and perhaps fairly low on water.
Too bad that you were unable to find a reasonable Hydrometer. If you are using one with floating colored plastic balls, they are fairly useless.
If you can get a good Hydrometer, you should check the SGs on each cell. A good glass Hydro is repeatable to about 3 points, and readable to within about 2 points. Some are better than that.
I would avoid the Brady brand Hydros. My favorite brand is Freas for glass Hydrometers.
MidNite distributes a fairly good one -- the Hydrovolt. It is easy to read, and is reported to compensate for the temperature of the electrolyte:
http://www.solar-electric.com/catalogsearch/result/?q=hydrovolt
You could disconnect one string of batteries, and charge the lowest string of batts first, then disconnect that string, and charge the other string in a day or two.
The largest disadvantage of parallel strings, is that one string can easily hog almost all of the charge current, keeping any other strings from getting charged much at all. This is much more pronounced on off-grid systems. Grid-charged batteries with parallel strings will eventually fully charge the lagging strings if they remain on charge for some number of days, generally.
If you pump needs about 10 amps at 120 VAC, that is about 22- 25 amps at 50-ish volts.
Hope that the pump is OK. Some have said that the Magnum inverters are a bit slow at voltage regulation, but have not heard of anyone complaining about poor ability in pump starting with them.
More Later, Vic
Its important that the wiring of parallel battery strings is balanced to avoid one bank or battery taking more charge than the others.
This article explains
http://www.smartgauge.co.uk/batt_con.html (http://www.smartgauge.co.uk/batt_con.html)
Gauge of cable you use from battery and for battery inter-connects?
and what gauge of cable do you have from Classic batt connections?
Also its a bit soon to say your SOC reading is accurate. Let a few Absorb cycles happen over a week or so then it should sort itself out.
dgd
Okay I didn't see the other replies until just now...
I updated my post from last night and added a picture of my battery bank. Here is a picture of the wiring diagram from the inverter manual that I used. The battery cable gauge is 2/0 and from the classic to battery its 8awg- the same gauge wire that feeds the pv's. I believe the cables are pretty close to the same length except for the negative cable that goes from the negative terminal on the batteries to the negative terminal on the inverter/shunt but that's exactly what it shows in the inverter manual wiring diagram. (see pic below) Is this not correct? Please look at the two pictures and let me know. **EDIT** After looking at the link dgd sent me it seems that I have some re-wiring to do in order to make the strings more balanced. I find it strange that following the wiring diagram in the inverter manual (In fact I saw the very same diagram at many different places on the internet) it could have possibly damaged my batteries. That's very discouraging to say the least...
So its okay to take the positive off of the one string and put it on the other? Won't that make my battery bank only 12v instead of 24v? Or will I have to re-wire that string to make the 4 batteries 24v 225ah? **EDIT** After looking at wiring diagrams I disconnected the two strings and have the 4 good batteries in series to give me 24v 225AH. This should buy me some time to figure things out.
I don't have a multistage charger so I'm not quite sure how to get the other string charged up. Would it be a good idea to turn the breaker to the house off and hook the dead string back up and let the pv's charge them? The system has been running for about 4 weeks now and I have always noticed the voltage falling below 24v. Is it possible I bought defective batteries from the start? Or is it more likely that my wiring has caused this? I'm just not sure if I should try to recharge them by the method I just described or contact the retail store I bought them at and try to return them today. Any suggestions?
On a positive note: I plugged in the well pump after disconnecting the dead string and it worked. ;D
**EDIT**
Okay I have decided to go ahead and try to recharge the dead batteries since we have clear skies and lots of sun. I will monitor the progress and see what happens. At 24v 225ah it should take around 5.4kwh to fully charge them. I will try to come back here to view responses on my phone but likely won't respond as I hate typing on such a small screen. Thanks again for everyone's help!
Quote from: inyour4head on June 28, 2016, 08:15:28 AM
Okay I didn't see the other replies until just now...
... Okay I have decided to go ahead and try to recharge the dead batteries since we have clear skies and lots of sun. I will monitor the progress and see what happens. At 24v 225ah it should take around 5.4kwh to fully charge them. I will try to come back here to view responses on my phone but likely won't respond as I hate typing on such a small screen. Thanks again for everyone's help!
YES, recharging the lowest battery string is your most important task, now. It is not exactly clear how low that they have gotten, but it is BAD to leave batteries in a low SOC sitting, uncharged.
GOOD DECISION. Generally, FLAs are rugged, and can take some "abuse". More Later, Vic
Iy4h,
Do use your Classic to charge up that weak set sooner rather than later.....I use the same hydrometer as Vic...the Frias as well as a U.S.Navy precision lab hydrometer.....the good ones have very repeatable readings.....the cheep ones.....well you know you get what you pay for. Those batteries are much more expensive than a good hydrometer. I also use a refractometer. I get over 10 years on my large format battery sets. Maintaince is the key. I keep a logbook for each set and read my s.g. Values every two weeks and log them.
td
Again I want to thank everyone for their willingness to help!
I spoke with the local retailer and he said they would replace any bad batteries so that was very reassuring. He told me to check the voltage of the batteries before and during the charge process and they were all at 6.4-6.5 before I started charging them. I then periodically checked them as they were being charged and they all stayed within .1 difference so I think that's a plus. I suppose the real test is whether or not they will hold the charge overnight. I checked the gravity with my fancy $5 hydrometer courtesy of AutoZone (actually all the other parts stores had the very same one too) and they are at 1.227 the best I can tell. If they hold the charge then we'll proceed to getting both strings running parallel again.
Speaking of that any advice on how to best connect the battery cables to my two strings would be much appreciated. The link dgd sent helps better explain things but there doesn't seem to be an example that specifically pertains to my bank. Since all of the +/- connections are equal length could it be as simple as connecting the +/- battery cables that go to the inverter somewhere in the middle of the bank like I have outlined in the picture? Or do I have to create a spiderweb of cables to get them more balanced? I like to keep things as simple as possible... if possible...
After researching the link Vic sent me I have decided to purchase Midnites Hydrovolt so I'll be looking forward to receiving that one in a few days and we'll see how that goes. The fact that these FLA batteries can take a beating is the very reason I purchased them. Maybe once I become more familiar with things I'll make a larger investment for batteries in a few years, then again maybe not. ;D
Also, could someone please clarify the proper way to determine the EA? Which display screen and amps to monitor? Thanks!
Hi, What breed is your jetpump?
I have a mate who runs a 12 volt standalone with a chinese inverter and he has had a lot of problems with
cheap pressure pumps failing!
We have had a "Davey" pressure pump in use at our property for over 25 years and apart from a bearing a long time ago and numerous
air tanks the basic unit has been unbelievable in reliability.
The better quality pressure pumps seem to be more tolerant. It should make no difference when using the power from an inverter,
but it makes me wonder why the cheaper pumps can fail so quickly!
Its actually a Wayne jet pump and they seem to have a pretty good reputation- that's why I bought it. I'm still not sure whats going on with it but if it ain't broke, don't fix it. Hopefully its just a result of the undercharged batteries but time will tell. Right now we're using a shallow jet pump to pump water from the cistern to the house but we'll be drilling a well in the next couple of weeks (our spring has reduced to a trickle in this heat) and we'll have to go with something that pumps at a greater depth. They have some pretty efficient pumps for off-grid living but the price tag can be a bit of a shock- hence the reason we went with a standard pump in the first place. However I will say this, when the pump kicks on at night there is such a draw that all the lights go dim for a couple seconds until the inverter is able to compensate. Perhaps that's what Vic was referring to about the MagnaSine Inverters being a bit slow at regulating the power.
Iy4h,
Yes , the Magna Sine is slow to regulate.......mine is a 120/240 and it's annoying. I use AC powered LED's and they go out completely when dimmed down low when the Magna-Sine is presented with a big loads ,ugh! Waiting for that MidNite inverter...
Td
Quote from: inyour4head on June 28, 2016, 04:13:17 PM
Also, could someone please clarify the proper way to determine the EA? Which display screen and amps to monitor? Thanks!
Forget about EA and just use the default 2 hour timed Absorb setting.
Your bank is almost new and already its apparently been well abused. Let it settle down over the next weeks or months before you consider attempting to use EA Absorb termination.
As Vic said new batteries take a while to settle in.
And considering you have just in the last few days properly wired your Classic and shunt you cannot trust SOC until after a few charge cycles are completed.
More urgent is the need to get some breakers into your system. Everything seems permanently connected and that in itself is not just inconvenient but just plain stupid from a safety viewpoint.
Straight away I'd get a Class T 400A fuse inserted into the main +ve of your bank. Then make it a priority to get a Midnite MNDC250 plus an extra surface mount (Carling type) breaker for the Classic +ve to battery connection (see NAWS for these)
dgd
The problem with just running the timed setting without EA is under or over charging the batteries, right? That seems logical to me but I could be wrong.
The batteries have definitely been abused but I'm not exactly sure what has done the most harm- following the wiring diagram or wiring the wbj and shunt incorrectly. I'm leaning towards the wiring of the batteries themselves as the wbj and shunt are just to monitor the current going in and out of the batteries in order to determine EA and SOC, right? I can still hardly believe manufacturers such as MagnaSine, Trojan, etc provide wiring diagrams that don't work as they should. Surely they are setting themselves up for repercussions.
Installing breakers will be done as soon as possible but at the same time I need to determine the best way to wire the battery bank. I'm guessing that the best way to do it would be follow method #4 on the link you provided so that will be in order as well.
Its unlikely to under or overcharge using default 2 hour timing, and in your case establishing an EA value is probably meaningless until the bank, both strings, settle down and get a few dozens of cycles completed.
As for battery wiring you only have two parallel connections so the diagram you included at end of previous post is the correct one to use.
Any imbalance of charging that ended with your two banks so different is more likely a faulty connection or cable
dgd
Are you saying the wiring diagram I used from the beginning was/is correct and the imbalance was likely caused by a bad connection somewhere?
Or should I proceed to make changes per method #4 on the link you provided?
Also, I checked the second string yesterday (the one that was dead) after it was charged and cells measured 6.5v/26.2a with gravity of 1.277 (as best I can tell) and this morning I checked and the cells measured 6.5v/25.8a with a gravity of 1.275. I'm not sure if the small loss is acceptable or not. The other string measured 6.6v/26.4a yesterday with gravity of 1.277 (as best I can tell) and this morning it measured 5.5v/22.2v (one cell was 5.7v) with gravity of 1.210. My loads over the last 12hrs were 2.5kwh at best (that's being very generous) so I don't quite understand the low SOC. If I figured things right I shouldn't have used quite 50% of the capacity. (24v x 225ah = 5.4kwh) I understand that it may take a few cycles for things to stabilize but how concerned should I be? Any input is much appreciated.
Iy4h,
I'm thinking you have too small a battery bank for the power you are drawing from them. I use the same inverter and have twice the size of battery. When I use big power tools I parallel both battery banks to run that big a load. My banks are 380 a.h. and 425 a.h.
I have never run my system down to 50 % depth of discharge on regular use. More reasonable for flooded lead acid batteries is 20-30% of total capacity.
True, my systems are much bigger at 5kw total panel and controller I run it hard....mig welding, grinding, fabrication.....I'm an Incurable tinkerer......but I do not have big loads when no solar power available.....DC refrigeration....pressure water system...only run one of the small inverters for audiophile quality sound system. I often have foul weather as I'm only 6 miles from the Pacific Ocean with sometimes 10 days of 2000 feet of marine layer so little solar input, that's why I have such a big system for a motorhome and workshop......planned it big enough to stand off 10 days with only net 15% solar harvest through the fog....no utility hookup....standby generator is installed in commercial work truck so not available for auto start backup use. Onan Emerald 4.0 kW
Plan for worst case, you are not leaving any reserve.
On the batteries....the Magna-Sine diagram is the correct hookup.....please note...
on the positive end of bank the output cable is connected to bank 1 and jumpered to bank 2
On the negative end of bank the output cable is connected to bank 2 and jumpered to bank 1
Did you get that......this is called a diagonal connection...reason it makes each string of batteries have exactly the same length of cable....Magna-Sine does a good diagram but they don't explain why.
On the string with the low cell.....charge that string until you have done absorb for at least 2-3 hours then equalize that string alone. Get all cells bubbling ..gassing freely..until you achieve 1.265 s.g.
Don't worry the little details until you get all the cells to that balanced state.
.020 difference is trouble coming
.050 difference between cell readings and you are in trouble.....
You still have time to balance out this system....I suggest lightening the loads a bit until system is more stable.
Again focus on the batteries.
I leaned a lot on this forum and at wind-sun/forum and other power forum and another power forum but had a huge head start as I've been an electrician for 50 years but I still had a learning curve to get my system stable
David
IY4H,
I'm not aware what your original battery wiring was but if it was the same as the diagram you posted then that does not, imho, account for the two series strings ending up with one charged and the other discharged.
I would be checking all the interconnects for a bad/loose connection or faulty cable. Or at worst it could be a dud battery in the discharged string although that does not appear to be the problem as the string is now charged
The ideal wiring of parallel strings has equal length seperate -Ve and +Ve from each bank to a common point such as stud, busbar etc as in that articles final suggestion
I still think your thinking a 50% DoD is acceptable is not quite right but I have said this earlier in this discussion so I will leave that for other battery experts to advise you.
dgd
Quote from: inyour4head on June 26, 2016, 09:45:15 PM
The terminal on the left goes on the negative lug on the inverter. The two negatives on the right are from the negative on the battery bank and from the negative on the Classic.
wire on Shunt on WB JR is backwards ?
EDIT add , 4 pages of a thread , Im late to the plate
Edit add . CDN day
I re-looked at the picture & Im still on , not wired correctly for the WB jr.
But then again , Im using a XP box with old browser , and Im way late from answering post 20 .
wow VT your an interesting fellow! ::)