Classic 150 Settings

[tecnodave]

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

[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 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

[dgd]

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

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

[inyour4head]

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. 

**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!

[Vic]

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

[tecnodave]

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

[inyour4head]

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. 

Also, could someone please clarify the proper way to determine the EA? Which display screen and amps to monitor? Thanks!

[russ_drinkwater]

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!

[inyour4head]

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.

[tecnodave]

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

[dgd]

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

[inyour4head]

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.

[dgd]

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

[inyour4head]

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.

[tecnodave]

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