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Other MidNite Electronics => WBjr => Topic started by: skylab on August 04, 2015, 11:45:50 AM

Title: incorrect battery AH Reading.. Need help
Post by: skylab on August 04, 2015, 11:45:50 AM
Hello everyone, i'm searching for some help in the form of an explanation of sorts.
I have a battery bank (8) Trojan T105RE, connected as 2 banks of 4, for a 24V 450AH battery , i also have another 400W of panels through another CC connected to the bank.
a whizbang Jr on my Classic 150. i have 1000W in panels wired in series. yesterday at the end of the
day my SOC was 88, I turned my classic off and on and when it finished booting up it showed my SOC as 42
i'm lost as to why this is happening and i can no long ascertain weather or not my batteries are being fully charged anymore
i went from being charge to 100% withing about 4hrs to not reaching 90 anymore , my loads hasn't increased
and my batteries are only about 5 months old. why am i not getting correct reading from my CC.
Title: Re: incorrect battery AH Reading.. Need help
Post by: Westbranch on August 04, 2015, 12:16:07 PM
what are your other charge parameters?  Especially check the voltage showing on the MNGP an din the Local App
Title: Re: incorrect battery AH Reading.. Need help
Post by: Vic on August 04, 2015, 03:22:02 PM
sky..,

The real measure of what is the State Of Charge (SOC) of your battery is to use your Hudrometer,  and actually measure,  at least your Pilot Cell.

IMO,  Battery Monitoring devices are a quick approximation of the Remaining Capacity,  and SOC.

Believe that the data on C and SOC is stored in RAM,  and you  probably will need to complete a full charge cycle,  and transition to Float for the C and SOC data to be updated ...   my guess anyway.

FWIW,  Vic
Title: Re: incorrect battery AH Reading.. Need help
Post by: Halfcrazy on August 04, 2015, 05:19:15 PM
If you shut off the classic it will loose its calibration for the SOC. It will however recalibrate after a full charge.
Title: Re: incorrect battery AH Reading.. Need help
Post by: Halfcrazy on August 04, 2015, 05:20:12 PM
Also you say you can not get the batteries full any more? So the Classic is not going to Absorb or float anymore?
Title: Re: incorrect battery AH Reading.. Need help
Post by: boB on September 27, 2015, 06:05:03 PM
I am also very interested in what might be going on here.

boB
Title: Re: incorrect battery AH Reading.. Need help
Post by: Jacotenente on November 04, 2015, 05:50:25 AM
Ditto...mine is not working right after increasing my battery bank size (went from 370 to 740 amp/hours). After a full charge, the Classic reads 100% and amp/hours left about 675 or so. These are brand new Trojan L16 batteries, temps were about 75 deg F. Someone said to disconnect the purple wire, re-input the amp/hour parameters, hit some arrow keys or something, and it will read correctly (SOC and amp/hours left). NEED this to work correctly...thanks.  -Chris
Title: Re: incorrect battery AH Reading.. Need help
Post by: Vic on November 04, 2015, 10:22:33 AM
Hi Jaco..,

There are several factors that affect the AH Remaining.  Battery temperature is one.

In the Temps Menu (if you have a standard Classic),  you can see what the Classic reads as the battery temperature.  The batteries may be cooler than you think.   Battery temps have a fairly large effect on Capacity  --  and this factor is one that you can set in the set-up of the WBjr.

The SOC,  AH remaining will reset then the Classic charge state transitions to Float,  BUT,  the AH Remaining  will still be affected by the measured battery temperature.

SOC  should be accurate at the transition to Float,  but the parameters that YOU have chosen,  and set  for your batteries will begin to affect SOC and AH remaining from that point on will affect the reading on SOC AH remaining.  There can be fairly large drift in the accuracy of those values,  until the next transition to Float,  when the SOC should be fairly accurate.

In general,  these values that the WB allows the Classic to display are estimates,  and,  IMO,  should not be taken as absolutes,  just approximations,  or rough approximations,  based on the values that you have chosen for parameters.

The WBjr can accurately measure  AH coming into and removed from your battery,  BUT,  the effect that these currents have on the ACTUAL SOC and AH remaining are not constant.  If one removes a large amount of current in a short time,  the actual SOC  will be lower than if the same total amount of current is removed at a lower rate,  and so on.  And,  this factor will differ from one battery to another.

There are many variables regarding battery SOC and AH remaining that the battery user cannot know very exactly,  and that are affected by a number of other factors that are difficult for us to define.

The WBjr is a great,  and inexpensive addition to the Classic.   But,  expecting for any battery Monitoring device to show actual SOC and AH remaining to be absolutely accurate,  will often disappoint the user.

Your young batteries will need a number of discharge/charge cycles to attain their advertised AH Capacity,  and this is just one additional factor that is difficult for the battery user to know,  and be able to accurately set into a battery monitoring device.

All just my opinions.   Vic
Title: Re: incorrect battery AH Reading.. Need help
Post by: Resthome on November 04, 2015, 10:42:57 AM
Quote from: Jacotenente on November 04, 2015, 05:50:25 AM
Ditto...mine is not working right after increasing my battery bank size (went from 370 to 740 amp/hours). After a full charge, the Classic reads 100% and amp/hours left about 675 or so. These are brand new Trojan L16 batteries, temps were about 75 deg F. Someone said to disconnect the purple wire, re-input the amp/hour parameters, hit some arrow keys or something, and it will read correctly (SOC and amp/hours left). NEED this to work correctly...thanks.  -Chris

What do you have the WBjr temp reference and % of capacity change values set to?
Title: Re: incorrect battery AH Reading.. Need help
Post by: Jacotenente on November 04, 2015, 04:07:55 PM
Hi John (and thanks Vic) - Here is what I have it set at:

Temp Compensation: -5 mv/ deg C/cell
Temp Window: 25 deg C

Battery Status Meter Efficiency: 94%
Capacity: 740 Ah
Compensation: 1%/C

I am running two standard Classics in "Follow Me" mode.

Thanks.
Title: Re: incorrect battery AH Reading.. Need help
Post by: Resthome on November 04, 2015, 04:38:37 PM
Has the Classic gone from Absorb to Float?  It's possible to get 100% SOC before all the AH have been put back in. What does the battery Temp say in the Temp Menu? There is also check box in the LA about going to 100% when going from absorb to float.
Title: Re: incorrect battery AH Reading.. Need help
Post by: Jacotenente on November 04, 2015, 05:42:00 PM
Thanks. Battery temp is 22C and that box is checked for both controllers in the Local APP.

Chris
Title: Re: incorrect battery AH Reading.. Need help
Post by: Resthome on November 04, 2015, 09:29:29 PM
Set the percentage of capacity lost or gained for every degree C to 0% and see what you get that will temporary disable the temp compensation for AH remaining.

You did not indicated if the Classic has made a complete charge cycle, Bulk, Absorb, Float.

I guess if End Amps is set that it could be going to Float too soon and the SOC would go to 100% when it goes to Float.
Title: Re: incorrect battery AH Reading.. Need help
Post by: Jacotenente on November 06, 2015, 08:32:38 AM
Quote from: Resthome on November 04, 2015, 09:29:29 PM
Set the percentage of capacity lost or gained for every degree C to 0% and see what you get that will temporary disable the temp compensation for AH remaining.

You did not indicated if the Classic has made a complete charge cycle, Bulk, Absorb, Float.

I guess if End Amps is set that it could be going to Float too soon and the SOC would go to 100% when it goes to Float.

Will do...thanks. And, yep, been through a bulk-absorb-float cycle with these batteries. What are your thoughts on "Water Miser" battery filler caps? You know, the yellow ones. Thanks again for your help. -Chris
Title: Re: incorrect battery AH Reading.. Need help
Post by: Vic on November 06, 2015, 02:05:29 PM
Quote from: Jacotenente on November 06, 2015, 08:32:38 AM
   ...    What are your thoughts on "Water Miser" battery filler caps? You know, the yellow ones. Thanks again for your help. -Chris

While this question was NOT directed at me,   ...

Have used Water Miser caps for some years on some 1280 AH Surrettes.  The Water Miser caps ooze electrolyte,  after a period of time  --  much more so than the standard bayonet caps as supplied by the manufacturer.

The WM caps also become plugged (probably with crystalized H2SO4),  and this causes a mild pressurization of these cells.

For  your L-16s,  the WMs MIGHT,  possibly,  offer some benefit,  as  the electrolyte Reserve volume is fairly small on L-16s,  vs the Surrette 5000-series batteries in use here.

Also,  believe that there are three available heights on the WMs.  If you could accommodate extra height above the battery,  would suggest choosing the tallest WM you can use.

But for my application,  the WMs are WORSE than standard caps,  and have noticed absolutely no reduction in water use on banks that use WMs and those that use standard caps.

On balance,  however,  the batteries using WMs here are 1280 AH nominal Capacity,  so,  one would expect that volume of gas passing through the WMs would be about four-ish times that of a standard L-16.   Although,  your batteries probably run at least 1.280 SG electrolyte,  which  would probably result in  a bit more gassing than batteries with 1.265 SG electrolyte (due to probable higher Absorption and EQ voltage required for higher SG electrolyte).

Just my experience.  And,  the one L-16 bank in use here does not use excessive water,  and does not splatter the battery tops with electrolyte vapor/drops to any large extent.

FWIW,   Opinions,   Vic
Title: Re: incorrect battery AH Reading.. Need help
Post by: Jacotenente on November 06, 2015, 03:00:15 PM
Quote from: Vic on November 06, 2015, 02:05:29 PM
Quote from: Jacotenente on November 06, 2015, 08:32:38 AM
   ...    What are your thoughts on "Water Miser" battery filler caps? You know, the yellow ones. Thanks again for your help. -Chris

While this question was NOT directed at me,   ...

Have used Water Miser caps for some years on some 1280 AH Surrettes.  The Water Miser caps ooze electrolyte,  after a period of time  --  much more so than the standard bayonet caps as supplied by the manufacturer.

The WM caps also become plugged (probably with crystalized H2SO4),  and this causes a mild pressurization of these cells.

For  your L-16s,  the WMs MIGHT,  possibly,  offer some benefit,  as  the electrolyte Reserve volume is fairly small on L-16s,  vs the Surrette 5000-series batteries in use here.

Also,  believe that there are three available heights on the WMs.  If you could accommodate extra height above the battery,  would suggest choosing the tallest WM you can use.

But for my application,  the WMs are WORSE than standard caps,  and have noticed absolutely no reduction in water use on banks that use WMs and those that use standard caps.

On balance,  however,  the batteries using WMs here are 1280 AH nominal Capacity,  so,  one would expect that volume of gas passing through the WMs would be about four-ish times that of a standard L-16.   Although,  your batteries probably run at least 1.280 SG electrolyte,  which  would probably result in  a bit more gassing than batteries with 1.265 SG electrolyte (due to probable higher Absorption and EQ voltage required for higher SG electrolyte).

Just my experience.  And,  the one L-16 bank in use here does not use excessive water,  and does not splatter the battery tops with electrolyte vapor/drops to any large extent.

FWIW,   Opinions,   Vic

Thanks Vic...appreciate your feedback on these Water Miser battery filler caps. I called the company and talked to them. And ordered 24 tallest ones. They said they have sold millions of them.
Title: Re: incorrect battery AH Reading.. Need help
Post by: Resthome on November 08, 2015, 12:46:06 AM
+1000 on Vic's response to WM caps. I saw no benefit what so ever and I doubt they saved any water.

My current set I opted for a Flow-Rite watering system and am very happy with it. No overfilling and very simple to check water levels with a small hand pump. Great investment IMHO.
Title: Re: incorrect battery AH Reading.. Need help
Post by: Jacotenente on November 11, 2015, 06:52:05 PM
Hey guys...I got them anyway and installed a few days ago (see pic). No more battery "smell" and they are condensating battery fluids inside the cap and flowing back down. Will continue to monitor/maintain/inspect per Trojan et al literature.

I also got the %SOC the way I want it...thanks for the help!

Chris
Title: Re: incorrect battery AH Reading.. Need help
Post by: zoneblue on November 14, 2015, 04:49:40 PM
Now might be a good time to get some sort of cover on those batterys. It only takes a cat, a kid, or a bit of an absent minded bump to drop something metal on those exposed terminals, and during absorb say, to make a nice wee science experiemnt gone wrong. Sparks plus hydrogen gas= very educational kabooooooooooooom. Well its only eduational if you actual survive to learn from the undertaking.
Title: Re: incorrect battery AH Reading.. Need help
Post by: boB on November 30, 2015, 11:40:14 PM

Just a few weeks ago, I was made aware of a bug that has plagued the Classic portion of
SOC% for a long time (since the beginning ?)...  It could stop counting UP amp-hours in
certain conditions.  I could NOT repeat it in the office but finally did.  Thanks to Ryan
and his friend, Karl, we got it figured out.  The newest firmware update, build 2079
fixes this.

This bug would not be visible unless the Classic was using the skip-day feature
where the Classic was not going to Float very often.  This, because going
to Float from Absorb would fix the count-up-stopping.

Sorry about this confusion !  This was a hard one to find.

boB
Title: Re: incorrect battery AH Reading.. Need help
Post by: Westbranch on December 01, 2015, 02:25:29 PM
boB, I have a similar issue,  my stand alone charger is connected directly to the shunt,  and the output registers on the L App main screen in WBjr but not in the + or - Ahr total as this comes from the Classic....

So for the last 3 months my NET (total) Ahr has been going further and further into the  negative so that the Ah remaining is decreasing, as is the SoC%... even though the charger has been doing a BULK , and into ABSORB charge  and solar is doing the main part of a 3 hr ABSORB.... however due to short PV exposure to the sun (last weekend  just less than 2 hrs total) there is not enough time  to even do a 3 hr (Solar) Absorb, thus no Float time....

My question is : will this new revision correct this 'loss' of Amps into the battery?

tks
Title: Re: incorrect battery AH Reading.. Need help
Post by: dgd on December 01, 2015, 02:58:22 PM
Wb,

Sorry to ask the obvious BUT the negative from the charger is connected to the side of the shunt that the negative from the Classic is connected to?
The other side of the shunt ONLY connects to the battery and nothing else?

I have 2 classics and an MX60 all connected to the shunt negative and the Classic with WBjr shows amps in and out including amps from the other two chargers. The AH remaining and totals and SOC all look good and take account of amps from other chargers.
In fact I can see the WBjr amps to battery well exceeds the amps being output from the Classic the WBjr is connected to.

This works so well that I have been able confirm the MX60 is telling big fibs about its power output and its as bad as 13% over stating its power output, ranging from 2 to 13%.

Just a thought  :)

dgd
Title: Re: incorrect battery AH Reading.. Need help
Post by: Westbranch on December 01, 2015, 04:24:24 PM
Sorry to ask the obvious BUT the negative from the charger is connected to the side of the shunt that the negative from the Classic is connected to?
YES

[/i]The other side of the shunt ONLY connects to the battery and nothing else?[/i]
YES

The AH remaining and totals and SOC all look good and take account of amps from other chargers.  This is the part that is not working for me for some strange reason.  I think it's because the Classic does not 'see' the extra input, thus the aggregate Ahr does not include the non-Classic (PV) amps.  for example, the last gen run, BULK, Day 1, hit it with ~ 30 A, for > 3 hrs =~100Ahr,  the -Ahr was reading ~ -150 and never moved, so the (-) Total  increased the next morning, the gen run on Day 2 was <= 2 hrs to Absorb, so those Day1 Amps went in! ....and left some evidence  as the overnight loads are now only the inverter, modem and router ~20W for ~16 hrs before we start to get a few watts coming in ... 

ps voltage rose and was steady till dark, and dropped a bit overnight.. Battery temp is about 0.5*C so V readings are lower than a few weeks before, charging is Temp adjusted by RTS for both charger and Classic.

Otherwise the WBjr is working great, I can look at the total A into the battery and mentally calc. the PV amps from the Classic.
Title: Re: incorrect battery AH Reading.. Need help
Post by: zoneblue on December 03, 2015, 08:58:27 PM
Bob did you ever implement retry if float never occured on the non skip-day.? Summer coming fast here, and skip day time soon. I also always used to think that the SOC tended to drift using skip day. Is there not some way to say if its held float voltage for x time, and/or EA achieved, to reset SOC to 100%.? Usually use 5 days for the record.

Quote from: boB on November 30, 2015, 11:40:14 PM
This bug would not be visible unless the Classic was using the skip-day feature
where the Classic was not going to Float very often. 
Title: Re: incorrect battery AH Reading.. Need help
Post by: dgd on December 05, 2015, 02:54:03 PM
Quote from: zoneblue on December 03, 2015, 08:58:27 PM
Bob did you ever implement retry if float never occured on the non skip-day.? Summer coming fast here, and skip day time soon. I also always used to think that the SOC tended to drift using skip day. Is there not some way to say if its held float voltage for x time, and/or EA achieved, to reset SOC to 100%.? Usually use 5 days for the record.

It is summer already  :D  and  in Auckland its been bloody hot. So much so that two 260watt PVs
I have connected to an MX60 get burn-to-touch hot. I have them laying flat on a deck and yesterday cracked an egg onto one of them to see if it would fry in a little olive oil. It did in under a minute  :o

If you do not reach float on a skip day does that not prevent the SOC from resetting to 100% ?
I thought that was the only way the SOC got reset?  when the battery was full.
I must have missed something about the purpose of skip day(s), is this just to reduce the cycle count to extend battery life? or to force a deep cycle every so often?

dgd

Title: Re: incorrect battery AH Reading.. Need help
Post by: Vic on December 06, 2015, 12:00:14 AM
Quote from: dgd on December 05, 2015, 02:54:03 PM...   
   ...   If you do not reach float on a skip day does that not prevent the SOC from resetting to 100% ?
I thought that was the only way the SOC got reset?  when the battery was full.
I must have missed something about the purpose of skip day(s), is this just to reduce the cycle count to extend battery life? or to force a deep cycle every so often?
dgd

Hi David,

Am still running the venerable 1849 Classic FW here,
BUT,  the only transition to Float that resets the AH Remaining is the transition to Float,  when Absorb parameters have been satisfied ...  So,  with this FW,  neither Forcing Float,  nor a Skip Day transition to Float causes the AH Remaining to be reset.

So,  with the systems here,  with this dated FW  will reset AH on Skip Day transitions from Float MPPT to Float,  cause the AH to reset ...

FWIW,   Vic
Title: Re: incorrect battery AH Reading.. Need help
Post by: boB on December 11, 2015, 08:28:14 PM

>>> ...   If you do not reach float on a skip day does that not prevent the SOC from resetting to 100% <<<

This is what normally hides the problem because it resets to 100% when going to Float.

So, yes, Westbranch, Skip Days will cause the problem to show up more and have more of a chance to
be "off" in the Amp-Hour remaining and of course the SOC%.

Build 2079 fixes this.  If you don't have problems updating firmware, I would suggest doing the update.

Keep us posted but I am fairly certain this will fix your issue.  And yes, the Amps will still work fine.

The problem really starts with the Remaining Amp-Hours reading which is how SOC% is calculated
along with the battery capacity.

boB
Title: Re: incorrect battery AH Reading.. Need help
Post by: zoneblue on December 13, 2015, 03:53:34 PM
Well its called skip day, but that just means the absorb is skipped. The bank still charges in float. What happens in my setup is that on a skip day the bank comes out of Sleep into Float MPPT. Once float voltage is reached in goes into Float proper. Then after a period the EA tapers down in exactly the same manner as an absorb cycle (after all its the same thing, just a lower voltage).

If the SOC settings are on the low side the SOC will drift lower and lower over those 5 days, despite reaching EA each day. Obviously if they are on the high side it will cap at 100% and a reset of sorts achieved. If they were perfect wouldnt be an issue, but hey what ever is perfect abut SOC?

Quote from: dgd on December 05, 2015, 02:54:03 PM
If you do not reach float on a skip day does that not prevent the SOC from resetting to 100% ?
I thought that was the only way the SOC got reset?  when the battery was full.
I must have missed something about the purpose of skip day(s), is this just to reduce the cycle count to extend battery life? or to force a deep cycle every so often?
Title: Re: incorrect battery AH Reading.. Need help
Post by: dgd on December 13, 2015, 08:04:41 PM
Vic and Zb,

So the firmware (in my case 1849) will only reset the SoC to 100% on transit from Absorb to Float. That transition is missing if skip days is used.
I can see how the SOC would become less accurate if the charging fails to complete Absorb, either due to insufficient power input OR the skip day function is not doing Absorb.

Would a solution for this SoC becoming less accurate be to reset SoC to 100% when charging reaches an EA value regardless of whether its during Absorb (if timer used) or Float stage?

dgd
Title: Re: incorrect battery AH Reading.. Need help
Post by: Vic on December 13, 2015, 10:13:11 PM
Hi dgd,

Well,  in my case,  the issue of using the set EA value to reset a Skip Day SOC to 100%,  is,  that there will (at least usually) be less charge to the batteries on a Skip Day (at Vfloat)  than on a full charge at Vabs.  So saying that these days actually returned a full charge, would be inaccurate.

It will be considerably "easier" to reach EA current at Vfloat,  than with Vabs,  so less charging will occur at Vfloat,  with the standard Vabs EA value.

In my case,  have set Charge Efficiency  (is that what it is called)  to 70%,  wanting to not be too optimistic,   so on Skip Days the accuracy of SOC drifts away from anything believable,  if for no other reason.

But,  I have never put any faith in displayed SOCs on ANY battery monitoring device,  just the AH removed from the battery on the day after a full charge ... however,  that is just me.

With FLAs,  can just measure the SGs for a fairly  - accurate - readout on the actual SOC.  That is what I pay attention to for SOC readings ...

FWIW,    Vic
Title: Re: incorrect battery AH Reading.. Need help
Post by: zoneblue on December 13, 2015, 11:05:24 PM
Quote from: Vic on December 13, 2015, 10:13:11 PM
It will be considerably "easier" to reach EA current at Vfloat,  than with Vabs,  so less charging will occur at Vfloat,  with the standard Vabs EA value.

Im not sure about that. I can show you Iwb curves of skip days and curves of absorb days and they look pretty similar. It just takes longer to get the full taper at the lower voltage setpoint.

Once mine has reached the 30 day uptime (record since 1609) threshold . After that ill upgrade from 2074 to 2079 and then start skip days again. Maybe its a good time for me to try to fine tune the charge efficiency setting a little.