incorrect battery AH Reading.. Need help

[Jacotenente]

   ...    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.

[Resthome]

+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.

[Jacotenente]

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

[zoneblue]

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.

[boB]

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

[Westbranch]

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

[dgd]

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

[Westbranch]

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.

[zoneblue]

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.

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. 

[dgd]

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    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 

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

[Vic]

...   
   ...   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

[boB]

>>> ...   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

[zoneblue]

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?

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]

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

[Vic]

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