Charging with Classic

Started by asdex, February 18, 2018, 02:53:32 PM

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asdex

Yes it is a vehicle type. I"ll try charging again using the Outback inverter/charger. I'll just keep the absorb voltage high until the batteries are charged up the start tuning with the hydrometer.
Cheers,
Graham
6 x JA Solar 320w solar panels facing NW, 4 x 300w panels facing North.
12 x 2volt Narada lead carbon batteries (24v 400ah), Classic and WBJr, Epever 50A controller, Outback FX2024 inverter and Mate, Trimetric monitor, Alibaba solar pump.

Vic

Hi Graham,

Thanks for the additional info.

The Outback's charger should be able to do a better job of charging your batteries,  as you can fairly easily set an appropriate Vabs,   and Veq (if needed).

Many automotive chargers,   these days have relatively low output voltages.   This might be what is causing a relatively low charge current when using it.

The Outback  inverter can adjust the charge voltage based upon the battery temperature,   if it is setup to use the Remote Temp Sensor,   as you know.  This can be an added benefit when using the OB.

When charging from the auto charger,   what was the battery voltage shown on the Charge Controller?

Have you measured the SG of each cell in the battery bank?

If you measure the terminal voltage of each battery during charge,  you can get an idea of how well balanced each battery is compared to the others.
What are those voltages?

There should be no issue in using a relatively high Vabs for batteries that are at a low SOC,  as these batteries seem to be.   Many off-gridders use similarly high Vabs settings,   particularly during Winter months,   and others use  these settings all year.   This is well above Gassing voltage,   but for deep-cycle Flooded batteries,   it should be fine until the bank is more fully charged,    and then EQed.   If/when the battery bank  is in its best condition,   asdex can try adjusting  the Vabs,    and perhaps  Absorb time,   to fully-charge the batteries on most charge cycles.

Thanks additional info that you can supply,    Vic
Off Grid - Sys 1: 2ea SW+ 5548, Surrette 4KS25 1280 AH, 5.25 KW PV, Classic 150,WB, Beta Barcelona, Beta KID
Sys 2: SW+ 5548s, 4KS25s, 5.88 KW PV, 2 ea. Classic 150, WB, HB CC-needs remote Monitoring/Control, site=remote.
 MN Bkrs/Bxs/Combiners. Thanks MN for Great Products/Svc/Support&This Forum!!

Matrix

My response to the Op's opening comment. I have been round and round with the same subject on this forum and on the Sun King forum, I have yet to get my 24 volt 435 amp hour batteries to fully charge unless I set my absorb voltage ro 31.5 volts and my end amp to 4.3.  In 4 months  I have had to add  almost no water at all.  And my temperature in the winter in Florida  has never gotten above 30 degrees Celsius . I have the absorb time set to the maximum and it's not that I run out of daylight, but if I use 29.6 volts as an absorbed charge voltage (manufacturers spec) , the charger just stops charging because it thinks that the batteries are full. But when I test the gravity they are not.

I called Trojan and told them what I was getting, and they said charging at 31.5 volts is not a problem. It is better than having undercharged batteries all the time. And they went on to tell me that golf cart batteries are charged at 32 volts everyday at the end of the day for the next day. Trojan said it is way better to overcharge than undercharge. But I was concerned about charging at such a high voltage because of corroding the plates. And I wonder if Trojan was merely telling me this, knowing that I was shortening battery life by charging at too high a voltage with my solar charger?

But I have monitored my batteries very closely and at this time of year so far what I have found is it takes 31.5 volts at the absorb setting to get a full charge according to specific gravity. Which is 1.277 for Trojan Batteries. If I use a voltage lower than this, save 30.5, I do not run out of time, the charge controller simply stops charging too soon. It stops charging at the end amp set point, but the gravity is still too low.
Grid-Assist Off-Grid
REC TwinPeak 2 285W 3S-3P 2565w-STC 1926w-NMOT Array / Classic 150 / Conext SW 4024 Inverter
Trojan L16H-AC 435Ah bank 4S  with 7' of 4/0 cable
24 volt system /  Need 3200Whs Daily
My System Install

Ron Swanson

Somebody correct me if this is wrong, but it is my impression that overcharging (within reason) will disassociate more water into gas, but does not chemically harm the plates at all.  It just becomes a maintenance issue, having to add water all the time.

Vic

#19
Charging Flooded batteries to the Gassing Voltage,   and above  does cause Erosion of the positive plate.

But this erosion is nothing to worry about,  as this erosion comes along with fully-charging Flooded batteries. 

Not fully-charging these batteries  is much worse for them,   than is the plate erosion,   at least for off-grid systems.

Excessive EQing  can be more detrimental on FLAs,  of course   ...
Chronic under-charging these batteries is generally worse than chronic "overcharging" them,

All   IMO,   Vic
Off Grid - Sys 1: 2ea SW+ 5548, Surrette 4KS25 1280 AH, 5.25 KW PV, Classic 150,WB, Beta Barcelona, Beta KID
Sys 2: SW+ 5548s, 4KS25s, 5.88 KW PV, 2 ea. Classic 150, WB, HB CC-needs remote Monitoring/Control, site=remote.
 MN Bkrs/Bxs/Combiners. Thanks MN for Great Products/Svc/Support&This Forum!!

asdex

Thanks Matrix, that has seemed to be my issue too.
I have set my absorb voltage to 30 volts for now to try and get the charge up. Hydrometer is now 1175 on most cells.
Cheers,
6 x JA Solar 320w solar panels facing NW, 4 x 300w panels facing North.
12 x 2volt Narada lead carbon batteries (24v 400ah), Classic and WBJr, Epever 50A controller, Outback FX2024 inverter and Mate, Trimetric monitor, Alibaba solar pump.

Matrix

#21
 : I would try 30 volts and Optimum conditions, test the gravity and if it is not come up to fully charge, on the next day I would increase by two tenths of a volt. And continue to do an increase until you have found a voltage that fully charges the batteries

The good news is with the Midnite solar charger you are only setting the absorbed voltage most of the charge is taking place in bulk which is constant current, but not constant voltage so the voltage at you set for  absorb does not get reached until the end of the bulk change. . What I have seen during bulk charge is that it runs about 29 to 30.5 volts when I have my voltage set to 31 +. It only goes over to the highest voltage of 31 when when it's nearing and crossing over to absorb
Grid-Assist Off-Grid
REC TwinPeak 2 285W 3S-3P 2565w-STC 1926w-NMOT Array / Classic 150 / Conext SW 4024 Inverter
Trojan L16H-AC 435Ah bank 4S  with 7' of 4/0 cable
24 volt system /  Need 3200Whs Daily
My System Install

Vic

One fairly important thing is,  that even with "most cells at 1.175 SG"s,   the battery bank is essentially   D E  A   D.

Screwing about,   but not really trying to actually get these batteries CHARGED,  is NOT a good thing.

It is  quite possible,   that this battery bank will never recover,  but allowing Flooded LA batteries to remain below about 50% charge for,   even a few days often makes recovery a long process,   that yields a battery bank with low Capacity,   and a very high self-discharge rate.

Personally,  I would get out the whip,   and really work to see if this bank will recover.  It is quite often the case,   that an FLA bank that has not been well cared for,   with some cells  at 25% SOC, or less,   will have some cells with 0% SOC,  which will NEVER RECOVER.

It is not clear,   from what has been stated here,  just how long this bank may have been sitting,  at these very low SOC levels.  The longer that FLA banks sit  at low SOCs,   the much more difficult will be any possible recovery.

Basic rules of thumb for most Deep Cycle FLAs,   is,  never discharge below 50% SOC.   Any bank that has been discharged to 50-ish % SOC should be IMMEDIATELY recharged,   fully  --  banks in this state should not sit at fifty-ish percent SOC,   for even one day.

asdex,  have you measured the terminal voltage of each battery?  What were those readings?

Not to be too emphatic,   just My Opinions,   good luck,   Vic
Off Grid - Sys 1: 2ea SW+ 5548, Surrette 4KS25 1280 AH, 5.25 KW PV, Classic 150,WB, Beta Barcelona, Beta KID
Sys 2: SW+ 5548s, 4KS25s, 5.88 KW PV, 2 ea. Classic 150, WB, HB CC-needs remote Monitoring/Control, site=remote.
 MN Bkrs/Bxs/Combiners. Thanks MN for Great Products/Svc/Support&This Forum!!

asdex

Just checked the voltages:
6.386
6.373
6.350
6.354
Total 25.47.
The batteries will be at their lowers level being 07:30 now.
Hydrometer readings around the 1175-1180 mark.
6 x JA Solar 320w solar panels facing NW, 4 x 300w panels facing North.
12 x 2volt Narada lead carbon batteries (24v 400ah), Classic and WBJr, Epever 50A controller, Outback FX2024 inverter and Mate, Trimetric monitor, Alibaba solar pump.

Vic

Hi Graham,

Thanks for those battery voltage readings. The variation is not as large as I'd expected  --  better than my guess.

What type of Hydrometer are you using?   Is it a glass float inside a glass tube?   Is it a Hydrovolt,   or is it a plastic case with a plastic pointer,   or (less likely)  plastic case with floating colored balls?

So,   your system is off-grid,   right?

Do you know approximately the number of Ah used from the battery bank,  each day?

More later,   Thanks,    Vic
Off Grid - Sys 1: 2ea SW+ 5548, Surrette 4KS25 1280 AH, 5.25 KW PV, Classic 150,WB, Beta Barcelona, Beta KID
Sys 2: SW+ 5548s, 4KS25s, 5.88 KW PV, 2 ea. Classic 150, WB, HB CC-needs remote Monitoring/Control, site=remote.
 MN Bkrs/Bxs/Combiners. Thanks MN for Great Products/Svc/Support&This Forum!!

asdex

Hi Vic, I'm using a glass hydrometer with weighted glass float. I think it's ok as distilled water although off the scale looks at about 1.000. I'll buy another tomorrow as backup and comparison. Yes we are completely off grid. Nearest grid power 5km away. I guess we use about 1.2 to 1.5kWh a day.
Cheers,
Graham
6 x JA Solar 320w solar panels facing NW, 4 x 300w panels facing North.
12 x 2volt Narada lead carbon batteries (24v 400ah), Classic and WBJr, Epever 50A controller, Outback FX2024 inverter and Mate, Trimetric monitor, Alibaba solar pump.

Vic

Hi Graham,

Thanks for the additional info.

Good that your Hydrometer is the glass/glass type. Having several,   is often a good idea.

Your power usage seems low for your L-16s.   So,  if the SG readings are fairly accurate,   and you have reasonable solar production,   and daytime loads light,  your batteries should get a full-charge on most sunny days.

More later,   Thanks,    Vic
Off Grid - Sys 1: 2ea SW+ 5548, Surrette 4KS25 1280 AH, 5.25 KW PV, Classic 150,WB, Beta Barcelona, Beta KID
Sys 2: SW+ 5548s, 4KS25s, 5.88 KW PV, 2 ea. Classic 150, WB, HB CC-needs remote Monitoring/Control, site=remote.
 MN Bkrs/Bxs/Combiners. Thanks MN for Great Products/Svc/Support&This Forum!!

asdex

Hi have a new hydrometer now and it reads 60 points higher than the old one. I'm expecting the old one to be wrong as cell voltages are 6.9, 6.9, 6.83, 6.9. hydrometer is 1260 with the new one and 1200 with the old. Both hydrometers look very similar. I have been looking online for a solution I could make up of a particular density to test the hydrometers but haven't had much luck.
I'll start checking with the new hydrometer each day and see if I can adjust the absorb voltage.
Cheers,
6 x JA Solar 320w solar panels facing NW, 4 x 300w panels facing North.
12 x 2volt Narada lead carbon batteries (24v 400ah), Classic and WBJr, Epever 50A controller, Outback FX2024 inverter and Mate, Trimetric monitor, Alibaba solar pump.


ClassicCrazy

#29
Yes I have a refractometer like that too . I believe if you calibrate it with some distilled water that is same temperature as your battteries then it is temperature compensated too. You only need a couple drops of he electrolyte so I would use the glass hydrometer to get the sample drops.  They show a lot more precision .   Just take proper precaustion with  putting acid up near your eyes .

Larry
system 1
Classic 150 , 5s3p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system 2
 5s 135w Kyocero , 3s3p 270w Kyocera  to Classic 150 ,   8s Kyocera 225w to Hawkes Bay Jakiper 48v 15kwh LiFePO4 , Outback VFX 3648 inverter
system 3
KID / Brat portable