What to raise my state of charge/SG

[Rngr275]

I would like to increase the amount of charge that my batteries are receiving. I have 740Ah battery bank (16 L16RE's). I have measure the SG when my FlexNetDC says I am at 100% and the controller has been in Float for most of the afternoon. The SG is around 1.261-1.269, less than the 0.030 SG difference where Trojan would reccommend an EQ be done. Trojan support/web site has an SG of 1.277 as 100% charge. What I am wondering is if my current settings are not charging the batteries enough to either maintain or increase the SG to reach the true 100% charge per Trojans web site/ owners manual that came with my batteries. I have 4Kw of PV and very minimal loads during the day so there should be more than enough available energy. My current settings are EQ V = 62.0, Absorb V = 58.8, Float V = 52.8 (all per Trojan reccommended voltage), Absorn times are 0.30minutes as a min time and 2hours max absorb time.  I am not sure about the end amps but I think it is ~5Amps but I will check. IS there a way where I can manually bump the charge (over ride the auto settings but then easily go back to auto?)

Thanks in advance.

FYI @ 1.261-1.269 SG the batteries are @ ~ 95% charge but the FNDC says 100%. I want to make sure the FNDC is giving me correct information.

[Volvo Farmer]

I would try and increase the absorb time to 4 hrs (minimum 3 hrs 59 min)and see if that makes a difference.  Might also want to experiment with the absorb voltage. I might back it down to 2.4 VPC with the longer absorb time to not use so much water.

How old are these batteries?  IIRC, it is somewhat natural for fully charged SG to drop as batteries age.

[Vic]

Hi Rngr,

Until you get the SGs up to the 1.277-ish range,  I would use the Trojan recommended 59.2 V,   and increase the minimum Absorb time to about 90 minutes.   Then you can reduce this time when your SGs get in the 1.277 range,  temp compensated.

Believe that these are High Capacity batts,  and as such,  they will use more water than an RE battery,  with the RE's lower SG electrolyte.

Believe that this bank is only a couple of months old,  so it is good that you are asking about charge parameters now.

There is a reason that battery manufacturers specify Absorption voltage.   Your V setpoint is still below the recommended 59.2.  Once your SGs get to the recommended 1.277,  then you might be able to reduce the Vabs,  and perhaps the  Absorb time.  But as we get into Winter,  you may well need the higher Vabs,  as the opportunity to charge from solar is short or nonexistant on many days,  as believe that you are in Northern USA.

Get the SGs up NOW,  and you can worry later about the exact settings your bank needs for the Depth Of Discharge that the batt bank normally experiences.

Also,  I would set your Classic CCs to Temp Compensate the EQ voltage.

Just opinions,   Good Luck,  Vic

[Kent0]

Are these batteries new? Did you make s.g. measurements when they were installed?

The Trojan Battery User guide says 56.4 to 58.8 volts for renewable energy applications. It also says 59.2 volts for a daily charge. With the specific gravity slightly low, it's not likely that the batteries are being undercharged. Increase the absorption time to four hours, two hours isn't enough. If that doesn't correct things raise the voltage too. If the batteries are using too much water; if water is needed more than once every couple months to keep the plates covered, they are using too much; then you should lower the voltage and possibly the absorption time. In any case turn off the ending amps. Unless the daytime load is very small and absolutely constant, the ending amps feature is of little use and is likely to prematurely terminate the charge.

[Rngr275]

Thanks all.....
The batteries are ~6weeks old.
The SG was not measured when they were installed. Per my installer the come fully charged from his supplier, and per Trojan web site they batteries need to be cycled to attain their full capability. It has been 6weeks and I measured the SG last week end on all cells. SG started at ~1.244 (~80-85% charge FDC thought they were at 98% charge). Did a 3hr EQ @ 62v and the SG came up to the 1.261-1.269 range. Chrge set points are set in the classic manually since the Flexnet Dc doesn't play well (programing wise) with the Classic. Water levels on all cells were fine when I checked.

I will take the advice up upping the Voltage and increasing the min Absorbtion time and Max to 90minutes min Time and 3:59 max time and see how things go for the rest of the week...

Supposed to be sunny the rest of the week.

Thanks
Again

[Rngr275]

Update... I just got off the phone with Tech Support at Trojan... side bar... very nice and helpfull....

They said that it usually takes 50-100 cycles for their new batteries to reach their full potential.
It is not unusual for the SG to be a low (not dangerously though <50% SOC), my 1.261 range seemed reasonable.
Suggested using the 58.8 absorbtion voltage or the 59.2 voltage if my system could handle it (make that much voltage).
The 30 minute absorb time is too low, and they suggested upping it to ~2 hours.
The 3 hours max absorb time might be OK but suggested upping that time to 4 hours.
Said that at this point it was not necessary to do an EQ since the batteries cell to cell SG was only 0.007 different (they suggest 0.03 difference).
Also recommended increasing my End Amps to ~ 2% of my battery bank or ~14 amps. Currently set @ 5amps.

So they verified everything all of you were saying, which I beleived. She told me to keep an eye on the SG and water level for a couple weeks and see if the SG is going up or down or no change. Then make another tweak as needed.
Thanks again to everyone here and I will keep you posted on my progress.

[boB]

I hear exactly the same thing about Rolls / Surrette batteries as far as needing a bunch
of cycles to break them in and get full capacity.

Glad to hear the same from Trojan.

Thanks !
boB