Trouble getting to 100% SOC

Re: Trouble getting to 100% SOC

Blackcherry04 wrote: »

You also need to check the electrolyte level and add any water before you start.

But definitely do not overfill for two reasons:
1. The electrolyte will expand as the temperature rises, but more important
2. The electrolyte will be full of gas bubbles which will raise the level.
You do not want to overflow the electrolyte in any cell during the process.

Also, since the batteries will be getting quite warm, make sure that your hydrometer readings are temperature compensated.

Re: Trouble getting to 100% SOC

Dan_ wrote: »

Electrolyte levels are all good, just below or at bottom lip. Have not had to add any water in 2 months (charging every 3 days though).
Before this I was even charging at 61.2 as recommended by Interstate. Weird to have zero water loss

Can an eq be done with the batteries at any soc or only when full? I assume full is best but having issues getting there

Why didn't SG come back to previous reading? Too much absorb time? Still not enough? Higher voltage needed?

It's easier to do a full charge, but the EQ does not start until you get the voltage up to the 61.2v. The acual voltage the batteries see is somewhat lagging what you see on the monitor. I am still thinking if you have less than 25-30 cycles on them ( some of their Pure Lead will take more cycles ) the plates are forming. You can have Voltage from a square of active plate and still have low SG levels. If they are sulfated, you see a rise in the SG level.

Re: Trouble getting to 100% SOC

You won't get much of a answer why the Absorb is higher than the Bulk. I emailed them once because I thought it was a misprint. One of their engineers answered back that it was higher because of the Pure lead content of the HD plates. The plates are very thin, but there many more of them than a regular GC-2. I got those batteries as a trade-in on a new set I installed, they were less than a year old. I did as coot advised, I started to cycle them and did a couple EQ's on them and they were fine. I sold them and as far I know they are still working fine.

not sure what that means since voltage is variable and increasing during bulk

Bulk Voltage is the trigger point to start Absorb. The actual Battery voltage tends to be a lag behind the displayed voltage because what your seeing is being raised by the over voltage of the charger. But it's not as much as they advise. I think I used around 58 v to absorb them.

I think the email was posted in a thread here several years ago. If you search there 100's

http://forum.solar-electric.com/showthread.php?10710-Absorption-voltage&highlight=Interstate+batteries

Re: Trouble getting to 100% SOC

Dan_ wrote: »

Interesting to read through that thread. I have contacted Interstate similarly and havent gotten the answers I'm looking for. Just about what I expected though given they're the cheapest option.

Hydrometer I've been using is East Penn temp calibrated. Should I even trust Interstates SG figure for 100% though?

So my issues are just related to the batteries being new and I should just cycle them more? Doesn't seem like I should go higher than 5 hours absorb...or should I?

I'd cycle them for a couple weeks and see if the SG level and the voltage begins to converge. 4 hours in absorb would be at the far end of what I have ever absorbed GC-2's. Usually 2 hours is about average. your using a fairly high voltage and that will usually cut the time back. The only have 6x6 inch plates.

Re: Trouble getting to 100% SOC

Dan_ wrote: »

Everyone's input is much appreciated thank you.

I read some discussion in other threads about discharging the batteries deeply to develop their plates when new. Is this advisable or should I stick with 30-40% DOD?
Is 1.265 the 100% mark or 1.285 as interstate claims?
I've done a few 2-4 hr 61.2v absorbs in the past. Any potential plate damage?

The forming action should work just fine with a discharge to 60% SOC (40% DOD), although some manufacturers may recommend 50%. Going deeper is more likely to do harm than good through sulfation, especially if the battery stays below 50% for several days.

As to the SG, different batteries are provided when new with different SG electrolyte, and in some cases the documentation that accompanies the batteries does not catch up with changes in the supplied SG.

Some battery manufacturers also supply "tropical" versions of the same battery with a lower initial SG to compensate for the faster battery deterioration in high temperature environments. Or "cold weather" models with higher SG to provide more current capability in cold weather.

Too much vigorous "boiling" of a battery can cause deterioration of the positive plates and irreversible loss of electrode material, decreasing the capacity and shortening life. It becomes even more likely if the battery temperature is allowed to rise too high during EQ. Even cool gentle EQ (almost just extended Absorb) can cause water loss requiring more frequent refilling of the batteries.

Re: Trouble getting to 100% SOC

The problem with Interstate is they have a lot of conflicting information out there. If the batteries were filled with 1.280 electrolyte then you'd have no problem getting to 1.285. On the other hand even with a EQ and massive over charge, I'v never been able to get 1.265 past 1.280. They are not clear about if their numbers are loaded or resting.

I found this today in what they term deep cycle batteries. To me their voltage is off and the SG levels sure are.

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