Test Results-Used T-1275s

What happens BFL13 is an aged battery has had sulfuric acid join with the lead antimony then be shed as particulate matter and gravitate its way to the sediment chamber. The capturing of the H2SO4 or components thereof, dilutes the gravity of the electrolyte. I have seen gray-bearded batteries operating with a 1.255 upper range. With very expensive 2-volt cells I will adjust the density of the electrolyte with concentrate back to OEM density which regains a portion of the lost cell capacity. It's not a miracle treatment but with a five hundred dollar cell it may be worth considering. I call it the "Last Rights" treatment :)

I am running the load test anyway, but I am not happy about the supposed "full" I am using. The SG could have stopped rising at 1.255 because charging was slowing down with solar at the end of the day or because that's as high as it will go, I could not tell.

They could be still stratified with the higher SG stuff still below hydrometer reach. The solar controller's two hour limit on Absorption at 14.6 then drop to Float limits stirring. Also T-1275s are a tall battery if that matters.

The engineer ref above says to get SG you first have to give the batts a good equalize stir, then leave them on Float for 72 hrs!

I did see 1.275 when I first charged them up after they had been "resting" for two months or so, but got tons of black stuff in the hydrometer--nasty looking. They were already showing 1.250 after a I got them to the trailer after they had been "agitated" some in the back of the truck on the drive back from the golf car place. I did not get a reading while they were still on the pallet there.

However, I don't want to equalize them like it says, or I will get that black stuff big time. Problems, problems. The way SG shoots up right at the end of the recharge does seem to mean that there isn't many AH during that time though, so if I missed the part from 1.255 to 1.275 that would not be much in the over-all capacity picture.

Best I can do now is get the est capacity from this load test and say that they are "at least that much" They do act like good batteries in use. I can't tell any diff operating from when I have my regular bank of four batts hooked up. That includes inverter loads for MW, kettle, and toaster with 90-110a draws doing that.

If these T-1275s are like this when beat-up, then new ones must be very nice indeed.

mena661 wrote:

Michael in MN wrote:
Does this article help:

http://www.smartgauge.co.uk/sg_soc.html

I think it's saying that you'll effectively have smaller battery with less capacity

If I'm reading this right then you'll see a lower SG.

After re-reading, I think you are correct.

Perfect. Just what I was looking for, thanks. So the Trojan spec says 1.258 is 90% SOC, so these batts must be approx. just under 90% of new as their full now at 1.255 where SG stops rising.

Will do another load test to 50% by voltage (now I know I can't use the SG to mark 50%) and accumulated AH from this "full," and see what we get.

Michael in MN wrote:
Does this article help:

http://www.smartgauge.co.uk/sg_soc.html

I think it's saying that you'll effectively have smaller battery with less capacity

If I'm reading this right then you'll see a lower SG.

Does this article help:

http://www.smartgauge.co.uk/sg_soc.html

I think it's saying that you'll effectively have smaller battery with less capacity

I can't tell from the situation before solar slows down at the end of daytlight, if I am just before SG jumps to final right at the end. Or if the 1.255 is the end.

http://www.engineersedge.com/battery/specific_gravity_battery.htm

SG is Specific Gravity. it is a comparison density RATIO of sulphuric acid to water with distilled water being the universal 1.000. The solution of the electrolyte (sulphric acid and water) at 1.275 is the full strength of the electrolyte solution. If you add more water to the solution (electrolyte), you would be diluting the solution and the SG would decrease. A low SG does not necessary mean the end of the battery. You need to charge the battery and then check the SG again. (It's like slowly pouring Irish Creme into a glass of water. If you don't stir the drink, the SG at the bottom of the glass will still be 1.000 because the cream is only at the top.) the main importance of the battery's SG is the variation between the cells. I look at SG as an indicator. So would be cell voltage readings, again variation. A Load Test or a heavy discharge test is probably more reliable.
BTW - some people tried adding fresh battery acid to an old battery to raised the SG, which it may well do, but the battery cell plates are usually so over-sulphated, it may not achieved anything. When a battery becomes oversulphated, the internal resistance goes up so that it may not accept a charge efficiently. If Resistance goes up, Amps goes down in order to maintain same voltage. Your 80 Amp alternator can put out 80 Amps, but your old battery can only accept 10 amps, between starting, lights, accessories, etc, it's a losing battle.

Never mind how good the question is, what's the good answer? :)

I am trying to understand what is the state of play with my "pre-enjoyed" set of T-1275s.

Thanks.

This is a good question! I would think they'd show lower SG but it might be something weird.