Are These batteries still good?

[paulcheung]

Hi guys,

One of my S-460 Rolls battery show some problem. one of the cell drop out of balance, way out. All the cells SG measure 1.250 when charged except one that show 1.175, It did not use any water at all last month(this cell). I try to do some Absorb and EQ. the bank get too hot before it finished. So I call the dealer who sold me these batteries. He said he has one battery that he can swap it for me.

When I carry my battery to his place. He has three of these batteries, all of them are in bad shape. The SG read 1.150 and the volt is 5.9 volt. He has these battery over one year and never charge them. I carry two come home to see if they can be charged.

I put them on 12 volts automobile battery charger, it charge at 15 amps, I have them over night. This morning I put them on my small 12 volt solar panel system and set the absorb voltage to 16 volts. at 10 am the SG start to rise and by noon it near 1.225 then the rain start to fall. it still charging on a small current. I will try to absorb or EQ tomorrow to see if the SG can reach over 1.255. Do you guys think these batteries still good if the SG can rise to 1.255?

Thank you in advance.

[Sunking]

Paul all SG tells you is SOC, nothing else. What you really want to know is capacity and load test. Your SOC appears to be OK, but meaningless.

Load test is pretty straight forward. Get it charged up then hit it with a C/4 load current and measure voltage sag. This will tel you the internal resistance. I will not tell you what is good or bad. You have to figure it out yourself. Two ways to find it. By comparing to your other known good batteries, or the specs via CCA. If it passes good chance the battery is OK.

Ri = [Voc - VL] / A

Capacity test is not so easy and takes a while. You have to fully charge the battery, then fully discharge the battery at some C Rate and compare it to the charts C rates for Peukert corrections factors. What I would do first is get it charged up and equalized with your other batteries and put it into service on a discharge. Monitor SG and voltage as it discharges. If it stays up with the other batteries, should be OK. If it falls faster than your other batteries, well you can figure out what that means yourself.

Good Luck I have done all I can do for you.

[paulcheung]

Thank you Dereck,
These battery are (new) never used, if the SG can reach 1.275, does it mean did not sulfated that can't reverse? or it can be sulfated to hard that can't be reverse still give high SG reading?

I have to make a choice either to keep my old battery or swap it with one of these.

My battery one cell has low SG reading and the whole bank not tape off when at absorb at 61.5 volts, it run hot instead tape off to 3% Capacity. it stay at 29 amps current very long time.

These (new) batteries sit at the warehouse over a year and have not been charged. if I can charge it and the SG reach to 1.275, does it mean better than my problematic battery?

Thanks again.

[Sunking]

Thank you Dereck,

You are welcome Paul.

These battery are (new) never used, if the SG can reach 1.275, does it mean did not sulfated that can't reverse? or it can be sulfated to hard that can't be reverse still give high SG reading?

Sounds to me like it might be OK. To me it sounds like sulfate crystals were not hardened off yet and you dissolved them back into solution which is what is suppose to happen with an EQ cycle.

I have to make a choice either to keep my old battery or swap it with one of these.

My battery one cell has low SG reading and the whole bank not tape off when at absorb at 61.5 volts, it run hot instead tape off to 3% Capacity. it stay at 29 amps current very long time.

These (new) batteries sit at the warehouse over a year and have not been charged. if I can charge it and the SG reach to 1.275, does it mean better than my problematic battery?

Paul that means a cell in that battery has shorted out. It is a boat anchor. Take your chances with one of the 3 other batteries. If you can find one that goes up to 1.275 is a hell of a lot better than a Boat Anchor.

The Red Flag is a dealer not keeping stock charged up. Rolls would likely want to know. Cannot help you with that.

Take care ole friend.

SK signing off.