How much water should I add to old AGM battery?

[davethedrummer]

Hey guys,

I have a bunch of old Northstar NSB 170FT batteries that are showing voltage in the 10's and 11's. I just realised maybe I can refill the water to give them a second chance at life.They have been in a pretty hot climate and were worked quite hard so I'm sure they have lost a lot of water.

Question is, how much water do I add? All the way to the top till it starts to overflow?

[Paul Land]

Hey guys,

I have a bunch of old Northstar NSB 170FT batteries that are showing voltage in the 10's and 11's. I just realised maybe I can refill the water to give them a second chance at life.They have been in a pretty hot climate and were worked quite hard so I'm sure they have lost a lot of water.

Question is, how much water do I add? All the way to the top till it starts to overflow?

If you add some seeds with your H2o you will have some pretty door-stops

[kingofbanff]

I don't have the answer but I'm sorry your first post resulted in an unhelpful/unfunny answer. Stick around there are lots of good people helping out here and one of them more knowledgeable will help you out.

[inetdog]

AGM batteries are susceptible to sulfation, just not as readily as FLA. Loss of water (only) from the electrolyte will cause loss of capacity but NOT reduced open circuit voltage after full charge. Your voltages and lack of response to charging are most likely the result of irreversible sulfation, not overboiling.
As such, the door stop idea has merit, but the value will be greater as lead scrap. Any AGM battery over five years old, used or unused, is suspect.
However, I do not know of any AGM (sealed) batteries to which you can add water without drilling or using a hypodermic and then resealing to hold gas pressure.
I may try looking the battery up.
Old FLA, especially ones that have been sitting uncharged are unrecoverable because of sulfation. Door stop recommendation still applies.
IF (and a big if) electrolyte was actually spilled instead of boiled off, adding electrolyte rather than water might get you some very limited use.
If the tops of the plates were uncovered for any length of time, the battery will have lost capacity.

OK, that part number is indeed sealed AGM, so there will be no way to add water, period. That is why AGM batteries should never see an Equalize cycle with a high enough voltage and current to cause venting.

[Mike90250]

He's dead Jim.

[Yet another Yeti]

batteryuniversity odd com could be some website to learn more about all different sorts of accumulators ...

[davethedrummer]

AGM batteries are susceptible to sulfation, just not as readily as FLA. Loss of water (only) from the electrolyte will cause loss of capacity but NOT reduced open circuit voltage after full charge. Your voltages and lack of response to charging are most likely the result of irreversible sulfation, not overboiling.
As such, the door stop idea has merit, but the value will be greater as lead scrap. Any AGM battery over five years old, used or unused, is suspect.
However, I do not know of any AGM (sealed) batteries to which you can add water without drilling or using a hypodermic and then resealing to hold gas pressure.
I may try looking the battery up.
Old FLA, especially ones that have been sitting uncharged are unrecoverable because of sulfation. Door stop recommendation still applies.
IF (and a big if) electrolyte was actually spilled instead of boiled off, adding electrolyte rather than water might get you some very limited use.
If the tops of the plates were uncovered for any length of time, the battery will have lost capacity.

OK, that part number is indeed sealed AGM, so there will be no way to add water, period. That is why AGM batteries should never see an Equalize cycle with a high enough voltage and current to cause venting.

Thanks inetdog.

The batteries I have do have venting holes and upon taking the cover off there are 6 holes with thin rubber caps on them.

IMG_20190227_094808_1.png

IMG_20190227_094504.png

IMG_20190227_094520.png

[Paul Land]

I don't have the answer but I'm sorry your first post resulted in an unhelpful/unfunny answer. Stick around there are lots of good people helping out here and one of them more knowledgeable will help you out.

It's still useful. You just have to find a system that runs on 10 volts.

[Mike90250]

It's still useful. You just have to find a system that runs on 10 volts.

And does not mind bad batteries pushed beyond the end of their service life and blowing up. At end of life, AGM batteries are prone to thermal runaway while being charged.

[Paul Land]

And does not mind bad batteries pushed beyond the end of their service life and blowing up. At end of life, AGM batteries are prone to thermal runaway while being charged.

Mike, you will find these Batts way up on-top that Mt, behind your house and they have 2 yr warranty/cycle when there new. they are a zero touch zero maint, back-up batts.

[sdold]

...and they have 2 yr warranty/cycle when there new....

What does "2 yr warranty/cycle" mean?

I think with batteries in the OP's state, any charge will be an over charge. These are a couple of Liberty LS12-100s that we recently pulled from service, left on a float charger well past their prime. At first glance they seem fine, but if you look closely, you can see what I believe are signs of oxidation (swelling) of the positive plates. These were installed 22 years ago and just pulled out of service.


libertys.jpg .

liberty batt 2.jpg

[davethedrummer]

These are the batteries I have, they just mention VRLA, nothing about AGM... http://www.northstarbatteri.com/PDF%...r/NSB-AP~1.pdf

[sdold]

These are the batteries I have, they just mention VRLA, nothing about AGM... http://www.northstarbatteri.com/PDF%...r/NSB-AP~1.pdf

The specs in the cut sheet imply AGM. I wouldn't expect to get any service out of them.

[Paul Land]

[QUOTE=sdold;n392744]What does "2 yr warranty/cycle" mean?/QUOTE]

2 years covers manufacturers defects
cycle (Life Cycle) means, lets say in very critical setting ie: Tsunami warning buoys batts must be changed out due to wet, salt, heat, cold and vibration damage . If not thats why they fail and 100s Die.
boy.jpg

[davethedrummer]

I have a total of 8 batteries so I went ahead and added 30ml of water per cell (that was yesterday). Tried to charge them up a bit (they got about 4kwh) today in a string of 4 batteries. 4 of them showed voltages of 16-19V while charging so those are no good. Kept rotating the bad ones out and of the remaining 4, one of them is giving me 15V, the other 3 seem be charging normally.

Disconnected them now and will test again tomorrow morning after which time I will charge them individually and do further testing.

Don't really know if the water did anything but hey it's worth a try rather than dumping them.