Lead alum battery attempt

[Tom C]

you are right D gel cells have the electrolyte suspended in fibreglass mat.... when they dry its goodbye!!

Tom C

[BobZilla]

Are you talking about the OP who said gel cells?

He may have meant AGM which are much more common than real gel cell. You can probably never get all of the acid out of them but in an AGM it is not locked up in a gel. I have a bunch of AGM's and for the longest time I would simply add a few drops to the mat to replenish the electrolyte. After awhile I got sick of doing that so I flooded them and added just a little acid to make up the difference. They work exactly like a normal flooded battery now.

I will try converting one to alum. Theoretically if you charge it fully before emptying the electrolyte you will be dumping the majority of the acid out. If you try to do it in a discharged state it will be locked up in the plates.

Over all I agree that AGM's are a terrible choice for this technology and I would not buy them, but I get them for free. All computer data centers regularly replace their UPS batteries about every 6 months to a year which means their are a ton of them for the taking. These batteries can handle massive loads for their size because they are meant to supply computer systems in an outage.

[Brian McNece]

Bobzilla
I too had a cost free supply of Agm batteries. A lot of wheelchair batteries are agm or gell. I have some that are prob 15 yrs plus. My experience with some has been positive, some you just can not fix.
I took one agm that had a standing voltage of 6.45V, when JB gave one of the electrolyte formulas for making our own batteries, I filled the Battery up with that solution let it sit overnight the voltage came up to 8.23V
I then put it on the energizer for 3 days and then a regular charger till it came up to 14.8. I then let it sit and would check the voltage once a week for about 5 months. After 5 months it sat at 12.05V. Now I Just charge it and use it as
I do any of my Batteries. I have since done this to 3 more AGM batteries and they work almost like a new battery. The gel cells are sort of hit and miss (mostly miss) All of these batteries are 75 AH batt. So if any body has access to
used AGM batteries its worth a shot, who knows. I do agree with you bob that I would not purchase AGM for this technology, however, if you can get them for free why not try.

Are you talking about the OP who said gel cells?

He may have meant AGM which are much more common than real gel cell. You can probably never get all of the acid out of them but in an AGM it is not locked up in a gel. I have a bunch of AGM's and for the longest time I would simply add a few drops to the mat to replenish the electrolyte. After awhile I got sick of doing that so I flooded them and added just a little acid to make up the difference. They work exactly like a normal flooded battery now.

I will try converting one to alum. Theoretically if you charge it fully before emptying the electrolyte you will be dumping the majority of the acid out. If you try to do it in a discharged state it will be locked up in the plates.

Over all I agree that AGM's are a terrible choice for this technology and I would not buy them, but I get them for free. All computer data centers regularly replace their UPS batteries about every 6 months to a year which means their are a ton of them for the taking. These batteries can handle massive loads for their size because they are meant to supply computer systems in an outage.