Hello All i was at our local scrap yard today looking around and found some interesting batteries and i was wondering if they might be good for an off grid power system
they had was about 10 to 12 mixed Hawker Power Safe V 8V100F & 12V100 Batteries. See Here ( http://www.timbex.cz/doc/Bat-HAWKER.pdf ) that the local phone people took there to scrap, they look well kept and maintained and if they would work for an Alt power system, i would go give them a test and see if there any good and at scrap price it might be worth it
One of the possible issues with that type of battery (sealed) is how their maximum advised charge rate compares to the standard flooded wet cell lead acid battery. A sealed battery may require a lower rate of charge to prevent unwanted out gassing. They have an internal pressure valve (Valve Regulated Lead Acid). So that would have to be reconciled with whatever charge controller the system used.
Call me old fashioned but I still like to be able to check the specific gravity of our twelve 6 volt batteries every so often. That makes it easy to keep track of the health of the individual batteries/cells.
Because they are sealed units they will very likely look good even when they are far past their prime. And because they are sealed it is hard to tell what they are like, how much useful life they have left. Maybe selecting one or two at random and running them through a charge and discharge sycle or two would provide some hint at their health. Telecomm companies usually swap them for new before they are really bad.
I have picked up a few ex Telephone batteries. The thing to remember is that they run them either in a 24v or 48v configuration. If they find the configuration not up to par, they replace all the batteries. Usually it is only one or two of the two volt cells that have tanked.
I usually bring a multi meter and check them out first, its easy to tell which ones are junk. If there is 2 12v batteries one battery is usually toast the other is perfectly fine. That way you can leave the bad ones behind since they are HEAVY.
I've run my cabin for the last two years on a set.
My dad got a set of old telephone batteries for a 12v solar electric set up. They went dead, but then he read somewhere you can add DDT to the fluid to revive them. It worked. (I'm fairly certain it was DDT). Also, make sure you check the fluid level every year or so and add distilled water as necessary.