Thanks to safety regulations, there may be a source of cheap batteries near you.
A rancher friend owns several commercial trailers having electtric brakes. By law he must inspect and replace the little 12V battery installed on the trailer as an emergency sto in case the trailer hitch comes adrift.
In regular towing use these batteries last several years but he parks the livestock trailer from one year to the next in between trips to bring cattle to auction or buy fressh stock. As a result these batteries sit uncharged for months on end. The result is lead sulfation and then the battery fails the safety check. I collected several of the batteries he was throwing out and recovered most of them with my desulfator.
These batteries are perfect for applicattions like isolated motion sensor triggered outside lights and even inside lights when you can run wires outdoors to a small solar panel. The sealed AGM batteries are good quality and typically range from 2.5 A-H up to 5.0 A-H caapacity
Then it dawned on me that all the fire regulations required exit lights etc you see in stores, apartment buildisngs, and most public areas also have batteries on float charge. I guess every juristicttion has differrent rules but all of these exit lights and emergency lights must conform to a rule calling for periodic test and eventual replacement. If you can connect up with one of the maintenance contract companies you may find a ready source of cheap or free batteries that had to be taken out of service due to regulattion not becaause they were really dead. They have a lead disposal problem and my welcome a low cost way to dispose of the batteries.
Desulfators can be had for under $100 in the smaller sizes. Mine cost $65 and has recovered well over $1000 worth of batteries that were tossed because they sulfated, not because they got used up.
The original 1987 patent has expired and now seveal clone products are available on the market in all parts of the world. I have seen ads from USA, the UK, Asia and Australia. They are available everywhere.
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