A Battery Primer Thread

[bryan1]

Hi Guys,
Recently I asked Frank (#supertech) who is a new member to our group to write a primer on the use of batteries in RE. This thread can kick the conversation off and other members feel free to add input as the end goal is condensing the valuable information into a sticky to sit up with the other 2 sticky's.

Some initial suggestions

1. The reasons not to use automotive batteries in RE as a power source
2. The different types of RE batteries and the pro's and con's of each type
3. The best charging solutions for each battery type and links to battery data files.
4. Battery Desulphators myth or do they work
5. The best way to hook RE batteries up for different voltages for the optimum charging solution.

Just a few thoughts to give this thread some discussion points.

Regards Bryan

 

[Pommie]

I'll add a little bit about battery desulphators or rather a little story.

When we moved to Australia everything got packed up and shipped from the UK including two old 5AH 12V sealed lead acid batteries. Well, we rented for a while, then built a house, then eventually got a horse and eventually an electric fence. I dug out the old lead acid batteries that were probably discharged before leaving the UK and hadn't been touched for over two years. I managed to get a charge into them with great difficulty and they ran the fence for a day or two. I was going to get new ones but after a while they lasted longer. They got to the point where they would power the fence for a week per charge. I never thought any more of this until I read the desulphator article in Silicon chip. It explained that this phenomena had been noticed by farmers and the circuit was designed to mimic the actions of an electric fence.

So, I believe (know) they work.

Edit, the resonant frequency crap seems to have been added by some nutter at some point. The fence units probably produce 1 pulse per second.

Mike.

 

[Sceadwian]

Battery Desulfinators will NOT resurrect a battery that has been used regularly over a long term, there's just too much material that needs to be worked with,

 

[Sceadwian]

The reason not to use automotive batteries is because of the surface area of the electrodes. They are meant to be constantly held at full charge and to supply cranking amps only. Marine/general use batteries are more useful for RE uses, better yet deep discharge rated batteries. They sacrifices overall total amperage (surface area) for anode/cathode durability. For lead acids the voltages and currents you can expect are well provided on the Internet already.

Aside from cranking amps, general use, and deep discharge applications and endless variety of tweaked chemistry's, plate geometries and what not will provide you with more information than you can deal with. Generally speaking since lead acid cells are already batteries in their own right you need complex cell management for higher voltages, and higher voltages are the best way to increase overall system efficiency. Bigger cell sizes are good for general management, but there is a law of diminishing returns. Take a few notes from industrial fork lift batteries. They need incredible amperage ratings, a huge number of cycles and large overall system capacity. System amperage, cycle ratings, and overall capacity will force you to chose one particular section to concentrate on, or go to a more general purpose or hybrid sollution.

 

[Mr RB]

Just remember cost effectiveness. A heap of iffy secondhard automotive batteries that cost zero can be a better capacity battery bank than ONE good deep discharge battery that costs $$$. I have a friend that has a heap of secondhard auto batteries obtained at zero cost he uses on his holiday shack with his solar panels and 12v fridge and he has a ton of excess capacity.

A Ferrari is "better" than an old Toyota, but that doesn't mean it's the one you should buy. Sometimes the old Toyota is much more cost effective for the specific needs you have... And a free old Toyota is not to be sneezed at.