Hey gang,
I just thought I'd post my battery bank configuration,since it's probably a little different than the usual setup.
My (smallish) 12V bank consists mostly of SLA's that I've randomly run across for cheap at the local surplus shops.The sizes vary from 2.5AH to 17AH,and even a (~50AH?)car battery.
Since the batteries are all different makes,ages,condition,etc. I didn't want to just 'straight parallel' them,I wanted to isolate them from each other,in case one decided to die.(And one did once,but it didn't take the rest of the bank with it!)
Here's a quick sketch..
http://i199.photobucket.com/albums/aa154/Nothing40/SolarStuff/batt-setup.jpg
I've included an example voltage of 13.0V input from the sources. (Wind,solar,hydro,whatever. In my case solar,and a grid-powered PSU for backup on cloudy days..)
The diodes I've used are from various sources,and are low forward drop types ('Vfd'or 'Vfwd' in the data sheets).The 'standard' diode has a drop of approx 0.6-0.7V each.The diodes I'm using have a drop of approx. 0.25V each. So even the two of them in series is a tad less than the 'standard' diode.
For small battery banks,the dual-diodes from old PC power supplies are a good start,they're usually the fast-recovery,low drop types.
I've been using this setup since the conception of my system..been working perfectly since,and even saved the bank from a deep discharge once when one battery died while I was gone..The only thing that happened was that the dead battery 'hogged' all of the charge current and the rest of the bank didn't get charged very well -BUT,none of the other batteries suffered,and all of the loads continued to function despite the battery failure.
