there  are instructions on how to build a dc dc charger on the
battery info doc i recently posted on my blog

http://shufti.wordpress.com

alistair

On 22-Apr-10, at 9:06 AM, Mike Rocket J Squirrel wrote:

I had all the details of the DC > DC charger on the now-gone wiki. I'd
need to open up the secret compartment on the van to see what I have.
Its maximum charge current is limited to 15A, which is plenty for my use
as a usually drive several hours at a time, so the charger always tops
off the 130Ah deep charge battery. The newer version of that same
charger has the 7.5A/15A switch removed and jumper wires on the board
permanently setting it to the lower current setting. Unsure why.

It does not have temperature compensation. However, my solar charge
controller does.