Hey I just hooked up a standard lead acid battery to mine with just the Rad shack rectifier and I was just getting a slight rise over battery voltage. The battery was fairly discharged, running my pumps was at 11.62v with the engine off, with it running over 3000r's or so it would go up to 11.76, and was very slowly climbing, showing that it was charging ever so slowly. Turn on my handwarmers and it would pretty much stop climbing. Didn't matter if I had the negative isolated or not.
I think my previous reading of 16v was because of the lithium battery that I had in there, and it wasn't charging that one at all. Last ride the battery was dead.
I Pm'd Jmgsnowman, he is the one I got the rad shack rectifier info from. He said he has been running it with nothing else but a battery for a season and a half with no issues and it keeps his battery charged.
Are you sure when your voltage was spiking that it wasn't A/C voltage? Mine will be up in the 20's A/C voltage through the DC side, but the pumps and battery only see the D/C voltage.
Going to get a battery today and going to run it on the mountain tomorrow. I will let you know how it goes.
