Late night post: Was using my 302 diesel in constant voltage mode to boost a small rigid frame haul truck last night.... No problem. Set to 28v watch the amperage drop then crank away... No problems. Tried this morning and the voltage shot up to 40+v and crazy amps, pulling the motor down hard. Immediately pulled off the cables. Fiddled about repeatedly and got nowhere. Not sure what senses or regulates output voltage but I'm thinking it's toast. Anyone familiar with these machines? Sorry on advance, no year or serial number tonight.... Been one of those days, but I'll get it tomorrow and update the post.
Might want to ask on the Miller forum on the weldingweb. There's a few really good welder techs on there. I wouldn't think it's a good idea to use a CV welder for boosting. I don't think there's a way to limit current. I say this because I've read of some welders preferring a CV machine for heavy gouging because the amps aren't limited. Wondering if a bad battery or starter could have caused your problems.
Curiosity made me try again with another machine later in the day. Not exactly the same complaint but very similar. I don't believe it is a bad battery or starter but your comments make sense. I'll check out welding web. Thanks
Sometimes you just need to use it again to spike the current adjuster.
When welding with a CV machine amperage is controlled by the wire feed speed. Eliminated that I think is what allows the amps to ramp up to the max. the machine can produce. Boosting a large engine could draw more amps than the machine is designed for. Don't know what kind of damage could be caused if it would be something simple like burnt diodes or something more serious.