diy solar

diy solar

Alternator sizing

kl3vr

New Member
Joined
Nov 14, 2020
Messages
26
Hey, my vehicle has a 90amp alternator. I'm building a large lithium battery with a 50amp DC-DC charger. Will this damage an alternator to output 50amps for possibly 4-5 hours on a long trip and a discharged battery to fill up?
 
I wouldn't want to do it. My vehicle has a 150A alternator and I'm planning to use a 30A charger.
 
You are probably pushing your luck. Assuming this is your only 12v alternator your base load could be easily 30-40 amps.
And I wouldn't load the alternator much above 70% for long-term use.
 
Hi, newbie here, question for you guys, I have a similar DC to DC charger, a Renogy dcc50s, with a 45/140 amp alternator.

Is it possible to throttle the current running to the charger? I wonder would it work at a reduced rate.

or does it mean buying a new charger, regards
 
Smaller gauge wire between the engine battery and the charger would effectively throttle the current as this video demonstrates, but someone comment is this is not correct.

I believe ideally you would use a smaller charger with appropriate sized wire though.

 
A 50 amp dc to dc charger will pull over 60 amps from the vehicle alternator. If you try to throttle the input, the dc converter will take more amps from the alternator not less. A 30 amp unit would be safer with a 90 amp alternator. At low engine speed the alternator would not have the capacity to deliver the power for a 50 amp unit.

Mike
 
Back
Top