Hi guys,

Is there an issue running a 180 amp alternator with lithium batteries?

When looking at lithium batteries on various websites I have seen them mention the max charge current rating of the batteries.
Does this mean any alternator with an amperage higher than this charge current is going to damage the battery?

The highest I have seen mentioned so far is 160 amps.

Thanks guys

 

Short answer, it shouldn't be an issue. The alternator amperage is the max amperage that an alternator can put out; it doesn't put out full amperage at all times.

Alternators are designed to put out a constant voltage and the systems in the car draw whatever amperage they need. As long as that amperage is less than the alternator's maximum output everything is good; if the car tries to draw more than that, then the alternator can't keep up and the voltage output of the alternator drops. Also, the maximum output of an alternator varies with RPM; a 180 amp alternator won't give you 180 amps at idle, it needs some revs to reach that number.

 

BTW, that answer assumed a lithium battery that has a charge controller (like the ones that are designed to be used as a car/motorcycle battery). If you just take raw lithium cells and wire them to your alternator (or any voltage source) they will not charge properly, so don't do that.

 

Exactly. The alternator (on an old car like this) for purposes of our discussion is basically a steady stream of electricity that increases with rpm. The control module in the battery will limit how much of that is used to charge it.