16.8v on a 12v starter?

[48V]

I have a Silverado (5.3L) that I am installing a large 48v electrical system in, to power most belt drive accessories. One of the major things I want to do is get rid of that giant lead battery!

Now, let's say I replace the starter battery with a 4 cell lithium ion battery? That's 16.8v vs 12 or less. It would not power anything else, I don't want 16 volts for anything else. Nothing but starter.

Is this going to damage a typical 12v American style starter motor? I know they sell 14 and 16 volt lead acid batteries for racers, and they claim it works fine, but is that true? It would not be the end of the world, starters are cheap and easy to replace, but I don't want to get stranded somewhere.

I might just try to leave the battery at 16.0v, not quite as hot and that way I don't have to float charge the lithium battery at max voltage.

I could use a 12.6v 3 cell, or 14.4v Lifepo4 batteries instead, but I would like it to crank super fast.

[Piotrsko]

For starters, the spec used to be 14.8v for charging batteries in very cold weather. In theory therefore most electronics should tolerate that and more, but in reality it varies case by case. My glowplug relay which is solid state has a limit of 14.6 stamped on it and I know from experience replacing said relay that 14.7 fails the relay.

The starter will draw more current, spin faster and develop more hp (maybe now 3 1/2). The brushes will arc more and live shorter lives but that shouldn't be noticable. I overvolt my traction motor significantly and know of someone that has doubled his traction system voltages to 400 volts on a 48v rated motor. The trick will be isolating the other systems from the 16 volts and the bemf produced

[freebeard]

Throw in a resistor in series.

[Isaac Zachary]

Originally Posted by freebeard

Throw in a resistor in series.

And put it in the intake to heat the incoming air.

[48V]

Originally Posted by Piotrsko

For starters, the spec used to be 14.8v for charging batteries in very cold weather. In theory therefore most electronics should tolerate that and more, but in reality it varies case by case. My glowplug relay which is solid state has a limit of 14.6 stamped on it and I know from experience replacing said relay that 14.7 fails the relay.

The starter will draw more current, spin faster and develop more hp (maybe now 3 1/2). The brushes will arc more and live shorter lives but that shouldn't be noticable. I overvolt my traction motor significantly and know of someone that has doubled his traction system voltages to 400 volts on a 48v rated motor. The trick will be isolating the other systems from the 16 volts and the bemf produced

Perfect, just wanted to know it won't instantly let out the magic smoke. I haven't decided entirely how I want to wire it up, but yeah, it will be annoying isolating the voltage everywhere, even the starter solenoid.

The 16v will charge off the main 48v battery and I could adjust the voltage of a 4S pack down by simply by not charging them all the way. Probably smarter in the long run, I'm basically just using the high output batteries like a capacitor, they don't need to hold many watts.

Then to complicate it even more I'll have a 100A 13.8v converter to replace the alternator and power everything else 12v. I could probably use the 16, it just kind of scares me with so many electronics on the engine these days that I don't even understand...

Eventually I'd like to add a motor to the main engine pulley, and be able to use it as a starter/generator...but I'm getting ahead of myself.

[oil pan 4]

Run it, you won't hurt it.
Race cars have ran 7 cell lead acid batteries for ever.