Is it OK to upgrade battery?

[Essayons]

I need a battery for my 1979 CB750k. Should I stick with lead acid type or is it OK to upgrade to lithium?

[franque]

Yes, you should be able to upgrade without much of a problem, just make sure you get a proper charger for the lithium battery, as many require a special charger.

Really though, the only major advantage is decreased weight at this point in time, so unless you're looking to save weight, I might consider an AGM battery if I were you, that way you don't have to monitor/top off cells.

[Megadan]

Ideally only if your charging system can maintain the minimum and maximum voltage needed for a lithium battery, otherwise you can potentially shorten the lifespan of said battery. Usually the main thing needed to achieve this is a modern solid state regulator/rectifier. In some cases the stator itself may not be strong enough, but that is pretty rare.

You will want to produce no less than 13.2 volts at idle, and no more than 15 volts maximum. Most batteries will specify 13.4 to 14.6 under normal operation, but there is usually a little leeway.
I had to sort this out on my GL1000 when I too went to a lithium. I replaced the separate regulator and rectifiers with a modern Mosfet unit and capped off the regulation/sense circuit (new unit was self regulating).

[Essayons]

Thanks Dan. I'm going with "Megaboost" from cycle gear. It's listed as a direct fit and it's half the price of the lithium. Is the "13.2 volts at idle" to be expected right away or after warm up?

[Megadan]

Thanks Dan. I'm going with "Megaboost" from cycle gear. It's listed as a direct fit and it's half the price of the lithium. Is the "13.2 volts at idle" to be expected right away or after warm up?

Under normal operation for all voltages, so I would say after warm up. Honestly, aside from the weight savings, the only real advantage to a lithium battery in my mind is if you can get an increase in cranking amps or amp hours. The battery in my GL1000 had 500cca lol. That starter never turned so fast.

[Essayons]

Thanks franque. Luckily I already have a charger for lithium batteries.