Lithium batteries and alternator protection.

StirCrazy wrote:

S Davis wrote:

theoldwizard1 wrote:

CA Traveler wrote:
Also 13.2V would not be a issue for me as it indicates a charged battery and the alternator is only supplying chassis and converter loads. A higher voltage indicates the chassis battery is drawing amps so at least the DC-DC converter has less conversion losses.

Almost all vehicles for the past 15-20 years or so, use some kind of a smart charging system. The voltage from the alternator is controlled by the engine computer and can vary over a wide range.

Not on 2009, 2013, 2019 GM 2500HD diesels, my last three trucks all have had steady voltage at about 14.2 no matter what. They must be in the almost none category.

One of my Redarc 50 amp chargers pulls 50 amps from the alternator and output is about 46 amps to the batteries, so on Redarc it looks like the rating is what is pulled from the alternator.

Im not sure when GM started doing it but your 2013 and 2019 should have smart altanators, but may not. you would have to look for the shunt as GM did it differently and it should be part of your negitive batery post atachment.

GM uses a shunt system whil ford uses a two wire bus.. as well other things might be different as in the voltage setting and such but ventualy when your battery is full in your truck and if your not using a ton of other power hungry stuff it will go down to a maintance voltage. this is to both give longer life to the altanator and the batteries. as for dc to dc chargers a lot of the input output power descrepencies are from wire size also.

I have monitored alternator voltage on all my trucks and they never have gone below 14.2, my 2013 used to run a little higher at about 14.4. Same voltage when I start the truck and the same voltage over a seven hour drive. I have a volt meter on the dash.