My truck puts out 15 volts and it is ruining my AGM batteries in my camper. The flooded cell batteries, in the truck, handle it well (got 7 years out of them) Does anyone have a suggestions on how I can lower the voltage going to my RV batteries?

 

I have found that the cable's need to be cleaned on all batteries, a little corrosion goes a long way to having battery troubles, it starts at the passenger side battery, normally 15 volt reading is dirty connections;;

 

The voltage has been at 15 volts since the truck was new. New batteries were just installed and the terminals were cleaned then

 

Not really sure if you can find one with enough value, but a zenor diode might be the answer. They limit the voltage applied to the entire system. Overvoltage is applied to ground.

 

Does anyone have experience with what Sherod is suggesting?

 

I reread U'r post, and Googled dv voltage regulator, I believe U will find what U need, put on rv batteries to adjust voltage to 12 volt input,

 

gcssr, thanks for your help. All the voltage regulators I find when I google are low amperage. My truck alternator puts out at least 100 amps so I need one that handles high amperage.

 

Are you using a good quality voltmeter to determine that you have 15Volts?

What is the voltage at each battery with the truck off and the truck running?


Don't rely on the in-dash gauge. It has a non-linear scale that makes it impossible to figure out what exactly the voltage is.

 

Thanks StealthDiesel Yes, my voltmeter is quality and I compared it with another voltmeter. With the truck off the voltage in each battery is 12.7 volts. With the truck at idle the voltage is 14.6 voltage. With the truck at 2000 rpm the voltage if 14.7 volts

 

If both batteries are at the same voltage while the truck is running, that is good.

However, 14.6V is a little high. Should be 14.0-14.3V.

Are both batteries in good shape?
Perhaps load test each independently. 1 weak battery could cause the charging system to increase the voltage.

Since the ECM controls the alternator output, it is not adjustable.


14.6V is a little high for the truck batteries and definitely too high for RV AGM batteries.
I'm not sure how you could lower the voltage to the AGM batteries.
Ideally, one would want a separate charger for the RV batteries but I don't think a 12V to 12V AGM battery charger exists.