Battery isolator

[John Evans]

My Ram 3500 5.9 loses charge after 3 days of inactivity while my camper is plugged in. I’m pretty sure there is already a battery isolator installed but I have read something about a .5 volt leak from the 6 pin plug is normal. Is that enough to cause an issue of a dead battery after 3 days? Also is the picture attached the isolator?

 

[Smokeybear01]

What you pictured appears to be a solenoid. They are not the same. Think of a battery isolator as a huge diode that only lets juice flow one way (LEDs work like that which are just Light Emitting Diodes). Solenoids are heavy duty switches that are turned on and off by smaller amounts of amperage current. Lots of people use battery isolators when they run more than one battery in their trucks that aren't diesel. Repeat-are not diesel. When I tow my trailer I do not have a battery isolator in line because I don't plan on leaving my truck connected when not in tow. You have a phantom drain in your camper that you need to track down. The 6 pin plug by itself is not the problem-it's what is plugged into it-the camper. Good luck,

 

[GTyankee]

this sort of explains the uses of Isolators & Separators

How to Choose Between Battery Isolators and Separators

Battery isolators are best seen as the distribution point of an automotive electric system.

info.waytekwire.com

 

[John Evans]

What you pictured appears to be a solenoid. They are not the same. Think of a battery isolator as a huge diode that only lets juice flow one way (LEDs work like that which are just Light Emitting Diodes). Solenoids are heavy duty switches that are turned on and off by smaller amounts of amperage current. Lots of people use battery isolators when they run more than one battery in their trucks that aren't diesel. Repeat-are not diesel. When I tow my trailer I do not have a battery isolator in line because I don't plan on leaving my truck connected when not in tow. You have a phantom drain in your camper that you need to track down. The 6 pin plug by itself is not the problem-it's what is plugged into it-the camper. Good luck,

Thank you for the information.
I will look for short, I kind of have an idea where it might be.
A little off thread but I want to install one 100ah LiFePO4 (14.6 Volt) for the house battery to replace a 120ah lead acid. Do you know what the risk is to my alternator in regards to charging one LiFeP04?

 

[Smokeybear01]

Should be zero risk. The Lithium Iron Phosphate 100Ah battery is still considered a 12V battery for all intents. My neighbor just bought 2 of them for his electric trolling motor. They're not cheap. If you're really concerned about your alternator, do your due diligence and verify with the company you buy the battery from for sure.

 

[John Evans]

Thanks for the reply, that's kind of what I thought too. I guess problems start happening when towing trailers with cars. The average passenger cars alternator is only 75 amps from what I read.
I thought about installing a 20 amp DC to DC onboard battery charger, but that's gonna cost more than a 150 USD by the time I buy cable and other bits, and its just another part to fail someday.

 

[pacofortacos]

The one thing I would check on the other battery is how much current it will accept from a discharged state. Some batteries can accept a boatload of current to charge quickly and alternator, voltage regulator, and wiring will need to be within spec. if that is the case.
An alternator is not technically a battery charger.

$150 for the charger might be cheap insurance to lessen the load on the truck and it's components.
Lose a charger and worse case the house battery is not charged, lose a part on the truck and you could be dead in the water wherever you are.

This may not be the case at all (as I don't know anything about the 3500 diesel truck itself), just something that I would check if changing to a different type of battery.