is there a handheld devices I can hookup to the batteries termainals and find out what percent of a charge it has?

[chovy]

The monitor on my 2nd battery always says 0%. its a lithium iron phosphate battery, i think the 1st battery is lithium ion but i'm not sure.

 

[Isaac-1]

Without knowing more details it is hard to answer this, though off hand this may be close to what you need Amazon.com: Victron Energy SmartShunt 500 amp Battery Monitor (Bluetooth): Automotive

 

[chovy]

Thanks. I mean I guess I already have that. Mine just says zero all the time.

 

[Jayflight]

Why not use a simple electrical meter with two wire leads.

 

[bzerull]

An inexpensive multimeter you can purchase at most hardware stores will do what you want.

 

[Mark_K5LXP]

Since you say your 2nd battery isn't hooked up the solar panel connection you can't find wouldn't do any good and you don't need to know if the battery is charged or not anyway.

(sorry...)

Mark B.
Albuquerque, NM

 

[Gary RV_Wizard]

Unlike lead-acid batteries, measuring the voltage of an LiFePO4 battery doesn't give an accurate picture of the remaining capacity. It will show good voltage as long as there is much of any charge at all.

 

[John From Detroit]

What gary said... on the small LiFePO4 I use the voltage stays within 1 or 2 tenths of a volt till it drops like a rock in free fall. The charge controller seems to know how full it is but ... Well.. it is very specific to the battery.

You can measure in and out. that will give you some indication but over time that will "Drift" off a bit and need a reset. The "Shunt type" battery monitors do that.

Finally LiFePO4 unlike lead acid.. If you run it down, and I mean Down. I'm told they do not mind that much so long as you bring 'em back up soon.. So. a "jump start" pack (I have two of 'em one lead acid one LiFePO4 if the thing dies clip direct to the Generator and give it a try. The lead acid seems to work better with a truly dead battery. (Had to do it once)

 

[Tom_M]

Finally LiFePO4 unlike lead acid.. If you run it down, and I mean Down. I'm told they do not mind that much so long as you bring 'em back up soon..

This is only true if the battery has a BMS (Battery Management System) otherwise the battery will be destroyed. The BMS prevents running the battery totally dead and will automatically disconnect the battery before any damage is done. Batteries that are considered "drop-in" replacements have the BMS built in.

 

[John From Detroit]

This is only true if the battery has a BMS (Battery Management System) otherwise the battery will be destroyed. The BMS prevents running the battery totally dead and will automatically disconnect the battery before any damage is done. Batteries that are considered "drop-in" replacements have the BMS built in.

Thanks Tom... Mine does have a BMS or so the maker claims

 

[creativepart]

Do you have the SmartShunt connected directly to your battery???

There was a person on the Winnebago Owner's forum that had connected the smartshunt to the converter not the battery negative post and he had the same issue.