DC to DC Charger Needed With Lithium Batteries?

CrabTab

Looking at Lithium Batteries for future upgrade to our T@B and came across a presentation about needing a DC to DC battery charger when using the TV to charge while driving. The reason given was the Lithium Batteries will draw too much current when charging and overheat the alternator. I'm not looking to upgrade the alternator in my 2019 Chevy Colorado.

Do I need to get one of these chargers to recharge, let's say 200AH worth, of Lithium Batteries while driving?

Cbusguy

The thing to keep in mind with lithium is they will take 1c worth of charge,  so it is concievable that your battery could take 200 amps from your tow vehicle.   Ugly for everything involved.

I have 200 amp hours of battleborn in my trailer.   I upgraded my wiring from the battery in the TV back to the connection into the trailer and I bypassed the connection and used 100 amp anderson connectors directly into a renogy dc to dc converter.      make sure you use an appropriate sized relay tied to your ignition switch or you will be a sad boy after a fairly brief fuel or lunch stop. 

I first ran the setup a couple of times with out the charger,  the wiring was warm to the touch on a couple of short trips.   I saw charge currents 70 amps so I decided it was better to be safe than sorry.   

I  bought the 20 amp version,  doing the math,   I could charge it to 160 amp hours in an 8 hour drive.  

The bonus is you can charge it to max capacity as the voltage on the charger is adjustable,   

Is it required,  no ,  if you chose not too I would look at some other method of limiting charge current    

ginsbuj

I just installed a Battleborn 100 Amp hour lithium battery so I checked with them. I have factory installed solar from NuCamp with Victron MPPT 75/10 Charge Controller. My tow vehicle is a 2018 Chevy Colorado V6

 Battleborn responded with the following:

You should not have any problems with damaging your alternator. 

The length and size of cable only deliver a small amount power back to the battery bank. It’s almost more like a trickle charger. The only thing we recommend is to disconnect the seven pin connection we you arrive at your final destination.

Battleborn was great in giving specific user defined settings on the controller. Although I haven't camped yet with the new battery I have been watching the charge each day with very good readouts even during cloudy days and parked along the side of my house with limited sun hours.

Cbusguy

Looks like battleborn is relying on the resistance in the wiring to limit charge amperage.    By increasing the cable size I may have introduced high amperage draw issue.     

keep in mind if you are only charging the battery a 5 or 6 amps,  a 50 percent depleted battery will take 10 hours to charge back up assuming 100 percent efficiency and  no use by the trailer, fridge running on DC. 

@ginsbuj have you checked to make sure your TV to trailer power connection is live?    

Tabnero

I never had any trouble with my Colorado, battleborn 100 amh

Rollingztone

I have two 100 amp hour Battleborns installed in my T@B. I have never had a problem with my GMC Sierra truck alternator. You should, as previously mentioned, disconnect the TV cord as soon as you arrive at your destination to prevent discharging the TV battery into the Battleborns. My fridge draws 5 or 6 amps from the Battleborns when connected to the TV the alternator running, and 11 amps when not connected to the TV.

N7SHG_Ham

A DC-DC charger isn't a bad idea for any type of battery. Necessary? I am not sure, but they certainly can help.