Undersize charging wire, WFCO to batteries, Upgrading to lithium in 2019 T@B 400

jimcenname

In my 2019 T@B400 (no solar) I just replaced the two original AGM Harris Batteries with a single Battle Born 100ah lithium. The original charger, 55 amp WFCO 8955PEC, isn't lithium compatible. Battle Born Rep offered a 55 amp Progressive Dynamics 4655V to convert the WFCO to Lithium capable. My problem was the factory wire between the WFCO and the AGMs is 8 gauge and runs 22 feet long behind cabinets and under the bathroom floor. Both Battle Born and nuCamp agreed that is undersized for that distance for a 55 amp charger. I don't know why it also isn't undersized for the existing AGM batteries. Though I know of no problem it caused in the 4 1/2 years I have lives in my T@B. Instead of running 22 feet of 4 gauge wire I bought a PD9345 "deck mounted" charger, installing it right next to the new lithium battery. Only 2 feet of cable required. Also I disabled the charging feature on the WFCO by removing a single power wire for the panel breaker. FYI, I also installed a shunt to monitor the lithium battery and an ANL fuse on the battery's hot wire. Progressive Dynamics said to run a dedicated ground wire from battery-negative to chassis-ground. The existing battery compartment vent hole provided a passage through the floor. Since Lithium doesn't require venting for gas I eliminated the battery encasement cover.

RMo

Thanks for the overview.  I’m considering something similar and have a few questions.  How difficult was it to remove the black cover?  Any tricks?  What are the dimensions of the space that remains after you remove the cover?  Any lessons learned that might be useful?

jimcenname

I removed the lower third of the bed platform. Then unscrewed about 10 screws holding the cover in place. I lifted the cover on the outbound side, disconnected the battery cables and feed them through the hole on the side of the cover. Then the cover lifted off. The AGM batteries weigh about 60 lb each. I flipped them on their side and pushed them out the cargo access door. The roughly 11 X 8 inch space of one AGM battery was used for the new charger, shunt and fuse. I gained no space but lost about 90 pounds. I'll have to see how much the tongue weight changed.

RMo

Did you use the original pos and neg leads from the battery, or replace them with larger gauge wires?

thanks,

jimcenname

They were 4 gauge cables about 2 feet long. That's sufficient to handle the current from the charger, which is at the end of a 2-foot long 4 gauge cable. They connect at the existing distribution studs.

Binghi

Nice mod, @jimcenname - I’m upgrading my 2021 400 to lithium and thinking of doing something similar.

A few questions:

How come you used the PD 9345 instead of the PD 9360? Wouldn’t the 9360 charge the battery faster?

It looks like you put in an AC outlet to power the converter. Did you create a dedicated circuit for the outlet by running the outlet cable back to the power center and installing another circuit breaker? What gauge cable did you use?

Did you keep the OEM inverter?

Thanks!

SLJ

When I installed my lithium batteries I also put in a Victron Smart Charger for charging them when on shore power. When on shore power I let my non-lithium WFCO (2021) supply DC and just shut off my batteries. If they need charging I switch on the Victron and let them charge. When I unplug from shore power I just turn them back on. I trust the Victron charger way more than any WFCO.