Grounding a battery bank

[dashriprock1]

Hello. I own a 2017 Era 170A. I have started adding a second lithium battery bank stored under the fold out sofa with a dc-dc converter and charge controller. My question is if anyone knows of a good grounding point in that area to keep my cables short and tidy. I believe there is one under the seat however, I can't figure out how to get under there. Thanks in advance.

[Morich]

For simple answer, the frame and most metal parts of the RV are all good ground points!
Many RV do have a specific ground bus bar of copper which is then bolted to the frame, but for practical use, just drilling and bolting the ground to the frame at some point which you have cleaned the paint off is reasonable.
Attachingthe cable to the metal is something to do well with locknuts, washers, etc. to avoid it bouncing around to come loose. RV are harder to keep bolted together than the normal house?

But then I might ask how far you have gone in the study? Are you proposing to add lithium to the existing coach lead acid battery string?

I'm not heavy into that part but was thinking there was a bit of mismatch when using both types together.

Meanwhile, are you aware of the interactive parts catalog online that lets you look at things like the electrical and all the parts including the battery cables?

Takes a bit of learning curve to get good at playing it but great stuff here:
https://catalog3d.winnebagoind.com/menu/Parts.htm

[powercat_ras]

Your best bet is to have the batteries negative lead or leads tied to a 500 amp capacity low resistance battery monitor shunt and then the other side of the battery monitor to a ground that is common with the inverter (unless you have a small inverter). There are some very affordable battery monitors on Amazon, that will show exactly how much power is flowing in and out of your battery bank and keep track in % how much energy is stored in your bank.

I agree that you can not mix Lithium and Lead Acid on a battery bank. They use a totally different charging strategy and charging voltages.

I'd use 0 gauge for all your battery cable runs, it's a one time cost that will make everything work better in the long run. If cost is an issue copper clad aluminum stranded 0 gauge is less expensive.

Generally if you have an OEM 1000 watt inverter it will have a negative wire run of 2 gauge to the ground bus bar that Winnebago weleded to the frame and the OEM battery ground will connect to the same bus bar with 0 gauge. It will have a 2 gauge positive wire run to a large ANL fuse and they often use the battery side of that ANL fuse as a stud where they connect multiple positive lines then one 0 gauge from that stud to the OEM batteries.

Personally I don't like trying to return power thru the frame unless you have good test equipment that can confirm that it is very low resistance path similar to what a dedicated 0 gauge wire run is. I always try to use the ground side stud on the 500 amp shunt as the common connection point for the inverter and solar charge controller, then heavy wire (0 gauge) jumper from there to the Winnebago ground bar.