The Problem
I’ve mentioned in other posts the problems we’ve had over the years with the DC power panel located (in the 32SA) in the passenger rear compartment, next to the batteries. This panel has the main battery cut-off switch, the Inverter DC power switch, four DC breakers for distributing power to various parts of the RV house and a hidden component the battery combiner relay.
The primary problem with this panel is the Inverter fuse which is a 1 by 1 by 3/4 
inch block mounted between the battery buss (leaving the main switch) and a buss bar that bolts to the back of the Inverter Switch. Apparently, this bolt that holds that fuse between the two busses isn’t torqued properly and the design is such that heat builds up and the fuse insulation fails (adding to the problem). As the fuse gets hot, heat conducts up to the inverter switch and melts part of the switch until it fails. There was even one report in facebook of this panel catching fire.
Recall
There is an NHTSA recall for this problem for various 2019 to 2022 models. I personally don’t like the solution as covered in the recall. If you have a 2000 watt inverter, the solution is to install a cable between the fuse and inverter switch (which won’t pipe heat directly up) as well as check the torque of the fuse bolt. If you have a smaller inverter, they just check the fuse bolt torque.
I consider this panel to be a total fail. In order to pull the panel to work on it, the only safe way is to disconnect the battery (usually recommended anyway) beause the support bracket comes very close to the main battery buss when removing the panel. Fuses shouldn’t be buried behind panels. The design of the fuse depends on a thin plastic insulator which fails as the fuse heats up which results in the bolt shorting the two busses which means there is no fuse. Finally – the four DC circuit breakers are poorly supported and heavy wires are connected to them, also not supported/restrained, so sometimes just pulling the panel out and putting back in causes one of the breakers to physically break (happened to me once and also happened to a tech at Red Bay while he was replacing this panel).
The Replacement
The following describes MY solution. I’m not recommending this for everyone. It requires significant expense, tools and expertise most RVers would have issue with.
I designed a “replacement” for the
Tiffin/Lippert DC distribution panel. It is all based on discrete components and thus takes up a lot more room. It is amazing just how much stuff, Tiffin (Lippert) stuffed into that tiny panel – and not amazing why parts of the original panel failed so often.
Note: some who are familiar with my story might say – you installed Lithiums and that overloaded the panel. Nope. Right out of the gate on our first trip, with the original Lead Acid batteries and original Magnum Inverter, anytime we used the inverter for a significant load (like the microwave), the inverter had fits and often shut down and the Spyder system rang a low voltage alarm. We ended up using the generator any time we needed to cook.
When we started out with the lithiums – I checked the alternator rating: 150 amps. I never saw the batteries charging from the engine more than 90 amps. I believe this is because the lithiums were never mostly discharged. We often used the generator when boondocking rather than the engine to charge. One night we spent boondocking behind a restuarant. We hit the road very early in the morning while still dark out after running the batteries down to below 40%. As we took off, I looked at the charging rate and it was 120 amps into the batteries. Add in headlights, heater fan and anything else – we had to be pushing the generator on the engine to its limit for the first hour. I didn’t like pushing it that hard. My solution was to install a Victron DC to DC battery charger. This will limit the engine to house batteries to 30 amps, which is fine because we rarely need to charge up the house batteries quickly with the RV engine. It should keep me from pushing the engine alternator so hard.
The Tiffin battery connect solenoid links the house and chassis batteries any time the engine is running or when the battery linking switch on the dash is depressed (also maybe when generator is running). I didn’t want it connecting when the engine is running – the DC to DC charger takes care of that by monitoring the chassis battery voltage to determine when the engine is running. I disabled the Tiffin logic by putting a switch between it and the solenoid. Thus I can flip the switch and still use the dash switch to connect the batteries. My inverter has a trickle charger to keep the chassis batteries topped off so I don’t need the generator function either.
