Question on making battery distribution panel

[maillemaker]

So my house batteries bought the farm recently - 5+ years old so it was time for new ones.

Originally, my 1990 Winnebago Warrior came with one single house battery, stowed under the hood in the engine compartment. Space was limited so it is a smaller batter. I had an 83 amp-hour AGM battery there.

About 5+ years ago I added a second Group 29 size Deep Cycle battery, in a battery box, in one of the underneath storage compartments. I hooked it up in parallel with the existing battery under the hood, to give us extended power when boondocking.

Now that I am replacing both batteries, I am putting two Group 29 Deep Cycle batteries in battery boxes in the underneath storage compartment where the single one was before.

I have wired the two batteries together in parallel, and have my two main terminals leaving the battery bank attached to one battery's positive terminal and the other battery's negative terminal. I understand this is the preferred way to wire battery banks in parallel.

So the question is how to manage the connections under the hood where a battery used to be. I used to use the under-hood battery posts as the termination point, but since it is now gone, there is nothing to terminate at.

I was going to make a home-made simple L bracket out of some sheet metal, and mount these junction blocks to it:

https://www.amazon.com/gp/product/B01LLZF7DW

And use these as the termination point for the output from the battery bank and for the connection to the house system. I have a battery cut-off switch on the negative post here also. Anyone have some better ideas other than home-made panel?

Second question:

I feel like I should have a fuse at the battery bank in case the main line running from the storage compartment to the engine compartment somehow develops a short (say, from wear).

The battery bank can be used as emergency start for the engine. What size fuse should I use on the battery bank? Or should I use a fuseable link?

Right now I have no fusing/overload protection from the battery bank to the engine compartment.

Steve

[maillemaker]

Hi Mex, looks like the Bussman breakers only go up to 150 Amps. Is that sufficient for the house battery bank if it is called upon to start the engine? From what I'm reading online starters can pull 250 amps or so.

I had already ordered a 300 amp inline fuse kit here:

https://www.amazon.com/gp/product/B017ARONCQ

But a resettable breaker seems nice, too, but I think I need more than 150 Amps.

Steve

[MEXICOWANDERER]

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Positive Insulated Battery Power Junction Post Block 3/8 Lug X 16 thread (Red & Black Set)
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Try and avoid cheap KUNGCHOW type Chinese breakers. Their housing is cheap play dump-truck plastic, and they have flaky performance. I prefer Bussman breakers. A breaker at the BATTERY end of the system will protect the positive cable bridging connection cable.

[maillemaker]

You should have on on either end of the wire, in my opinion, since the chassis starting battery can also supply virtually unlimited current to the wiring.

I believe the vehicle battery is already fused from the factory. Could be wrong though.

Steve

[DrewE]

Fuse size is based largely on the wire size that it's protecting.

I think my class C uses 175A fuses for this connection. You should have on on either end of the wire, in my opinion, since the chassis starting battery can also supply virtually unlimited current to the wiring.

[Ranger_Smith]

Usually the fusible link on the battery is 300 amps. That is what was on our Winnebago Adventurer. If it were me I'd have the battery cutoff on the positive terminal.