Right sizing the resistors attached to battery

[mdfas]

Hi,


I am about to test out my newly restored 2006 Rockwood 256 HW running off the battery. Everything is running perfectly off the 110v house outlet so there are no shorts internal to the camper that I know of.



I had to replace the battery and the resistors on top of the battery ( see photo ). I believe I have the wrong capacity on the resistors and would like to know the correct amperage for each of these. I assume the purpose of the resistors is to limit the current flowing into the camper to 20 amps. The blade fuse inside the housing was/is 20 amps. It blew a fuse inside the camper when I tried the first time as I believe the resistors are letting in to much amperage.



Should each resistor be 10 amps, 20 amps ? They seem to be in series ( i.e. the current passes through one at a time?). Not sure. Any help is appreciated.

[NavyLCDR]

They are not resistors. They are circuit breakers. They are wired in parallel and you are only using one of them. They are usually 30 amp for main feed in to the trailer. The second may be smaller like 15 or 20 amp to supply an accessory like a tongue jack or a charging input from a solar panel.

[Rick the Rocket]

You need to find what the black wire that blew the fuse goes to. There is a heavy load on it if it blew the fuse. The red wire looking at it's size probably feeds the 12v distribution in the camper. The parallel circuit breakers is unusual to me, as stated above there is usually one 30 amp breaker that is manually resettable.

[Bama Rambler]

As said above, those are resettable breakers.

The way they're wired, they're in parallel so if they're the same rating then whatever the rating is will be double. So, if they're 20 amps each theoretically it will take 40 amps to trip them.

Having said that, they have nothing to do with the circuit with the inline fuse holder. That's a separate circuit than the main power to the RV power center.

[5picker]

Originally Posted by Bama Rambler

As said above, those are resettable breakers.

The way they're wired, they're in parallel so if they're the same rating then whatever the rating is will be double. So, if they're 20 amps each theoretically it will take 40 amps to trip them.

Having said that, they have nothing to do with the circuit with the inline fuse holder. That's a separate circuit than the main power to the RV power center.

X2
The way they are connected isn't the typical way to use them. Not that you can't, it just isn't typical.

[jk510]

I only see 1 breaker there. It connects the positive to the red wire (you have to zoom in and look close). I don't know what that red wire goes to but it is protected. Is it coming from solar panels maybe?
I am concerned about that black wire on the negative terminal of the battery. Usually black is hot and white in ground. There is already a black on the positive terminal.

[cfo111]

enlarge the picture there is one in front and in back hidden

[mdfas]

Thanks all.



Also, didn't want to embarrass myself, but here is the scenario that blew the 20 amp fuse inside the camper. I had most things running off the house 100V line including the lights ( led). When I unplugged the house power ( as a test), the lights came on when flipping to the battery, but the 20 amp fuse for the 3 way fridge blew. At the time I didn't have the gas hooked up and maybe the 3 way fridge was stuck in a cycle between testing for the electric and trying to ignite the gas? Also, the blade fuse housing in the pic was super hot and melted a bit.



Below is a link to the circuit breakers I installed. They are 50 amps each? The old ones were too rusty to see what they were. Should they be less amperage? I am hearing 30 amps and 15 amps.



https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[cfo111]

any auto part store sells them

[Bama Rambler]

If you bought 50 amp models you only need one of them (just remove the extra one), and looking at the size of that red wire it doesn't even look to be large enough for 50 amps. Do you know what size wire that is?

[NavyLCDR]

PI didn't notice the buss bar connecting the outlet sides of the breakers, that is odd. If the DC side of the refrigerator is blowing the 20 amp fuse, there is likely a problem with the DC heating element.

[jk510]

OK, I didn't look close enough to see that it was 2 side by side. I don't understand that at all. Maybe that's why I missed it.

[NavyLCDR]

Interesting, I found this:
https://www.centurytool.net/39990000...3999000052.htm



I do not know what the purpose of the dual circuit breaker is. I can understand 2 separate circuits with a buss bar across the hot (battery side). My trailer has two, one for loads to the trailer, and the other on the solar panel charging connection. But I don't understand having buss bars on both sides. The two copper/gold posts are the battery side, and the two silver posts are the load side. They are in parallel.