Auto resettable fuse blows and 7 way plug not fully wired.

[Wolfie_Wolf]

Hi All,
A couple of years ago, I found my batteries not very well charged on a 5hr travel day to the bench. When we got there, I could not lower my Jacks until I let them charge from plugged into the RV park's 50amp service.

After the trip, we took it to Explore USA (we bought it there) and they replaced the batteries free of charge because they kept the vehicle for a long time for maintenance and those batteries may have been damaged. I said it still seems not to charge the batteries at all while we are in transit. They are two AGM types. They looked it over and replaced the 7 way cable etc....

Two years later, a Mobil Tech comes to do other work but insists I have my break away checked as he has found many not connected. He indeed finds that there is a 30 A auto resettable fuse that blew AND that the 7 way was not wired for the break away nor the positive for the charging from the tow vehicle.

Now my question ... finally...
1. So is it normal for RedWoods to have an auto resettable fuse inline from the 7 way to the connection that charges the batteries?
2. How can I find out what the wiring should be from the 7 way cable to the couch? Just worried even if the mobile tech did it correctly.

[XCMARK]

It would help to know what year and model your Redwood is. On our 2015 RL38 the red#8 wire coming from the floor above the hydraulic pump is the wire up to the 7 way cord. on the back of your pin box you should have a splice point for the 7 way cord , check the wire color at that point for your battery positive. If you use a DC meter you should also have 12 volts at the cord end when it's not plugged into the truck. The breakaway switch should have one side tied into the 12 volt red #8 wire and the other side of the switch tied to the brakes on the coach (assuming you have drum drakes) Disk brakes is a little more complex. If you pull the key out of the breakaway switch you should hear the brakes tick and maybe a slight hum down at the wheels. DO NOT LEAVE THE KEY PULLED OUT FOR MORE THEN A FEW SECONDS! The brake magnets get very HOT quick and can cause them to fail and smoke.

[Wolfie_Wolf]

Our rig is a 2018 3401RL. It does have disk brakes, so what is the difference there? Sorry I did not give enough detail earlier.

[Wolfie_Wolf]

BTW, the auto resettable fuse had to be replaced by the mobile tech so that we got the 12V power from the 7 way. Just seems a bit strange, but does yours have a auto resettable fuse on that circuit from the 7 way>

[Nedshred]

I have a 2020 3401. The truck charging wire from the 7way is connected through a 30 amp short stop resettable breaker to the rv batteries. There are other wires connected to the same breaker.

The only non fused connection I have is for the brakes’ break away switch..

[Wolfie_Wolf]

Thank you very much for that info!

Sometimes I wonder if the AGM batteries (which suppose to charge 5 times faster than standard lead acid) may be the cause of the damaged auto-resettable fuse.

[XCMARK]

Originally Posted by Wolfie_Wolf

Thank you very much for that info!

Sometimes I wonder if the AGM batteries (which suppose to charge 5 times faster than standard lead acid) may be the cause of the damaged auto-resettable fuse.

Normally unless there is a short circuit to ground the voltage drop at the trailer is so much you can only get 5~6 amps at 13.6 volts, any high amp draw will only result in the voltage dropping to below 12.5 volts which will not charge any battery unless it's almost completely discharged. The wire front to back of the truck isnt heavy enough to carry the current from the truck manufactures regardless of the brand. I suggest to everyone to install a 15~20-amp DC to DC converter so you can boost the voltage at the RV battery and completely charge them while you drive. With a inverter and a a residential refrigerator you really don't have enough battery and charge rate from your truck to do multiple days on the road without park power or generator. If you have a really good battery monitor like a Victron BMV-712 or something similar you can't tell what the state of charge is on your battery anyway. I was shocked to see my two 6-volt Trogen battery's where down to 50% after driving all day and knowing the trailer was charging when its on road. I installed a Victron 18 amp DC to DC charger and now get a full 18 amps at the battery in the coach. Basically, the voltage at the back of the trucks is around 11 volts with a 20 amp draw and the DC to DC charger brings the voltage back up to 14.6 for bulk charge and then drops back to 13.6 volts for float charge ( or what ever voltage you program it for ) The are AGM,FLA, Lithium compatible and the limit the current charge rate for Lithium also.