21 replies to this topic

[ri-f]

For 4 AWG I used this tool (about $125) with excellent results:

https://www.amazon.c...uct_top?ie=UTF8

 

It will handle crimps as small as 6 AWG, as well as battery cable  2/0 size, easily. Nice large crimp tool to have.

[PaulT]

Harbor Freight has a hydraulic wire crimper that has worked well for my needs.

 

https://www.harborfr...draulic crimper

 

Not necessarily what I would choose for professional use but how many large connectors does one need to install on an ongoing basis.?

 

Paul

[mobilelists]

.....Not necessarily what I would choose for professional use but how many large connectors does one need to install on an ongoing basis.?.....

I too use to think that was my case. It is surprising the number of times I have found a use for a good crimped cable. Granted I have old farm tractors needing repair. Buy a good crimper that will work for the brand of connectors that you will always use.

Edited by mobilelists, 20 November 2022 - 01:59 AM.

[craig333]

I bought a hammer crimper. Used it on my camper and haven't used it since so I'd say I saved money by not by a spendy crimper. Who knows, maybe I'll have another project come up and regret that.

[FreezingMan]

Using 4awg for nearly all of the run and then reducing to 6 or 8 awg for the last few inches, assuming good connections, would have lower overall resistance than using the smaller wire over the whole length.

In this case, I may be able to provide information that can convince the OP that 6 awg is adequate. I have a 2021 GMC 3500 hd crew cab long bed with a Grandby front dinette, which has its battery compartment at the left rear of the camper. I suspect my wire run is about as long as any truck camper would have, and I can look closely at it to estimate the total length later today (it’s about 30 feet one way). The truck has a smart alternator obviously. I use the Victron 12/12-30 isolated Orion Smart charger installed at the rearmost part of the camper battery compartment.

With about 60 total feet of 6 awg Ancor Marine type 3 wire and an SB50 connector at the front of the camper, the voltage drop is low enough that the Orion’s engine running verification cycling function is NOT triggered at any time. The charger’s engine running detection function is able to detect engine running purely through the basic voltage detection thresholds. This is what you ideally want with the Orion to avoid cycling and lower average charging output. I would suggest reading the engine running detection portion of the Orion manual if what I’m describing is not clear.

I can make a more precise estimate of my wire run length and answer other questions about the installation for the OP if desired.

What size breakers or fuses did you install from truck to the b2b charger?

[FreezingMan]

I ran 4AWG from the truck battery back to the camper with an 80amp breaker next to the truck batteries. At the camper end I used an Anderson connector and stepped down to 6AWG prior to entering the camper. Do not try to stuff 4AWG into the Orion.

Dean

On the B2B charger end what size breaker did you use?

[Jon R]

What size breakers or fuses did you install from truck to the b2b charger?

Short answer: 80 amp fuses at truck battery and camper battery.

It’s important to think about why you are installing fuses (what failure modes and effects are you trying to address) and then locate and size your fuses accordingly. In the case of the dc to dc charger wiring, the threats that can cause high current from the batteries and the potential for fire or major damage are a hot short of the positive wire to some ground from chafing or damage (typically a short to structure but could be to a ground stud, bus bar, or wire), and a failure of the charger to limit the current. If you think about it, you want an appropriately sized fuse at each energy source (each battery) to address both of these threats.

Location of fuses:

So to protect against a hot short of my 6 awg main power wiring to ground at any location, I have an 80 amp fuse on the truck battery fuse block, and I have an 80 amp ANL fuse in a Blue Sea fuse holder inches away from the camper battery. (The camper battery itself also has a 300 amp internal fuse. ). With these fuses there is no reason to have an additional fuse or CB at the charger end of the wire from the truck to the Orion charger other than to switch the charger off. Since the Orion has a software switch to turn the charger off and my battery itself has a main switch, I have no additional fuse at the charger end of the the truck-to-Orion positive wire. Also, I can easily disconnect the Orion from the truck for maintenance by disconnecting the SB50 connector between the truck and the camper pigtail.

Sizing of fuses:

80 amps is the recommended fuse size for 6 awg wire. Everything in the camper could be running and it would not add up to 80 amps. In addition, the Orion limits it’s current draw from the truck in normal operation to about 35 amps. So my main fuses are primarily for hot short protection of the main power wiring or a catastrophic charger failure.

Edited by Jon R, 26 November 2022 - 04:19 AM.

[veryactivelife]

On the B2B charger end what size breaker did you use?

I used 60, but you want to use whatever is appropriate to the wire being protected. Use the Blue Sea chart for guidance.

[Vic Harder]

2 AWG in my setup, 100A Blue Sea breakers at either end, inches from the batteries

[FreezingMan]

Thanks to everybody for the input.  This was hugely helpful!