Wiring 4 awg charging wire to upgrade 8 awg factory wire.

S Davis wrote:
I removed the rear seat in my crew cab and made the enclosure. So have room for the two 280ah batteries inverter and associated wiring.

Removing the back seat opens up a lot more space. We travel with a space-challenged TC, so the entire back seat area becomes a critical storage asset. If we lost this space we'd be forced to tow a trailer--for us, absolutely no fun.

All our equipment (inverter, batteries, dc2dc charger, etc.) is installed out-of-sight in our TC. Never take-up or use any interior, closet, drawer or storage space for equipment. We also don't cut any holes in the immediate interior for displays, meters, cables and such. It's been quite a challenge to do it this way, but it's been worth it.

I removed the rear seat in my crew cab and made the enclosure. So have room for the two 280ah batteries inverter and associated wiring.

^4/0? :E

S Davis wrote:

otrfun wrote:

S Davis wrote:
My Redarc 50amp just senses the voltage increase from the alternator and turns on, no trigger wire.

Nice to have that capability built-in. I don't understand why all dc to dc charger manufacturers don't include the equivalent of a Battery Isolator (BI) or Automatic Charging Relay (ACR) with their units. It's a basic requirement for operating a dc to dc charger in the vast majority of installations.

The 50a Redarc dc to dc charger is a nice unit, built like a tank. See a number of off-roaders using them.

One big caveat though, they cost $500+. One could potentially purchase & stack 4, 40a Renogy dc to dc chargers for 160a of output for $519. Of course, this would require a dedicated, high capacity alternator to provide the necessary current. I've been told Renogy doesn't recommend stacking (connecting in parallel), but I've stacked 2 of them with no issues.

I know but having the charger just work without babysitting it is priceless, especially for LifeP04 batteries. Next step is a dedicated alternater.

It only took us 10 min. and a few short wires to install a BI on the input of our dc to dc charger. Agree, having the ability to run our dc to dc charger in the background, unattended, 24/7, with zero concerns is nice.

Thumbs-up on the dedicated alternator. Have plans to purchase a new truck this summer. A dual alternator is definitely on the option list. Hoping to use a 2nd, stacked 60a dc to dc charger so we can power our truck camper a/c unit via alternator indefinitely. Right now, using both the lifepo4 and dc to dc charger at the same time we can run it for up to 2.5 - 3.0 hours. Lifepo4 only, about 1.5 hours. All times are with the compressor running a 100% duty cycle.

Envy all the room and easy access you have. Like you, we installed a DIY lifepo4, silicone heating pads, thermostats, inverter, dc to dc charger, etc. Unfortunately, we were working with a fraction of the space you have. Just running/pulling the 4/0 and 2/0 cable throughout our truck camper, took 2-3 days. But, all said and done, it was 200% worth it!

otrfun wrote:

S Davis wrote:
My Redarc 50amp just senses the voltage increase from the alternator and turns on, no trigger wire.

Nice to have that capability built-in. I don't understand why all dc to dc charger manufacturers don't include the equivalent of a Battery Isolator (BI) or Automatic Charging Relay (ACR) with their units. It's a basic requirement for operating a dc to dc charger in the vast majority of installations.

The 50a Redarc dc to dc charger is a nice unit, built like a tank. See a number of off-roaders using them.

One big caveat though, they cost $500+. One could potentially purchase & stack 4, 40a Renogy dc to dc chargers for 160a of output for $519. Of course, this would require a dedicated, high capacity alternator to provide the necessary current. I've been told Renogy doesn't recommend stacking (connecting in parallel), but I've stacked 2 of them with no issues.

I know but having the charger just work without babysitting it is priceless, especially for LifeP04 batteries. Next step is a dedicated alternater.

otrfun wrote:

S Davis wrote:
My Redarc 50amp just senses the voltage increase from the alternator and turns on, no trigger wire.

Nice to have that capability built-in. I don't understand why all dc to dc charger manufacturers don't include the equivalent of a Battery Isolator (BI) or Automatic Charging Relay (ACR) with their units. It's a basic requirement for operating a dc to dc charger in the vast majority of installations.

The 50a Redarc dc to dc charger is a nice unit, built like a tank. See a number of off-roaders using them.

One big caveat though, they cost $500+. One could potentially purchase & stack 4, 40a Renogy dc to dc chargers for 160a of output for $519. Of course, this would require a dedicated, high capacity alternator to provide the necessary current. I've been told Renogy doesn't recommend stacking (connecting in parallel), but I've stacked 2 of them with no issues.

Would be nice? If it only costs 20% of one that does and performs the same function, seems like nothings wrong with the picture.

S Davis wrote:
My Redarc 50amp just senses the voltage increase from the alternator and turns on, no trigger wire.

Nice to have that capability built-in. I don't understand why all dc to dc charger manufacturers don't include the equivalent of a Battery Isolator (BI) or Automatic Charging Relay (ACR) with their units. It's a basic requirement for operating a dc to dc charger in the vast majority of installations.

The 50a Redarc dc to dc charger is a nice unit, built like a tank. See a number of off-roaders using them.

One big caveat though, they cost $500+. One could potentially purchase & stack 4, 40a Renogy dc to dc chargers for 160a of output for $519. Of course, this would require a dedicated, high capacity alternator to provide the necessary current. I've been told Renogy doesn't recommend stacking (connecting in parallel), but I've stacked 2 of them with no issues.

My Redarc 50amp just senses the voltage increase from the alternator and turns on, no trigger wire.

LaneW wrote:

Grit dog wrote:
You want to connect to the opposite terminal on the ACR from the one that goes to the batteries like I said earlier. But the easy way to figure it out is check continuity of the existing wiring.

Mine has 4 awg on both the line and load terminals - and yet, the wire from the truck is only 8awg. Odd.

But I am of the understanding that I should remove the ACR completely and replace it with this MPPT/DC-DC charger. If so, I would just move the load cables from the ACR to the charger and run a new 4 or 6 awg directly from the tuck battery straight to the line, or incoming, terminal on the charger. Am I misunderstanding?

Ok yeah that’s weird as I can’t think of where the 8ga in would be spliced to a 4ga before the ACR. ACR should be first thing in line.
It’s just an automatic disconnect from the truck 12v power. ACR is just a voltage sensing relay. If it sees +13.6v or charging voltage when the truck is running, from the source it latches and provides power. If not it unhooks from the truck when the engine isn’t running.

DC DC charger could run after the ACR but ii presume they already perform that function.

Camper_Jeff_&_Kelli wrote:

Bedlam wrote:
I believe Ford is still the only one with switched power at the trailer plug.

I was just thinking, there could be a condition where you're sitting in the Truck, key on, engine off, and the DC DC charger is pumping 30 amps from the truck battery back to the TC batteries. That could be a recipe for a dead battery . . .

To prevent this from happening you can use a battery isolator (BI) which can be installed in the truck or the truck camper, or anywhere in between. Lot easier to install vs. running a trigger wire from the alternator/engine all the way to the dc to dc charger. Takes very little wire/cable to connect a BI.

The BI won't allow power to the dc to dc charger unless it senses voltage higher than 13.3v. This indicates to the BI that the alternator is active. The BI simply closes a relay that allows power to flow to the dc to dc charger. When voltage drops below 12.8v (alternator not active), it opens a relay and cuts-off power to the dc to dc charger.

You can wire the BI to cut-off primary power to the dc to dc charger input, or you use the BI to cut power on/off to the dc to dc charger's ignition trigger wire. Either way, it works in the background, seamlessly, automatically.