Alternator Power to DC-DC Charger

[DesertGladiator]

After my solar on my camper struggled over the course of a few cloudy days, choice was either generator or run power off the Gladiator.

-Ran 4awg from battery to receptacle in rear bumper

-Ran 4awg from receptacle in camper to Renogy MPPT (Bluetooth and also handles solar)

-Ran 4awg from Renogy DC to DC Charger to 3 Lithium's in camper

-Create 4awg jumper wire to connect Gladiator to Camper

Results - I can charge the lithiums in about 30 minutes from a running Gladiator (240 Alternator) without having to haul an extra generator. I highly recommend this for those that off-grid camp but don't prefer noisy generators.

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[fourfa]

Any setup problems with that Renogy unit? I’m considering the same one, though a little spooked by some negative reviews

 

[DesertGladiator]

Nothing so far. My buddy has been running one of these units for the last 6 months with no issues either. Not saying they are perfect but so far so good.

 

[HooliganActual]

Any setup problems with that Renogy unit? I’m considering the same one, though a little spooked by some negative reviews

Been running mine for almost 2 years and no issues...other than I didn't buy one of the "Smart" batteries from the outset:

Love using the Renogy DC Home App too:

 

[HooliganActual]

Nothing so far. My buddy has been running one of these units for the last 6 months with no issues either. Not saying they are perfect but so far so good.

Make sure you buy a couple of spare ANL fuses. They aren't easy to find except online and I've actually blown one (not a system problem, I shorted it while removing it).

 

[WK2JT]

The high watt dc to dc chargers are game changers. Curious, what are the capacity of your lithium batteries?

 

[HooliganActual]

The high watt dc to dc chargers are game changers. Curious, what are the capacity of your lithium batteries?

Not sure who you were asking but mine is a 100aH Renogy Smart Battery.

If you are trying to make a decision for your own setup, my suggestion would be to do an energy audit on your particular use case in order to size your own.

For example: My fridge is my largest and most consistent load and it runs at around 1aH/hour; so I need 24aH capacity in a day to keep it running. I have some lights in my RTT and we may need to charge a phone here and there and we have a few other small intermittent loads, but I figured that 30aH/ day would be my typical usage. That means with a 100aH battery, I can go roughly 3 days without any charging input to the battery.

I'm retired and while we may go out for a weekend, our main use case is multi-week overlanding and that's what I built my system for. We don't tend to post up in a campsite for a week at a time, typically only a day or two. That means that we are moving every couple of days and so the DC-DC charger setup will almost always top off the battery.

But in those scenarios where we decide to make camp for a longer period of time, the 200W of solar panels do an excellent job of exceeding the demands with good sunlight. I just looked yesterday and sitting parked at the homestead, I have made 30+ aH/day for the last week in good Arizona sun.

Ultimately, you need to look at how much power you will consume and then how much and what method you will be using to recharge.

 

[DesertGladiator]

This dude knows alot more than me, good info HooliganActual

 

[WK2JT]

I was trying to quote DesertGladiator, but it didn’t quote. Great info! I have an 85ah battery with a 800w DC2DC charger, so was curious about capacity with the 30 min charge time. Mine takes a bit over an hour.

 

[HooliganActual]

This dude knows alot more than me, good info HooliganActual

BTW, love to see the Vets from AZ!!!

 

[DesertGladiator]

BTW, love to see the Vets from AZ!!!

Hell yeah thanks for your service.

 

[Limestone]

I’m A big fan of DC-DC charging as well and have a Mastervolt setup for my Gladiator (240A alternator) to Epro Mastervolt Power Package equipped trailer. At 750rpm the DC-DC system outputs around 75A and at 1000rpm 80A. I’ve been running this setup for about 2 years now, both at idle and while traveling down the road without any issues.

Does anyone know the maximum amps available for DC-DC charging from the 240A alternator? I could configure this setup to output 100A.

 

[CrazyCooter]

Wouldn't the assumption be 240Amps minus any other loads in the vehicle?

Not sure I would want to drive an alternator that hard for long, but 100A to your trailer is some serious current. Are you trying to run the A/C while underway?

What are you doing for cabling back to he RV? 175A Anderson?

 

[Limestone]

That would be the question. What are the total loads possible on the vehicle before DC-DC charging load?

The cabling is 1 Awg. The 400Ah Mastervolt battery is rated for a 120A continuous charge.

 

[Limestone]

Yes, the plugs are 175A Anderson plugs. At 80A, the battery SOC increases about 25% per hr as the available Ah is 320Ah and at 0% SOC, 80Ah remains as unusable by design.

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