How are you guys charging your house batteries off the alternator?

Hey folks, On my last rig I had a 150 amp alternator and thus the Samlex ACR-160 was a good device. I'm reading mixed things, but it seems the stock alternator is 220A on a 2017? So I would need a device capable of handling at least that many amps, even if it were just for a bit at startup, correct?

What are all you guys using?

I'd love a device that would isolate the starter, but also allow it to be topped off by the solar as well. Any ideas?

Cheers,
Alex

Which type are the batteries in the house bank? That will affect the answer

The max amps that your alternator is rated for is not directly related to the choice for charger or charging system layout. For example, a 220A alternator will be regulated to target a certain voltage, and most of the time will be putting out much less than 220A. You would not want to select a B2B charger which would overload the alternator, but in the 220A case, this is an unlikely problem. With an ACR, I think it's also a non-issue, but you want to compare your house batteries' charging parameters to your alternator voltage setpoint and make sure they are an appropriate match. With Lithium batteries, they would not be, so ACR is a bad solution. With other chemistry, it may work fine.

Sorry, I should have specified that I am not going lithium. I strongly considered it, and I would have used a DC-DC charger. This time I am going AGM. Perhaps 3 pairs of 6v 225AH batteries.

Withalligators said:

Sorry, I should have specified that I am going lithium. I strongly considered it, and I would have used a DC-DC charger. This time I am going AGM. Perhaps 3 pairs of 6v 225AH batteries.

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Are you using Lithium or AGM , your post contradicts itself

Haha, it was late and I was on my phone. I am NOT going lithium. I will edit the post to make sense. Sorry.

Planning to use Blue Sea 7622 ACR. It has a lot of functionality and goes up to 500 amps so no problem with alternator.

http://shop.pkys.com/Blue-Sea-7622-ML-Series-500-Amp-12-Volt-ACR_p_1670.html

I will connect it to a Lifeline 12v 255Ah GPL-8DL

mbsprinter144 said:

Planning to use Blue Sea 7622 ACR. It has a lot of functionality and goes up to 500 amps so no problem with alternator.

http://shop.pkys.com/Blue-Sea-7622-ML-Series-500-Amp-12-Volt-ACR_p_1670.html

I will connect it to a Lifeline 12v 255Ah GPL-8DL

Click to expand...

Interesting. Will this allow current back towards the starter to allow the solar to top it off?

I have the SI-ACR which I believe is rated 120 continuous amps and 210 amps for several minutes. This is plenty adequate for most. It will charge both ways, it doesn't matter which side you hook up to what battery. So solar will charge the start battery. But if you're talking 6 batteries at 675 AH at 12 volts, there may be some significant charging amps that may warrant the larger relay.

Si-acr is more than enough for the factory alternator.

I'm looking at finally adding this to my build also. I have a 2014 2500 Sprinter high roof. 3x100W renogy panels in parallel, with 2 x Lifeline GPL-30HT (12v 150Ah) batteries in parallel for a total of 300Ah. Would the Blue Sea SI-ACR be sufficient for my needs? What about the Batterlink ACR? Or would I need something with higher amperage rating like the Samlex ACR-160? Any help would be much appreciated!

The SI-ACR is rated at 120 amps continuous and 210 amps for 5 min and some sort of sliding scale depending on conditions between those numbers. Being a marine product, I'm guessing that rating is for an enclosed engine space with high temps. If you were ever to get 120+ amps, it likely would be for a short period and taper to something much less fairly quickly. I'm sure either would suit just fine though.