Opinions on 400W Alternator Charging Blueprint

[bajajoaquin]

I have a 24' Class C with a factory 4x4 option, so I can go to remote places. I also camp in the US. This gives me two distinct, but three separate use cases:

1. Baja California. I camp in remote beaches with fairly good sun, but sometimes bright overcast. There is never any way to plug in. I don't want to run a generator, because the point is to get away.
2a. Pacific Coast Traveling. We go to Washington, Oregon, and Northern California staying in state and county parks as we go, that typically have no hookups. I want to be able to last a couple/few days without much sun or hookups and be able to recharge a bit on the 4-5 hours to the next place.
2b. Pacific Coast Traveling. Sometimes we stay with friends or the kids get their way and we stay at a KOA with power. Maybe one night on a long trip. I want to be able to charge to top-off without damaging any batteries.

I mentioned in a question about starter draw that I'm all but set on Will's 400W Solar with Alternator Charging blueprint. https://www.mobile-solarpower.com/simplified-400-watt-fewer-wires-and-alternator-charging.html I'm going to add an AC to DC charger to the plan, and then it addresses all three of my use cases. I have bought a 206AH SOK battery already, but have yet to buy the solar equipment.

I know this is Will's forum, so I'm not looking to be a naysayer, but are there any other opinions or comments on this setup? Any alternatives to the equipment he suggests? Any suggestions on an AC to DC charger?

 

[MisterSandals]

I would look for big cheap solar panels on Craigslist and max out that space.
Get a very good SCC, it’s the heart and brains of what could be most of your charging.
If you provide your location, maybe someone can chime in with local deals. $.50 per watt for big heap panels is easy.

 

[bajajoaquin]

I would look for big cheap solar panels on Craigslist and max out that space.
Get a very good SCC, it’s the heart and brains of what could be most of your charging.
If you provide your location, maybe someone can chime in with local deals. $.50 per watt for big heap panels is easy.

That’s great advice. I’m in San Diego.

 

[NVS]

If you don't want to spend the big $$$. You can use a power supply like this and tie it into the supply side of your dc to dc charger. Using a single pole double throw relay (SPDT). Co,ect the power supply to the NC side and alternator to NO side. With relay coil hooked up to ignition. I would oversize the power supply.. you didn't say what size dc to dc charger you bought. I bought the Renogy 40a dc to dc charger and the 50a power supply. I've been using this to bench test lifepo4 batteries. The 40a dc to dc charger pulls around 42amps from the power supply. And the power supply does get pretty warm to touch. So make sure it is vented an extra fan would help too.

 

[NVS]

If you don't want to spend the big $$$. You can use a power supply like this and tie it into the supply side of your dc to dc charger. Using a single pole double throw relay (SPDT). Co,ect the power supply to the NC side and alternator to NO side. With relay coil hooked up to ignition. I would oversize the power supply.. you didn't say what size dc to dc charger you bought. I bought the Renogy 40a dc to dc charger and the 50a power supply. I've been using this to bench test lifepo4 batteries. The 40a dc to dc charger pulls around 42amps from the power supply. And the power supply does get pretty warm to touch. So make sure it is vented an extra fan would help too.

Sorry here's the link to power supply.

DC 12V 1A to 50A Amp AC 110V 220V Switch Power Supply LED Strip Light 12 V Volt | eBay

Out put: DC 12V. This is a perfect choice to use as a LED Driver for all type of LED lighting 3. without flickering light & ensue the life span of your LED. GND: DC power output "-". V: DC power output "+".

www.ebay.com

Link to a relay.

IRHAPSODY 12V Continuous Duty Relay, 5-pin SPDT 250 Amp High Power On/Off Starter Relay, Split Charger Contactor for Truck Boat Marine Van Golf Carts https://smile.amazon.com/dp/B08F2G1...abc_9E1V9EQA74RRQS127QQN?_encoding=UTF8&psc=1

 

[bajajoaquin]

I guess I don’t understand. Supposedly the advantage of that dc to dc controller is that it can manage the alternator charging as well as the solar charging, while isolating my truck battery from my house battery.

Is that not correct?
What does that relay add to the equation?

 

[NVS]

The dc to dc charger is for the alternator. You will still need a solar controller for your panels.
The relay just makes it so you can use the dc to dc charger with its lifepo4 settings to provide proper charge voltage from alternator and the power supply while keeping them separate and not back feeding the other.

 

[MisterSandals]

You'll have to play Tetris on your roof but these look like a good candidate if they fit: (250W for $79)

solar panels -250 watt for Rv or off grid - electronics - by owner -...

USED 250 WATT POLYCRYSTALINE SOLAR PANELS IN GOOD CONDITION. UPGRADED TO LARGER PANELS AND PRICED TO MOVE SO WILL GO FAST. Have over 20. WE CAN MEET AT 7-11 STORE OFF THE 67 FRWY AND RIVERFORD EXIT....

sandiego.craigslist.org

 

[bajajoaquin]

The dc to dc charger is for the alternator. You will still need a solar controller for your panels.
The relay just makes it so you can use the dc to dc charger with its lifepo4 settings to provide proper charge voltage from alternator and the power supply while keeping them separate and not back feeding the other.

Thanks.

The charger in that blueprint is specifically designed to handle both solar charging and alternator charging, isn’t it? Renogy DC to DC MPPT

Or am I missing something? I thought I was giving up panels in series to get a charger that can manage DC from to inputs. If not, I’ll choose a different setup. The goal is to isolate the truck battery and still charge house batteries from the alternator.

 

[bajajoaquin]

You'll have to play Tetris on your roof but these look like a good candidate if they fit: (250W for $79)

solar panels -250 watt for Rv or off grid - electronics - by owner -...

USED 250 WATT POLYCRYSTALINE SOLAR PANELS IN GOOD CONDITION. UPGRADED TO LARGER PANELS AND PRICED TO MOVE SO WILL GO FAST. Have over 20. WE CAN MEET AT 7-11 STORE OFF THE 67 FRWY AND RIVERFORD EXIT....

sandiego.craigslist.org

Thank you. If I need to buy a different controller because of alternator charging requirements, I’ll get a solar controller that can handle the volts. The Reonogy controller in the blueprint is limited on input volts.

It’s a class c, so there’s a lot of room on the roof.

 

[MisterSandals]

The Reonogy controller in the blueprint is limited on input volts.

It really a weak solution, especially if you intend to put any amount of solar on the roof. I strongly recommend getting a dedicated (aka real) DC-DC charger and SCC. If you look at how limited every aspect of that Renogy and look at what you're proposing, its significantly undersized before you get started.

 

[bajajoaquin]

I was just writing up that I was reconsidering using that controller, thanks. It's only about $40 cheaper than buying two separate controllers, and as you say, it's kind of limiting. If I use a separate charge controller, I can run panels in series, raising my voltage, and probably saving that money on wiring alone.

Any opinions on what my AC-DC charger should be? I've got a 4kw genset, 30a shore power feeding a SOK 206ah battery. I think that implies a max 100a charger, right? I was thinking something smaller in the 50a range, since rapid charging really isn't a major use factor for me.

 

[MisterSandals]

Any opinions on what my AC-DC charger should be?

As you stated in your OP, AC-DC charging is 3rd on your list of scenarios. So if it were me, I'd maximize solar first. You'd be amazed at how much power you can produce with your rig in the sun all day. Next, i'd maximize DC-DC based on what your alternator and driving style allows you.

After that, I'd be looking at how much you need from AC. I only have 330W on the roof and AC charging isn't even on my list of needs.