Solar charging a dual batt setup?

4Roamer

Member
I already have a solar panel and a portable 12v deep cycle battery. I'm about to pull the trigger on a National Luna split charging system, so I can mount the battery in the truck. I want to install an Anderson plug in the grill so I can have a clean hookup for the solar power. The question is, should I hook it to the starter battery? If I hook the solar to the starter battery, once that one is charged, will the Split charger allow the extra juice to charge the 2nd battery? I use a 400w inverter, lights, ham radio gear and other misc 12v gear. I am also planning to get a fridge soon.

http://www.equipt1.com/item/12V-split-charger-system-surface-mount - proposed isolator
 

SameGuy

Observer
While I'm sure that National Luna system is a nice piece of kit that's a LOT of scratch for a solenoid, some wire and battery meter. You could build yourself a nicer system for half the price with some welding wire off ebay and a fancy Blue Sea ACR (automatic Charging Relay) some terminals and a cheap cigarette plug voltage meter. To your original question: you could attach the solar to the starter battery, like you say and top it off before you charge the second battery, but I don't really see the point in this. Your alternator should charge your starting battery just fine. IT will also charge your second battery through the isolator / splitter / ACR. I would cut out the middle man (starting battery) and hook the solar to the second battery. Then when it is topped off, it will go through the isolator / splitter / ACR to top off your starting battery. There is a really great thread in this section of the forum about How to make a cheap isolated dual-battery setup for $50. It is long but chock full of fantastic information. Grab a beer and read the whole thing. Every question you can think of has been answered in it. [h=2]http://forum.expeditionportal.com/threads/77503-How-to-make-a-cheap-isolated-dual-battery-setup-for-50[/h]
 

john61ct

Adventurer
Ideally all significant charge sources get wired to the House bank, starter needs f-all.

Blue Sea ML series ACR is the one if you're spending money, but wait.

First get the House batt in place, heavy enough wires so not too much voltage drop from any charge sources, confirm with accurate DMM.

Because of it turns out you want a DCDC charger, you won't need the VSR.
 

coolfeet

Mark Keeler
Before you drop the cash on the National Luna, take a look at the CTEK D250S dual battery isolator. It's pricey-$250 US but works as a dual battery isolator and MPPT solar charge controller. CTEK recently sent me a new unit to replace my first faulty unit which I believe never worked properly. I connected it this week to my house battery with a 160 watt solar panel. I parked in partial shade for 46 hours and it kept the battery maintained. Never dropped below about 12.58 volts. When it finishes charging the house battery, it charges the my starting batteries (when connected to solar).

I think it's a fine unit for the price. Easy to install.BatteryBox.jpg
 

Bbasso

Expedition Leader
Blueseas 7622 has very little draw and has been performing flawlessly for me over two years.
I'd recommend it.
 

jeffjeeptj

Adventurer
Put the anderson connector for the solar electrically on the 2nd battery side of the acr. Just use some 1/0 or larger cable to connect the batts and the acr. I also use and recommend a blue sea 7622 like many others for separation/connection purposes. I have read too many reliability comments about the natluna and i had a lower cost victron acr fail way too soon in the sequoia. I have used a manual continous duty solenoid in a different vehicle, but the latched amp draw compared to the 7622 was too high for this installation containing solar.

I have a "split" dual batt system. I use a #31 agm odyssey for a starting batt and power for a fridge in the sequoia. it will go 2 or 3 days before i get worried about the charge level in the sequoia. I do check it every morning with a known good dmm. I put a 7622 near that batt, then ran 1/0 cables to the rear bumper with an anderson sb350 connector. The trailer has a mating sb350, then more 1/0 to an odyssey pc2250 batt with a bogart batt monitor. Trailer has an iota 55 amp charger, if hooked to shore power. I had some older but never used solar. 160 watts (2 panels) and a blue sky mppt controller. The solar stuff got mounted to the trailer. The system works as it should with either the alternator in the sequoia or any of the charging sources triggering the 7622 when the two vehicles are connected by the anderson. There is less than 0.1 volt difference between the batt voltages when solar charging both sequoia and the trailer. Batt temp monitor is in the trailer.
The fridge in the sequoia is due to space constraints in the trailer. Also, id rather a bear visit the car with a fridge inside than the trailer with me and wife inside. cooking and other food activities are placed well away from either vehicle. Bear spray and other bear repellant is always in the same location as the humans.
I do have an anderson sb175 thru the grill for a front portable winch. Will be converting to the sb350 so the winch can go at either end of the sequoia.
 
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