Dual battery, solar trickle charger for both? (1 Viewer)

[Randy88FJ62]

I have a blue sea 7622 ACR dual battery setup. I don't drive it often so I want to keep the batteries charged.

I want to mount a permanent solar panel on the roof and some sort of controller setup? I don't know enough to do this with a dual battery setup.

Where do I start with this? Who has a solar trickle charger setup for dual batteries? Worst case I mount two small solar panels and two separate controllers so they both charge independently.

 

[cruiserpilot]

Go down the page on the forum and look for POWER SYSTEMS

 

[OSS]

Since you mentioned mounting a panel permanently to the roof, I assume you've got a full length roof rack. There's lots of solar trickle chargers for cheap on Amazon (12-15 watts) and most of them come with an integrated controller- just connect them & you're done.

If you want a solar panel that can actually charge a low battery, none of those cheap solar battery maintainers have enough juice. They're only for preventing a discharge (usually from a <100mA parasitic drain.

If you mount a larger "real" panel on the roof, there's always the risk of it getting stolen. Not insignificant unless it's mounted with tamper-proof fastners.

If you want to maintain charge both batteries, it's fine to connect them in parallel. They'll both stay at the proper float voltage.

If you don't get one of those small battery maintainers that have a built in controller, buy a 3 stage controller that has a Float function so it will keep the batteries at a lower float charge - usually around 13.3V.

You only need one panel and one controller. Keep the batteries connected in parallel while they're hooked up to the solar charger

 

[Taylorious]

Literally going through this right now.
Identical 'heart' as yours (ML-ACR 7622) which I'm just finishing installing.

...based on what I understand about the system... you'd want to have the Solar Charge Controller plugged onto either battery (probably the aux/house) and then the ACR in 'combined' mode (ratchet handle left, punched in) and the trickle solar voltage would bleed across both batteries.

(This would be the same as alternator charging, albeit charge is coming from the 'aux/house' as opposed to the 'start/main')

The only question I still have is if you want the ML-ACR's other wires (green or orange) put into the Solar Charge Controller to identify the incoming charge and therein link the batteries.

 

[Randy88FJ62]

The batteries I have are not identical. One is standard style battery and other is an AGM Gel.

I don't think linking them in parallel would be a good idea.

The though the charging through the ACR is an interesting idea.

Regarding theft, I don't feel like my truck would have that issue given where it is parked daily. The goal would be to buy a solar panel capable of real charging, not just trickle charging.

 

[OSS]

Yes a wet cell lead acid battery has a slightly lower resting voltage than an AGM, so yes, over night the AGM would trickle a little current over to the lead acid battery. But the next day they'd equalize when the sun came up. After trying lots of different dual battery setups in my old 60 over the years, the conclusion I came to was it was best to have both batteries identical. But when I had one AGM and one wet cell, I never ran into any problems when camping years in Mexico with a solar panel.

Since your 62 is draining the starting battery due to parasitic drain from the ECU, it's the only battery that needs a trickle charge. The other AGM can sit for 6 months and be fine since nothing is sucking its juice

 

[Randy88FJ62]

My main is the AGM Gel and the secondary is a lead acid I got for free which was the largest battery I could literally fit in the bay. I had a little trimming of the second battery tray base to fit it.

My Ideal setup would be two gels but that's a bit $$$ to bite off given the current economy.

 

[Cruzerman]

Is a battery tender an option? They work well. Also, I have a much simpler setup with an A, B, Both, or None mechanical switch. When I'm not using my rig for months, I just put it to None and thus neither battery is connected to anything. Leaving things connected will cause the battery to be drawn down due to small loads for extended periods but they hold up well when not connected to anything. Perhaps just disconnect one of the battery cables on each battery when not going to use for a long time?

 

[OSS]

Don't disconnect the main starting battery from the ECU on the 3F-E (which is what's causing the parasitic drain). If the power gets disconnected, the computer loses its memory and has to re-learn everything all over again. That takes a while.
On more modern engines (and maybe the 3FE) the engine will fail a smog test if the battery was disconnected then reconnected before the test without driving several hundred miles before hand for the sensors to get into ready state.

 

[Randy88FJ62]

I'm looking at the cost of good controllers and they are more expensive than buying two battery tenders for the dual batteries. I may go down that road for the short term.

 

[MANUCHAO]

may go down that road for the short term.

i said the same thing...."short term".... it's been 8 years now on battery tender while parked at home.... I'll do solar one day soon.....

 

[87CRUSR]

Don't disconnect the main starting battery from the ECU on the 3F-E (which is what's causing the parasitic drain). If the power gets disconnected, the computer loses its memory and has to re-learn everything all over again. That takes a while.
On more modern engines (and maybe the 3FE) the engine will fail a smog test if the battery was disconnected then reconnected before the test without driving several hundred miles before hand for the sensors to get into ready state.

My buddy recently had this issue on his ‘15 Taco. Had to drive it for 50 miles or so in order to get the system to reset just so he could pass the smog test.