I have a buddy who has a parasitic drain somewhere in his twin battery diesel f250. I've walked him through on how to trace it down, but since he only uses the truck every other week or so, I'm thinking a solar battery maintainer would be good to have. He's building a home in a rural fairly remote part of Texas and is by himself. Any suggestions for a solar tender? Can he use the 12v "cigar" receptacle? Or if he needs to connect to the battery directly, can he just connect to one of them?

 

Maybe install a Master Switch under the hood and he can just turn it off.

This is 200 AMP and at Amazon for less than $20.

 

And can be an anti theft device. Good idea thanks.

 

Please do not use one of those disconnects.. You did not specify what year, truck, or engine combination so just guessing on this fact.. Glow plugs alone draw about 80 amps before even cranking the engine so you are already near half the capacity of the switch. Those switches may be ok for a RV for main power disconnect to the house batteries but not much more.

On the question of charger or maintainer..
The batteries (if two) are in parallel so pick one battery and connect to it. You do not need to get fancy. You can consider that their is really only one big battery the way the crossover works, it is just on two sides of the truck ( simple explanation).

If you have a regular outlet the available for the truck just get a good maintainer/ de-sulfation unit like NOCO.. and put it under the hood preeminently hooked to the batteries.

If no outlet available a good solar maintainer may be the best option but do not use the cigar port. There is not system protection if you have an issue. Use a proper controller and hook to the batteries directly.

Please note that none of the options will be very effective on keeping the batteries in good condition if the parasitic draw is not properly addressed.

 

All heavy equipment uses those master switches. Graders, bulldozers, frontend loaders, etc and they have no problems. The example I gave was a bad one. You are right that you'd need one with more capacity. At any rate I would choose it over a solar panel. It might also work to simply disconnect the battery grounds and that would cost nothing.

 

The switch is more than sufficient, its rated for 200A Continuous duty, the 80-100A of 30 seconds or less of glow plugs every start won't even bug it, nor the 300A+ of the starter when you wing that over. We used them on k whoppers and freight shakers and those were way bigger power hogs and much higher continuous power flow even when running and the starters draw 4x the power. on a semi you could chase a ghost power draw for weeks, disconnect made them so they could start on their own in the spring after 3-4 months.

 

All I can add to this is I bought one of those solar chargers with the plugin to the cigar lighter for my Harley. Plugged it in, set the solar panel in the window so it would get light all day, and come spring the battery was trashed, had to spend another $180.00 on a new battery.

 

I use a harbor freight solar charger and plug into my cigar lighter for 5+ years now. No issues and batteries stay topped off. I even hid the wires in the dash between the radio and glove box. I velcro the panel on dash in front of pax seat. Works great...

 

FIRST find and fix the problem.
THEN You should NOT use 1 charger to charge 2 batteries (unless it has a 2 bank system which will have leads for each battery) A fully automatic charger will treat each battery separately and maximize its charge and maintenence. Even if you bought 2 exact batteries at the same time they will have minute differences in how the charge/discharge. That being said, if you go solar get a system that is not fully automatic you will fry them. You don't need a bunch of amps since charging time isn't really an issue. Do not just get a panel and plug it in to the power/cigarette lighter socket. It will ultimately overcharge them.

 

IT would help to know the trim level and year of truck because the newer and higher the trim level the more parasitic drain the truck will have normally.

Denny

 

I did exactly what you describe here, its rather simple, I used a 25 watt solar panel from harbor freight, the small 100 watt solar regulator, and the solar cable kit they also sell that has the aligator clips, cigarette plug, and several other bits, works great and keeps my truck at 12.8 volts even after 2 weeks, it should be plenty to keep up even two batteries, I wired mine in permanently and put the solar panel on the roof so its just always there, no need to get it down before driving off, but that part is up to the person installing it.

 

Not exactly correct - it depends upon the charge controller. If you have a properly-designed maintainer, there is absolutely no issue with connecting it to two batteries that are in parallel. So long as your maintained voltage is under the gassing voltage of the battery (roughly under 14V depending upon the ambient temperature), there won't be an issue.

 

I second this, i have solar panels on 3 of my vehicles, and they have been on there for years without issues.

My 07 GT has been sitting for 3 years now with only the occasional drive around the block to keep the tires and fluids fresh, it has been parked for 6-8 month stretches, with a small 12 x 12 solar panel sitting on it, constantly plugged into the cigarette port, no charge controller even involved, it keeps the battery at like 12.8 - 13 volts and the car has never once had a hard start when i have gone out to circulate it, instead it fires instantly almost like the battery is brand new.

My 2005 Ford Expedition 4x4, my original off-road crawler, has similarly been mostly parked with occasional jaunts to haul stuff in the cargo bay, and once to teach my father inlaw how to use a 4x4 vehicle since he never has, and told me, "oh you just flip the switch and drive right?" it has a 12 x 15 solar panel sitting on it, also with no charge controller, just plugged into the cigarette lighter, it has sat for 2-3 months stints over and over since 2019 as its a spare vehicle, and it fires instantly every time.

My 2000 Excursion has a permanently wired in 12 x 36 solar panel mounted on top of the roof rack, with a charge controller this time, its a 25 watt harbor freight panel, and 100 watt charge controller, the little orange one harbor freight also sells, and the truck stays right at 12.8-12.9 volts, turns over and starts quickly, and has also had no issues with batteries since the solar was installed on it, before the install i had battery drain issues if it was left parked more than 3-5 days, it would be a hard start or need jumped...

in short, unless you put a solar panel the size of texas on your truck, you will not do any harm to your batteries, and if you do want that super huge one, just put a regulator/controller on, and your solid.

 

that means his ECM is gonna have to relearn sensors every time he reconnects the battery…..why not fix the actual problem instead of Mickey Mouse “fixes”. Start to troubleshoot before any parts are ordered. Once the problem is found order the part.
…..now install a battery maintainer/charger.