Solar trickle charging

[rd_macgregor]

It is a long extension cord reach to my tractor parking spot, so isn't convenient to keep a battery maintainer hooked up through the winter. I was wondering about putting a 12V solar cell array in the tractor window to trickle-charge the battery. Would this likely do any good (assuming the sun hits the cell for several hours per day)? Would there be much risk of overcharging the battery with a small solar array (2 to 3 W) directly connected to the battery?
Thanks,
Bob

 

[Travelover]

The price of solar panels has really come down. You can get a 10 watt like this one, for instance, for $17 plus shipping. Solar Cell, Solar Panel, Solar PV, Solar Products, Charge Controllers, Solar Trackers


Add a cheap controller like this........: CMP Solar Panel Charge Controller Regulator 10A 12V 24V | eBay

..........and you can charge and maintain a fairly large battery. A smaller panel would not need a controller, just a blocking diode.

 

[k0ua]

It is a long extension cord reach to my tractor parking spot, so isn't convenient to keep a battery maintainer hooked up through the winter. I was wondering about putting a 12V solar cell array in the tractor window to trickle-charge the battery. Would this likely do any good (assuming the sun hits the cell for several hours per day)? Would there be much risk of overcharging the battery with a small solar array (2 to 3 W) directly connected to the battery?
Thanks,
Bob

They seem to be fine Bob. I don't have one on my tractor as I use it often enough to not seem to need it, but I have one on my lawn mower, and it keeps the battery up all winter. Doesnt seem to boil the battery. I use one of the 1 watt solar chargers made just for this purpose. Like this one. It just maintains the battery from discharging from disuse. It would take forever to charge up a discharged battery.

Amazon.com: Sunforce 50013 1-Watt Motorcycle and Powersports Solar Battery Charger: Automotive

 

[Soundguy]

HF even sells a 9$ one.... I have used them for years on seldom used equipment.

fights parasitic drain... though I wouldn't charge a deader...

 

[k0ua]

HF even sells a 9$ one.... I have used them for years on seldom used equipment.

fights parasitic drain... though I wouldn't charge a deader...

Come to think of it, I think mine was from "the freight" too.!

 

[Soundguy]

hard to find cheaper these days. and as hard as it sounds.. their quality is on par with other american retailers that charge more... for similar import items..

 

[rd_macgregor]

Thanks, all. I have a unit a lot like the one K0ua linked to. I found its output wasn't enough to keep up with an electric fence energizer, but it might work to keep my tractor battery going in the winter when it sits for a week or two (in the cold!) between snowstorms.
I'm thinking of installing a cigarette lighter outlet connected directly to the battery (ie, not through the ignition switch), so I can easily plug the solar charger up inside the cab...I think I saw a post by another TBNer a few months back who had done something similar.
My original battery lasted 7 yrs, but just won't hold a charge through this winter's cold; I want to take good care of the replacement.

Bob

 

[k0ua]

Thanks, all. I have a unit a lot like the one K0ua linked to. I found its output wasn't enough to keep up with an electric fence energizer, but it might work to keep my tractor battery going in the winter when it sits for a week or two (in the cold!) between snowstorms.
I'm thinking of installing a cigarette lighter outlet connected directly to the battery (ie, not through the ignition switch), so I can easily plug the solar charger up inside the cab...I think I saw a post by another TBNer a few months back who had done something similar.
My original battery lasted 7 yrs, but just won't hold a charge through this winter's cold; I want to take good care of the replacement.

Bob

yep, the one I linked to is just a Maintainer, and does not have any charge controller in it. If you need to keep up with some usage you will need a much larger panel and a charge controller to keep the voltage where you need it.

James K0UA

 

[RalphVa]

I've a 5 watt "Mule Gate" solar panel that I bought long ago @ TSC and wired through a battery tender that I bought on line that I use to keep the battery up on my electric fence.

Been thinking about replacing the powered battery tender on my generator with a solar one. TSC has them all in one, panel plus tender. Actually, you can get away with connecting the panel directly to the battery. I did this for about 10 years when I had the electric fence on the garden down by the creek. The little utility batteries last 2+ years then instead of just 1 year, letting them run down and recharging.

Ralph

 

[Soundguy]

for those not wanting to install a cig lighter adapter.. you can get a clip on style from radio shack.

it's a power socket like a gig lighter, with 2 hd gator clips and 6" of line.

clip right to battery and plug in accy's there.

I have them on a few machines for air pumps or similar..

 

[moeh1]

The HF little solar charger actually comes with the alligator clips too.

 

[LindenBruce]

I have this one on my F250 PSD and it's not enough. Both batteries are to weak to start the truck if it sits for more than three weeks. For one battery it may work just fine. But two on a diesel it's not enough. B.

1.5 Watt Solar Battery Charger

 

[94BULLITT]

I have this one on my F250 PSD and it's not enough. Both batteries are to weak to start the truck if it sits for more than three weeks. For one battery it may work just fine. But two on a diesel it's not enough. B.

1.5 Watt Solar Battery Charger

I have two 2 watt solar panels and a 5 watt and neither is enough to keep the battery up on a car or truck with one battery. I am sure they help some but not enough. The 2 watts put out 100-130mA and the 5 watt puts out 350mA. I have the 5 watt on the BX now. It will bring the battery up from 12.59 to 12.62.

 

[Jkott]

What do you have for parasitic drain on them? Just internal battery loss, or do you leave anything plugged in?

It doesn't take much to add up. 1 watt is about 0.083 amp hours. In a day that 2 amps. Three weeks is 40 amps, or over half your normal 60-80 ah*hr auto battery.

I know my garmin gps in my truck, just plugged in but "off" and attempting charge the internal battery can drain nearly a half amp an hour. It can kill both my truck batteries in 5 days if it's below zero.

If you have an old tractor with no electronics plugged in, and no computer or circuits that stay powered on with the key off, a small charger should keep up.

 

[mikehaugen]

Back around y2k I worked for a trailer manufacturer. They had what I thought was an ingenious idea (at the time it wasn't as common) where they had aluminum battery boxes, with a cast aluminum top on them. They built a solar panel into the cover of the battery box to maintain the battery. The batteries where only there for the emergeny break-away for the trailer brakes and I imagined they worked great. The panel was only as big as the top of the battery (maybe 6"x10") and had no controller- it was wired straight to the battery. Some day I will do this for my trailer.

 

[Soundguy]

i agree.. for a truck wit 2 bats.. like that PSD.. there must be some POWERFULL drain for it to die that soon WITH a solar charger even...

What do you have for parasitic drain on them? Just internal battery loss, or do you leave anything plugged in?

It doesn't take much to add up. 1 watt is about 0.083 amp hours. In a day that 2 amps. Three weeks is 40 amps, or over half your normal 60-80 ah*hr auto battery.

I know my garmin gps in my truck, just plugged in but "off" and attempting charge the internal battery can drain nearly a half amp an hour. It can kill both my truck batteries in 5 days if it's below zero.

If you have an old tractor with no electronics plugged in, and no computer or circuits that stay powered on with the key off, a small charger should keep up.

 

[k0ua]

Back around y2k I worked for a trailer manufacturer. They had what I thought was an ingenious idea (at the time it wasn't as common) where they had aluminum battery boxes, with a cast aluminum top on them. They built a solar panel into the cover of the battery box to maintain the battery. The batteries where only there for the emergeny break-away for the trailer brakes and I imagined they worked great. The panel was only as big as the top of the battery (maybe 6"x10") and had no controller- it was wired straight to the battery. Some day I will do this for my trailer.

That IS s good idea

 

[LindenBruce]

Thanks for the input guys. Nothing is plugged in or left turned on. The only draw on the batteries is what Ford has for electronics. The batteries are two years old and both were bought at the same time. They are AC Delco 875 CCA batteries. So, I guess I will have to step up to a 5w solar panel? Hopefully that will keep the batteries topped off. B.

 

[k0ua]

Thanks for the input guys. Nothing is plugged in or left turned on. The only draw on the batteries is what Ford has for electronics. The batteries are two years old and both were bought at the same time. They are AC Delco 875 CCA batteries. So, I guess I will have to step up to a 5w solar panel? Hopefully that will keep the batteries topped off. B.

That 5 watt probably won't be a problem with 2 large batteries and the "parasitic" load of the trucks electronics. but what I would do is monitor the voltage for a few days and make sure it does not crawl up above 14 volts or so. You would not want to cook your batteries. I doubt the 5 watt panel will, but I would still look at it with a good digital voltmeter.

James K0UA

 

[94BULLITT]

Thanks for the input guys. Nothing is plugged in or left turned on. The only draw on the batteries is what Ford has for electronics. The batteries are two years old and both were bought at the same time. They are AC Delco 875 CCA batteries. So, I guess I will have to step up to a 5w solar panel? Hopefully that will keep the batteries topped off. B.

You could still have something draining your battery, a radio, glove box light or a module.