Charging the truck battery with solar- will a 1.5W panel do?

...I had our "heating and air conditioning blower motor resistor: service and repair blower motor resistor replacement" done by GM on our 2500HD under recall (the truck was 7.7 years old when the "no charge work" was done!). This large electrical component was under the dash on passenger side inside the cab. Word is that this component was subject to in-cab humidity, and corrosion, even though it is not directly exposed to outside weathering elements.

I can imagine older trucks having (possibly) similar vulnerable under-dash electrical components that, over a decade or two, could degrade due to in-cab humidity (ie. your floor mats are wet over many winter months over many years, then bingo, intermittent electrical issues) ?

...now that you've isolated all the components on that 30A circuit causing a parasitic draw, you just need to isolate the single component, and replace it...

Ah, I never updated my thread! Because I solved it (sorta) and forgot about it. Net positive I suppose. Two issues- batteries were knocking on heaven's door and replaced with new DuraLast Platinum AGMs. Plenty-o-volts now, no issue cranking. I'm just leaving the 7-way out unless I'm using the camper. But the main problem was a 3.5A parasitic draw coming from my convenience circuit that controls the dome lights, interior lights and radio! Pulled that 30A fuse and voila! No more trouble. I just plug the fuse in when I'm using the truck, like the 7-way. I pulled some lights and didn't see any shorts, could be the old factory radio, but after an hour of checking around I gave up and will mess with it another day.

I also threw out (saved) the 1.5W panels and replaced it within a single 10W panel on a nice 7A charge controller- it's definitely keeping the batteries topped up properly and working through the windshield.

Anyway, problem solved-ish! Truck cranks right up after sitting for weeks at a time now as it should. Thanks!

Not having an easy means to hook up 110v maintainer I've been using one of the 1.5 watt panels. $12, small enough to set on dash-My hope was just to offset normal parasitic discharge in our truck of about 110ma. Figured anything it put back good. Surprisingly it does (did) seem to help.

Plan was to get another when they go on sale as max output is about 100ma at best, however placing inside thru the windshield cuts in about half. Depends though how bright as to how much sun gets thru. Super bright sun will get about 80ma if not so bright may drop to 40ma. With 2 closer to what truck uses. It does extend the discharge time for us. At 2 weeks batts would be about 12.4 instead of 12.2.
Though OP stated a few different things and future plans, Id agree about checking parasitic drains-sounds excessive.

I just went thru mine again yesterday. Though drain more panel output batteries were dropping excessively again. This thread motivated me. Found drain was at 280ma. Not a lot but double what it should be. Easy enough pulling fuses to see which circuit-not so easy determining what to fix. Spent a good part of the day and accidentally found it. Also discovered why it seemed to be intermittent untill it became a constant problem. But a Ford thing.

Checked batteries this morning 12.6 and only charged by driving for 15 min last night. Amazing what a few milliamps can do. Played with the panel. To see what it could do or larger panel. Placing panel outside in full sun, some of aux drains off so parasitic down to about 60ma can actually see positive flow of about 15ma. So another panel maybe or single larger watt is planned.
Checking your parasitic drains would yield what you need for panel. Curious what 10 watt panel with controller you found. Size?

....several things reduce incoming solar per surface unit/surface area: the 1st is the angle of incidence of the sun (time of day; time of year) relative to your collector aperture (your solar panel); and the second is filtration (clouds; curtains; glass treatment; etc)...

You can measure this by buying an incoming solar energy meter and mounting it in various locations inside your truck (on top of your small solar collector) and data-logging (the streaming data) where you park your truck (home and work)...IMO, it would be a dubious endeavor to mount a 2, 3, 4, 5 watt mini solar collector inside your vehicle as a trickle charger, unless you are moving your parked vehicle every hour on the hour, to maximize incoming solar energy at the collector! If you have a parasitic draw (and this is in all likelihood the case, if you have dead truck battery after only 1 or 2 weeks parked!) and can't find it, use a "battery minder" of some sort every day when parked.

Off topic: some trucks (and other automobile manufacturers' various models) use steel brake lines that are very susceptible to early corrosion; so knowng this, I've always manually coated all my brake lines "from factory new", every year. I'm happy to read that your later model GMC has factory coated brake lines! Good news.

If the solar panel really is 1.5 watts and not 1.5 amps, it's basically worthless.

But you got me thinking;
Will a solar panel work through a truck's windshield? Perhaps the UV coating blocks some of the sun's energy. The only way to tell for sure is to check with a meter. Also, if the solar panel doesn't have a diode in line, the panel will DRAW power from your battery when the sun isn't shining on it.

silversand wrote:

When I bought my 03 Chevy I would not drive it for weeks at a time. When I would go to drive it the battery was dead

...our 2004.5 Silverado 2500HD OFTEN sits for 1 or 2 months after we reconstitute it from winter storage, with absolutely no issue whatsoever vis starting (no battery minder connected, and the batteries never disconnected). We've been doing this since September 2004-- almost 10 years. Our truck batteries are OEM factory, and are just about as strong today, as the day we bought the truck. I did use a battery minder one winter over the past 10 years of storage, however, the other 9 years, no supplemental trickle charge at all.

I would say that perhaps rust has played havoc with your electrical system over the years? I rust-proof every square centimeter our truck chassis (both undercoating and the engine compartment, and every linear centimeter of brake line)) twice a year, right from the hour we took delivery from the showroom new almost 10 years ago. I wouldn't replace this 10 year old Silverado even if I was given a brand new one free from GM (I go on record here with this statement).

I have 08 Silverado and the brake lines have some kind of special shiny black coating on them that must be corrosion proof,since in five years it still look shiny like new!!
..I'm guessing all newer truck have brake lines made like that,,,
I still undercoat the frame with the good old Rust Check at least once a year before winter anyway..

My 2002 GMC has a problem with the battery when it sits for a while, figured that it is the security system draining the battery. Let it go down one time and took the battery in to get it tested and they said not an issue with the battery. So I bought one of the 1.5w solar chargers and it did nothing to help. So went out and bought a trickle charge system that mounts in the engine compartment and just leave that plugged in with the TCer and it is fine now. Plus the charger will desulfate and vary the charge cycle to keep the battery in good shape. Was worth the $60.00 just to know that the truck is always ready to go.

If your battery tests out fine, you have a parasitic draw. Get an amp meter and find out what the parasitic draw is to start.

1.5W is next to nothing. If you have a battery with no parasitic draws, it might replace the natural loss of charge or at least give you a longer period before it becomes an issue.

As someone mentioned, something as small as a glovebox light might be drawing 10-15W and unlike your solar panel, it's drawing 24/7.

While a 200W panel on the camper should compensate, it's best to fix the underlying problem as it could be a sign of something else that will cause other issues if left unfixed.

With five vehicles stored all over the place, I have a lot invested in just the batteries and since it can be up to two years before I get to drive some of them, it is pretty important to keep them charged. All have reasonable amount of solar input so the house batteries are OK and I have triklstarts or equivalent to keep the engine batteries charged as well. The triklstarts feed current to the engine battery any time the house batteries are reasonably charged so even during normal camping with good solar input, the truck battery is always more charged than normal so turns the motor over faster too.
So far, so good.

Slightly off topic, latest toy is a F350 with a Bigfoot camper and I have added extra solar and house batteries and the next enhancement will be to run heavy two core cable and suitable isolators from the engine battery direct to the house batteries to eliminate the huge voltage drop involved in the current thin wiring which runs from the engine to the rear, then back to the front left of the bed and into the camper and over to the right rear of the camper to where the batteries are. Couldn't design it worse if they tried.

With an older Chevy I think the 7-pin is always connected to the batteries with no isolation. Once you get that 200w feeding the camper just leave that 7-pin in place and you should be good to go. Just verify by checking battery voltage after a few days.