Battery Maintainer - Good/Bad/Ugly?

[oldyellr]

First, I'd hook an ammeter in series with the battery to determine what the parasitic draw of the GPS locator was. I'm surprised that it would be enough to kill the battery in just a few weeks. The parasitic draw is cars to maintain the computer and radio presets isn't enough to kill the battery, so there may be other problems. Nevertheless, if that's what's doing it and it's normal, you need a battery maintainer that will keep up with the drain. Sure, you can get a $10 1 amp trickle charger or equivalent solar charger, but if you leave it can overcharge and boil your battery if left on too long. The Battery Tender Plus will charge 1.25 amps max and the Battery Tender Jr. will charge 0.75 amps. Either one will handle any expected parasitic draw. If a trickle charger or solar charger kills your battery you could be out $200.

 

[Snowback]

Alright - I settled on a very well reviewed 10W solar unit from and outfit called Micro Solar. Picked it up on Amazon and delivered in two days. It appears to be well built and sealed nicely. Installation was very easy with only four screws and a hole for the cable to run into the shed. (It's a nice 16.4' long which is handy...) My unit has adjustable mounts unlike the picture in the listing. I like the ones I received better.

I have included a couple pics of the install and the spec sheets below. It comes with everything you need out of the box including a controller built into the lighter plug. You can use the supplied alligator clips, but I picked up a Delton kit to permanently mount a pigtail plug to the battery, and also a Delton adapter to use that plug and then mate with the supplied controller's male lighter receptacle. 15 minutes to install and all the lights flashed the right sequences when connecting controller to battery first, and then to the panel. I'll update if anything goes sideways with the product.

Here are the items I picked up:
Main Solar panel and standard kit: https://amazon.com/gp/product/B00EB3OC9W/ref=oh_aui_detailpage_o04_s01?ie=UTF8&psc=1
Permanent battery mount: https://amazon.com/gp/product/B000NCOKZQ/ref=oh_aui_detailpage_o04_s01?ie=UTF8&psc=1
Quick connect adapter: https://amazon.com/gp/product/B0041CDPQO/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1


South facing - will need to adjust down for winter angle.
Goes from zero degrees, (horizontal), down to angle of shed roof which is about 65 degrees. Houston winter angle of 45 degrees should be fine...

Small hole to fit cable with connector through into shed. That cable there is over 16' long. Only four screws, a hole, some clear drying silicone sealant, and it was done...
(Also connection of quick adapter to battery.) All the flashing lights checked out and it started taking a charge even with sun setting and cloudy skies.

 

[JRobyn]

I use a panel just like that on my solar gate operator. I had to fab my own mount out of perforated angle iron and designed it so that I could easily adjust its seasonal angle by just moving 1/4-20 screws in the perf'd holes. I found after the first season that it really didn't make a substantial difference in voltage output to align it precisely so I just leave it "in the middle" now. Mine has no regulation built in (regulation is in the gate operator control panel) and it will output as much as 17-19vdc in full sun.

It really surprised me just how well it performs, especially in the summer when it gets shaded and filtered light through the tree canopy. It is evident to me that these panels perform well with just LIGHT. It does NOT need to be direct sunlight right on the panel. I'm sure that direct sunlight is good for absolute maximum performance, but just not necessary in many applications.

 

[Fallon]

Shading 25% of a solar panel can easily result in a 75% or more drop in power output. Some panel types are more sensitive than others.

Not that big of a deal for a battery tender as their requirement are minimal & spread out over a long time.

 

[silvertramp]

True. I've had my Battery Tender for a long, long time. No issues. A minimal investment for sure.

 

[JRobyn]

Shading 25% of a solar panel can easily result in a 75% or more drop in power output. Some panel types are more sensitive than others.

Not that big of a deal for a battery tender as their requirement are minimal & spread out over a long time.

See figure 8.

http://docs-europe.electrocomponents.com/webdocs/001b/0900766b8001b744.pdf

This is from over 10 years ago, for a polycrystaline panel. Performance has improved.

"The important characteristic that makes them so suitable for supplying electrical power is that the voltage builds up quickly to a reliable plateau at very low light levels (about 8% of peak intensity). This means that voltages suitable for battery charging are reached even on a dull day."

 

[Snowback]

See figure 8.

http://docs-europe.electrocomponents.com/webdocs/001b/0900766b8001b744.pdf

This is from over 10 years ago, for a polycrystaline panel. Performance has improved.

"The important characteristic that makes them so suitable for supplying electrical power is that the voltage builds up quickly to a reliable plateau at very low light levels (about 8% of peak intensity). This means that voltages suitable for battery charging are reached even on a dull day."

Thanks for the feedback and info on optimum panel angles and efficiency. I'm hoping this setup works out well. All I need to do is offset a small parasitic draw from a GPS module, and that is only a major issue when the tractor sits for more than a few weeks.

 

[varmint]

I was going to mention snow accumulation shutting down your charger, but then I see you are in Houston. Oughta be okay.
I have several of the cheapo HF trickle maintainers, which seem to work fine, but I don't leave them on constantly- just a couple days or so every now and then when I haven't run the equipment. Maybe I should check out the more sophisticated maintainers...

 

[Fallon]

The current theory on pannel is dollars per watt. Monocrystaline vs polycrystalline doesn't matter, just go for the cheapest one in terms of dollars per watt.

That's for household roof installs at least where size doesn't matter to much & there generally aren't shading issues. Not that it's as relevant to a battery tender install.

 

[Snowback]

I was going to mention snow accumulation shutting down your charger, but then I see you are in Houston. Oughta be okay.
I have several of the cheapo HF trickle maintainers, which seem to work fine, but I don't leave them on constantly- just a couple days or so every now and then when I haven't run the equipment. Maybe I should check out the more sophisticated maintainers...

Sorry about that... My handle is a little misleading as I am originally from Northern Canada - also I am a legal immigrant, so I'm taking liberties there.

I had not thought hard about the type of usage, but planned to just leave it hooked up and let the controller do its thing. My assumption is that if the controller fails, it will fail closed and stop sending a charge. A little bit of a learning curve here I suppose.