Solar battery maintainers

[Gfrost]

As some of you know, I have a cabin in alaska that we plan on using mainly only in the summer and for maybe a month total.
We will also have a vehicle and boat stored there.

I am considering getting a couple of those small solar maintainers to attach to each battery and attached to the window or side of the boat to keep the batteries some what charged. I understand that which ever one I decide to get that it have a diode restricting backflow and that it won't over charge to battery.

This particular one was recommended on one of the boat sites

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Do any of you have any experience with these little guys

 

[timselectric]

I've used a few (not that particular brand) , and they worked pretty well.

 

[Gfrost]

Did you leave it connected for a long period of time,11 months??

 

[Rednecktek]

I wouldn't expect anything rated at 8w to do jack squat in Alaska. Your sunlight is gonna get you about half that output and 4w is only 330mA. Your batteries can cold discharge more than that in a day.

I can't imagine anything smaller than a 25-30w can deal with the low sun and cold.

 

[mountkay]

I was surprised when I got one of these and it started to overcharge my battery. I had an old PWM SCC so I wired that in to stop it from overcharging.

It’s wired from the SCC into a fuse splitter that is connected to the Brake Light fuse. Gotta wire it into a circuit that will have power even when the key is not in.

I wired a switch in there as well, but I wish I put it so that I could shut off the SCC too. Not sure how much it draws, but in the winter sometimes I feel like it’s not worth having it.

You could do something similar, maybe with a larger 100w panel and an easy way to disconnect it when you are in town as actually using the vehicle.

100w panel can be cheap and those charge controllers are less than $20.

Just make sure the terminals are tight, I have had a few that loosened up over time.

 

[Rednecktek]

I've done similar with SAE plugs connected right to the battery on my motorcycle and riding mower. I have a small system (100w panel, PWM, 14Ah agm) and I connect the SAE to the Load ports so it doesn't kill the battery.

Works great in theory, not in reality due to clouds/rain. The standby draw of the SCC and cold drain the battery faster than the panel can recharge it. ?

 

[dirt diggler]

As some of you know, I have a cabin in alaska that we plan on using mainly only in the summer and for maybe a month total.
We will also have a vehicle and boat stored there.

I am considering getting a couple of those small solar maintainers to attach to each battery and attached to the window or side of the boat to keep the batteries some what charged. I understand that which ever one I decide to get that it have a diode restricting backflow and that it won't over charge to battery.

This particular one was recommended on one of the boat sites

Ford Transit USA Forum

A forum community dedicated to Ford Transit owners and enthusiasts. Come join the discussion about performance, modifications, troubleshooting, storage capacity, maintenance, and more!

www.fordtransitusaforum.com

Do any of you have any experience with these little guys

I have a few of these on 4 of my vehicals BUT i allways park facing south and i stick them to the screen to get a better angle on the sun (UK, London), they have been fine for the odd week/s when i don't drive the particular vehical but on my camper i ended up with a roof (flat) mounted 30W panel and a PWM controler (renogy £39 kit) that kept my chassis battery topped up for 6 months with no starting and it spun over like a champ when i finaly got round to starting it, checking the chassis bat voltage it was around 13.6V every day over winter, whereas the dash 20W ones struggled to get the battery over 13V on the same day/time of day, if that helps at all ?

 

[Vigo]

Before i had my entire house running on solar i had about a dozen 'solar maintainers' on various vehicles. I used the cheapest thing i could find with leads already on it which was usually $13-15 5w panels from Amazon.

In my case it worked fine as far as power because of where i live. The issues i actually ran into were related to wind gusts sending them flying and ripping the leads off. I tried to stick them under windshield wipers to prevent this, but it wasn't a guarantee i wouldn't sometimes find one hanging off the side of the car with one or both the leads ripped off. I repaired them numerous times. I also had the cheap alligator clips corrode.

But the 5w limit prevented overcharging.

I was surprised when I got one of these and it started to overcharge my battery. I had an old PWM SCC so I wired that in to stop it from overcharging.

So ive written about this on other vehicle-related forums. Basically, the only way a solar panel with no 'brains' can be safe for a battery is if it doesn't put out more energy than the battery can comfortably dissipate as heat when it reaches full charge. So a 20w panel with no electronics is bad because it can overcook a battery. For that amount of power you need a small amount of electronics to protect the battery from overcharge. If you want the cheapest thing in existence with no circuit board involved you are limited to small numbers like 5w to be 'passively' safe.

A $10 pwm scc is all the brains you need. It's a little more DIY but it's not really a lot more money..