12v solar battery charger for short trip driving

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Sep 23, 2017
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hello i have a 2003 hummer h2 and i do tons of short trip driving and i believe i already partially ruined my 1 year old battery as it was always discharged and never recieved a full charge. i was thinking of getting one of those 12v solar battery chargers and hooking it up thru my cigarette lighter port since in my vehicle the ports are live 247. Is this a good idea to keep the battery topped up? the only thing i am scared of is that i do not want to over charge my battery nor do i want to get a solar panel that has too little wattage to even make a difference, or are the 5w units fine?

i am in canada so i found this on amazon:
https://www.amazon.ca/ECO-WORTHY-Portable-Battery-Charger-Batteries/dp/B015ZGDYII/ref=sr_1_4?crid=1OBOM2DUH0NCF&dchild=1&keywords=12v%2Bsolar%2Bbattery%2Bcharger&qid=1591933961&sprefix=12v%2Bsolar%2Caps%2C298&sr=8-4&th=1

its a 5w unit

what do u guys think any input?
 
A 5 watt solar charger is only going to put out a little over 400 mA (0.4 amps) max. Factoring in the amount of sunshine per day, then you'll be able to see that unless your battery is close to being 100 percent charged, a 5 watt solar charger is not really going to do much in the way of charging/maintaining.

You would be better off purchasing a decent battery charger/maintainer built for that purpose. I know there are several posts that recommend specific charger/maintainers in the this forum. All you need to do is dig a little.
 
The poor angle of the sun in Canada and the short days in winter will seriously degrade the output of any solar battery charger used there. You probably should be thinking about a much larger size, realizing that it will most likely put out a maximum of something like 1/4 of what it is rated for where you are.
 
oh yeah im just thinking about for summer cuz its gonna be sunny, in winter ill be doing trickle charge for sure
 
I'm curious how your short trips are killing your batteries in a year. Are you running audio equipment or something else that draws faster than your alternator can top up the battery each time you drive? Maybe there's a parasitic draw you aren't aware of?

This sounds like a fundamental issue that needs to be solved before you use solar panels or trickle chargers to help things out.
 
Mighty I suggest a battery maintainer/float charger/tender?
Though IDK if this will be convenient for your specific situation(you'll need a place to plug in). However when your vehicle is parked, you can just plug her in and forgetaboudit!

I have a Schumacher Battery Maintainer mounted atop the battery in my Firebird(in signature). I plug in every time I put her away at night(when I do drive). Otherwise, it just stays plugged in all the time.
 
Originally Posted by Reddy45
I'm curious how your short trips are killing your batteries in a year. Are you running audio equipment or something else that draws faster than your alternator can top up the battery each time you drive? Maybe there's a parasitic draw you aren't aware of?

This sounds like a fundamental issue that needs to be solved before you use solar panels or trickle chargers to help things out.



Thanks for the reply. Actually here where I live the winter was super cold like -40 fahrenheit paired with short 5 min winter trips I believe my battery was severely discharged during the winter. I rarely take longer trips and I heard from other people on here that the alternator can't fully recharge the battteeh in short trips like mine. So I believe I sulfated the battery within a year, I tried using a noco to repair it but no go so I'm just gonna run it till it dies. I believe it was probably discharged even before the winter as well.
 
Two things . Get an electric engine heater and a trickle charger / maintainer and plug the vehicle in .

Also , take it on a good drive every weekend .
 
Originally Posted by apollo18

Originally Posted by Reddy45
I'm curious how your short trips are killing your batteries in a year. Are you running audio equipment or something else that draws faster than your alternator can top up the battery each time you drive? Maybe there's a parasitic draw you aren't aware of?

This sounds like a fundamental issue that needs to be solved before you use solar panels or trickle chargers to help things out.



Thanks for the reply. Actually here where I live the winter was super cold like -40 fahrenheit paired with short 5 min winter trips I believe my battery was severely discharged during the winter. I rarely take longer trips and I heard from other people on here that the alternator can't fully recharge the battteeh in short trips like mine. So I believe I sulfated the battery within a year, I tried using a noco to repair it but no go so I'm just gonna run it till it dies. I believe it was probably discharged even before the winter as well.


We talked about the situation a bit in this thread:


https://www.bobistheoilguy.com/foru...rger-alternator-a-no-brainer#Post5440224
 
Your windshield will block half the sun to any panel you put inside the vehicle.
If you can mount a panel outside, you would need a 25W panel to output what a typical trickle charger will do.
Sounds like you have a parasitic draw that you need to find.
 
Originally Posted by apollo18

Originally Posted by Reddy45
I'm curious how your short trips are killing your batteries in a year. Are you running audio equipment or something else that draws faster than your alternator can top up the battery each time you drive? Maybe there's a parasitic draw you aren't aware of?

This sounds like a fundamental issue that needs to be solved before you use solar panels or trickle chargers to help things out.



Thanks for the reply. Actually here where I live the winter was super cold like -40 fahrenheit paired with short 5 min winter trips I believe my battery was severely discharged during the winter. I rarely take longer trips and I heard from other people on here that the alternator can't fully recharge the battteeh in short trips like mine. So I believe I sulfated the battery within a year, I tried using a noco to repair it but no go so I'm just gonna run it till it dies. I believe it was probably discharged even before the winter as well.


Are you able to take long drives on the weekends? Not just for the battery, but for your vehicle in general. Short tripping it constantly means your oil never fully warms up in the colder months and you're going to have condensation buildup inside the crank case.
 
In Canada I'd start with 20W through the winshield.
I'm in Wash DC and 10W is working well on the dash. Max I've seen on a sunny day is 13.6V
It doesn't take much to go over voltage (>14V) if there's no regulation.
A maintainer would be nice, but I park on a city street and plugging in isn't an option.

This link talks about the issue of overcharging with a small solar panel:

https://marinehowto.com/do-i-need-a-solar-controller/
 
My f150 has does the mpg thing where battery charging is reduced to save a few points of mpg. A few years ago I put a fairly sizeable flexible panel on the camper shell... it feeds .9 amps in full sun at 13.8 volts, don't recall the wattage. It's about 3' x 1', glued down with silicone and screwed at the four corners. It's about 2mm thick so most folks don't even notice it. On the average day, the charge controller shuts it down about 3 hours after getting to work. If you you are just looking for a maintainer, I'd think 1sq ft panel, as long as it's not the single-sheet-of-glass type, would be fine. Those square glass sheet types are less than half as efficient (powerful) as real PV cells.

Truck starts quickly every day with a 5-6 year old battery. I'd do it to the car if there was a way to make it look ok.
 
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