What's everyone's thoughts on a setup for maintaining a 12v car lead acid car battery year round. I've tried 5 and 10 watt panels (10a Renogy Wanderer charge controller) and they tend to be too weak during the winter months. Would a 30w panel be about right? Thanks in advance?
Everyone's thoughts on best size solar panel to maintain 12v car battery year round?
- Thread starter nick777
- Start date
sunshine_eggo
Happy Breffast!
Too many variables.
How weak is the sun during winter months?
Is the controller using temperature compensation?
Is the panel on the dash or mounted outside?
What's the parasitic drain of the vehicle?
OffGridForGood
Catch, make or grow everything you can.
just buy a solar battery maintainer off amazon and plug it into the car?
10W and 20 W models seem to be common.
(I have no experience with these at all).lol
10W and 20 W models seem to be common.
(I have no experience with these at all).lol
sunshine_eggo
Happy Breffast!
CA = California or Canada?
Worth noting that flat roof installations in are lucky to get about 40% of summer output in winter.
Worth noting that flat roof installations in are lucky to get about 40% of summer output in winter.
I use a 25w eco-worthy solar kit ( https://www.amazon.com/gp/product/B00PFGP0EA/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1 ) for a keep alive for my RV. Mounted almost vertically inside front window rv faces S/SW. Works great
underdog5004
New Member
I use a flexible renogy 100w panel. It's on a 10ft cable that goes under the hood, to a sunsaver 10a cc, which is connected to the cars 12v battery.
The alternator went out, and it's not cost effective to replace.
Keeps the battery topped off. I drive it 3 miles per day, to work and back. Battery has enough ah to run plugs and hotel load about 20 to 30 miles.
I throw the panel on the windscreen when I park (paying attention to sun angle). Stick it in the car before I leave.
Been thinking about securing it to the roof using super velcro tape, but don't really want to commit yet.
Old_Skewler
Solar Enthusiast
Hey, I went thru the same issue and to be honest I am currently at 50W renogy with the same Renogy charger controller and still struggling to keep the battery charged in winter - also struggling with the smoky fire sky these past weeks...
I recommend you go 100W panel. This is what I am going to do with my setup. If you want to try 50W then I could sell you my Renogy 50W panel.
I use two 30 watt panels and a solar duo controller to maintain at the moment the following :
exmark zero turn mower
cub cadet riding mower
f150 pickup
corvette
This is the controller I use :
Its $39.99
The controller can charge two different vehicles at the same time. I use dc powered timers to switch out what its charging automatically. I have used that single controller to keep 20 vehicles charged up at one time. By setting up a schedule it kept everything charged up nicely.
These are the timers I use :
$14.95 each
If your just charging two or less vehicles you don't need the timers.
The reason for the two 30 watt panels which are wired in parallel was to keep the angles spread a bit for the area I have them mounted at. So far I haven't needed more than that but you could go larger if you wanted to.
I also have a mt1 display and a 100 foot network cable hooked to the charge controller to monitor it but its not really needed and was bought to "watch" what it was doing more than anything else.
exmark zero turn mower
cub cadet riding mower
f150 pickup
corvette
This is the controller I use :
Its $39.99
The controller can charge two different vehicles at the same time. I use dc powered timers to switch out what its charging automatically. I have used that single controller to keep 20 vehicles charged up at one time. By setting up a schedule it kept everything charged up nicely.
These are the timers I use :
$14.95 each
If your just charging two or less vehicles you don't need the timers.
The reason for the two 30 watt panels which are wired in parallel was to keep the angles spread a bit for the area I have them mounted at. So far I haven't needed more than that but you could go larger if you wanted to.
I also have a mt1 display and a 100 foot network cable hooked to the charge controller to monitor it but its not really needed and was bought to "watch" what it was doing more than anything else.
OffGridForGood
Catch, make or grow everything you can.
Wow,
If I get up over 10-12 "She" tells me to get rid of some of them...then I have to start hiding a few...solar isn't my only addiction er I mean Hobby!
Your not going to believe this but at one time I had over 200 vehicles
I bought a pawnshop and it had like 150 vehicles in a field where they had taken them in on pawns and never did anything with them. When I closed the pawnshop right after the first gulf war thing crashed the local economy here I had a few cars on my hands.
I'm down in the 50's now ! ?
I had a 15 watt panel/controller that I used on my UTV that had maybe a 400 CCA battery. It wasn't enough. I switched to something much larger (1000 watts of PV, which is overkill but it's what I had available). I wouldn't use anything less than a 50 watt panel. Go as big as you can.
I've been there...Your not going to believe this but at one time I had over 200 vehicles
I bought a pawnshop and it had like 150 vehicles in a field where they had taken them in on pawns and never did anything with them. When I closed the pawnshop right after the first gulf war thing crashed the local economy here I had a few cars on my hands.
I'm down in the 50's now ! ?
I personally collected over 100 in my yard
...
People would bring them to me, I'd drive all over and get em...
The city was not amused...
I have like 30 now...
Most all stored away
For about 69.00 a 4 amp Battery Tender brand charger/ trickle charger with all the attachments and quick connect and covers included is the easiest way to do charge almost all batteries.. 6 v , 12 v,FLA, lithium…AGM … big ones - little one- short or long term storage…+ they are well made and safe…
I have some solar stuff to do it but it’s to easy and hands free to just plug them in and forget it…
they take it to up to 14.4 then just sit and float ( at lower V) . I have two and have used them on every type battery I own …B Borne , truck batts , down to 50 dollar lawnmower batts ….and AGM RV house batts…
They make different sizes , I found the 4 amp fit my needs the best…I think they start at about 1 amp and go up…I forget exactly…
if I need to go stronger with more controls and options I have a couple of Victron 12 & 24 v IP model chargers but those would be way overkill expensive for what your trying to do…
The Battery Tender is a great little unit from my experience over the last 4 years…
good luck..J.
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