Changing My Car Battery With A Solor Panel

[Deano 1]

Hey all,

I dont realy drive my GTR much it sits in my garage under covers for weeks on end, i recently brought a Dry Cell Battery for it and with all this cold weather and my alarm on in my car, my battery seams to run flat, so i brought a Solar panel just a little one, that i can put on top of my shed and run some small cables into my engine bay and onto my battery, so when it comes time to fire the old girl up i can just unclip the panel and turn the key....

this is the panel i brought http://cgi.ebay.com.au/ws/eBayISAPI.dll?Vi...e=STRK:MEWNX:IT

my question is, will it harm the Ecu or anything eles, having a small amount of Ac Current tickeled into the battery if i leave everything conected under the bonnet. my clocks and all dont run out of wack. If you get what i mean.

thanks all

bit of a weird Question i no, but theres some smart cookies on here im sure one of you can help.

Deano : D

[GTRPowa]

Looks like a cost effective idea. It says you don't need a regulator, I don't know if that means it has one though or what.

On top of that, does the panel draw current (residual) at night?

I recently purchased the Projecta charger that fits in the engine bay, purpose built, but only 250mA, charged a dead battery in a day and a half. So the 350ma from the panel would be more than enough on sunny days.

I also don't see anything about overcharge protection?

[75coupe]

A sparky was telling me he had done a few installs of solar panels for keeping batteries charged for cars that are only used on the occasional sunday...

[jiffo]

So long as your car battery is in good order you won't damage anything. It's DC, not AC.

But if your car battery dies, there's no resistrance for the panel and they'll go to nearly 20V on open circuit.

I drove for years with a 40W panel bolted to the roof racks of my mini back in the day.

Generator had died and the panel kept everything going great, until it rained.

[GTRPowa]

Overcharging:

http://www.ehow.com/about_5099009_causes-c...overcharge.html

In there it also mentions the need for a regulated supply.

Think of the panel simply as the power supply, as normal battery chargers have a power supply. But any half decent battery charger will also have trickle/overcharge protection, amongst others. However with a solar panel you'd also want the added protection of undervoltage.

If I went the solar panel alley, and had what you have, I'd be looking for a 14v regulator (15 is hard to regulate if that's the max you'd get from this china panel) and some form of deep cycle battery. Plug the panel in on a sunny day once a week for a few hours. Therefore you won't need overcharge protection, you have a regulated constant 14v charge at 350mA, and not much risk of undervoltage. (Which undervoltage wouldn't be disastrous, just possibly drain a tad from the battery instead of charge)

Edited July 1, 2010 by GTRPowa

[Deano 1]

hmm i was hoping to just plug the panel in and forget about it till i wanted to go for a cruise, pull the conectors off the battery and start it up. haha looks like its not goin to be that easy, The battery is a Brand New dry Cell prob max 2months old. where would be the best place to get a regulator?

when i think about it the overcharge protection would be a good idea, plus over voltage will fry my ecu if its pumping a heap of volts into my battery when i go to start the car??

[JonnoHR31]

aslong as you disconnect the charger before turning the ignition on the ecu should be fine in the event of an overcharge

[GTRPowa]

Well you'd have the charger off before even turning on the ignition, but by overcharge I refer to damage to the battery from sitting at a higher than normal voltage for too long.

Examples to look at for regulators, I found:

http://cgi.ebay.com.au/12-VOLT-6AMP-SOLAR-...=item3f00832ce1

http://cgi.ebay.com.au/Solar-Panel-Chargin...=item2a069822fc

http://cgi.ebay.com.au/NEW-Solar-Panel-Vol...=item563dc1d1f0

etc etc, just search for 'solar panel regulator' - sort by price, look around the $50 and under section, lots there.

"It also includes reverse-current protection for connection to solar cells - this is so that the battery won’t discharge into an inactive solar cell during night."

I bought this: http://cgi.ebay.com.au/PROJECTA-CHARGE-N-M...=item335e8438b4

Can be mounted in the car, comes with Aligator clips, as well as a set of lugs so you can wire up permanently, very small unit, comes with mount bracket too, leave in car for good. Charged a 6 month old dead battery to full in 30 hours, then maintains it from there. The 240v lead is about 200mm long so you don't have excess leads in your bonnet.

Edited July 1, 2010 by GTRPowa

[The Dan]

Don't forget, guys, that it's a dry cell battery he is talking about. These need to be charge-discharged slowly. It's a special process that can only be achieved with smart chargers. It will charge the battery, sure, but it will fail quickly if you keep charging it like that

[SoFreshSoClean]

Yeah, dry cells and new calcium batteries need different charge modes. The new projecta ones have seven modes! I remember reading about it, they are something like boost, hold, pulse, maintain, stuff like that. Its definitely not a simple process.

However I guess you could wire up the solar panel to power the battery charger if you were keen enough

[PM-R33]

Mines constantly connected to one of these now after hearing great things from every one that has used one. And for $70-$100 its a bargain.

http://www.skylinesaustralia.com/forums/Tr...tml&hl=ctek

Edited July 1, 2010 by PM-R33

[tridentt150v]

If you get a solar panel where you can access the rear connections then you can put in a blocking diode. The diode will stop overnight or really cloudy day discharge and also protect the solar panel from spikes when you start the car. If not then you can solder one into the lead, not as neat, but it works.

I would always run with a regulator, solar panels can get up to 20-25 volts on a hot sunny day, a regulator will stop this charge from going straight to the battery and probably peak out at 14 volts.

Also if you have a solar panel that is epoxied in then you can place the blocking diode at the regulator. We use PR10L Sunergy's and 30w solar panels everywhere and have few problems. I can't remember the size of the blocking diode, but it would be around 5mm thick and 8mm long.

If anyone wants more info I'll hunt up exact gear specs and supplier contacts etc

[R31Nismoid]

Mines constantly connected to one of these now after hearing great things from every one that has used one. And for $70-$100 its a bargain.

http://www.skylinesaustralia.com/forums/Tr...tml&hl=ctek

Yeah we have CTEK come along to a SAU-Vic Gen Meeting, and gave away a few of their chargers

VERY interesting product for the price the way the cycling works (as Dan mentioned it's a requirement for battery life) and so on.

While this is a great idea, I think given the practicality of the product already on the market for around $30-40 more (I'm counting setup time as added expense)…

It's close to being equally viable in many respects. If you were talking several hundred then perhaps it would be a different story.

And I believe you get a reasonable warranty

[PM-R33]

Yeah i'm very bloody pleased with the product. Being so small and light makes it so much easier to use. Can't believe they gave you guys some free ones, bastards lol.

[R31Nismoid]

They gave away one super big one as well, their $250 one or whatever.

That was a beast

[GTRPowa]

Don't forget, guys, that it's a dry cell battery he is talking about. These need to be charge-discharged slowly. It's a special process that can only be achieved with smart chargers. It will charge the battery, sure, but it will fail quickly if you keep charging it like that

Yeah I noted that as I was shutting down last night

Whats the discharge cycle on a dry cell? Aint it around 1 discharge per 30 recharges?

[tridentt150v]

OK, I did this today.....used a BP Solarex 10 watt panel [i can get them surplus from work] and a Plasmatronics PR1210L regulator. I routed a a wire off the postive terminal on the battery and took it around via the drivers side and along the firewall to the number plate light lead grommet. I made up a small bracket with a spade fitting and pop rivetted it to the car just above the number plate. Then I used a sealed connection plug and slid it onto the spade of the bracket. So now I have a plug just above the number plate that I can plug a solar panel lead in any time I need to.

I'll see how the battery goes, its only 11.4 volts at the moment [because I'm waiting on my WMI control unit to come back from the USA], so it will be interesting to see how it responds.

[tridentt150v]

It hasn't been a good 10 days here, only one or two with full sun......otherwise overcast and wet.

But the battery has charged up from a low of 11.65 to 12.35 volts and likely more to come. The end voltage [from measuring output] will be more like 13-14 volts. I haven't bothered measuring amperage input because of the cool and less than ideal conditions. If I get a couple of days of good warmish weather, I'll do an inline amps test and post up the results.