Solar Powered Car Battery Charger Circuit

This is the place for any magazine-related discussions that don't fit in any of the column discussion boards below.
mrwilder
Posts: 3
Joined: Fri Jul 14, 2006 8:29 am
Contact:

Solar Powered Car Battery Charger Circuit

Post by mrwilder » Fri Jul 14, 2006 8:44 am

Hi all,

Okay, there are a LOT of charger discussion threads here and on the web.

However, I appear to be suffering from overload.

What I need is a basic, easy to build solar powered trickle circuit to keep my car battery charged.

The power source is already set: I have two solar panels rated at 15V @ 100mA.

That's not much power, and in a later circuit I might use bigger solar panels, but this is what I have to test with.

I had guessed that it might be as easy as putting a diode inline and pluggin it all in through the cigarrette lighter.

Does anyone have a clear cut circuit for this exact use?

Thank you!

dyarker
Posts: 1750
Joined: Fri Aug 22, 2003 1:01 am
Location: Izmir, Turkiye; from Rochester, NY
Contact:

Post by dyarker » Fri Jul 14, 2006 10:02 am

"I had guessed that it might be as easy as putting a diode inline and pluggin it all in through the cigarrette lighter."

If the cigarette lighter has power with key OFF, then it is that easy.
Dale Y

JPKNHTP
Posts: 488
Joined: Wed Jun 29, 2005 1:01 am
Location: Missouri
Contact:

Post by JPKNHTP » Fri Jul 14, 2006 2:35 pm

-JPKNHTP
-God Bless

User avatar
Chris Smith
Posts: 4325
Joined: Tue Dec 04, 2001 1:01 am
Location: Bieber Ca.

Post by Chris Smith » Fri Jul 14, 2006 3:22 pm

With only 200 ma a diode will work just fine, no regulator needed.

If the cig lighter is on, with the power off, it also should work just fine.

The sole purpose of any regulator in a battery circuit is to protect both the charge and the battery should they get out of hand.

User avatar
moe
Posts: 80
Joined: Fri Jan 11, 2002 1:01 am
Location: USA
Contact:

solar charger

Post by moe » Fri Jul 14, 2006 6:20 pm

Most remote generator sites use a max of 250ma current also called a float charge and will not charge a battery but maintain a fully charged battery. It would also depend on your location and season in the winter if you where in a cold climate you could use a higher current to charge-maintain the battery a security system will draw about 125-200 ma in a armed state. The lighter plug as others have said would be the best way to gofast and easy.
Moe

mrwilder
Posts: 3
Joined: Fri Jul 14, 2006 8:29 am
Contact:

Post by mrwilder » Fri Jul 14, 2006 7:23 pm

Would a more normal circuit include a regulator?

And by that, I'm assuming the circuit would then become a solar cell, an LM7812, a diode, then the battery.

Should I assume that most cars' cigarette lighters are indeed "on" when the car itself is off?

By the way, I'm in Phoenix, AZ, and it's July.

User avatar
Chris Smith
Posts: 4325
Joined: Tue Dec 04, 2001 1:01 am
Location: Bieber Ca.

Post by Chris Smith » Fri Jul 14, 2006 7:46 pm

“Would a more normal circuit include a regulator?

And by that, I'm assuming the circuit would then become a solar cell, an LM7812, a diode, then the battery.

Should I assume that most cars' cigarette lighters are indeed "on" when the car itself is off?â€

JPKNHTP
Posts: 488
Joined: Wed Jun 29, 2005 1:01 am
Location: Missouri
Contact:

Post by JPKNHTP » Fri Jul 14, 2006 9:02 pm

-JPKNHTP
-God Bless

dyarker
Posts: 1750
Joined: Fri Aug 22, 2003 1:01 am
Location: Izmir, Turkiye; from Rochester, NY
Contact:

Post by dyarker » Fri Jul 14, 2006 10:46 pm

At 'up to 200mA' should be enough current. mrwilder said he wants "to keep my car battery charged." It would be very slow charging a dead battery, but okay to maintain charge.
Dale Y

JPKNHTP
Posts: 488
Joined: Wed Jun 29, 2005 1:01 am
Location: Missouri
Contact:

Post by JPKNHTP » Sat Jul 15, 2006 12:19 am

-JPKNHTP
-God Bless

User avatar
jwax
Posts: 2200
Joined: Mon Feb 09, 2004 1:01 am
Location: NY
Contact:

Post by jwax » Sat Jul 15, 2006 4:13 am

If the solar cell is rated at 100 ma, you won't be getting 200 from it, not without a concentrator- which is a possibility.
Use a regulator if you have more source energy than your load needs- in this case your load needs all it can get from your source so no reg.
700 ma sounds like a lot, JP! Alarm system? Computer? Seat warmers left on? :smile:

User avatar
jwax
Posts: 2200
Joined: Mon Feb 09, 2004 1:01 am
Location: NY
Contact:

Post by jwax » Sat Jul 15, 2006 4:16 am

mrwilder- You may be better served by powering one of those window fans with your solar supply for a July day in Phoenix. Your battery ought to be fine.

mrwilder
Posts: 3
Joined: Fri Jul 14, 2006 8:29 am
Contact:

Post by mrwilder » Sat Jul 15, 2006 9:47 am

Sounds like in order to keep a car charged, I'd need, say, 15 V @ at least 750mA just to keep up... so, lets just say I'd need between 12 and 15 watts to make a solar panel charger that will keep the battery charged.

Won't need a regulator, just a diode.

Thanks all.

JPKNHTP
Posts: 488
Joined: Wed Jun 29, 2005 1:01 am
Location: Missouri
Contact:

Post by JPKNHTP » Sat Jul 15, 2006 12:55 pm

-JPKNHTP
-God Bless

User avatar
Chris Smith
Posts: 4325
Joined: Tue Dec 04, 2001 1:01 am
Location: Bieber Ca.

Post by Chris Smith » Sat Jul 15, 2006 2:04 pm

Car batteries today, and the bank account are the same.

Draw more than the account has over time and perhaps you will end up bankrupt?

But remember that most cars run each day so the account is full each night. when you park it and don’t use it, and only then it helps to keep adding as many pennies as you can afford over time, because like a meter, some bucks are just going out the window and so any replacement is good.

Im not familiar with any older car battery going dead on its own, because with out any major draw like the alarm system, all my cars still start even after 6 months on their own, cold, hot or dry?

BUT if you do have an active draw on the battery,[alarm] help it along with a solar charger.

A friend did this on his small 6volt Yamaha MC with a tiny solar charger and never had to worry about time or dead batteries. It always started and ran.

Post Reply

Who is online

Users browsing this forum: No registered users and 39 guests