Solar Charger

Zorch · Post by **Zorch** » Mon Jun 23, 2008 4:39 pm

So! I am making my first foray into the world of solar energy (jumping in blindly with both feet would probably be a better description) and I could use some advice.

I need to jurry-rig/cobble together or (shudder) buy a solar based unit that can run this:

http://www.toolbarn.com/product/bosch/BC230/

Size and weight are not really huge factors in the project (altho the smaller the better) but the price tag is. So I'm guessing I'll need:

1. Box to put the whole thing in
2. Solar Panel
3. Charge regulator

Anything else I need or should be aware of? And what are the best places to find this stuff for cheap?

phil · Post by **phil** » Mon Jun 23, 2008 4:49 pm

I see a problem on the right side of this photo:

It looks to me like this recharger is expecting 120VAC. You need to run the solar panels into a battery, if I understand correctly, then run the battery into an inverter. Plug your recharger into the inverter.

I hope I'm wrong on this.

Marscrumbs · Post by **Marscrumbs** » Mon Jun 23, 2008 6:07 pm

How many watts is the recharger? That will determine size of inverter. Then you need a battery to run the inverter to be charge by the solar panels. It may be eazier to buy more battery packs.

capjbadger · Post by **capjbadger** » Mon Jun 23, 2008 6:25 pm

Solar panels --> Charge Controller --> Deep Cycle Battery --> Inverter --> Bosch charger

Solar Panels: Not cheap. Best I've found is around $4.50 per Watt. I make my own panels from cells bought off of ebay, so I get mine down to about $2/Watt.

Charge Controller: Ebay again. You can get cheap chinese controllers for around 5-10 bucks plus shipping. Just make sure the amps output on your solar panel is not higher than what the controller can handle.

Deep cycle Battery: You don't want to buy this online because shipping stuff that heavy sucks. The battery should list Amp Hours. If it says anything about "cold cranking amps" then it is a starter (car or marine) battery and is NOT suited for what you need. You'll kill it.

Inverter: Pretty easy. Get a "Pure Sine Wave" output one instead of the "Modified Sine Wave" inverter if you can. It will be a little more expensive, but worth it.
Make sure the wattage output of the inverter is higher than what the Bosche charger draws in.
Lots of good info on inverters: http://www.donrowe.com/inverters/inverter_faq.html

Few other things to know:

What "parallel" and "Series" wiring is.

Amps x Volts = Watts

Badger

Zorch · Post by **Zorch** » Tue Jun 24, 2008 1:52 pm

Excellent. This is exactly what i needed to know cap. I just need to find a good place to buy the deep cycle battery and the panels. Any good places to look for these? Besides ebay that is. ;)

MikeVDS · Post by **MikeVDS** » Tue Jun 24, 2008 2:50 pm

I know I'm not answering your exact question, but I think you may be going about whatever you're doing the wrong way. It looks like the Bosch is a DC charger for charging batteries, correct? The only thing that is doing, is converting AC power from your house into lower voltage DC power to charge batteries. The thing is that solar panels already have DC power at a similar voltage (which you can match for your purposes) so you should be able to charge whatever you're charging directly from the solar panels. What is it you're using the Bosch for? It should be simpler, cheaper and much more energy efficient to charge directly instead of converting to AC then back to DC unless you have some weird reason for doing that.

Courtesy Flush · Post by **Courtesy Flush** » Tue Jun 24, 2008 2:57 pm

Zorch wrote:Excellent. This is exactly what i needed to know cap. I just need to find a good place to buy the deep cycle battery and the panels. Any good places to look for these? Besides ebay that is. ;)

The best retail deep cycle batteries are golf cart batteries. You need to buy two of them, because they are six volt batteries. They're bigger and heavier than marine batteries, but I think they're cheaper, and they are real workhorses.

Keep the batteries topped off as much as you can. Every time you drain them they lose a little bit of life expectancy. When you're finished with them you'll probably be able to find a golfer looking for a bargain, and get some of your money back, so take care of them.

Zorch · Post by **Zorch** » Tue Jun 24, 2008 3:20 pm

You raise a good point Mike

I'm using the batteries to power the lights on my bikes (plus the tools if I have need of them).

Maybe I could bypass the inverter and charging station and just go right from the charge regulator to the bosch batteries?

capjbadger · Post by **capjbadger** » Tue Jun 24, 2008 4:18 pm

Zorch wrote:Excellent. This is exactly what i needed to know cap. I just need to find a good place to buy the deep cycle battery and the panels. Any good places to look for these? Besides ebay that is.

Glad the info is helpful.

Courtesy Flush is right. Golf cart stores will have them (usually in 6volt). Solar stores as well. And most UPS's (Uninterruptable Power Supplies) have them too. The four 12v 185AH deep cycle batteries I run my mutant Vehicle off of came from UPS's.

Ebay is the cheapest place I've been able to find solar, unless you can manage to score some free VW Solar panels from a dealership. They ship the cars with them to keep the batteries fresh. Ask around, you might get lucky and convince them to donate.

MikeVDS wrote:I know I'm not answering your exact question, but I think you may be going about whatever you're doing the wrong way. It looks like the Bosch is a DC charger for charging batteries, correct? The only thing that is doing, is converting AC power from your house into lower voltage DC power to charge batteries. The thing is that solar panels already have DC power at a similar voltage (which you can match for your purposes) so you should be able to charge whatever you're charging directly from the solar panels. What is it you're using the Bosch for? It should be simpler, cheaper and much more energy efficient to charge directly instead of converting to AC then back to DC unless you have some weird reason for doing that.

The Bosch charger is made to charge those batteries correctly. To hook them up straight to the solar setup would be to run the risk of destroying the batteries and would be a fire hazard. The small loss of efficiency/power isn't worth the risk.

Badger

phil · Post by **phil** » Tue Jun 24, 2008 4:28 pm

See costco at

http://www.costco.com/Browse/Product.as ... 1&Sp=S&s=1
Free shipping and it has a charge controller, connectorts, and other necessary stuff. US$290, shipping included. Check and see if it's on Amazon. It was a day or two ago, same price, free shipping.

capjbadger · Post by **capjbadger** » Tue Jun 24, 2008 5:03 pm

Fixed link:
ColemanÂ® CL3600 Solar Back up Power Kit 54 Watts by ICP $290

Damn near the same thing on Ebay, yet $70 less even with shipping:
45 Watts (15W x 3) Solar Panel Power Lighting System Kit $222

Badger

MikeVDS · Post by **MikeVDS** » Tue Jun 24, 2008 10:15 pm

The Bosch charger is made to charge those batteries correctly. To hook them up straight to the solar setup would be to run the risk of destroying the batteries and would be a fire hazard.

That is true. I wonder if it just tests the voltage every minute to see if it's at a certain point to stop? Regardless, he could use other, more robust batteries (lead acid) and not worry about it. If he charges the batteries for his tools "if he needs them" before and uses a separate set for his bike there should be no worries. Probably still much cheaper. And the "fire hazard" is a pro, not a con.

Also, if you use a mid sized battery (large than a flashlight battery, smaller than a car battery) and LED lights on your bike, you probably won't need to charge all week. Heck, I doubt you'd even go through a D battery if you only have a few lights.

The small loss of efficiency/power isn't worth the risk.

Inverters and power supplies aren't generally very efficient. I'd be surprised if he didn't lose half the power through that mess. Converting to AC seems like a overly complex solution where there are elegant answers.

capjbadger · Post by **capjbadger** » Tue Jun 24, 2008 11:14 pm

I agree. If he's mostly using the power for lighting, then just hook up the deep cyccle batteries to some DC LED light and have fun.

Also very true about the D batteries. There are tons of lights made for bikes that run off of AA and the like. Hell, get some NiMH rechargables, charge them up right before you leave, and bring a few regulars as backup.

Badger

Captain Goddammit · Post by **Captain Goddammit** » Wed Jun 25, 2008 5:35 am

It'd be more reliable and burnier to construct a small-scale coal-fired power plant to get your electricity. And it'd help piss off the Sierra club!

Zorch · Post by **Zorch** » Wed Jun 25, 2008 12:35 pm

Mmmmmmm steam powered dynamo....

I get all worked up just thinking about that lol Mayhaps next year