Wiring up some solar Christmas lights

Blindowl1234

A month or so ago I got two sets of the little Led solar fairy lights. One set has 100 lights the other has 200 lights. The lights worked good until we got virtually no sun the past couple of days. The little 3" panels they have are too small I guess. I'm thinking of wiring them to work with my 225 watt solar setup, that I put together for all our outdoor lighting this summer.  I've got some outdoor lights that were designed for 3 volt running fine on 5 volt...taking the 12 volt down to 5 volt. I can tie these into that circuit pretty easily. Is 5 volt going to be too much for these little Led lights that were using 1.2 volt? I've looked all over the web and can't find any info on what the maximum voltage is a small Led can handle without frying them all. Anyone that has any ideas I'd appreciate it. I've looked at an LM2596S module which is adjustable if I'm better to go that route, than taking a chance of frying the lights

mike95490

depending on the color of the LED, the voltage requirement changes. Green & Blue LED's need more voltage to work than Red,
BUT - the critical thing is you have to limit the current (amps) through them,  They are foward biased diodes and will instantly burn themselves out if you don't limit current

Blindowl1234

Thanks Mike, I was reading something last night about the current going through them. I guess I'll come up with some other idea lol. Really don't want to burn them up

littleharbor2

Are you trying to power the lights or charge the battery in the module? I would think the 1.2 volts is based on a single rechargeable battery in the module. The led's may have a higher voltage tolerance.

Blindowl1234

After the issues I've had I was going to power the lights off of my 225 watt solar setup. I can take 12 volt down to 5 Volts easy enough. I think I got it figured out lol. The small set of 100 lights seems to run all night with the 3" panel that came with it. The larger set of 200 lights worked a few days now it runs about 10 minutes and dead. The sun has been non existent for 3 days now...we know that's part of the issue. Strange how one set works fine the other doesn't. I noticed it has a 600 mah 1.2 volt battery which isn't much. The voltage tolerance of the Led's would be the issue. We'll see how it does tonight with a few hours of sun.

littleharbor2

I have a few 200 light strings at my place. One has worked every night, all night. the other just quit early in it's life. It's too bad quality control is so bad on Chinese electronics. They have lots of cool solar/LED stuff but it's a crapshoot weather you will get a reliable one or not.

animatt

I had 12v led lights in a rv. The house battery bank was 24v but power dropped down the 12v with a converter.  One day my led lights looked brighter. The a few minutes later the solder joints melted.  And fell to pieces.
What happened was converter died and was passing 24v to my 12v loads. Led did not last long. Luckily I caught the problem quickly. 

Blindowl1234

littleharbor2 said:

I have a few 200 light strings at my place. One has worked every night, all night. the other just quit early in it's life. It's too bad quality control is so bad on Chinese electronics. They have lots of cool solar/LED stuff but it's a crapshoot weather you will get a reliable one or not.

Yeah I liked the idea of 300 or so little solar lights outside and it wasn't costing anything to run them. The quality control on most Chinese stuff is not that great. Two little 3" x 3" panels sitting side by side and one set is working like a charm with 3 cloudy days in a row. The other larger set runs maybe 30 minutes and quits. I went and bought a 225 bulb Led set that are 110 Volt A/C and just plugged them in the outlet today. The smaller solar set is still up and running 10 to 12 hours a day lol

Blindowl1234

animatt said:

I had 12v led lights in a rv. The house battery bank was 24v but power dropped down the 12v with a converter.  One day my led lights looked brighter. The a few minutes later the solder joints melted.  And fell to pieces.
What happened was converter died and was passing 24v to my 12v loads. Led did not last long. Luckily I caught the problem quickly. 

Wow, So far I've not had that happen here. I've got several outdoor lights that are running at about 5 volts. I've been taking the 12 volt down to 5 volts since the Spring and no problems. Most of the lights were originally 3 volts I think. If they ever suddenly went to 12 volt they'd be fried no doubt

littleharbor2

I know the point of this discussion is trying running these on a larger solar source but the problem might be a sour ni cad or whatever type rechargeable battery is in the 3 x 3 solar module. These batteries are pretty inexpensive. I know mine are easily accessible.

Blindowl1234

Figured out what it was I guess. #1 lack of sun. The larger set charged the other day and stayed lit all night. The small set works every night it doesn't care. Same size 3" x 3" panel on both. Maybe the bigger light set should've had a larger panel from manufacturer. Problem figured out I guess...

westbranch

One of those small ~1 foot by ~3 inch 'battery saver' (on the dashboard of your car) pv's should be able to do the job...run about $10 in the big box /discount stores... might need something (??) to prevent overcharging the Li type batteries