What type of solar cell/battery for a garden lamp?

I was looking at an instructable (https://www.instructables.com/id/Solar-Powered-Light-Graffiti-Projector/) involving a garden light hooked up to a red led instead of a white one. It shoots a picture out at night onto a wall or something like that.
I'm wondering if the garden lights are too dim or don't charge fully. We used to have some lights of those type, but they would make a dim light for about 5 hours, then emit a very very weak light. I'm thinking about just buying a trickle charger from here, then getting a bright green or blue led, batteries, and waterproofing it. The problem is, I have nil knowledge about solar chargers/what voltage to use.
Can anyone help?

Picture of What type of solar cell/battery for a garden lamp?
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NachoMahma8 years ago
. It's going to take quite a bit of power to project an image, especially if the surface is not very reflective. Figure up how much current everything will draw and you can determine the size battery you need (Kiteman's 1800mAh will probably put you in the ballpark). From that you'll know which charger to get. . . Might want to add some weight to the feet or anchor them somehow - that housing looks like it will make a pretty good wing in a windstorm.
Carmelite (author)  NachoMahma8 years ago
alright. thanks. one more thing though, do you think a red LED will be better than a green one or blue one?
i think all in all blue leds are better we see more shortwave (to blue and violet) stuff better at night blue led requires smaller resistor so its more efficient
. IIRC, our eyes pick up red better in low light, but my memory may be faulty. Try searching for "nocturnal ocular spectral response" or some such nonsense.
Kiteman8 years ago
Normal solar garden lights have pretty feeble rechargeable batteries, around 600mAh. You could try replacing them with a decent 1800mAh set.
110100101108 years ago
i'd try some batteries of low capacity the bright led (or leds) wil end them fast but they will be full charged and give full brightness at the beginning you may want to use larger solar cell or 2 cells together you may make it light up once in 2 or more days and not each day and this way itll charge more