DIY Solar USB Charger - Altoids

Step 6 Connect The Battery Pack

Now we connect the solar wires to the battery pack wires.

Just connect all the positive wires (red) with all the negative wires (black).

Solder.

Easy as pie.  Sweet sweet solar pie.

Comments

[coloskibum]

Actually original poster has a good question. I have a 2w 6v solar panel and bought a handful of bulk .9v-6v to 5v USB circuits like you have. The way you have this wired I'm trying to think through if this will push 8.4 or just 6 v to the usb circuit if I'm in the sun and have fully charged batteries (I'm a noob but go with me here)...I guess I'll just wire the panel and fully charged batteries and see what the good old meter says before I wire it to the USB...

[JoshuaZimmerman]

It depends on how well your circuit handles the extra voltage. The voltage regulating chip on it may be just fine, or it may burn down your house. I'd most certainly do some testing before hooking up any gadgets.

(Though I'm guessing you're going to be ok.)

[NeMewSys]

Dont you need a circuit to manage the batteries charge state? Wont this "directly connect the solar panel to the batteries' ends" harm the batteries? What if they are already charged? I dont know nothing about NiMh.
Im thinking of using a lion polymer btw, not sure yet.

[srosenberg]

"USB Charging Circuit" is what you need. It's on the list.

[NeMewSys]

Im talking about NiMh batteries, not USB charging ones (that are made of li-ion).
Im asking if we can charge NiMh safely just like that "directly connect the solar panel to the batteries' (NiMh) ends".

[fryingsquirrel]

Mmm... pie

[JoshuaZimmerman]

Solar pie.