Using 2 AA batteries to recharge 4 AA batteries while powering a motor.

[stevensrd1]

Here is a little setup I use to recharge 4 AA batteries with 2 AA batteries while powering a motor. Made a video on it at http://youtu.be/_cYHYROV8c0

[MarkE]

I don't know what kind of batteries you are trying to recharge.  Alkaline primary cells like you buy at the store aren't designed to be recharged.  NiMH batteries that are designed to be recharged really want to be charged at a constant current which if you want to be efficient, you can manage with a fairly simple switching circuit.  The catch is what you do to determine when to cut-off charging which can require some finesse.  Get yourself a copy of the Panasonic NiMH battery manual if you are interested in pursuing that.

[tinman]

What is the amp hour rating on the two drive batteries?
What is the amp hour ratings on the 4 charge batteries?
Remember-voltage is not an indication of battery capacity-this is where the bedini lovers get all screwed up.

[Magluvin]

I don't know what kind of batteries you are trying to recharge.  Alkaline primary cells like you buy at the store aren't designed to be recharged.  NiMH batteries that are designed to be recharged really want to be charged at a constant current which if you want to be efficient, you can manage with a fairly simple switching circuit.  The catch is what you do to determine when to cut-off charging which can require some finesse.  Get yourself a copy of the Panasonic NiMH battery manual if you are interested in pursuing that.

Actually, regular rechargeable batts can be recharged. The biggest problem with doing so is the casing of the batteries compared to rechargeable batts.

The key to recharging normal so called non rechargeable batts is to do it slower as to not heat them up. If they are overheated, the casing could expand and open causing leakage, where rechargeable batts have a casing that can handle quite a bit of heat and not leak. In fact, I have not had a rechargeable leak in any of my devices in the past 5 or 6 years I have been using them exclusively.

I have a book on pdf somewhere that provides circuits for charging normal batteries, carbon and alkaline. It takes near 24 hours to do so though.  Even 9v batts. No big deal really.  From what I remember, when the normal batts are left in low charge state, the reactions inside can cause expansion and cause leakage.

Ill see if I can find that book/pdf.  Excellent source about batteries of all kinds.

Mags