I have posted this in my GP2x project in the "Handheld Hacking" forum, my thread is getting some interest, however there is far more chance more people will visit this thread in T&A so therefore a greater chance of a reply to this technical question (this question deserves to be in this T&A forum anyway).
For my project I intend to install 6 x C 5500NiMH rechargeable, high drain batteries in series, to give 7.2v.
I would rather seal them in my project case rather than having to take them out and recharge them via an external charger.
I would like ideally to plug in my PSone power supply (7.5v, 3 amp) into the batteries (7.2v across all 6 cells) and thereby recharge them.
Questions:
(1) Can I do this ok, is it safe?
(2) Any longterm ill effects?
(3) How long would the charge take - does it work out that in effect 3amps divided by 6 cells = 500mAh per cell, so to recharge 5500NiMH cells would take 11 hours from 7.5v 3amp mains power inlet (ie PSone power cable): or am I on the wrong track?
Thanks guys!
If the above isn't good, how about a recharger like this one http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... :IT&ih=014 although it would take a really long time to recharge (55 hours!?) - I would rather it be far faster!
Recharging cells
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Honestly it's very unsafe to do this. Regardless, you'd need to charge it with something 1.2v higher than the actual voltage (8.4v).
That eBay link seems it would do the job, and could be used just as a regular wall wart would. Do you really want to sit there for 55 hours to wait for it to charge though?
Gerenally, I'd use something like this.
That eBay link seems it would do the job, and could be used just as a regular wall wart would. Do you really want to sit there for 55 hours to wait for it to charge though?
Gerenally, I'd use something like this.
you have the math slightly wrong. The current through a series connection of anything is the same at every point. Using the water analogy, if you have 1 gallon per minute of water flowing in the end of a pipe, you would expect that much to be flowing out the other end (or past any point in between). Therefore, if you were to put 3 amps across 6 cells in series, every cell would have 3 amps flowing through it. leave it running for an hour, and each one will collect 3Ah (3000mAh) of charge.
The voltage of anything in series is equal to the sum of the voltage drop across each circuit element (i.e 6 x 1.2 = 7.2). Im sure you know this already. Thats probably what you were thinking of.
In that case, your charger should take about 6 hours to charge on the 1,000mA setting.
also, your ebay link make my head a splode. its screaming out for URL tags
The voltage of anything in series is equal to the sum of the voltage drop across each circuit element (i.e 6 x 1.2 = 7.2). Im sure you know this already. Thats probably what you were thinking of.
In that case, your charger should take about 6 hours to charge on the 1,000mA setting.
also, your ebay link make my head a splode. its screaming out for URL tags
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