Need A Basic Li - Ion Charger

[rhuck60]

to charge one or two of AW's protected "C" batteries. Im hoping not to spend a fortune.

Also maybe I wont need a function to balance/condition the batteries.

Does DX or Kadodomain make something close to this? Or is there maybe a way to modify some other charger intended for AA size batteries?

I think there should be lots of interest in such a charger. It seems like to me the price is too high for 2 of the C batteries and a charger vs 6 AA Eneloops and fivemegas excellent 6AA to 2D carrier. Given that the AA is rated 2000mah and the C only 3300 mah.

Add 6 spare Eneloops and a holder and they will outlast the 2 C Li - Ion batteries, and still cost much less.

This is where the cost of the charger will come into play. I havent seen anything much under $100 dollars.

 

[VidPro]

$100 ouch, i can buy a whole cheap bench power supply and build a pulse charger for 100$ . oh i did

potentially you could wire any one of the single cell li-ion chargers that stop at 4.2v up to the single or parellel battery with a slide clamp you can get from the hardware store. total costs about $30 +shipping .
in the case of Large cells like C and especially D , i would avoid any charger that has a very high peak voltage, and go with the ones that are toned down a bit.

it is better to charge much faster for the first 80-90% of the charge, than to be so slow as the cheap chargers will be, but on the other hand its so slow there should be less issues with heat , if the battery is damaged, dying , or failing, and would heat on the charger.

i slow charge or fast pulse charge , and dont have any problems yet, my most favorite charging so far is Voltage Max Pulse charging with high initial charge rate, that tapers because of a voltage max. the only things that get close to that kind of charging cost $100+.

so you could potentially "get away" with a $30 setup, then once you get boored with it, or get them credit cards paid off you could get a second mortgage for a real charger :laughing:
the price of them would be dropping, if they werent advancing the computer junk in them every year. the next version is going to have an AMD mobile processor in it and run linux on a 15inch Color LCD display

i totally agree with your assesment of the LSD. If LSD ni-mhy had existed before i converted MANY things to li-ion, i probably wouldnt have converted most of them, li-ion is still lighter in weight, and higer in density, and lower in self discharge, but the LSD would have solved enough issues for enough time.
You know that they have LSD C and D cells now? that might be the answer to all your prayers or is it payers

 

[jeffosborne]

Hey vidpro, have you published any technical details of your LiIon pulse charger? I would be interested to see what you have done.

Thanks,

Jeff O.

 

[VidPro]

its simple, take a 555 timer curcuit, attempt to assemble all the junk to make it go on and off repeatedly , there are curcuits on the web for things like asyncronous and other stuff that i dont know what it means

then feed the 555 output to a relay , like a 4-5volt type relay that will trigger with less than 3.8v. Unless you can get it to go to 2 mosfet things that will be flipped from eachother, and i am sure anyone that understand flip flops can.
then feed your power supply into the center of the relay, and get 2 battery connections off the on and off positions of the relay.

the 555 runs with as low as 3.5 volts or something, the relay runs with the 3.5 volts , and they can handle 4.3volts max. so everything runs off the same 4.25Volts.
use some adjustable regulator on some power supply and it costs about 50$ mabey and takes me 2 weeks to assemble

one set of leads goes to one battery, and is connected when the relay is off, one set of leads goes to the other battery and is connected when the relay is on. you adjust the 555 to be 50-50 and can charge 2 batteries 50% pulsed.

the first one i made was a "bug" it had all the parts soldered together in a ball, even had 2 indicator leds, and was only 1/2 inch. the closest i am going to get to SMD parts

the one that has worked forever non-stop, has a leetel box, bananna plugs for the in, and 2 sets of banana plugs for the out, and power led, and Flop led, and 2 dial pots for timing. but its just the same thing, 555 timer 5 wires commeing off it, driving a relay, in a box

variations of it used smaller weak cheap power sources ($12) and fat capacitors that would slap the li-ion upside the head on each switch, even though the total charge current is low, sorta like the idea they use for desulfators (desulfators are magic, there is little factual proof that they work)

with a DPDT relay you could potetntially balance out a 7.2v pack wired in series, by hitting each one 50% of the time, and waiting long enough for them to both reach the peak voltage. from just one power supply. or a wall wart and a $12 adjustable regulator kit.

someday they are going to make one for real, and i will still buy it.
lots of chargers Use PWM anyways to get to the charge current, and would do the same dang thing all electronically and correctally.