Cheap Li-Ion charger

[azzachaz]

Like the title says. Anyone know of a cheap way to charge Li-Ion batteries. Probably 7.2V packs or 3.6V single cells.

I'm talking about Li-Ion not Li Poly

[Bowling Ball]

How about the Duratrax ICE charger?

can pick them up in AU for around $200

otherwise bring it in from elsewhere ($130US)

BB

[azzachaz]

OK, cheap being less than $50

[Bowling Ball]

hmm

http://www.modelflight.com.au/electric_battery_chargers.htm

cheapest for Ion seems $100

[azzachaz]

Just found a design for a Li-Ion charger. Went to DSE today and brought enough parts to make two chargers. All up it cost me $20.
More info later

[toxxic]

Sounds good azza, cant wait to hear back!

[azzachaz]

ok, well I found this website.

http://shdesigns.org/lionchg.html

His name is Steve Henion and he has designed a basic Lithium-Ion charger that I plan to build.

I have broung all the parts, just need to solder it all together and buy some Li-Ion batteries ;)

I will be builing his second revision with the charge monitoring LED. The circuit is quite simple but is very safe if you take the right procautions. Basically it charges a full rate until the batteries hit a pre determined voltage then it trickle charges down to almost 0 amps.

I will be setting it up for 2 cell charging but it can be simply modified for 1-3 cells.

Read the webby for detailed info.

e107_files/public/8_lionchg.gif

[azzachaz]

Just ordered some 4/5AA Lithium Ion's. Also brought some of those safety circuits which stop you over/under charging the Li-Ion's.

I hopped right in and finished off the charger. Took me about a hour to solder it up. I used his design that has the LED.

It is the best feeling to solder away for ages and then see the little LED smile back at you when you plug it in. All that is left to do is adjust the trimpot for 2 cells and get my batteries pumping.

[toxxic]

that sounds great azza, let us know asap on how it goes!

[azzachaz]

I took it apart and added a heatsink to the regulator. Apparently it can get a little hot :D

[azzachaz]

here it is...

e107_files/public/8_charger_030_small.jpg

[azzachaz]

I CBF getting out the flood lights to take a nice pic. But you get the idea

e107_files/public/8_charger_031_small.jpg

[azzachaz]

I've tidied it up a little bit and insulated the LED leads. Pretty basic really, put 12v in one end and you have an adjustible Li-Ion charger.

I'm using an old mobile phone charger as the power source

e107_files/public/8_charger_032_small.jpg

[Bowling Ball]

Looks nifty! !clap

Dude you really need to invest in some drill bits :)

BB

[azzachaz]

Tell me about it.

High on my list is a proper drill press and some drill bits which aren't made of cheese x)

[azzachaz]

Well according to the guy who designed it. I have read reviews of a few people who have made it.

Supposed to work really well, because the current drops towards zero at your predetermined voltage you cant overcharge them unless it is your fault (setting it wrong).

I have ordered some failsafe modules for the batteries so I can build up trust in the charger without worrying about explosions

[azzachaz]

nah, still waitong on the li-ion batteries to arrive from HK.

Apparently you get a good speed boost with iWavers by using them instead of NiMH. Alot of guys use them in their Mini-T's as well.

Not quite as good as Li-Poly but Li-Poly aren't for everyone if you know what I mean.

[azzachaz]

li-ion wont hesistate to burn your house down either.
The main difference is that poly has a higher energy density than ion, but not my a huge amount.

They problem with poly for 'average' users is the cells are relatively unprotected compared to the hard shells found on most other battery types so they are more prone to puncture/damage.

I'm not an expert so if anyone want to correct me feel free...

[justo316]

Yeah, I thought li-ions were considered 'safer' but it was mainly due to their hardcase and I think they have special computer chips built in to prevent them from over charging/discharging and blowing up.

[azzachaz]

because they are nOObs

[azzachaz]

or because they need to be ultra light for helicopters and stuff

[toxxic]

How's the charger going azza?

[azzachaz]

good, i tried it out last night but it was only charging to 8V rather that 8.4V

I worked it out that DSE had put their 10K POTs in the 1K spot. I brought some actual 1K POTs today and will try it out tonight.

[azzachaz]

put the POT in last night. Still need to adjust the POT so it stops as 8.4V, didn't have the time to sit and watch it.

Seems to charge the batteries fine though, at least my Bigfoot thinks so ;)