DIY Charger: 14 Batteries at once! (Now with pic)

[LikeitBright]

So I'm thinking I'll have a lot of CR2 batteries to charge shortly.  14 or so.  Now, I don't fancy buying 7 chargers, so as a cheap hack I could use a lab power supply set to 3.3V open circuit (or whatever the open circuit voltage on a charged 3.0V CR2 is) and connect up the 14 CR2 in parallel between two conductors and charge at around 300mA per cell or a bit over 4 amps for a couple of hours using the current limiting of the lab power supply.  This would be a cheap equivalent to a dumb single channel charger.  Does anyone know what kind of intelligence the CR2 chargers from DX have built in?

 

[LikeitBright]

Re: DIY Charger: 14 Batteries at once?

FYI, it works fine. Just gotta keep an eye on them is all. If I set the PS to 3.6 volts then each battery wants to draw around 80mA. They stay nice and cool at this setting. You could charge faster but need to up the voltage to 3.7-3.8 V.

I used a couple of metallic conductors and magnets on either terminal of the parallel battery array to form good connection.

 

[artix]

Re: DIY Charger: 14 Batteries at once?

no pics :-/

 

[LikeitBright]

Re: DIY Charger: 14 Batteries at once?

Ok, just for you    I've only hooked up 4 batteries but its the same with any number you want, provided you can supply the correct current.  So a regulated power supply with variable current is ideal but so far it seems if you set the voltage out to 4V then as the batteries charge the current drawn tapers off as they top up so that works somewhat as well.  Just be careful not to put a larger charging voltage across and find yourself drawing a heavy in-rush current.

I'd set the power supply open circuit voltage to 3.3-3.6V for a start and see what kind of charging current you get and determine if that is sufficient to charge your batts. Beware when they first come off the charger they will have a higher voltage than usually the case so you don't fry anything. I'd let them go off the boil first just in case.

 

[Rhith]

Re: DIY Charger: 14 Batteries at once! (Now with p

Wow nice little impromptu charger you have there!

 

[erdabyz]

Re: DIY Charger: 14 Batteries at once! (Now with p

this will kill your batteries, tbhere's no way you can see when they're charged. There are some DIY lithum batteries charger circuits in the net. I'll see if I can adapt one to supply high current and to be able to charge 14 batteries

 

[woop]

Re: DIY Charger: 14 Batteries at once! (Now with p

its fully charged when the current drops below 5% of the original charge current
it might be 1%.
thats just to stop them trickle charging, which can damage the batteries.

 

[Maelstrom]

Re: DIY Charger: 14 Batteries at once! (Now with p

I prefer...
http://youtube.com/watch?v=brdmnUBAS00

 

[chimo]

Re: DIY Charger: 14 Batteries at once! (Now with p

I have to say I would not recommend this approach to everyone.

There are many people out there that do not know about the dangers of Li-ion batteries. There are some pre-charge criteria that should be met prior to charging. It would be sad to see these people set their homes on fire or inhale toxic gasses.

Instead, I would recommend picking up some linear Li-ion chargers from say, Linear Tech, and creating a PCB with individual charging channels per cell. They are inexpensive and require a minimal of external components. An older model Linear chip I have used in the past is the LTC4054 - I'm sure there are newer models out there now. I would also recommend a spacer to ensure the charging bars do not come into contact each other if they get bumped - this could cause a short circuit at the battery.

 

[woop]

Re: DIY Charger: 14 Batteries at once! (Now with p

I prefer...
http://youtube.com/watch?v=brdmnUBAS00

lol ;D
the sad thing is, people don't realize the entire video is a joke

this comment hits the nail on the head
"Just reading the ridiculous comments makes me laugh too - not only did you create a funny show, you proved that 90% of people on YouTube are stupid."

 

[Maelstrom]

Re: DIY Charger: 14 Batteries at once! (Now with p

Hahah, yeah the first time I saw it I almost choked I was laughing so hard. I cant understand how he can keep such a straight face with something so ridiculous

 

[Switch]

Re: DIY Charger: 14 Batteries at once! (Now with p

Hahah, yeah the first time I saw it I almost choked I was laughing so hard. I cant understand how he can keep such a straight face with something so ridiculous  

You know, I belived it until he said "it's called electrical tape because it conducts electricity" and started spiling lemon juice on the terminals as a "catalyst" :

 

[Murudai]

Re: DIY Charger: 14 Batteries at once! (Now with p

I prefer...
http://youtube.com/watch?v=brdmnUBAS00

I can't believe people are still calling him an idiot on youtube comments.

Like his wireless thing. It sounded and looked legit, but when you think about it, it's crap. But he's not trying to make to make things work, he's trying to dupe gullible fools by talking a whole lot of clever sounding nonsense. All for the sake of comedy

And he is doing an awesome job +1 rep infinitesolutions

 

[Benm]

Re: DIY Charger: 14 Batteries at once! (Now with p

Hehe.. i think its quite funny, but i know there are people with very limited insight that will probably believe something like the trick with the batteries actually works. On a positive note, nothing bad will happen to you or your batteries if you try, so i guess its just good fun.


As for paralel charging the CR2's from a fixed-voltage current limited supply: I'd say this is an emergency solution only. Proper battery charging circutis do more than measure clamp voltage while charging and are probably safer to use. If you use the approach her, at least check the battery temperatures by touch regularly!