Battery charger By MacGyver!?!?!?

[caparobertsan]

Hello again everyone!
I have got 2 cheap batteries from H&K today. I have measured voltage it registered 3.8V. That is good. Label says 1700mA so 200Ma less than Leica original one.

Anyway I have read this forum previously, and I have found A genius Dr. MrakNorton`s modified battery charger. From His picture I figured out only 3 contacts from battery charger. and Which is negative or positive.

I found this Pentax charger on my desk and spec. is similar to leica original. 4.2V output 660 mA. I know leica one`s output is 3.7 V exact according to label. But close enough.

I have connected some wires and metal pieces at end of each wires. ANd connected end to Pentax battery charger(didn`t solder them because I still need this charger).
I have connected battery and Red lamp came on(means it is charging-green lamp at full charge). I have placed whole CIRCUIT in a controlled environment(Postal Box!).

I am waiting now to see if lamp will turn to Green.

I am not expert of electronics. I only know positive and negative. But I do`nt see why this doesn`t work.

I will let you know. Or Expert Advice please!

[caparobertsan]

Charger is still indicating "RED" = still not sully charged. Battery is cold but charger is hot. Wrong wiring? Or Normal. I need to place some kind of cooler ???

[marknorton]

Charging Li-Ion batteries is a much more involved process than charging lead acid batteries or even Ni-Cads. They need to be taken through a particular charging cycle which is established by the controller chip in the charger, normally programmed by setting component values.

Towards the end of the charging cycle, the battery voltage will be fixed and the charging current will decline over time; when it reaches about 1/10 of the initial current, the battery is effectively fully charged and the charger should switch off.

That voltage needs to be set quite accurately to +/- 0.05v; the Leica battery will charge at about 0.7A to begin with. It may be the charger is getting hot just because the battery is drawing more current than the charger is capable of supplying.

If you can, I recommend measuring the charger voltage and charger current and take readings every few minutes when charging the Pentax battery from flat, then do the same for the Leica to see what difference there is.

Either way, you are correct to treat the Li-Ion batteries with respect - that can explode when misused.

[caparobertsan]

If you can, I recommend measuring the charger voltage and charger current and take readings every few minutes when charging the Pentax battery from flat, then do the same for the Leica to see what difference there is.

Either way, you are correct to treat the Li-Ion batteries with respect - that can explode when misused.[/quote]

Thanks Mark!
I have measure voltage from charger It was 4.2 Volt.
I have measured pentax batteries they all say 3.7v but actually 3.9-4.0 V.
I measured original Leica battery which was left in a camera it was 3.8 V. So I think if it was fully charged, it will go more than 3.7 V.

It is still saying RED. Maybe circuit is not same as Leica one.( I hve chraged Panasonic lumix Fz-10 battery with this, and it worked perfectly!

I will wait longer.

[marknorton]

The voltage on a fully charged battery will be aound 4.1 - 4.2v but quickly drops to a nominal 3.7 - 3.8v in use - the higher charger voltage is required to "force" the charge into the battery. Li-Ion batteries are far from constant voltage sources however.

The Pentax charger will be programmed to respond to a particular charging characteristic of the battery - how quickly the current falls - and if this is not what the Leica battery is doing, it will not correctly sense the end of charge. For safety, most chargers give up after several hours, though yours appears not to.

[andybarton]

Originally Posted by caparobertsan

Expert Advice please!

Get yourself down to Maplins and buy a proper charger...

[jaapv]

And wear safety glasses when looking at Li-Ion batteries you are experimenting with....Your eyes are worth more than a charger.

[SJP]

Just did some Googling on Li-ion chargers, how about this one?
Smart Fast Charger (1.5A) for 3.7 V Li-ion Rechargeable Battery Pack

Any volonteers to try if it works?

For the more adventurous we could design our own using TI datasheets

[vanhulsenbeek]

Originally Posted by caparobertsan

Hello again everyone!
I have got 2 cheap batteries from H&K today. I have measured voltage it registered 3.8V. That is good. Label says 1700mA so 200Ma less than Leica original one.

I can't reconcile a considered expenditure of > 6000 EUR on m8 plus lens, and then exposing that investment to this sort of junk. Plus spending valuable photo time on that junk.

Please do yourself a great favour: buy an extra battery at < 100 EUR! Or buy two. The cost of 10 rolls of Velvia including development!

[caparobertsan]

Hello everyone! Thanks for the comment.

It worked!!!! Lamp turned to green after 3 hours. It was 660 mA charger Leica one is 750mA. So I think I will put it together neatly and test it again.

This charger is about 1/3 of Leica one so it is good for traveling. Third party company make charger for most of battery. So it should not be that hard for them to make one. Because of demand issue they don`t make. Not many M8 users compared to Canon or Nikon D-slr users.

[caparobertsan]

Originally Posted by SJP

Just did some Googling on Li-ion chargers, how about this one?
Smart Fast Charger (1.5A) for 3.7 V Li-ion Rechargeable Battery Pack

Any volonteers to try if it works?

For the more adventurous we could design our own using TI datasheets

Not recommended.
1)capacity is too high 1500mA!!!! Faster charger = damage battery quicker.
2)No third contact which must mean something like tell charger to stop charging because battery is charged full.

[SJP]

also smaller current available apparently the charge current is constant until it reaches 4.2 V and then the current is monitored to establish the level of charge reached, see here. Charging at 1.5 A is still at only 0.8C so that should be safe for Leica battery, for your 1700mAh batteries it is getting a bit high at 0.9C.

[JumpStart]

I will never understand behavior like this.

Spend thousands on camera, then spend the rest of your life trying to outfit it with cheap accessories.

The current Leica charger is not that bad. Put it in your suitcase and get on with your life.

DBK

[jaapv]

It is not so much the price, as the size of the standard charger that is the problem.

[youngarl]

I must have wandered into a terrorist site.

[fotografr]

Forget the charger. Leave the battery in the camera, connect the usb cord to the jack at the side of the M8, then stick the other end of the cord into any electrical socket. Leave it connected for 30 minutes and it should be good to go.

I don't know if this will work or not, but it's worth a shot.

(Attorney members--Do I have liability issues here?)

[stunsworth]

Brent, you forgot to mention that the cable should be plugged into the mains first, and the other end should then be licked to make sure there's come current flowing - no point in connecting it to the camera otherwise.

[fotografr]

Originally Posted by stunsworth

Brent, you forgot to mention that the cable should be plugged into the mains first, and the other end should then be licked to make sure there's come current flowing - no point in connecting it to the camera otherwise.

Steve--I was assuming everybody already knew that, but you're right to bring it up.

[mustafasoleiman]

Sh*t That Hurt.....

[fotografr]

Originally Posted by mustafasoleiman

Sh*t That Hurt.....