Finally - a compact battery charger!

[RichC]

At last a compact Leica M8 battery charger!

This battery charger is self-contained, and does not require an external lead or transformer unit. It has removable plug blades, allowing the blades to be changed when travelling abroad, and making the charger smaller and more portable when the blades are removed.

The standard M8 "brick" measures 6.5 x 6 x 11.5 cm, and the compact charger a mere 3 x 4.5 x 8.5 cm (ignoring the plug blades for both chargers). In other words, the compact charger takes up 75% less space – and that's before taking off the removable blades. The compact charger is also less than half the weight of the "brick": 100 g versus 225 g.

Photos of the compact charger are attached.

Unfortunately, you can't buy this charger - I made it! I'll explain how in the next post. Why Leica didn't gave us the Brick instead of something like this beats me!

[RichC]

First, to forestall the doomsayers, I should point out that my compact charger is perfectly safe - I'm a dabbler in electronics, so I ran what I wanted to do past an electronics engineer friend, who gave the project a thumbs up. The compact charger and the original M8 brick both seem to take the about same amount of time to charge a battery discharged by roughly the same amount, and when a battery registers as fully charged in one charger, it is still shown to be fully charged when swapped to the other charger. In other words, the chargers perform identically – as expected.

There is no good reason for the original Leica M8 charger to be so huge: there are plenty of examples of this type of charger for lithium ion batteries with similar specifications that are significantly smaller (like that for the M8-2!). One of these small chargers can easily be adapted for the Leica M8 battery, since the chargers for this type of battery all need to meet the same requirements (charge voltage, charge current, etc.).

The Leica M8 lithium ion battery is typical of the lithium cobalt oxide type used in digital cameras. Like most such batteries, it has a third important contact in addition the positive and negative terminals: the thermistor (or T) terminal. The charger uses this T terminal to control the charge current during the charging process.

"Caparobertsan" successfully modified the Pentax D-BC7 lithium ion battery charger to take Leica M8 batteries: see http://www.l-camera-forum.com/leica-...-macgyver.html (despite the mocking posts!). This charger is ideal: it's tiny, cheap and common on eBay. Its output is 4.2 V, 770 mA max., and the matching battery (used in various Optio cameras) is the Pentax D-LI7 (3.7 V, 1800 mAh). Not surprisingly, these specifications are almost identical to those for the Leica M8: 4.2 V, 750 mA max. for the charger; 3.7 V, 1900 mAh for the battery. Both chargers also have three contacts: positive, negative and battery status (T).

The Pentax charger is also convenient as it incorporates a mains transformer, reducing clutter and bulk: simply plug in a standard "figure 8" AC power cord.

Caparobertsan’s modification is effective but ugly – he made a mould of the M8 battery out of epoxy. However, now that Delkin has released M8 plates for its Universal Battery Charger, for a mere £2.99 (for two!). Grafting the Delkin plate onto the Pentax charger is a much more elegant solution.

There is no retaining mechanism for the battery. I could have used the retaining arms on the Delkin plate, but the battery is held tightly when pushed onto the contacts, so I decided to omit the arms to make the charger more compact.


Materials

• Pentax D-BC7 battery charger (see photo)
• Delkin Leica M8 Universal Battery Charger plates
• Genuine Blackberry Storm travel charger
• Two 8 mm screws for plastic (I nicked these from the TV remote!)
• 3 Amp fuse
• Tools: Dremel kit, screwdrivers, craft knife, soldering iron, ruler, file, wet & dry paper
• Araldite
• Insulating tape

The cost of the Pentax charger, Blackberry charger and Delkin plates totalled about £20.


Instructions

Before gluing and soldering, do a "dry run" first.

1. Dismantle the Delkin plates and cut the three wires from the battery contacts where they attach to the lower cover (i.e. leaving a length of wire attached to each contact. Next, using the Dremel, cut the sides off one the dismantled top parts, so that the modified plate fits inside the inside the Pentax charger battery cavity (the battery contacts will be in the way - this will be sorted later). Note that the bottom of the plate is cut to align with retaining tab. The modified Delkin plate can be clearly seen in the front view photo, above. Trim the screw posts on the rear of the plate so that they’re level with lower central area.

2. Take the modified plate, and make a mark 2.5 mm to the left of the left battery contact. Carefully cut a slot that matches the other two contact slots, and insert a contact from the unused Delkin plate (again, see photo). Check that an M8 battery will fit. If you mess it up, remember that you have a spare plate!

3. Dismantle the Pentax charger: undo the screw in the base, and prise apart gently. Push the three battery contacts into their holes, and lift out the circuit board.

4. Drill two holes in the Pentax charger battery cavity for the battery contact leads. The modified Delkin plate should now meet the floor of the battery cavity squarely. Tidy up the edges of the plate with a file and wet & dry paper. Check that the M8 battery will fit on the plate when in the battery cavity. Epoxy the plate into the battery cavity, and place epoxy ver the rear of the battery contacts. Leave to set overnight.

5. Modify the circuit board: cut off the three original spring contacts just above the "circles" close to the circuit board (this makes sense if looking at the circuit board!). Next, unsolder the AC lead socket - assuming you want to use removable mains blades instead of the mains lens, to make the charger more compact.

6. Check that there is enough clearance for the battery contact leads above the circuit board - there should be. Solder the leads to the stubs of the old contacts. Do get these in the right order: from left to right, T, +, - (as marked on the circuit board).

7. Roughly cut open the Blackberry charger with the Dremel. With more care, cut the bottom part just above the contacts (see side view photo, above). File square, and tidy up with wet & paper. Peel off the Pentax specifications sticker off the charger, and mark where the contacts locate on the bottom of the charger. Drill two holes in the Pentax base. The Blackberry charger base should now sit squarely on the Pentax charger.

8. Solder leads suitable for mains electricity to the fuse, and solder one lead to the underside of circuit board where the left-hand contact of the mains socket went. Solder another mains lead (NB: not that going to the other end of the fuse!) to the former right-hand contact of the mains socket. Epoxy the fuse to the inside of the Pentax case, making very sure that it is well away from components and will not short circuit anything when the circuit board is replaced. The free ends of both leads should be about 2 cm - just long enough that you can easily solder them to the contacts in the Blackberry base (looking at the plug blades, the left-hand one is live). NB: let the epoxy set now - do not solder the leads until the next step.

9. Replace the base of the Pentax charger, with the mains leads exiting through the two holes you drilled earlier. Do up the screw holding the two halves of the Pentax casing together. Solder the mains leads to the Blackberry base.

10. Drill two holes for the screws you nicked from the TV remote, and screw the Blackberry and Pentax parts together (see back photo, above) - make sure the screws won't touch the circuit board. It's unlikely that you'll need to dismantle the charger once assembled, so you could simply epoxy the parts together (you won't be able to get to the screw holding the Pentax charger halves together).

11. Almost there: cut a rectangle of plastic and glue it into the hole where the mains socket used to go.

12. Finished!

[lars_bergquist]

Do not Leica include the new compact charger with new deliveries? So there's little use railing at the old 'brick'. Me, I like the new charger, and people who are glued to their automobiles will also like the fact that you can exchange the cord for one to fit the cigarette lighter.

The old man from the Age Before Batteries

[RichC]

Originally Posted by lars_bergquist

Do not Leica include the new compact charger with new deliveries? Me, I like the new charger, and people who are glued to their automobiles will also like the fact that you can exchange the cord for one to fit the cigarette lighter.

Fine, unless you bought the original M8 (like me) or don't mind paying £100 to buy Leica's new charger.

Also, one of the things I dislike about the modern world is the rampant consumerism with its short product life cycles. No one seems interested in being thrifty, keeping machines going or tinkering with things these days (granted, most things have chips in these days, making this difficult - even my toaster!). So, why not spend a couple of hours making a compact battery charger that works as well the commercial one, costing far less, and recycling unwanted items?

As far the cigarette lighter socket, this can easily be fitted (search for Mark Norton's DIY compact charger post). Not much use to me personally, since I don't drive. Interesting statistic: nearly 40% of UK households don't have a car, compared with only 8% in the US (I know a major reason is practicality owing to spread-out US cities etc., but, nonetheless, I found the difference startling).

[chris_tribble]

Rich - how elegant. I'm not sure I can follow the text instructions without having all the bits in front of me (sounds like a Mark Norton cooperation would be good here!) but the principle is clear and the solution rather attractive.

As I got the small M8.2 charger with the camera, I'm not immediately tempted - and I'm still thinking about the Delkin as it would be great to have one brick that charged M8 / 5D and 5D2 (waiting for this latter). Although the Delkin isn't as compact as your neat job, it would have this advantage when on the road.

Well done anyway!

[Bo_Lorentzen]

Rich,

Very elegant, outstanding hack, well done.

It looks from the pictures like the form-factor size is maybe about half of the "new" Leica charger.? This seems like a very attractive size for traveling.

Actually I have engaged in a different type of fiddeling and have been putting together a solar charger lith-ion pack combo with a 12v outlet for the M8.2 charger. unlike the pocket size jobs this one is actualy big enough to take a full charge in a afternoon of sunlight and actually finish charging a leica battery. probably got a bit de-toured here because most of my trips lately have been around mechanized transportation.. (Land Rover Defenders turns out to have 12v plugs.) so the solar charger is a bit off the grid, however it give me some sick comfort to know that next time the power goes down in Los Angeles I will be able to continue taking pictures. (no mention of how I am going to unload the images)

.

[marknorton]

Nice solutuion, especially with the availability of the contact plates.

Personally, I'd keep to a figure of 8 cable, in my case needed for a lap top anyway, because it makes travelling to the US, Europe or Australia easier.

To US eyes, the UK power socket must seem impossibly large. Keep in mind it's for 230-240v, not 110v and the power pins are shuttered to prevent a child inserting something into the holes and killing themselves. Still big though.

[k_g_wolf]

>> Rich

Great work !

Posts like these make this forum so valuable for many users.
Thanks for all your technical informations.

Almost as interesting as M. Norton´s M8- adventure ...



Best

[dcoombs]

Originally Posted by marknorton

Nice solutuion, especially with the availability of the contact plates.

Personally, I'd keep to a figure of 8 cable, in my case needed for a lap top anyway, because it makes travelling to the US, Europe or Australia easier.

To US eyes, the UK power socket must seem impossibly large. Keep in mind it's for 230-240v, not 110v and the power pins are shuttered to prevent a child inserting something into the holes and killing themselves. Still big though.

Very nicely done, Rich! Congratulations!

For Mark, slightly OT for which I apologize in advance, regarding your comment on pin size and 230-240v needs - how does this square with the french plugs? Same current, small pins. I'd like to know as it's always bugged me.

Thanks. Doug

[RichC]

Originally Posted by dcoombs

Very nicely done, Rich! Congratulations!

For Mark, slightly OT for which I apologize in advance, regarding your comment on pin size and 230-240v needs - how does this square with the french plugs? Same current, small pins. I'd like to know as it's always bugged me.

Thanks Doug!

I'm not Mark but I'll answer. British legislation requires three-pin pugs for all electrical devices (ignoring shavers!), with the top pin being earth ("ground" to Americans) - even if the device doesn't need earthing (like my charger). In fact, sockets are designed only to work if an earth pin is present.

Also, British plugs incorporate a fuse, adding to bulk - other countries, like France, have (arguably safer!) systems in which the building circuits use bi-polar circuit breakers instead, so fuses in plugs aren't needed.

France permits two types of plug, unlike in the UK: non-earthed and earthed. The former is the common two-prong plug with round pins - a British plug without its earth pin would actually be about the same size. The French earthed plug has the third (earth) pin in the socket - the plug is round in shape and quite bulky.

Other European countries, and the US, I believe, also use a similar system of two plug types, depending on a device's need to be earthed.

[caparobertsan]

WOW yor one looks so pretty! But Mine is just finnnnnnnnnnnnne!!!!!!

[RichC]

Originally Posted by caparobertsan

WOW yor one looks so pretty! But Mine is just finnnnnnnnnnnnne!!!!!!

Not knocking yours, Cap - if it weren't for your pioneering spirit, it wouldn't have occurred to me to make my own charger...! So, cheers!

[k_g_wolf]

>> Rich


Could this charger-project be done for the DIGILUX 2 as well ????


Best

[RichC]

Originally Posted by k_g_wolf

Could this charger-project be done for the DIGILUX 2 as well ????

It could but you'd need a different charger: my charger is suitable for batteries comprising one cell, like the M8. The Digilux 2 battery puts out 7.2 V - i.e. it comprises two cells. Anyway, aren't there plenty of third-party chargers for this camera?

[caparobertsan]

Originally Posted by RichC

Not knocking yours, Cap - if it weren't for your pioneering spirit, it wouldn't have occurred to me to make my own charger...! So, cheers!

But I like your power plug underneath solution! Where those part come from???
I want built mine like yours, too!

[k_g_wolf]

>> Rich

thx for the hint !

Never thought of this. Should have had this idea by myself ...


Best

[Fotogo]

Originally Posted by RichC

At last a compact Leica M8 battery charger!

This battery charger is self-contained, and does not require an external lead or transformer unit. It has removable plug blades, allowing the blades to be changed when travelling abroad, and making the charger smaller and more portable when the blades are removed.

The standard M8 "brick" measures 6.5 x 6 x 11.5 cm, and the compact charger a mere 3 x 4.5 x 8.5 cm (ignoring the plug blades for both chargers). In other words, the compact charger takes up 75% less space – and that's before taking off the removable blades. The compact charger is also less than half the weight of the "brick": 100 g versus 225 g.

Photos of the compact charger are attached.

Unfortunately, you can't buy this charger - I made it! I'll explain how in the next post. Why Leica didn't gave us the Brick instead of something like this beats me!

Well done Rich. Your solution is elegant and simple. The size alone makes it a winner for me. I am one that is still hauling around my Franken Charger and unwilling to ante up for the new compact version.

[steich]

@marknorton:

...still waiting for your "S2 Anatomy" thread

Regards

Stefan

[wolfloid]

It is astonishing to me that you have to resort to this sort of thing, when if Leica had given it any thought at all they could have come up with something as small as this from the beginning. But no, they preferred to offload charger bricks on to M8 buyers, who thought they were buying into a svelte little travel outfit.

It is things like this, and many other things,like burying the ISO adjustment in the menu, that make me wonder whether they have learned joined-up thinking at Solms.

[doubice]

Rich,

A fantastic idea and a project that I will probably embark upon.....

I do have a question though - one that could also be answered by Mark Norton:

There are aftermarket chargers available, which already have the mains plug built-in. They are mostly of Chinese origins (what isn't nowadays...) and do not have the ' T ' contact; just the + and -. I am using one of those chargers at the moment, for my wife's little Canon SD something, without any problems and am wondering how important the ' T ' contact is.

I have another one of those chargers coming for my Digilux 2 - it is quite ingenious as the charging plate is removeable, similarly to the Delkin. I am wondering if I could adapt one of these beasts for the M8 as well....

Are these aftermarket charger manufacturers using different interior circuitry to provide the function of the ' T ' contact?

Best,

Jan