# modify a DC battery charger

#### mollydog

Joined Mar 25, 2021
12
Hello, this is my first post so I hope I’ve placed it in the right sub forum

I am building my second motorised camera slider, to be used in conjunction with either compact cameras, action cameras or smart phones, keeping the kit light for transporting

this will be my second motorised slider I’ve built, the first was built around DSLR camera, this time round I’m aiming for lightweight

One very similar to this one

The heavy battery soon put me off taking the slider with me due to it’s weight and bulk

my Canon cameras are powered by the BP 511 batteries, over the years I’ve amassed quit a few of these

These batteries now won’t be used much, so I was wondering, if the battery chargers for these batteries could be used/modified, converted so with battery inserted in the charger, it can power my 6v to 9v DC slider motor, these new chargers use USB 5v (not 240AC) to charge the BP 511 batteries so maybe still be able to charge thew batteries when in the charger

This one has struck me (if it can be made to work)

There are more basic ones I’m happy to use if able to modify them

These batteries are stated 7.4v but are 8.4v, is there a way I could use the charger as more or less a docking for the battery with some minor re wiring?

I’ve seen exactly what I need and it’s called Power Junkie, two things that put me off is price (I’m retired) and it’s made to accommodate one particular model of Sony battery, I would like to make use of my many BP 511 batteries

Many thanks for any help

#### Hymie

Joined Mar 30, 2018
1,088
Surely, all you need to do is make reliable connection to the + & - terminals of the BP511 battery pack to connect to your slider motor circuit.

#### mollydog

Joined Mar 25, 2021
12
Thank you for getting back to me, I opened up my BP511 battery charger, as mine is one that needs to be plugged in too a 240AC socket maybe the internals are a lot different to the ones powered by 5v DC

I’ve took some images of my opened up charger so maybe it will make it easier for me to understand

There are 4 markings on the battery terminals, from right to left they are: +, -, D,B (Plus, Minus, D,B)

And the markings on the battery

here showing the battery in contact with the pins

can I take it that the two marked - and + will be the ones I connect to to power my DC motor?

Another question, I suppose these Lithium Ion batteries contains their own safety circuitry?

#### Hymie

Joined Mar 30, 2018
1,088
It may be that you only need to connect to the + & - terminals of the battery pack to supply your slider motor circuit (to the terminals you say). It is likely that the terminals marked B & D are providing a temperature monitoring function during charge.

If you are able to take power from the battery terminals alone – you could make connection to them within the charger (at the battery charge terminals). But you would need to take care that the wires are kept well away from the primary circuit and if they were to become detached for some reason that they also were prevented from contacting the mains parts.

There is no guarantee that the lithium battery pack has internal protection, therefore you should ensure that your slide motor circuit cannot place a short circuit across the battery due to a fault.

#### mollydog

Joined Mar 25, 2021
12
Thank you for this information (it all helps) as I now have my old charger opened, this afternoon I’ll (as a temporary measure) use a couple of crocodile clips and with some gaffe tape in true Heath Robinson fashion, try this out

I’ll post up either a burnt out charger or the motor working

#### mollydog

Joined Mar 25, 2021
12
In the end I decided to solder the wires to the charger as the crocodile clips I had were a bit on the large size to use

It looks like with a single battery it works work, the only free motor I had was a 12v DC, 35 RPM, with my 7.4v battery it was driving a bit on the slow side but the motor I plan on using with this battery is rated for 6v, a bit of a Heath Robinson

On a side note, if I went with a twin battery charger, could I wire them in serial? my Canon power winder holds 2x BP511 and draws power from each in turn so gives twice as long a run time

If I could do this any recommendations on how to wire it up (if different to normal serial wiring)?

#### mollydog

Joined Mar 25, 2021
12
To my surprise two items ordered from Aliexpress came this afternoon, I wasn’t expecting them till at least the 16th of April

One item was the belt tensioner

And the other was the 6v DC motor

It didn’t take me long to put together the belt tensioner and fit it to the v slot rail

Using the BP511 battery I see it will also work on the 6v motor

As for my power pack to power the motor and to maybe supplement the iPhone battery and rotating hear for long time lapse, I think ~I may have found what I’m looking for, it will mean having to use new LPE6 batteries but the package looks good,

Here is a video clip on Aliexpress showing it’s features

https://www.aliexpress.com/item/328...earchweb0_0,searchweb201602_,searchweb201603_

#### Ya’akov

Joined Jan 27, 2019
6,269
You really only need to connect to the + and - terminals on the battery. The charger is not required for using the batteries.

For example, Edelchrome makes this: https://edelkrone.com/products/battery-bracket-canon-lp-e6

You can find many more options with the search "lpe6 battery plate".

#### mollydog

Joined Mar 25, 2021
12
Thank you Yaakov, that’s a good find,

when I started on this project, my plan was to use those USB power banks, light weight and with my action cameras I can get at least 5 hours power from them after the built in battery was exhausted very near a full day’s time-lapse from a compact power bank

Then thinking I have a few (around 8) of my Canon fitting BP511 batteries that won’t be used much from now on, so I had this bright spark that if I could find a BP511 battery holder I could power the slider motor with it,

I spent a quit a few nights doing some Googling with no luck and I could find no information of converting a BP511 battery charger converted to power DC motors, that’s the point I came across this site and posted my question

Thinking if I can’t find a BP511 batty holder maybe the way to go is to convert a BP511 charger, then I came across BP511 chargers that could be powered by USB

As most of my time lapse photography runs in to the many hours, I though this would be good in the sense that if I modified these chargers to also power the DC motor, then as the batteries run low I could pop in a USB power bank in to this charger for the remainder of the time-lapse

Then I came across that charger on Aliexpress that was more or less what I wanted from my BP511 battery charge

The down side is, it uses different batteries and I still can’t make use of my BP511’s

A bit long response but you see where I’m coming from,

#### Ya’akov

Joined Jan 27, 2019
6,269
The down side is, it uses different batteries and I still can’t make use of my BP511’s

A bit long response but you see where I’m coming from,
You can find a battery plate (not an adapter, just the plate to make a universal charge work) for you BP511 batteries for about 3 bucks. That would let you mount the battery, and the contacts on the other side can be soldered to. You can also provide an alternative input for a USB powerbank but you’ll have to use a boost converter (cheaply available as a module) to get the 5V up to the voltage you want for your motor.

Alternatively, if you simply ignore your existing batteries, what I would do is choose a cordless tool battery that is available for a decent price and buy an adapter for that. Many are available because they get used in amateur robotics. If you’ve already bought into a cordless tool ecosystem, you could stick to that. The batteries are 1.5AH to 8AH at ~20V which is a lot of power, with a good switching (not linear!) regulator, you’d have a very long run time.

I have a nice pile of LPE6(N) batteries but if I was going to power something that needed long term power I wouldn’t use them, they re very expensive with relatively low capacity. I know you have the BP511s but don’t let that drive your design when you can do better. If the cost is a big issue, then I can see why you’d try to use them but if it’s just “feeling bad” about not making use of them, remember the rule about sunk costs when making financial decisions, its true here, too. Using these batteries will make your design and end result worse, that’s the cost of making use of something not well suited because it is on hand.

#### mollydog

Joined Mar 25, 2021
12
It’s been a few days since I followed up, but not been idle with this project, did a lot of googling regarding what batteries and power setup was both suitable and economical for my needs (non professional these days)

@ Yaakov

You are so right regarding using my old batteries with technology dating back maybe 15 - 20 plus years, and bite the built with updated power source might/would be a better choice, I feel sometimes you do need to hear it from someone more knowledgeable to make you see, thank you

After doing lots of googling my thought are towards using Sony NP-F batteries,

Coming in various sizes, the three I think will be good for my needs are the

NP-F 550, NP-F 770 and the NP-F 970

Here’s a YouTube clip regarding these Sony batteries and/or Sone copies

If I go this route, options I could take not using Sony original but Chinese copies are:

Option1,
buy one or two of these NP-F batteries and a battery mount for the NP-F battery

input power would be USB 5v, output power would be 7.4v DC and/or 12v DC, but would still need to buy a charger, the cost of this option from Aliexpress is around £7 excluding the battery and charger that might add up a further £20 - £25

Option 2,

Buy the twin battery charger for these NP-F batteries with two batteries included, this battery charger can charge the batteries either by 12v DC or USB 5v, the beauty of this charger is that it has one USB output to power 5v DC items, I’m not sure if an adaptor with say a twin USB output could be added to it (safely)

Cost of this setup from Aliexpress would be around £30 to £40, again from Aliexpress, I saw that Amazon UK sell this setup for not much more, around £59

Option 3,
Again using these NP-F copies I could go for an item called Power-Junky, the thing I like about this item is that it is a it’s not just a battery charger, charges using USB, and has 3 outputs, 2 are USB and one is a 7.2v DC

Input, USB micro and USB C

3x output ports

I’m not sure if this is what’s in the box, or an order can be made with camera dummy batteries of your choice

Here’s a YouTube clip of it’s features

Cost, around £65 - £80 plus battery cost

That out of the way, I’m surprised the amount of items that have arrived from Aliexpress, the only thing I’m waiting from them now is the PWM Motor speed controller, the relay I bought from another supplier, these items I wasn’t expecting them till mid April

The wiring for the limiter switch, one strand needs to be at the far end of the control unit and not wanting wire dangling (like I had with my first motorised slider I built, I was able to thread a ethernet cable in one of the two holes in the V Slot

Then this past Saturday the postman posted the slider carriage all pre assembled which pleased me

After a few adjustments of the wheels on it went

One surprise was that the centre hole wasn’t tapped for 1/4 20 or the 3/8 thread,

on measuring the diameter of the holes I saw that they were 5.12mm across, as near as dam it to 13/64, so I got out my 1/4-20 tap and tapped a 1/4 20 thread

I threaded a bolts to it from the under side to mount a ball and socket head to the carriage,

dam there wasn’t enough clearance under the carriage for a bolt with a 5mm head, so I had to ground off just about all of the head off,

I left maybe just over a mm of head on the bolt and even then I could just about slide a sheet of paper between the blot head and the V slot

The carriage plate is approx 4mm thick so I didn’t counter sink the thread in fear there won’t be to many threads left for the bolt to cling to

Once that bolt was tightened to the carriage I placed my small ball head used with my action cameras, compacts and the iPhone, with and without the motorised head

While at it I fitted my ball head I used to use with my Hasselblad cameras

Any opinions regarding which combination of batteries and/or chargers would be a good choice?

#### Ya’akov

Joined Jan 27, 2019
6,269
The choice of Sony batteries is good. My Ikam on camera monitor uses LP-E6s but all my lights use the Sonys and they are avmaialbe everywhere cheap.

I haven't used but am familiar with the Power Junkie stuff, it's got a decent reputation. Of course the Small Rig products are top notch.

Edelkrone, who of course make sliders and related rigs offer this:

https://edelkrone.com/products/battery-bracket-sony-np-f

#### mollydog

Joined Mar 25, 2021
12
I’ve done some googling on the edelkrone bracket for the NP-F batteries, with the limited information I could gather, I’ve come away thinking the the NP-F double charger from Aliexpress or Power Junky, maybe would fit my needs

My reasoning is with the edelkrone, I would still be needing a battery charger,

So now it boils down to (for my non professional needs) which better fits my needs

On a different note my relay to connect the end limiters to the motor arrived this morning

It didn’t take me long to copy their wiring diagram

I’m now waiting for the PWM speed switch to arrive once that arrives I can work out the size box I need to fit it all in

With the PWM and a forward & reverse switch ( so I can move the camera to where I want it to start on the slider before start filming

Here’s what it should look like once those two items arrive

Looks a bit messy, I never was too good at wiring

Here’s maybe a better image of the wiring and my PWM and the direction switch

I don’t know why in my last post some of the images don’t appear, they worked fine when pre testing on another forum

#### mollydog

Joined Mar 25, 2021
12
I tried to post a thread hear but quit a few of the images wouldn’t show, but they do on another forum I belong to, so as not to have any images missingon here, I have a link to the other forum,

You need to scroll to the bottom of the page, the thread is split in to two parts, so start with “part one” and the following thread is part two

Sorry for this hassle but I tried with only having 7 images on this thread butstill a few were missing

here's the link any issues please let me know, I don't think you need to sign up to view the link if you do then I'll take out the images and re post onb here, thanks