Let's Make Robots!

Holder & charger for mobile LiPo batteries (Open letter to Jack / DAGU)

Since I had good luck last time (http://letsmakerobots.com/node/7046) - I will try again.

This time, it is batteries.

As I was just talking with Gareth about, it is a shame that all the used mobile phones get thrown away, with nice LiPo batteries, even chargers.

And you can get really cheap LiPo's if you get some that should be sold as spare batteries to common cel phone types, or outdated models.

What I would like, would be a HOLDER and second a CHARGER. This would open a world for us!



Biggest problem is using these batteries are to make sure that you get a good connection out to your circuit - and specially if you want to stack 2 batteries.

I am very sure that a universal holder / one that would cover major brands or could be adjusted, would be a huge selling hit; The easiest way in the world to get all the LiPo action that you would ever need. Make sure this holder is light weight, could even just be a clip to connect.


CHARGER (and discharging circui?):

Charging LiPo's are scary. And I am not sure if it can start fires to hook up a motor to a battery that was designed to last for a week with low usage. So, I would also like to be able to purchase what ever (possibly) needed to be able to use the battery without causing too much dangerous stuff. And as a pure luxury, it would be cool if the clip could be hooked up with a charger, so one would not have to move the battery from the robot, to be charged by the phone. In the event that one only has the battery, not the phone, this would be really nice.


So, all you clever people :) Can we design such a clip/holder, can the electronics be done?

Let's build, gentlemen :)

All inputs below, thanks.

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Well, just like with the mounting brackets there where a lot of "YOU DONT NEED THIS", but .. well.. I still have easy access to a lot of nice LiPo from old phones. And I still am not using them for my next project.

If DAGU had made this clip, I know I would.

well, dagu may not make one, but you can buy them for $2 delvered from here

Now, that clip may be a charger. But I am interested in a nice thing that I can use to power my robot with say 2-3 batteries.

It would really be a clumsy bot (and it would not take much movement before it lost power) if it wa to utilize these.

But thank you for showing me that shop, that just cost me USD 54,93!


DescriptionUnit priceQtyAmount
Virtual 5.1-Surround USB 2.0 External Sound Card
Item# 22475
$2.14 USD1$2.14 USD
Mini USB to Micro USB Adapter
Item# 41527
$2.20 USD1$2.20 USD
Real+Growable Lucky Bamboo Plant In-a-Bottle Keychain (2-Pack)
Item# 10684
$2.38 USD1$2.38 USD
Car Cigarette Powered 1000mA USB Adapter/Charger - Black (DC 12V)
Item# 40470
$2.59 USD1$2.59 USD
Jet 1300-C Butane Lighter JODKEN
Item# 1320
$2.78 USD3$8.34 USD
Neodymium NIB Magnet Spheres (6mm / 20-Pack)
Item# 13503
$3.74 USD1$3.74 USD
Novelty Dippy Drinking Bird
Item# 29233
$4.35 USD1$4.35 USD
Super Strong Rare-Earth RE Magnets (20mm x 2mm / 100-Pack)
Item# 13515
$29.18 USD1$29.18 USD
Registered Air Mail ##
Item# 0
$0.01 USD1$0.01 USD
Subtotal$54.93 USD
Total$54.93 USD

I got 3s1p (11.1V) lipo from hobby king, and it was about $12 (USD). In fact it was considerably cheaper to buy that LiPo and have it delivered to my door (from Hong Kong or wherever) than it would have been to buy one at any of the shops in NZ, even the same model battery was going to cost at least double what I paid.


I highly recommend them. Also they sell all the connectors, chargers, monitors etc that you could need.

Phone batteries just seems like more trouble than they're worth...

Hmm.. But phone batteries are often free, and it is good for the invironment.

There would be no trouble, if this clip could work, that is my point.

But good info, you may be right.

My battery holder set up for Lipos(Li-ion), here you see two 3.6V lipos in series.

Please note ON/OFF Switch and more importantly an "inline fuse" the red thingy on the left.

Also its good idea to get a good terminating plug - in my case a Tamiya rc car connector.

The battery holder on the Right has been cut out of a second identical dead natel (i had a batch of 3 the same)

Lots of Hot Glue to insulate the terminals.

Then its easy to release batteries and charge via a simple natel phone of the same make.

The Metal enclosure may be over the Top for natel batteries - but for highpower LIPOs Saftety comes first.

Some people use special bags - however choose carfully as tests have shown that even these go up in flames


Hey, that looks like a fine proto type.

The perfect "clip" will be a lot thinner & lighter - like if made from vacuum moulded plastic sheets, and only covering what is needed, perhaps shaped like a cross.

Man, that would be nice to have, just clip on, and you have instant access to LiPo's - charged by your phone, simple and cheap, if not free.

Is there any industial design-kind of talented persons listening to this?

Charging lipo's is actually quite easy today with the multitude of li-ion/po charging integrated circuits that are avaliable.  I am building a li-ion charger now using the MCP73861 from microchip.  A lot of phones actually use chips like that in them, and the devices that oddbot posted most certainly do, as do the cheap hobbey lipo chargers such as this .

In China these are very common. Universal mobile phone battery chargers. The two spring loaded antenna are adjusted to make connection with the battery terminals.

Brilliant! Then there is already taken care of

* How to clip on to any battery

* Make the circuits to charge

Now, in one hand I have my robot, in the other a LiPo - possibly charged by this universal charger.

In the middle I have a problem; I want to place this battery on the robot. Or in my plane. Or..

I need that "thing" to do that. And I need it to be made, so it is small, and so that if I have 2 or more batteries that I want to hook up it is not a problem.

I want to be able to make something like a racing pack, a strong little beast that I can fill up with these cheap / free LiPo's.