Lipo battery charging specs for mbot

#1

Can you advise what the battery charging current is set to and is is able to be changed

#2

To continue on this question what is the size of battery that Makeblock is proposing to use with the mBot? (how many mAh)
I had a look on the Kickstarter, Makeblock pages and forum, without success.
Thanks.

#3

I should imagine 2500mah should be enough the issue is how long it would it take to charge it whilst connected to mbot. I wouldn’t want to have to remove it each time I wanted to charge it. Some technical specs on the unit would help.

#4

Lack of details on the charging of the lipo battery has forced me to do my own investigation. The mcore circuit drawing shows that the charger uses the TP4056 chip (U2) whose datasheet is a available on line. A 1k2 resistor is connected to pin 2 (prog2) of the charger chip and according to the datasheet this will result in a charge current of 1000ma. On the mcore itself this is the resistor marked 122. The circuit drawing also shows that charging is achieved through the USB connector (VBUS) so it would be better to charge the battery using a phone type charger able to supply 1 amp as opposed to a USB port on a PC.
I am using a 2500ma battery and this is working very well.

#5

Hi Ian1. Thanks for investigating this as I also have been trying to work out what sort of battery to use. I am using 4 Duracell AA 2200mAh batteries in the meantime that I have to take out to charge. Please give details of the specific battery model that you used and where you purchased it. I’m struggling to find a suitable one.
Cheers, Mark.

#6

Does this one look like a good match?
http://4tronix.co.uk/store/index.php?rt=product/product&product_id=407
Adafruit 2500mAh Lipo battery 3.7v
It talks about only charging using 100mA which makes me wonder if it would be too slow to charge.
Thanks, Mark.

#8

Hi IrishClanger, That is the same battery as I am using.
Please find the datasheet for the battery in question here:

The datasheet shows that the standard charge current is 0,2CA which in this case is 500ma, the max charge current is 1CA which will be 2500ma. Since Mbot puts out 1000ma @3,7v this equates to 0,4CA which is well below the max of 1CA.

an excellent tutorial on these batteries can be found here:

The datasheet of the Li-Ion charger chip TP4056 can be found here:

A PDF schematic for the mCore can be found here and at the top left hand side is the charging circuit

https://github.com/Makeblock-official/mBot/blob/master/pcb/mCore.pdf

The charging chip on the actual board is directly behind the DC barrel jack socket for the battery pack and the regulating resistor for charging current is to the right of it, 2nd one up and marked 122.

#9

Hi Ian1. Many thanks for confirming this is a suitable battery and it is working well for you. I will bow to your greater knowledge on the technical electronic details! I’ve ordered 2 of them for my 2 mBots and will use the rechargeable AAs for something else. I had a read of the Adafruit tutorial which was very useful so I think I understand things better now - thanks for the link. As you suggest I will use a phone type charger that can deliver 1 amp.
Cheers,
Mark.

#10

Could you post details of what, if any, modifications were required to use the LiPo battery? I’m working up a course for a class of middle schoolers with the mBot as the hardware and I would like to be able to have them use LiPos if possible.

Thanks!

#11

Hi Chuck, There are no modifications needed, just plug the LiPo battery in and charge it via the USB port when required.
Regards

#12

Hi all, this seems to be the most informative thread for batteries. I have the Starter Robot Kit and am a real noobie. I realize batteries are mentioned here, and plugging it in, but i have no clue where.

Do you plug it into the Power Supply port (where the AA batter holder plugs into) or somewhere else (like the plug next to it). Also, does USB charging work for any LiPo you plug in?

here are a list of batteries. Are they all adequate and would i need to change the plug end to be compatible with the MakeBlock Orion board’s power port?

I’m sure i’m not the only beginner here, so any information would be highly appreciated. thanks!

Here are the batteries i’ve found:
Lithium Ion 3.7v 2500mAh

Lithium Ion 3.7v 4400mAh

Lithium Ion 3.7v 6600mAh

#13

The Starter Robot looks like it is using the Orion board and the motors are a bit bigger. The battery pack (which takes 6 AA batteries, so the 3.7v ones won’t work. The battery packs seem to have the batteries lined up in series, so you need 9VDC (6 * 1.5V) to power everything properly. I saw this one on eBay which might work.

@danjger, can you offer any insights? You’ve got experience with the Orion board and I don’t.

#14

I’d put a 3cell lipo 11.1v on an orion board.
http://learn.makeblock.cc/orion/

Onboard default not working and random modes
#15

Oh cool, the learn site is back up (it was down the last time I tried to get there).

Thanks!

#16

thanks @danjger ! so if i use an 11.1v lipo, i can just wire on a 2.1x5.5mm male end and i should be fine?

thanks again for all the help

#17

Hi @danjger, would one of these work?

#18

Yea, those are fine. You can pickup some from a local hobby shop too but they might be more pricy.

#19

I’m not sure of the connector but the lipo shoudl work ok. I do wonder if makeblock has installed a low voltage cutoff to prevent issues with over discharge. You might want to conform that if you think you will run the batteries down.

#20

Hi, can anyone tell me if with 4400 mAh battery the mbot will work fine?
I have big problems in finding the 2500 mAh. An other option would be the 1200 mAh, but for how long will the mbot work? I need to use it for an art installation so it shoul work as long as possible! Thank you to anybody will give some suggestion!

#21

The milliamp-hours (mAh) is more about the storage capacity, i.e., how long the batteries will last. As long as the voltage is the same, you should be fine.