Mini Remote Upgrade

Have been using a mini 2.4GHz remote with dual vescs for about 8 months now with no issues at all. - very reliable and consistent. Love the trigger control .

Have now decided to do a bit of an upgrade on it with following features:

  • Fit a small Li-Ion battery to replace need for AA cells - including micro USB charging port with leds

  • Replace the mini remote stock slide power switch with a more robust rocker switch

  • Fit a mini electric bell on side of remote -with a push-button switch - powered from new battery

I will include links for all material in case others want to repeat process.

Battery - went for Hobby King 750mAh battery


BMS - went for AliExpress - this has mini usb port and staus leds (charging and fully charged led) AliExpress 1S BMS bms

Electric Bell mini bell

First step is to carefully separate the two halfs of the remote body . Then remove AA battery cell pouch and this opens up quite a bit of depth to mount stuff

Then hot glued battery to bottom of housing

Then hot glued BMS to battery

Will update as build progresses


just a word of advice, dont keep the hotglue on the battery for too long as its not good to get liion cells too hot

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Bit more progress - fitted miniature rocker switch and “charging” and “fully charged” leds. These leds are wired in parallel with leds on BMS pcb. Works OK. Put a bit of thought into the right position for the bell switch. - finally settled in a position were I can operate bell switch with right hand thumb without interfering with trigger throttle control. I used a miniature tactile switch here to achieve positive activation. ( Tactile Switch link

Wired it all up including a diode in series with battery +ve to rocker switch ( inside red heat shrink) to drop full charge voltage a bit. Did a trial discharge on battery down to 3.4V - then charged up OK via mini USB port with red light on for charging and amber light on for fully charged ( battery at 4.2V)


Looks great! What’s the rated voltage range for the mini remote? Since it uses 2 AAs I assumed 4.2v would be too much. How has the remote handled the increase in input voltage?

I dont know rated voltage of mini is.

See post above - I connected one diode in series with +ve from battery to switch so mini electronics will only see 3.6V max for fully charged condition. The mini bell has 3V cells and I think it will be fine operating at 3.6V (max)

The mini remote electronics draws 20mA so 750mAh cell will give around 35 hours before recharging.

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I’ve been too lazy to do all this stuff, and it’s paid off. I’m just gonna copy everything you’ve done here. :slight_smile: Thanks for posting!

Is the mini bell mounted in the remote? Or is that the yellow wire?


no worries i do not use the steering wheel on RHS of remote -so removed that and I will fix bell on outside of remote where the steering wheel was Will post pictures when complete Cheers

@SkaterBoy58 genius, especially the diode. Much thumbs up.

It’s all fits in the 2xAA cavity under the cover, and is reversible for now.

The diode drops the voltage from 4.2v to 3.3v at the battery contacts with the remote turned on.


  • the usb charger module has a little bms built in. The overdischarge voltage cutoff is 2.8v, scary low for lipo. Perhaps eventually will put in a cylindrical cell, maybe even 18650.
  • the board’s charge rate is 1a, which is a bit higher than necessary. Generic usb ports will only give 500mah. I’ll be looking to change a resistor somewhere to adjust this.
  • the little voltmeter shows 4.01 but actual voltage is 4.2v.

Kind of scared to test this on a ride :slight_smile: Maybe I’ll leave it on for a few hours and see how it does.


18650 won’t fit in a Mini Remote. An 18500 or a 14650 will, take your pick. I modded one as well…

Also I have an extra 14650…

The BMS I went with has adjustable charging from 130mA to 1A by adjusting a resistor - see details in BMS link above.
This BMS is used for charging only so no undervoltage discharge protection ( which I don’t see as a major problem) The mini remote led starts to flash on low voltage but I haven’t measured when this starts. I will end up charging remote after every few rides so will probably never get below 75% . I may be able to fit a small voltmeter ( similar to yours) above the rocker switch - just to finish it off.


Edit - To add to above - the LiIon battery itself has a small BMS inbuilt into top of battery - presumably to provide over and under discharge protection for the battery

LiIon cell

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I went one step further with my mini remote mode…


cruise control or horn pb?

The button? No it’s for changing telemtry information on the screen

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Managed to fit a small volt meter mini voltmeter link above rocker switch . Could connect this volt meter direct to battery if you want direct battery voltage displayed. Looks quite nice . These are simple two wire devices so connected -ve to BMS output -ve and +ve after rocker switch. This draws 5mA current so about 25mA in total including remote electronics. Basically cut a rectangular hole in enclosure and hot glued display in level with outside face- then poured hot glue over the lot to hold it all in place.


@ervinelin any details of this remote upgrade?

See here

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Next thing is to attack the bell. The RockBros mini bell looks like rockbros bell

First thing is to pull it to bits (as per normal) and see how it is built. It has 2x 3V button cells in it so 6V supply. You take off the rubber cover and can get to the internals.

First thing is to cut off the 3V cell metal holder . Then soldered +ve and 0V wires in place of cell. I will connect these directly to battery to give it a bit more voltage and to provide constant supply to bell pcb. Then soldered two wires in parallel with switch on horn ( yellow wires) for connection to the tactile switch on remote handle . If you don’t have power on bell pcb constantly - you need to set up the preferred sound every time which is a bit of a PITA.

Then cut rear plastic cover with a junior hacksaw to provide a level surface to mount bell to side of remote. Used araldite to glue bell mount to remote poking wires through hole that was for steering pot wires . mini 22

Final step is to cut rubber cover to suit and stick back on .

Tested out and works fine . There are three choices for the sound and you change by long press of bell pushbutton.


Are you finding this meter accurate? I’m off by .2v at 4.2v. I think maybe there’s a calibration resistor…

All complete and works well


checked on my multimeter and display reads about 0.1V higher. no big deal for this application!