Auxiliar battery pack for X3

[kalmira123]

Hello everyone! here Horace from Uruguay, South America.
In my country, the EUC´s are very rare to see and very expensive, the only brand that has vendors is Airwheel, for that reason, i have an Airwheel X3.
The X3 is fun and the speed or the torque are fine for me, however, the range are very limited.
My X3 is the 130 Wh version, which only has a maximum range of 8k away. (my weight is about 70 kg)
I have been thinking about doing and adding a secondary battery pack in parallel over the charger port, using the secondary package as a backpack.

I will buy 16 batteries Samsung INR18650 30Q and putt them in series, adding an secondary EMS board and connectors.

Im not sure how charge the packs using the X3 original AC adaptor:
A) Independent way, this mean charging the internal X3 battery in first place, and after that charge the backpack.
Charging both coneccting the AC charger to the GX16-3 female conector on the backpack, which is atached to the X3 in parallell over the charge port..
I need a diagram on how to make this modification in detail, especially the wiring and the pinout on the GX16-3 male connector attached to the new battery.
I know that passiongadgets site sell ones ready to plug, but now they are out of inventory, and the seller is located Singapore, very difficult for me to bring them, due to Uruguay customs restrictions.
I made a simplified schematics on how i will make the battery, please any help will by appreciated.
Thanks in advance:

Horacio.

[Keith]

I suggest you do a search on this site as this has been discussed before however a few things to note:

1. I think you might know this but it is so dangerous if you do not it is worth ensuring you do: Both batteries must be at exactly (within 0.1V) the same voltage when they are connected or huge wire melting, fire starting, currents will flow from the higher voltage battery to the lower. I.e. you cannot run one battery down then plug in the other battery.
2. charging both in parallel will be fine and will ensure both are at the same voltage, it will just take twice as long to charge them both if you use the same charger. Charging separately would also be fine except it is easier to have one at a lower voltage than the other. First time you absolutely need to charge them separately and monitor them to ensure they are at the same voltage when connected together. To charge in parallel just make up a Y lead with GX-16 male and female connectors such that the charger plugs in at one end and the two batteries at the other. Or simply leave the second battery connected to the wheel and plug the charger into the charge socket of the second battery the will still be in parallel. Note on the BMS you will typically find a P- (for neg power out) and C- (for negative power in) and either a common positive or possibly a P+ and C+ Charge connects to the  C connectors and power out to the P, but obviously check the design notes for the BMS you buy. 
3. I do not know the Airwheel GX-16 pin-out but it will just be positive and negative to two of the pins with nothing on the third pin. do a Google search or simply take the side panel off so you can see the wires, I would be surprised if they are not simply a red wire and a black wire.
4. There is one other potential problem of connecting the way you are intending. You are paralleling the second battery via the charge lead of the first battery. That lead expects nothing higher than 2 Amps or so charging current whereas running current could possibly reach 10 Amps, half that would come from the first battery so you might have possibly as much as 5 Amps going through the charge wiring which might not be able to handle the current if it is deliberately quite thin. The X3 is fairly low powered so this may not be a problem but the two batteries in parallel will increase the power available as it will halve the battery’s internal resistance.
5. Be aware that soldering 18650 cells is a bad idea unless you buy ones with solder tags on them. Heating an 18650 cell to soldering temperature can damage the cells very easily. Untagged 18650 cells need to be spot welded.

The ideal way is to parallel the batteries inside the case, but this is not always possible. Several others have done what you are suggesting (not necessarily with an Airwheel but the principle and problems are the same on any EUC) and talked about it on this forum so do search for existing threads on this.

Edited March 12, 2018 by Keith

[Andres F]

On 3/12/2018 at 6:55 PM, kalmira123 said:

Hello everyone! here Horace from Uruguay, South America.
In my country, the EUC´s are very rare to see and very expensive, the only brand that has vendors is Airwheel, for that reason, i have an Airwheel X3.
The X3 is fun and the speed or the torque are fine for me, however, the range are very limited.
My X3 is the 130 Wh version, which only has a maximum range of 8k away. (my weight is about 70 kg)
I have been thinking about doing and adding a secondary battery pack in parallel over the charger port, using the secondary package as a backpack.

I will buy 16 batteries Samsung INR18650 30Q and putt them in series, adding an secondary EMS board and connectors.

Im not sure how charge the packs using the X3 original AC adaptor:
A) Independent way, this mean charging the internal X3 battery in first place, and after that charge the backpack.
Charging both coneccting the AC charger to the GX16-3 female conector on the backpack, which is atached to the X3 in parallell over the charge port..
I need a diagram on how to make this modification in detail, especially the wiring and the pinout on the GX16-3 male connector attached to the new battery.
I know that passiongadgets site sell ones ready to plug, but now they are out of inventory, and the seller is located Singapore, very difficult for me to bring them, due to Uruguay customs restrictions.
I made a simplified schematics on how i will make the battery, please any help will by appreciated.
Thanks in advance:

Horacio.

Hola Horacio, soy de Uruguay también, estás aun utilizando tu rueda? podriamos entrar en contacto, estoy tratando de unir a los pocos que somos aqui rodando, @windowsplit en insta, un abrazo!