Advice for choosing a battery on a Solex Mobiky

[Aleosha]

Hello,

May I ask you some advice for putting a folding electric bike back on the road ?
The bike is a Mobiky by Solex and it is missing a battery, the original one is very compact and rather pricey : around 350€ for 9v 5.5 ah, a 29v 11ah is also sold for around the double. Would it seem a good idea to adapt unto the back of it a cheaper battery?

Here's a video showing the bike and it's caracteristics :
https://www.youtube.com/watch?v=ryoM215HRdw . It's got a 250W brushless motor.

Would any of the batteries sold on aliexpress be compatible like those found on bikeschool's “list of great (and inexpensive) electric bicycle parts » or like this one :
https://www.aliexpress.com/item/Hot-sale-1pcs-lot-Rechargeable-Electric-Bicycle-Battery-36V-12AH-Li-ion-Battery-with-PVC-case/1804700610.html?spm=2114.30010308.3.18.0IkGoK&s=p&ws_ab_test=searchweb0_0,searchweb201602_2_10091_10090_10088_10089,searchweb201603_1&btsid=fdea4205-4f92-4b9a-8e62-274e86f3f3a4

Thanks for helping me out,

 

[LewTwo]

really awful video. Better information here: http://www.tech-cycling.it/solex-mobiky-piccola-bici-pieghevole-in-versione-classic-electric/
... rear mounted removable Samsung lithium polymer battery 24V and 5.5 Ah cells.
front hub brushless geared electric motor with maximum power 250 Watts

I suspect an enterprising person could rebuild the battery.
At this point it is a black box that may contain BMS, Controller and/or charger as well as the batteries.

 

[dogman dan]

Once you find the wires that take the power from the original battery to the controller, you can re route that wire to the outside. Then any decent 29v (24v?) battery can run the bike, by plugging into that wire. carry the battery somehow, rear rack, backpack, whatever works for you.

29v sounds like a 24v battery, but called 29v because seven 4.2v cells actually charges to 29.4v. If you still have a charger, see what that things output voltage really is. It might be an 8 cell, but that is rare.

I'm not sure if your bike can tolerate a 36v battery, which charges to 42v. If the capacitors inside the controller are designed for 24v, they might be 30v max or maybe just 40v max for an 8 cell battery charged to 33.6v.

 

[carbo]

Hi Aleosha:

Were you able to find the wire set-up on the Mobiky for re-routing to an external battery? I'm looking at getting a pre-owned one and the pictures and information on the web don't show these connections - so I can't figure out how easy or difficult it is to do this.

Thanks

 

[Aleosha]

Hello Carbo,
I don't know anything about this stuff..
the controller is easy to access its just under the battery charger socket, which is easy to take off.
There's two cable from the controller to the battery , 1 black, 1 red.and a lot of other cables. The red one goes back to the lock of the battery then goes out again orange and which is then connected to the red cable of the controller.

 

[Aleosha]

I'm just hoping if I connect the red cable to the red cable, and the black cable to the black cable its gonna work.
I got this battery https://www.aliexpress.com/item/Electric-bicycle-24V-11Ah-battery-With-free-24v-2a-charger-24v11ah-Li-ion-battery-24v-11a/32708171540.html?spm=2114.30010308.3.17.ERjJJp&ws_ab_test=searchweb0_0,searchweb201602_2_10091_10090_10088_10089,searchweb201603_1&btsid=f5b4b02f-39b3-4a76-a999-350ef927d9b6
which is just a bit to big to be put where the old one was.

 

[tuanito]

Hi, I am unearthing this thread as I just bought the same Mobiky, I had a battery of 24V 5.5Ah, brush motor of 250W and I am trying, just like you, to increase the capacity. Here are some pics.

Here are a few things worth mentioning :
-the charger is indeed rated for 29.4V,
-there are a few cables, red, black and yellow (the yellow cable seems to be there to charge only),
-there is an electronic board stuck to the battery, I am not sure what it is though (I am a newbie in battery wiring).
-if you rebuild the battery block, you need the key as it activates internally the connections from the battery to the controller.

Here is a schematic of the wiring at the 4 slit-plug level :


Battery seen from below (part which plugs into the bike)



Towards the front of the bike
[-----------------------]
|                                          |
|                                          |
|                                          |
|                                          |
|                                          |
|                                          |
|                                          |
|                                          |
|                                          |
|                                          |
|                                          |
|      1      2      3      4          |
|      ||      ||     ||      ||         |
|                                          |
|                                          |
[-----------------------]
Towards the rear of the bike

Slit 1 : red wire coming from the battery + fuse 30 amp
Slit 2 : red wire coming from the recharge plug
Slit 3 : empty
Slit 4 : black wire coming from battery.


Now the questions are :

-what does this electric which is stuck to the battery do ?
-increasing the capacity from the original 24V 5.5 Ah to another stock 24V 10 Ah battery is as simple as rewiring the slit 1 to the positive wire ofthe stock battery and 4 to the negative wire of the stock battery ?
-what about slit 2 and the recharge side ?
-what about the circuit board stuck to the battery ?
-while charging, the yellow wire goes from the charging plug to somewhere to the battery (probably to the black wire coming from the battery), but the red wire seems to go nowhere (see picture) as it goes to slit 2 which is not connected anywhere once the battery is removed from the bike. How is possible to charge then ?

I may intend to build from scratch a battery case + baritone battery of 24V, 21Ah, which is 4 times the capacity of the stock battery, which should bring 80 km / 100 km of usage. Ideally, I will try and mount an integrated USB charger for a phone.


Thanks a lot.

 

[phonitel]

Amazing post thank you so.much for the efforts really ?

I am in situation. How did it go ?