Does any one know what is the charger port is for Himo C20 Ebike battery?

I ordered mine it's on its way now I couldn't find the information online. Also I was wondering if I can add this battery to my Himo C20.

Aliexpress - 36V 20Ah E-Bike Battery 18650 Lithium ion Frog Batteries For 36Volt Bafang 500W BBS02 250W BBS01 TSDZ2

They are both 36 volts but Himo C20 battery is 10ah and this one is 20ah is that gonna be a problem?

Also how do I do it? Should I just connect the second battery's discharge cable the main battery's charge port?

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    \$\begingroup\$ Please clarify - do you intend to daisy-chain these batteries? Charging a battery by discharging another battery is a sure-fire way to kill both batteries, by severely reducing their service life. Instead you would be better paralleling both outputs together (NOT SERIAL) \$\endgroup\$ – Criggie Jan 15 at 22:48
  • \$\begingroup\$ I don't know what daisy chain is but I saw a video on YouTube that some guy extended an electric scooter range by making another battery and plugging the discharge to the charge port of the default scooter battery. In there he said that both batteries should be same voltage I was wondering about the capacities cuz he didn't mention in his video \$\endgroup\$ – E-bike noob Jan 16 at 11:21
  • \$\begingroup\$ I think you're confusing "charge port" with connecting batteries in serial/parallel. Do not charge one battery off another battery. (which is the same as "plugging the discharge of one to the charge port of the scooter battery" ) Go read battlebornbatteries.com/… to learn the difference. You want to have your batteries in PARALLEL to increase the capacity without increasing the voltage. If you series them you'd sum the voltages, possibly frying your controller. \$\endgroup\$ – Criggie Jan 16 at 19:06
  • \$\begingroup\$ I'm tempted to migrate this to Electronics because its about a battery, not a bike. Thoughts ? \$\endgroup\$ – Criggie Jan 16 at 19:07
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    \$\begingroup\$ That throw switch seems like a good idea \$\endgroup\$ – E-bike noob Jan 19 at 11:17

As long as your ebike controller doesn't check if the "correct" (original) battery is installed you shouldn't have an issue replacing the 10ah battery with the20ah battery. If however it does check you could theoretically swap the BMS from the 20ah to the 10ah battery but this will most likely not be needed.

The difference in capacity shouldn't be an issue (when using both batteries) as long as both batteries (or at the least the smaller capacity battery) have a BMS (battery management system) or PCM (protection module) with a low voltage cutoff function (to prevent the cells from overdischarhing).

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  • \$\begingroup\$ My plan is to use both batteries at the same time. So I just basically connect the discharge wire from the 20ah battery (the new battery that I'm ordering) to the charge port of the default 10ah battery? \$\endgroup\$ – E-bike noob Jan 15 at 16:08
  • \$\begingroup\$ yes I am quite sure that should work. Regarding the first thing I said in my original answer: Even if your BMS only accepts batteries specifically made for your controller it should not be a problem as long as you have both batteries installed (since the controller will 'accept' the original battery as a 'matching' battery and the other battery which you will put in parallel will just add more capacity). \$\endgroup\$ – Maarten -Monica for president Jan 15 at 17:19
  • \$\begingroup\$ In summary: Yes I believe if you connect the outgoing wires of the 20AH battery to the discharge port of the 10Ah battery (sometimes the charge and discharge ports are 1 port (aka 'common port') and in other cases they are seperate ports) it should work just fine. If you do indeed have a seperate charge port it could perhaps work to connect the new 20Ah battery to the charge port of the 10Ah battery but this depends on the minimum charging voltage at which the BMS of the 20Ah battery will charge. \$\endgroup\$ – Maarten -Monica for president Jan 15 at 17:24
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    \$\begingroup\$ @Maarten-Monicaforpresident connecting two batteries together in the way theOP describes way sounds entirely wrong to me. Charging a LiIon battery is much more involved than sticking a voltage across it's terminals, it requires charging management circuitry. It would make much more sense to connect the two batteries in parallel, but I'd still have questions about how the motor controller would deal with that. \$\endgroup\$ – Argenti Apparatus Jan 15 at 18:17
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    \$\begingroup\$ I would not advise doing this!!! In theory it could work but in reality when wired in series it's 72V. It would require balance charging and all 18650 cells go into sleep mode when discharged below 2.5V. \$\endgroup\$ – Dan K Jan 16 at 20:44

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