Hello Everyone
I would like to know if anyone in the community has successfully wired a third party battery in parallel with their stock battery to the Controller without any problems. I have a TC Max (72v 45AH) and want to run another 45ah battery in parallel.
I am a Mechanic with strong electrical knowledge and have been playing around.
This is what I’ve discovered
- The bike will turn on but it will not drive without the data wires being connected from the stock battery
These are possible issues that can happen if I do go ahead with the project and blow all the money
- one battery could possibly charge the other while driving and shut down bike because it thinks it’s in charging mode
- The Controller will only draw the current from the stock battery even though both are wired in parallel
- The aftermarket battery will charge the stock battery while under load and the BMS will block its current and data which will therefore shutdown the bike
I would love to hear you’re advice or any knowledge you guys have
Thank you in Advanced
Assuming a TC Max controller is somewhat similar to a TC (which I assume it is), let me address some of your statements.
- one battery could possibly charge the other while driving and shut down bike because it thinks it’s in charging mode
This is only the case if a voltage-difference is present between the two batteries, where the stock-battery is of lower voltage. That said, it will not "shut down" the bike while driving, it will only prevent it from engaging while standing still.
A significant voltage difference shouldn't occur if the wiring and the batteries are of equal spec and resistance. (Which unfortunately isn't the case with my current setup, causing the charging-issue)
- The Controller will only draw the current from the stock battery even though both are wired in parallel
If both batteries are wired in parallel, the controller can't "decide" where to draw current from.
- The aftermarket battery will charge the stock battery while under load and the BMS will block its current and data which will therefore shutdown the bike
Current can only flow one way at a time. Hence, when both batteries are under load of any significance, the one won't charge the other.
@knockknuckles thank you for the input and advice. When I said shut down I meant disengage. Hopefully the voltage difference is little enough to not trigger any problems. The TC max controller is far different from the TC. It is a Lingbo controller that is rebranded as a Soco. I have found a supplier here in Canada that sells the exact same one that they rebrand and it also comes with its own software for tuning using windows. Ive also spent countless hours and finally found the wiring diagram for the OEM controller and this other one and they are indeed both the exact same. If this new controller works I am going to make a separate post about it and share.
Interesting. I am planning to do similar thing with my TC. I have ordered a double capacity battery pack from Ali with a more powerfull controller to upgrade the performance and the top speed from 65kmph to 90kmph. My initial idea was to separate the batteries by shottky diode arrays. That will secrifice around 0.7V drop of the battery voltage, but the batteries would not interfear each other at all. Than I realized that I would like to have regen, which the diodes disable, so I am only going to place one diode array for the smaller original pack. That would allow the smaller pack to charge the larger one, but the large pack BMS is configurable, so I can limit the recharge current of it not to damage the batteries cells. I honestly did not consider that both BMS needs to communicate to the controller, I hope it is not the case with the upgraded controller, othervise my setup will not work. As the hipment is still ongoing, I am not sure of my setup, but I wanted to share it for your consideration anyway.
@tib tell me more about the batteries you bought from Ali. I was browsing one for the TC max (Woodniu tech store) seller had a 70AH one for nearly have the cost of dealer but I still have red flags I just want to make sure it will communicate with the ecu and have zero problems. These Soco bikes have 2 different computers. The ECU and controller and not many people know the battery talks only to the ECU. The ECU is somehow connected (wired) to the controller in a way for it to cut power from motor. That I hope to figure out soon.
Yes, it is from Woodniu. It is a 60Ah battery and the 72300 controller. Cost me around 1k€, but has not arrived yet. Ordered a month ago. According the tracking, it is on the train, but still in China.
When you say ECU, you mean the charger or what? Because ECU could mean also the electronic controller unit. I expect another 2 month, before the stuff arrives and I will be able to wire all up. I will update the community, when it is done with my findings and achievements.
@tib yeah keep us updated it would be great to know if they work and are any better. The ECU is the engine control unit or electronic control unit, different names for it but same purpose. Its the central computer that communicates with all the other modules like the BMS, motor Contoller, Alarm theft unit, instrment cluster/tachometer. That’s what I was worried about with the aftermarket batteries because the ECU and BMS talk to each other and Soco has their own special software comm in their batteries and if the ECU detects a problem because it can’t read the data it will throw an error code or check engine light possibly disabling the bike just like all the modern day cars do. The motor controller is a different computer but unlike the ECU it’s main function is to distribute power to the motor from the battery and controls all the signal and sensor data like hall sensor, throttle signal, park brake for motor operation.
I hope you get a good results.
@NickPD99, for your battery in parallel I suggest you go check Rodrigo Ono YouTube channel he has done a parallel connection of batteries with a Tc max.
I think the second battery was wired in parallel at the controller.
I’m also in Canada and have a TC max since last August. The controller in the max is a Lingbo HC3X.
@paslecwar Thanks for the input I’ll go check his YouTube out. I am going to be upgrading the Controller soon here it’s going to be the Vector 300 series from Golden Motors pretty much the same as the Lingbo and I’m also getting the Program cable for it so I can tune it.
@nickpd99 Using the VEC300 you will lose your instruments as there is no RS485 output as standard.
I have a VEC300 that I fitted to my Max briefly and then removed due to the lack of instrumentation. Also the maximum current is the same as the stock controller is capable of.
If you get the GM programing lead and the Lingbo Software from here :- https://drive.google.com/drive/folders/1ZBXscIUssj2y7akjxSmxm30SJVLfPGCa
You will need V4.0 and you can then program the stock controller to allow 110A max current and adjust the intial field current to improve acceleration and the field weakening settings to gain a little more top speed.
I have a thread on here about my progress modding my Max and I shall soon be posting my settings so others can try them.
@petesscalefabshop hey thanks for the heads up. Did you ever have to change or bypass that 80Amp circuit breaker under the seat.
@nickpd99 Your welcome. I have the 80A breaker bypassed on the discharge side, so I still charge through it and it still switches off the power to rest of the bike, but the main feed for the controller is direct from the battery.
