K2 Energy battery packs in Goped ESR750

[pgrachev]

Hi people!

Please help with some advise. I got my hands on 4 K2B24V10EB packs from K2 Energy (http://sunshineworks.com/downloads/k2-lithium-batteries/K2B24V10EB-K2-Lithium-Battery-24-Volt%20-10-Amp.pdf). I plan to wire them in parallel and implant into my Goped ESR750 that currently runs a stock SLA charger and controller. I understand the stock motor is 750W, but eventually I plan to upgrade to the (1000W?) torkinator. The K2 battery packs are LiFePo4 and each (rated 24V 9.6Ah) has its own BMS in situ. I would like to know the best way to charge (Goped parked) and discharge (Goped in use) this sort of battery setup, ensuring maximum balancing. Feel free to recommend the ideal solution, and/or answers some of my qualms below:

- Am I right in thinking that in order to charge/discharge in a balanced fashion, I would need to remove the 4 individual BMS units and replace with a unified BMS capable of balancing a 4p setup?

- Do I need to consider how many individual cells make up each K2B24V10EB pack? If so, I'd appreciate your wisdom, as the manufacturer does not specify on the data sheet (link above).

- What is the difference between Goped's SLA and lithium ion controllers? Is a lithium controller needed for this setup or can I keep the stock SLA controller?

- What gauge wire would be advisable to use to connect 4 K2B24V10EB packs in series if I intend to draw the full 1000W (at 24V) once I upgrade to a torkinator motor?

Your comments and suggestions are much appreciated.

Cheers

Pasha

 

[Vanarian]

Hi,

I can only help you with one point : chargers are classified as SLA, Lithium-Ion or LiFePo4 depending on the nominal voltage these are supposed to feed the battery, and also the frequency at which current is sent to the batteries.

So you cannot and shouldn't mix chargers for different chemistries, you might end up at best with a short/sparkle/smoke, at worst with fire. :wink:

 

[pgrachev]

Thanks for your reply. I have purchased the intended charger for the K2B24V10EB batteries, which K2 Energy calls K2C24V2A. The company advised me that if I connect the 4 batteries in parallel, I can use the charger to charge all the packs simultaneously by connecting the positive and negative terminals to posts on distal packs, ie positive to battery 1, negative to battery 4. They also said that the 2A charging current would mean that it would take a long time to charge the 40 Ah setup, which is fine by me. The stock SLA Goped controller seems to handle the voltage and the current of the LiFePo4 batteries, given the BMS units built into the battery packs, but I would not have much faith in the traffic signal style capacity monitor with this setup.

I am interested to know whether what you said about the frequency of chargers for different chemistries would also be true for controllers during discharging (operation). I hope someone can clarify the difference between the stock SLA and Li-ion controllers used in Goped ESR750s.

Also, the stock SLA controller has two separate sets of positive and negative leads that connect to the original 2s2p SLA batteries. Since my new setup is 4p, am I good to use either and/or both of the sets of leads? Does this wiring make much difference? As far as I understand, most Goped LiPo conversions are 7s, as people seem to prefer to faff around with smaller packs (headways and Zippys). Please advise me on the optimal wiring for my setup.

 

[sharinginfos]

Hi people!

Please help with some advise. I got my hands on 4 K2B24V10EB packs from K2 Energy (http://sunshineworks.com/downloads/...4V10EB-K2-Lithium-Battery-24-Volt -10-Amp.pdf). I plan to wire them in parallel and implant into my Goped ESR750 that currently runs a stock SLA charger and controller. I understand the stock motor is 750W, but eventually I plan to upgrade to the (1000W?) torkinator. The K2 battery packs are LiFePo4 and each (rated 24V 9.6Ah) has its own BMS in situ. I would like to know the best way to charge (Goped parked) and discharge (Goped in use) this sort of battery setup, ensuring maximum balancing. Feel free to recommend the ideal solution, and/or answers some of my qualms below:

- Am I right in thinking that in order to charge/discharge in a balanced fashion, I would need to remove the 4 individual BMS units and replace with a unified BMS capable of balancing a 4p setup?

- Do I need to consider how many individual cells make up each K2B24V10EB pack? If so, I'd appreciate your wisdom, as the manufacturer does not specify on the data sheet (link above).

- What is the difference between Goped's SLA and lithium ion controllers? Is a lithium controller needed for this setup or can I keep the stock SLA controller?

- What gauge wire would be advisable to use to connect 4 K2B24V10EB packs in series if I intend to draw the full 1000W (at 24V) once I upgrade to a torkinator motor?

Your comments and suggestions are much appreciated.

Cheers

Pasha

hello Pasha,
i am also thinking about doing that k2 in parralle.
i see that your questions did not find answers, with the time that has passed and your experience , would yoube kind enough to answer the questions you first asked because i am asking myself the same thing

thanks

 

[ESR_RSE]

I had the same setup and the Go Ped ESR controller will trip the BMS in the battery if you slam the throttle to 100%. Disconnect the battery and plug back in and able to drive again. I have yet to find a way to limit how many amps the Go Ped controller wants to pull from the BMS.

 

[sharinginfos]

I had the same setup and the Go Ped ESR controller will trip the BMS in the battery if you slam the throttle to 100%. Disconnect the battery and plug back in and able to drive again. I have yet to find a way to limit how many amps the Go Ped controller wants to pull from the BMS.

how many amps do you estimate the goped ESR asks (my 24 v project is a ebike )?

. is what you are saying is that apart from high amp problem(by bms tripping do you mean it shuts the system down to protect im still learning english) you can use them in parallel good? does the system uses all parallel battery equally? any other problem encountered?

how about charging how do you do it? success or problems

thanks

 

[ESR_RSE]

Chargers typically apply a voltage across both parallel pack and then the BMS handle the cells.

Ebike controller should work just fine with the K2 since likely not asking for 100A