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LTCUSTOM 08-13-11 08:08 AM

Electric bike problems
 
Hi All,

Having a few teething problems.

We have fitted 2 x Li-ion 24V batteries in serial (reading upwards of 50V)
1 x Infineon 35A controller
1 x Ultra Motor 500W motor
1 x Cycle Analyst

Fitted to a Schwinn Stingray.

Works fine up to 25mph from stationary. But if you accelerate to any speed release the throttle and re-apply it cuts out and you have to reset the system. Once reset if will pull away at full throttle no problem again?

Any ideas.....?

Many thanks

morph999 08-16-11 12:33 AM

So it doesn't happen if you hold the throttle down continuously and take it up to it's highest speed? Are you sure that it's not cutting out on the way up to top speed? Cuz that's what mine did when it would trip the BMS. We need to know whether the LI-ION is really LI-ION or if it's LIFEPO4 and also does the battery have a BMS? Also, does the Infineon controller have a voltage cutoff limit? If it really is LI-ION or Lithium polymer then it's not a BMS problem because those batteries can handle really high amps. If it's LIFEPO4 then it's probably the battery tripping the BMS. Did you buy it off e-bay? A lot of those e-bay batteries are weak. You might just need a better battery. In that case, do your research. Don't buy off e-bay. Make sure you look at the maximum discharge current. It will say "maximum discharge current: 20 amps" or something like that. You're going to need a battery that allows about a 40 amp maximum discharge current and most of those batteries are LIPO (lithium polymer). LIPO and LIFEPO4 are different kinds of batteries so be careful and know what you are getting.

I'll just say that at first when the battery would trip the BMS, I originally thought it was a throttle problem but I soon understand that it was the battery tripping the BMS. And it feels like you are actually cutting the throttle off on your own but it's really the BMS cutting the throttle.

LTCUSTOM 08-16-11 02:16 AM

Quote:

Originally Posted by morph999 (Post 13089122)
So it doesn't happen if you hold the throttle down continuously and take it up to it's highest speed? Are you sure that it's not cutting out on the way up to top speed? Cuz that's what mine did when it would trip the BMS. We need to know whether the LI-ION is really LI-ION or if it's LIFEPO4 and also does the battery have a BMS? Also, does the Infineon controller have a voltage cutoff limit? If it really is LI-ION or Lithium polymer then it's not a BMS problem because those batteries can handle really high amps. If it's LIFEPO4 then it's probably the battery tripping the BMS. Did you buy it off e-bay? A lot of those e-bay batteries are weak. You might just need a better battery. In that case, do your research. Don't buy off e-bay. Make sure you look at the maximum discharge current. It will say "maximum discharge current: 20 amps" or something like that. You're going to need a battery that allows about a 40 amp maximum discharge current and most of those batteries are LIPO (lithium polymer). LIPO and LIFEPO4 are different kinds of batteries so be careful and know what you are getting.

I'll just say that at first when the battery would trip the BMS, I originally thought it was a throttle problem but I soon understand that it was the battery tripping the BMS. And it feels like you are actually cutting the throttle off on your own but it's really the BMS cutting the throttle.

Hi Morph999,

Thanks for your response.

If I hold throttle down from a standstill it works continuously to 27mph, everytime with no problems. Its only when I release the throttle and re-apply that it has an issue.

Its 2 x Li-ion 24v 9000mAh/215Wh Panasonic cells. So not cheap *crap*! The infineon controller can handle up to 48V, so again- should be fine?

Many thanks
Mark

crackerdog 08-16-11 09:03 AM

Does it do this if you don't use full throttle to get up to speed? If you use your legs mostly?

ShinyBiker 08-16-11 09:08 PM

What do you mean when you say, "have to reset the system"?

LTCUSTOM 08-17-11 01:44 AM

If I don't use full throttle it gets up to top speed again fine, or if I start from a standstill again it goes straight to top speed. But if I am moving slightly and full throttle it cuts. By reset, I mean turn off both batteries and the controller then turn them on again!

morph999 08-17-11 09:56 AM

I'm pretty sure that LI-ION has the same problems that LIFEPO4 has in that they can't handle high currents. Ok, try this. When you are first starting off, turn the throttle to the maximum and get up to speed that way. If it cuts out doing that, then it's a battery problem. You still haven't said whether the battery has a BMS or not. I assume the battery has a BMS. In that case, your battery might be just fine and it's the BMS that is the problem. To correct this, what you could do is remove the BMS from the battery by cutting only the wires connect the BMS...Be careful that you don't render the battery useless. Then rewire the battery with anderson connectors or whatever connector is used to connect it to the controller. Then, you will have to use the cycle analyst to determine when the battery is low. I do this on my bike. I have no BMS. I'm not very familiar with LI-ION so you'll need to find out how many cells are in your battery pack. And what the battery reads on a full charge. And then find out what the lowest battery voltage per cell is considered safe. So for example, if 2.8v per cell is considered safe, then I wouldn't take it below 3.0v per cell. So if you had 15 cells then that would be 15 x 3 = 45v so when the Cycle analyst read 45v (at rest), you will want to stop.

Cpt Stevo 01-12-14 09:10 PM

Hello Folks
i need some help, I have a electric kit that is cutting out on me. It's a 48 volt lipo4 battery with 36 volt front hub and 36 volt controller. The battery has a bsm. The kit was working fine then all of a sudden it cut off, so if I turn the power key off then on & turn the power switch off then on it will run for a little while, it seems run for 15 seconds then 4 seconds or even a few minutes. I don't know where to start to find the issue, I thought maybe it was the throttle switch but I don't think that's it, on the throttle there is a power light that shuts of when the motor quits. Any help would be great.


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