Natasha Posted October 19, 2020 Report Share Posted October 19, 2020 (edited) We purchased a second hand oset 12.5 for my 3 year old son. It has subsequently developed an issue where is cuts out and we have to turn it off and on to reset the motor when he accelerates hard from a stand still. The bike will not cut out if we hold the back wheel up and accelerate hard so it seems to be a load issue. If we help him accelerate at half throttle the bike runs fine and there is no issue. We have looked at all the wiring and replaced all the fuses on the bike that we can see but the issue persists. Has anyone encountered this issue? Edited October 19, 2020 by Natasha Quote Link to comment Share on other sites More sharing options...
tjums Posted October 19, 2020 Report Share Posted October 19, 2020 Hi Natasha I haven't seen this problem before on a Electric Trials, but I have read others on the net, reporting similar problems on a ebike. In that case it was a battery problem. When the battery drain was high (max load) the battery didn't perform, causing the controller to cut off the motor. Please try to test with a alternative battery pack. Regards Thomas. Quote Link to comment Share on other sites More sharing options...
Natasha Posted October 19, 2020 Author Report Share Posted October 19, 2020 Hi Thomas Thanks for replying. We recently changed from led acid batteries to lithium batteries as the battery drain was too quick with the led acid batteries. We have bought a smart charger for the lithium batteries so I'm not sure that it is that. With a hour of riding the batteries are only drained about 50%. Thanks for your input though. I appreciate it 1 Quote Link to comment Share on other sites More sharing options...
gwhy Posted October 20, 2020 Report Share Posted October 20, 2020 It Sounds like your lithum battery may not be able to deliver the current demand and the battery is shutting down ( bms built into the battery ) this could also be a cell problem within the battery itself, do you have a link to the battery that you bought or do you know the specs of the battery ?. Quote Link to comment Share on other sites More sharing options...
Natasha Posted October 20, 2020 Author Report Share Posted October 20, 2020 Here is the link to the batteries purchased https://bluenova.co.za/wp-content/uploads/2019/03/BN13V-8-104Wh.pdf Thanks for your feedback Quote Link to comment Share on other sites More sharing options...
gwhy Posted October 20, 2020 Report Share Posted October 20, 2020 (edited) looking at the specs for the battery I would say that this may be the problem , 7.2A peak/burst is very low for this application with a over current shut down of 24-36A , if it is a cell problem within 1 of the battery's this can also have the same symptoms as your seeing. if you have a volt meter you can confirm this by seeing if there is any voltage on the battery when the fault happens ( measured without disconnecting or turning off the bikes battery ).. basic things to check are is the back wheel nice and free to rotate ( with chain disconnected ), or if there is any grinding noise from the motor when rotated by hand , both these things can increase the current of the system and in turn trip the battery, if you have a current meter you can also check the no-load current of the bike i.e full throttle with back wheel lifted off the ground, I guestimate that the noload current should be no more than around 2.5-4.5A ( maybe someone with the same bike could measure this and post it up on here for future ref. edit: is should have also said if you measure for voltage as above but do still see the 24v but bike still do not work then it could be the controller shutting down due to the low voltage cut off of the controller, which may point to a faulty battery cell. Edited October 20, 2020 by gwhy Quote Link to comment Share on other sites More sharing options...
Natasha Posted October 21, 2020 Author Report Share Posted October 21, 2020 Thank you I will look into this. I really appreciate your feedback Quote Link to comment Share on other sites More sharing options...
Natasha Posted October 31, 2020 Author Report Share Posted October 31, 2020 So an update on this thread. It seems it is the batteries. I used the old 9ah lead acid batteries and there was no issue. Obviously the lithium batteries are better as they run longer and dont allow for a complete drain. Is there something I can install on the system which will stop the peak burst cut out? I have not been able to find a battery that will fit the space with a higher amperage. Quote Link to comment Share on other sites More sharing options...
tjums Posted October 31, 2020 Report Share Posted October 31, 2020 I know that https://www.boost-bikes.co.uk makes batteries for the OSET 12.5 ? Quote Link to comment Share on other sites More sharing options...
gwhy Posted October 31, 2020 Report Share Posted October 31, 2020 9 hours ago, Natasha said: So an update on this thread. It seems it is the batteries. I used the old 9ah lead acid batteries and there was no issue. Obviously the lithium batteries are better as they run longer and dont allow for a complete drain. Is there something I can install on the system which will stop the peak burst cut out? I have not been able to find a battery that will fit the space with a higher amperage. yes there is but i dont know if this will help and i dont know if the cost of a gamble would be worth it, Im not sure what controller is on that model oset but some controller you can turn down the current, if you can only turn down the speed this will not do the trick. if someone can post up the peak current of these bikes it would then be easy to source a battery for them. you can have a look at power tool batterys these tend to be high drain and a cheaper option to boost-bike battery's , this is acually a good option on the smaller bikes, but not so good on the bigger bikes. Quote Link to comment Share on other sites More sharing options...
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