scottk Posted August 8, 2015 Report Share Posted August 8, 2015 Hi. I have installed a high tech custom lithium ion battery pack , 20 amp hour ( it's. for a 2014 20 Oset It runs all day and has impressive power. However when my boy is riding slowly it cuts out and there is massive engine braking. He then twists the throttle and a lag then boom it's off. It's like the engine cuts out ? Any ideas? Otherwise it's now perfect and he can ride all day just not slowly........ Quote Link to comment Share on other sites More sharing options...
gudah Posted August 9, 2015 Report Share Posted August 9, 2015 Had the same symptoms on our 20, it was a damage to the commutator (the part of the rotor that meets the brushes) and unfortunately itd already wrecked the whole rotor so we had to change the entire motor. If disassembled in good time, the fault may be corrected by changing a perhaps damaged brush. Water entering the interior can also mix with coaldust and clogg the commutator with a sort of pastelike residue, smelling rather nasty Quote Link to comment Share on other sites More sharing options...
gudah Posted August 9, 2015 Report Share Posted August 9, 2015 Edit: The residue paste does 2 things, shorts the windings causing the motor to brake a bit itself And at low currents it keeps the incoming power in the commutator area instead of running through the rotor windings creating emf as its supposed to, this can cause the jerky feel when hitting the throttle slowly, but you should def check it out as a stuck brush can cause similar problems and ignoring it can burn the motor out. Quote Link to comment Share on other sites More sharing options...
scottk Posted August 10, 2015 Author Report Share Posted August 10, 2015 hi, thanks for the reply. So did this throttle lag / engine braking problem stop with a change in motor? My bike is only 4 months old so I would be surprised if the motor has packed up already........ Quote Link to comment Share on other sites More sharing options...
collyolly Posted August 10, 2015 Report Share Posted August 10, 2015 Sounds more like a motor control problem, I would seek advice from Oset. These issues can be expensive to correct if you just start changing major components without proper diagnosis, it could for instance just be the twist grip not working properly at the very first part of its movement. Quote Link to comment Share on other sites More sharing options...
gudah Posted August 10, 2015 Report Share Posted August 10, 2015 If its that new you have a IP6x motor and its more likely that its a throttle/controller error. If it was there when the bike was new i'd call oset for help, if it started with the new battery, i'd try testing with the standard SLA's first to rule out batteryrelated problems. (Warranty normally only goes for non-customized machinery;-) For those who have the old motor it can be good to remove the vent plugs overnight, preferrably with a slightly warm motor, to naturally vent out humidity(perhaps twice a year if youve been washing it alot). Quote Link to comment Share on other sites More sharing options...
scottk Posted August 10, 2015 Author Report Share Posted August 10, 2015 Hi. Can you recommend a throttle that is more linear and doesn't have such a lag? I'm confused whether to get a hall or a pot throttle...... Some recommend the Magura throttle. My em 5.7 has a super nice feel so ill ask if that unit is compatible. Thanks for the help guys. Quote Link to comment Share on other sites More sharing options...
gwhy Posted August 10, 2015 Report Share Posted August 10, 2015 The magura may not work to well ( if at all ) with the oset as the standard standard throttle its hall.. 99% of all hall throttles are linear but some are better than others.. also the maguras are just so over priced for what they are ( and dont tend to be very reliable electrically as the pot can and will become noisy effecting control). Any hall throttle will work with the oset but can be a bit of a gamble as regards the quality ,. As regards the lag .. the chances are that its nothing to do with the throttle unless you are talking about the dead band at the start of the twist. Quote Link to comment Share on other sites More sharing options...
scottk Posted August 10, 2015 Author Report Share Posted August 10, 2015 Hi. So the lag you think is related to the controller? If I reduce throttle response on the controller it's really laggy.... Then on deceleration the motor all of a sudden engages and the boys lose balance. It's like the motor turns off? Really weird and a nightmare for balance trials. Quote Link to comment Share on other sites More sharing options...
gwhy Posted August 10, 2015 Report Share Posted August 10, 2015 I would say the lag is 99% to do with the controller ( but always worth trying another throttle to confirm ) , has it always suffered from the lag ?.. how many adjustments do you have on your oset 20 controller is it one or two ? the only 20 controller i have played with had 2 adjustments , it had a max speed and a max power and the response curve ( as far as i know is hard coded into the controller on the 20 ) but there may be other controller versions for the 20.. if it has always had a lag then i would have a word with a oset dealer to see if they can reprogram the response ( if its reprogrammable ) .. as regards the cutting out with the new battery pack ... do the pack have a bms built in ? Quote Link to comment Share on other sites More sharing options...
scottk Posted August 11, 2015 Author Report Share Posted August 11, 2015 I've just ridden the bike again. Power normal on twist of throttle.... Usual lG etc. Let off throttle and normal coast. No engine braking. Then when you twist on again it's like the motor is engaged but at a slower resistance than the roll forward and you lurch forward. In other words the engine seems to disengage completely then re- engage with twist on but at a slower than coast speed. Really lost...... Quote Link to comment Share on other sites More sharing options...
gwhy Posted August 11, 2015 Report Share Posted August 11, 2015 I've just ridden the bike again. Power normal on twist of throttle.... Usual lG etc. Let off throttle and normal coast. No engine braking. Then when you twist on again it's like the motor is engaged but at a slower resistance than the roll forward and you lurch forward. In other words the engine seems to disengage completely then re- engage with twist on but at a slower than coast speed. Really lost...... So its not consistent... this makes it sound like it may well be the motor as gudah has already said. there are a couple of tests you can do yourself.. With the rear wheel off the ground and battery connected do it 100% always start when twisting the throttle very slowly ? With the motor wires disconnected ( and battery disconnected ) can you rotate the rear wheel i.e is there any very high resistant spots when rotating ( should be consistant ) , then try again with the motor reconnected ( should be identical resistance ). it could be brushes or commutator or worst case senorio could be a fried motor ( winding ) Quote Link to comment Share on other sites More sharing options...
scottk Posted August 12, 2015 Author Report Share Posted August 12, 2015 righto, its not the motor or the throttle but looks like the controller not working well with lithium batteries. Below is an email to Oset that explains what is happening, I'd love some advice on controllers from you more technical guys out there........... Good thing - LITHIUM has super fast delivery of power, a solid 54 v from resting, this means a very snappy acceleration that can be tamed via the throttle response switch. Problem - as fast as the power is delivered it is cut off. This means that via the controller output to the motor, the voltage goes instantly to 0. The effect on the ride is that in effect the engine instantly disengages then when you twist on the throttle, its is instant again albeit at a very low voltage and hence reduced speed. In effect a huge and choppy lurch forward, then backwards. Unrideable at slow speeds. I did some testing of the of the SLA's and they have a lower voltage but also a much slower ramp up and run down of voltage from the controller to the motor. The ride effect is a much smoother acceleration and deceleration / reengage of power. Solution - this is the tough bit and I'd love to hear from Oset or Oset riders as I know hundreds have converted to lithium and will have addressed this. In my mind, the controller needs to be programmed to have a gradual ramp up and gradual ramp down of power when the accelerator is engaged but importantly disengaged. Also, a residual voltage when throttle is zero should be evident (will result in a small battery chew) to keep the motor live. Quote Link to comment Share on other sites More sharing options...
gwhy Posted August 12, 2015 Report Share Posted August 12, 2015 the oset 20 controller i have played with had no issue with using li ... have your battery pack got a bms ?... the only time a controller will cut back the power is when it hit its current limit and this will be a gradual reduction in power and not on/off unless there is a fault.. with the output bms's can cut in and out, a faulty winding/brush in the motor can also cut in and out , a bad plug/contact can also cause this problem and so can a bad throttle.. its very unlikly to be the controller ... but dont rule it out .. and it will be nothing to do with using li as a battery chemistry did you say the back go backwards at on point ? Quote Link to comment Share on other sites More sharing options...
gudah Posted August 12, 2015 Report Share Posted August 12, 2015 Do you have a friend who can lend you another controller before opening the motor? -thats the lazy way to continue as opening the lid of the motor takes a bit of knowhow and i can share the experience as i have a motor in pieces lying about if it helps you. Quote Link to comment Share on other sites More sharing options...
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