original Posted February 12, 2019 Report Share Posted February 12, 2019 Hi All, My son has a Oset 20 Racing, I believe it’s a 2016. He’s been competing in schoolboys events for approx. 6 months on the bike, the club has acquired a new piece of ground which has more hills. We went to a trial last Saturday at this new venue. When my son opened the throttle the bike accelerates as it should and he was carrying enough speed to easily reach the top, but when he’s nearing the top of the hill the bike completely cuts out, no power at all and he falls off, when I picked him up the bike worked completely as normal. All it needed to "reset" was to close throttle. The bike did this on every largish hill for the next 4 sections, eventually I decided this was becoming dangerous so he retired (with tearsL). We went back and watched the sections and others on oset 20’s weren’t having this issue The hills weren’t particularly large and there was a bit of mud to go through. Can anyone advise me on how to fix this issue and cheer up a fed up son thank you wayne Quote Link to comment Share on other sites More sharing options...
gwhy Posted February 12, 2019 Report Share Posted February 12, 2019 What batterys are you using ?.. it sounds like it could be a bms problem. Quote Link to comment Share on other sites More sharing options...
original Posted February 12, 2019 Author Report Share Posted February 12, 2019 its just the standard 4 x 12v ones that the bikes are supplied with, mine are lucas 12v 10Ah. wayne Quote Link to comment Share on other sites More sharing options...
gwhy Posted February 12, 2019 Report Share Posted February 12, 2019 ok, so no bms. one thing you could check is the lvc ( low voltage cutoff ) built into the controller, if the bikes voltage drops to below the lvc limit of the controller the bike will cut out. The battery voltage drops under load i.e going up hills Im not 100% sure what the lvc is on the oset controller but I think its around 38v, you will need away on logging the voltage under load to fault find this problem, or if you can borrow a set of batterys to see if the problem goes away. It may not be the batterys at fault but could be just a poor ( high resistance ) connection between the battery and the controller, you may be able to feel for this by feeling the temprature of the connections when this fault happens as if it is really bad then connections will be much hotter than normal. Quote Link to comment Share on other sites More sharing options...
original Posted February 12, 2019 Author Report Share Posted February 12, 2019 33 minutes ago, gwhy said: ok, so no bms. one thing you could check is the lvc ( low voltage cutoff ) built into the controller, if the bikes voltage drops to below the lvc limit of the controller the bike will cut out. The battery voltage drops under load i.e going up hills Im not 100% sure what the lvc is on the oset controller but I think its around 38v, you will need away on logging the voltage under load to fault find this problem, or if you can borrow a set of batterys to see if the problem goes away. It may not be the batterys at fault but could be just a poor ( high resistance ) connection between the battery and the controller, you may be able to feel for this by feeling the temprature of the connections when this fault happens as if it is really bad then connections will be much hotter than normal. thanks, the low voltage cut off sounds like it could be the issue, would I just be looking for a connector or something more complicated? I have two sets of batteries for it so i'll charge up both sets and take it to some hills to try and feel the connections when (or if) it does. I've emailed Oset uk to see if they can help, no reply yet Quote Link to comment Share on other sites More sharing options...
gwhy Posted February 12, 2019 Report Share Posted February 12, 2019 28 minutes ago, original said: thanks, the low voltage cut off sounds like it could be the issue, would I just be looking for a connector or something more complicated? I have two sets of batteries for it so i'll charge up both sets and take it to some hills to try and feel the connections when (or if) it does. I've emailed Oset uk to see if they can help, no reply yet Yes it can be more complicated than that, but unlikely. Check all connectors and make sure that they are clean and well connected tot he wire at the crimp ,even at the battery's, The relay is also inline to the controller so this is another place to look at the connections, but it could be the relay itself ( high resistance contacts in the relay). Quote Link to comment Share on other sites More sharing options...
lennie Posted February 14, 2019 Report Share Posted February 14, 2019 If you ride the bike yourself the extra weight of an adult rider would show the problem up, ride it on the hill have a look at the battery light see if it drops to the bottom light that means its "flat" then goes back to the normal 3 lights when you stop and "reset", could be the battery isn't great and cant handle the load of riding big hills. Quote Link to comment Share on other sites More sharing options...
original Posted February 14, 2019 Author Report Share Posted February 14, 2019 thanks for your replies, Oset have rung me back and were extremely helpful, I'm going to do a battery test when its under load (hold brake on and open throttle) and read the battery level, If this fails to show anything they said try the relay, so everything you said gwhy, thanks so much!!! 1 Quote Link to comment Share on other sites More sharing options...
gwhy Posted February 14, 2019 Report Share Posted February 14, 2019 4 hours ago, original said: thanks for your replies, Oset have rung me back and were extremely helpful, I'm going to do a battery test when its under load (hold brake on and open throttle) and read the battery level, If this fails to show anything they said try the relay, so everything you said gwhy, thanks so much!!! Out of intrest and information, did oset say what the lvc is on the controller ? Quote Link to comment Share on other sites More sharing options...
original Posted February 18, 2019 Author Report Share Posted February 18, 2019 On 2/14/2019 at 2:22 PM, gwhy said: Out of intrest and information, did oset say what the lvc is on the controller ? they didnt say, they just asked me to do the tests and let them know the numbers, FYI the batteries were all around 12.6 v and went down to 8.5v on load Quote Link to comment Share on other sites More sharing options...
gwhy Posted February 18, 2019 Report Share Posted February 18, 2019 (edited) 5 hours ago, original said: they didnt say, they just asked me to do the tests and let them know the numbers, FYI the batteries were all around 12.6 v and went down to 8.5v on load So thats a total of around 34v for the 4 batterys, did the bike cut out at that voltage? . that is pretty low and to be honest I would expect it to cutout, I have a recollection that the lvc is around 36v for the oset 48v controllers Edited February 18, 2019 by gwhy Quote Link to comment Share on other sites More sharing options...
original Posted February 26, 2019 Author Report Share Posted February 26, 2019 On 2/18/2019 at 6:28 PM, gwhy said: So thats a total of around 34v for the 4 batterys, did the bike cut out at that voltage? . that is pretty low and to be honest I would expect it to cutout, I have a recollection that the lvc is around 36v for the oset 48v controllers yes it cut out , oset have said its too low and the batteries aren't good enough, i've got 13 in total (three bikes) so we're going to do a drop test on them and fit the best performing and see if it cuts out, sorry for the lack of replies. Quote Link to comment Share on other sites More sharing options...
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