Tested mosfets on bbs01b, help needed with results

minexplorer

Esteemed Pedelecer
Aug 22, 2017
532
93
56
Four Lanes,Cornwall
So ive been having prolems with my bbs since rain.Detailed in my thread ‘is rain to blame for bbs01 problems‘ .I finally took the controller off and tested the mosfets as described by d8veh.
The results, when connecting the meter to the battery negative wire, were 9.8 ohms on the 3 phase wires. When connected to the positive,the figures just kept climbing on all settings until the display showed a 1 on all 3 phase wires.I guess thats toast?
Yet after the PAS was dead for days it has worked ,tho it has randomly cut out after some miles and not re started. 2 days ago i rode 12 miles without incident .Last night when i re connected the dead throttle it worked.Though i havent had a chance to see if its still causing the PAS to cut in and out.As it was before ceasing to work.
Both the brake cut outs work ,but one of the wires coming up from the controller to them suddenly stopped working the other day. That was after i briefly reconnecting the dead throttle and didnt work again after disconnecting it. Are these all symptoms of a controller going up the shoot?.I thought when the mosfets are blown it wouldnt work full stop. Some advice much appreciated.Eclipse bikes suggested a week ago if i think the controller faulty to send it in for testing .Still under warrenty.But i want to be sure first. Thanks
 

minexplorer

Esteemed Pedelecer
Aug 22, 2017
532
93
56
Four Lanes,Cornwall
So ive been having prolems with my bbs since rain.Detailed in my thread ‘is rain to blame for bbs01 problems‘ .I finally took the controller off and tested the mosfets as described by d8veh.
The results, when connecting the meter to the battery negative wire, were 9.8 ohms on the 3 phase wires. When connected to the positive,the figures just kept climbing on all settings until the display showed a 1 on all 3 phase wires.I guess thats toast?
Yet after the PAS was dead for days it has worked ,tho it has randomly cut out after some miles and not re started. 2 days ago i rode 12 miles without incident .Last night when i re connected the dead throttle it worked.Though i havent had a chance to see if its still causing the PAS to cut in and out.As it was before ceasing to work.
Both the brake cut outs work ,but one of the wires coming up from the controller to them suddenly stopped working the other day. That was after i briefly reconnecting the dead throttle and didnt work again after disconnecting it. Are these all symptoms of a controller going up the shoot?.I thought when the mosfets are blown it wouldnt work full stop. Some advice much appreciated.Eclipse bikes suggested a week ago if i think the controller faulty to send it in for testing .Still under warrenty.But i want to be sure first. Thanks
Dug my other multi meter out to run a comparison test.The phase wires when connected to the negative still all read 9.8 ohms .But when connected to the positive all read 128 ohms.On the other meter i just get a 1 for them on the positive,even the 2000k setting.Dont know what to make of it.Hope someone will be able to clarify.Ive also read ,blown mosfets make the rear wheel stiff to turn backwards? But mine is turning fine.
 

Danidl

Esteemed Pedelecer
Sep 29, 2016
8,611
12,256
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Ireland
If the controller drove the motor for 12 miles, your MOSFETs are still ok. They do not believe in life after death. The odd readings have to do with trying to trying to measure semiconductors with multimeters. Not going into it here, but the resistance depends on the test voltage coming from the meter and it's polarity.
 

minexplorer

Esteemed Pedelecer
Aug 22, 2017
532
93
56
Four Lanes,Cornwall
If the controller drove the motor for 12 miles, your MOSFETs are still ok. They do not believe in life after death. The odd readings have to do with trying to trying to measure semiconductors with multimeters. Not going into it here, but the resistance depends on the test voltage coming from the meter and it's polarity.
Yes relieved they seem to have survived the troubles that have plagued the bike lately . The PAS is finaly performing without issue again fingers X .