BESV PSA1 Problem - Any ideas?

cranksbrighton

Finding my (electric) wheels
Jun 26, 2020
5
1
Hello Pedelecs! We run a community bike workshop in Brighton, see www.cranks.org.uk

We had a very generous donation of a BESV PSA1 a few weeks ago but we can't get it working. The head unity needed 2 wires soldering but that now starts with the key. The battery appears to charge as it shows around 40v when tested with a multimeter. Unfortunately the head unit display works but shows no bars for the battery and does not give any power selection options and there is no power assist. Does anyone have any experience with these strangely beautiful things? We have searched and emailed BESV but to no avail.

Many thanks in advance,
Iain
 
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KirstinS

Esteemed Pedelecer
Apr 5, 2011
3,224
899
Brighton
Hiya, I live in Shoreham these days but you guys helped me out years ago (at least 10 )with repairing a 50 quid beat bike which was my only form of transport at the time. I was also totally skint as between jobs . I owe you one

Is it this ?


If so it does look like parts are worryingly bespoke. However, If you can get the bike to me I'll happily take a look and diagnose/repair as I'm able

Cheers
Kirstin
 
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Nealh

Esteemed Pedelecer
Aug 7, 2014
21,415
8,750
61
West Sx RH
A couple things to check, wired brake cut outs and the PAS sensor.
If wired brake cut outs fitted check levers are full seating back, some sensors are very sensitive. Disconnect them at the controller end to check PAS works first without them.
Power assist (PAS) is cadence based so will have a BB sensor and magnet disc probably on the RHS part hidden by the chain wheel/s , the sensor to disc should align and the magnet disc needs to be in a fixed state on the BB axle or attached to the inner ring , the sensor gap ideally should be about 1 - 2mm. Sensor may have a Red led if so it should light up as the magnets pass the sensor.

If the PAS works and kicks in try the brakes connectors one at a time to see if nay are faulty.
 

cranksbrighton

Finding my (electric) wheels
Jun 26, 2020
5
1
A couple things to check, wired brake cut outs and the PAS sensor.
If wired brake cut outs fitted check levers are full seating back, some sensors are very sensitive. Disconnect them at the controller end to check PAS works first without them.
Power assist (PAS) is cadence based so will have a BB sensor and magnet disc probably on the RHS part hidden by the chain wheel/s , the sensor to disc should align and the magnet disc needs to be in a fixed state on the BB axle or attached to the inner ring , the sensor gap ideally should be about 1 - 2mm. Sensor may have a Red led if so it should light up as the magnets pass the sensor.

If the PAS works and kicks in try the brakes connectors one at a time to see if nay are faulty.
Hello Nealh, I'll try all that when I'm back in the workshop and see if it makes sense... Thanks!
 

cranksbrighton

Finding my (electric) wheels
Jun 26, 2020
5
1
Hiya, I live in Shoreham these days but you guys helped me out years ago (at least 10 )with repairing a 50 quid beat bike which was my only form of transport at the time. I was also totally skint as between jobs . I owe you one

Is it this ?


If so it does look like parts are worryingly bespoke. However, If you can get the bike to me I'll happily take a look and diagnose/repair as I'm able

Cheers
Kirstin
Hello Kirstin, that would be amazing, thank you! I'm going to try the things that Nealh suggested and if we don't get anywhere I'll get back in touch with you to arrange dropping it off in Shoreham, apparently it rides OK even without the motor so I can ride it over and get the bus back. Cheers!
 

KirstinS

Esteemed Pedelecer
Apr 5, 2011
3,224
899
Brighton
Hello Kirstin, that would be amazing, thank you! I'm going to try the things that Nealh suggested and if we don't get anywhere I'll get back in touch with you to arrange dropping it off in Shoreham, apparently it rides OK even without the motor so I can ride it over and get the bus back. Cheers!
No worries at all :) Hopefully you can get going
 

KirstinS

Esteemed Pedelecer
Apr 5, 2011
3,224
899
Brighton
No worries at all :) Hopefully you can get going
A super nice chap dropped this bike to me yesterday, it is a right headsctracher tbh. I'm going to start a fresh repair thread to explain, might help them and someone else too

Will post redirect thread soon