Help! controller broken?

Johnwat1980

Pedelecer
Aug 11, 2020
25
8
41
Newcastle upon Tyne
Hi everyone im back for some more helpful information from this great community
, ok so i was commuting back from work the other day on my newly built 1500w ebike i had used it 3 times prior on the same journey everything was fine, so my last one id got right near the end and went to engage the throttle when it sort of stuttered then cut out, so powered it up again came back on used the throttle and nothing then cut out again, i did feel the motor which was quite hot im wondering if ive blown a mosfet something like that because i turned the bike back on after a day all worked apart from throttle, walk mode and peddle assist

motor 1500w rear hub
battery U004 52v 20 ah
controller model KT36/48SVPRK-SLS02G RATED VOLTAGE DC36V/48V RATED CURRENT 22A MAX CURRENT 45 + 1A

now im just new at understanding it all but i suspected that the controller might not be the correct one, it did come with the 1500w kit but my battery is 52v and when i gave it some welly the display was reading nearly 2000w of power


any help would again be greatly appreciated thanks in advance john
 

wheeliepete

Esteemed Pedelecer
Feb 28, 2016
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Post a link to the battery you've got, it needs to be able to supply 50amps con. to handle full throttle. If the PAS is still working, then nothing in the controller has blown, check the connector on your throttle. There have been problems reported on running KT controllers at 52v with standard firmware.
 

Johnwat1980

Pedelecer
Aug 11, 2020
25
8
41
Newcastle upon Tyne
Post a link to the battery you've got, it needs to be able to supply 50amps con. to handle full throttle. If the PAS is still working, then nothing in the controller has blown, check the connector on your throttle. There have been problems reported on running KT controllers at 52v with standard firmware.
 

wheeliepete

Esteemed Pedelecer
Feb 28, 2016
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OK, so the battery you linked to can only supply 30amps con. which does not match the 45amps the controller can demand with high PAS and throttle, so is likely cutting power to the controller. Depending on the handle bar display you have, you may be able to lower the power in the C5 setting. You should have gone for the one with 50amp BMS for an extra £4.
 

Johnwat1980

Pedelecer
Aug 11, 2020
25
8
41
Newcastle upon Tyne
OK, so the battery you linked to can only supply 30amps con. which does not match the 45amps the controller can demand with high PAS and throttle, so is likely cutting power to the controller. Depending on the handle bar display you have, you may be able to lower the power in the C5 setting. You should have gone for the one with 50amp BMS for an extra £4.
yeah silly really i will give it a try anyway, can you recommend a decent controller that would suit my set up?
 

wheeliepete

Esteemed Pedelecer
Feb 28, 2016
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yeah silly really i will give it a try anyway, can you recommend a decent controller that would suit my set up?
Don't feel too bad, most on here have made similar mistakes, it's how we learn. You have a decent controller, it's just not matched to your battery. Lowering the power will be the cheapest solution. What display do you have?
 

Johnwat1980

Pedelecer
Aug 11, 2020
25
8
41
Newcastle upon Tyne
Don't feel too bad, most on here have made similar mistakes, it's how we learn. You have a decent controller, it's just not matched to your battery. Lowering the power will be the cheapest solution. What display do you have?
ive just went to turn it on the bike jumped a bit and now nothing is coming on no display nothing my display is a kt-lcd3
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
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Basildon
You don't need a 50 amp battery for a 22 amp controller. A 25A one would be fine.

The main problem is that the controller is underrated foe that motor, especially if it's a fast winding. You need to tell us how fast the motor goes. If it's a 40 mph winding, then you need to keep it above 20 mph to be efficient. 22A wouldn't allow that as soon as you get on any incline, which means that the controller would be giving out 22A all the time, but it's only rated at 11A continuous. What people don't understand is that controllers are protected from running at maximum power all the time by the motor speed. When the motor spins fast, it cuts down the current below what the controller can give. By speed, I mean it's actual speed under load compared with it's maximum speed with no load.

Those motors run better with at least 25amps at 48v. 35 amps brings them to life, but then you need a 40A battery.

If the motor was hot, then the controller would have been very hot and something probably got damaged. If a mosfet blew, the motor would be very difficult to turn while connected, so if it spins like before, it's probably not a mosfet, but could be, not that it matters because you'd be better off with a bigger controller anyway.

Edit: This p0st is irrelevant. See my post below.
 
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Johnwat1980

Pedelecer
Aug 11, 2020
25
8
41
Newcastle upon Tyne
You don't need a 50 amp battery for a 22 amp controller. A 25A one would be fine.

The main problem is that the controller is underrated foe that motor, especially if it's a fast winding. You need to tell us how fast the motor goes. If it's a 40 mph winding, then you need to keep it above 20 mph to be efficient. 22A wouldn't allow that as soon as you get on any incline, which means that the controller would be giving out 22A all the time, but it's only rated at 11A continuous. What people don't understand is that controllers are protected from running at maximum power all the time by the motor speed. When the motor spins fast, it cuts down the current below what the controller can give. By speed, I mean it's actual speed under load compared with it's maximum speed with no load.

Those motors run better with at least 25amps at 48v. 35 amps brings them to life, but then you need a 40A battery.

If the motor was hot, then the controller would have been very hot and something probably got damaged. If a mosfet blew, the motor would be very difficult to turn while connected, so if it spins like before, it's probably not a mosfet, but could be, not that it matters because you'd be better off with a bigger controller anyway.
thanks for your reply, can you recommend a controller for my kit?
 

Johnwat1980

Pedelecer
Aug 11, 2020
25
8
41
Newcastle upon Tyne
You need to tell us what you want the bike to do.
to get the most potential from the kit i have without it overheating or blowing something up so my battery is 52v 20ah at 30amps my motor is 1500w and i have kt-lcd 3 display..... i would prefer a sinewave than a square wave but depends how expensive the sinewave is haha
 

wheeliepete

Esteemed Pedelecer
Feb 28, 2016
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pedrodelgado

Just Joined
Oct 4, 2021
2
0
Looking for a controller recommendation...

I have a Hallomotor conversion kit (36v 1200W/48v 1500W) with the same controller (KT36/48SVPRK-SLS02G). It was running fine for a few months. Mostly I never went beyond level 4 PAS (750W). One day, coming up the long hill home, I had a bit of spare juice so I went up to 5 (1200W) for a few minutes. After a while the KT3 displayed 8W instead of 1500W. I switched it off quickly, but was too late - the controller is toast.

Neither Hallomotor nor Risunmotor (who make the controller, but seem to be the same company as Hallomotor) will answer my emails, even though I'm within warranty (but beyond Paypal returns).

Today I went into town. I borrowed my girlfriends controller (for a 750W/1000W Hallomotor). I had a heavy cargo (125kg / 300lbs) to carry 10 miles up a moderately steep hill. I was trying out my new battery using Nissan Leaf modules (5 modules, 10s, 36v, 64Ah, no BMS yet). I mostly avoided using maximum power, but the controller did not do well, it cut out several times.

In the end it got extremely hot, three quarters of the way up the hill and I had to stop for 20 minutes (fortunately my cargo included a bottle of beer) to allow it to cool down.

I'm not impressed with these controllers (and have read of others having controllers burn out, with no support from Hallomotor). They are advertised as 1200W, but only rated at 22A (800W) continuous.

But perhaps my motor is just not suited for my needs? It was interesting to read vfr400's comments about motor winding and efficiency - it is when I'm climbing a hill at 5mph that I most frequently have problems.

Primarily, I need to be able to pull heavy cargo up steep hills (50kg/120lbs), but it is also nice to be able to zoom to town and back travelling light (if that is also possible?).

Can anyone recommend a controller for my needs?

- 36v battery (could change to 48 or 52 if necessary)
- KT-LCD3 display
- 35A motor

Thanks!
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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5mph is too slow for hills using PAS 5 with kt controllers, the mosfets thermally cut out when they get too hot, if they aren't blown /shorted they will switch on again once cooled down. How many mosfets does the controller currently have ?
 

pedrodelgado

Just Joined
Oct 4, 2021
2
0
How can I find out how many mosfets? Once I left it all to cool, managed to get going again, but felt as though I was lacking a bit of power, so probably blew a few mosfets? What controller should I be using?

Thanks for your time
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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West Sx RH
If a mosfet fries nothing will work, they don't have an in between except the thermal cut out.
Show us a pic of your controller or unscrew the top 2 screws each end and pry off lid/cover and count them lined up along the side.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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West Sx RH
I had cut outs on my Boardman CX bike ove the S/Downs climbing in PAS 5 so swapped out my 6 fet controller for a 9 fet on both KT and since not had any issues.
It is dependant under what circumstances they are used and whether they have issues. Mostly is is high power and slow speed as well so is important to know the motor winding or KV/rpm.