Blown bl-36 controller at 48v - twice :(

10 replies [Last post]
ahough
Offline
Joined: 10/08/2008
Points: 4

My tale of woe begins with me happily spending the summer ebiking to work using a new stock bl-36 system, bought this year. The bike ran at 20 mph with no pedaling, 24 mph pedaling.

I first changed the throttle to a 36v crystalite half-twist instead of the the thumb throttle that came with the kit because my thumb got tired.

I then upgraded the system to 48v by adding another 12v SLA battery. The bike ran at a plenty-fast-for-me speed of 27mph with no pedaling, 30 mph pedaling. My first problem was stripping the front dropouts and having the one of the motor wires damaged at the axle when the axle rotated in place. I tore the motor apart and brought a new wire out from the windings. And put in some wonderful torque arms from ampedbikes.com

About a week later of daily use, controller #1 dies. The voltages were good coming from the throttle, the little green light on controller changed blink pattern when twisting the throttle, but
no voltage coming out of the controller on the motor leads. I took it apart, but seeing no obvious damage, and wanting to get back on the road, I bought another bl-36 controller.

This ran fine for about a week and then it died with the same symptoms as controller #1. I tore controller #1 apart, scraping the black gunk off from everything. The FETS looked okay. The in circuit resistances for the fets wer:
for fets 1,2,5,6,9,10: gate-drain 4Mohm, gate-source 4Mohm, drain-source 20Kohm
for fets 3,4,7,8,11,12: gate-drain >20Mohm, gate-source >20Mohm, drain-source 9Kohm

These two groups seem to be the upper and lower portions of H-bridges, where one H-bridge of
4 transistors is associated with each motor wire.

I pulled FETS 1 and 3 out of circuit and they look okay, I think. The gate-drain resistance is >20Mohm, gate-source resistance >20MH. Using a diode tester, I put meter negative on the source and meter positive on the gate (to charge the gate). Moving the positive lead to the drain I then got a non-zero, non infinite number which I assume is okay indicating the FET is conducting. Putting my finger on drain and gate, the reading went to infinity, indicating the FET switched off. This was repeatable for both FETS.

I'm at (my very small) wit's end. The FETs seem plausible. Something, however, is blowing up in the controller.

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.
whome
Offline
Joined: 09/10/2008
Points: 82
Re: Blown bl-36 controller at 48v - twice :(

This same thing just happened to me yesterday. I also have a new BL-36 with the "50amp" controller and yesterday the motor just quit pulling suddenly. I checked all of my connections and could find nothing wrong. The controller was still powered up with lights and the green light was blinking, but no response when throttle applied although the throttle also is displaying normal lights. I was suspecting it was my throttle though. I have not had a chance yet to check out the controller due to another project. Sorry I may not be able to contribute to help you fix it. I've only had mine a month.

Do you know what the blinking green light means? I never noticed it changing it's pattern? Was your controller not covered under warranty?

-Whome

engr_scotty
engr_scotty's picture
Offline
Joined: 07/01/2008
Points: 68
Re: Blown bl-36 controller at 48v - twice :(

I wonder if you blew your caps or something, running at 48V? I have an old pedal-first controller and the caps are rated at 50V (which is very close to 48V nominal) operating, 63V surge. My ping runs at 60V charged. The caps may have blown, but you'd probably have seen some evidence of the failure.

If you have to replace it you may want to try one of the controllers from ebikes.ca...I know they're rated at 48V.

Arno J. Wulfert
Offline
Joined: 08/12/2008
Points: 94
Re: Blown bl-36 controller at 48v - twice :(

Hey Guys,

Now I'm worried.... Just bought the Ping 48V 20AH... Haven't got it yet... Anyway, others at this site commented the slock BL-36 50 amp controller was good to go 48 volts. Your messages are the first I've seen that there may be a problem... Scotty, I checked ebikes. ca. and they have multiple controllers. Wonder if they all would work or will I need to buy the high end one... ARG.... I'm going to run until I blow the stock one... hope not too far from home

Thanks for the info guys... ARG....

Cheers,
Matt

__________________

Arno J. Wulfert

whome
Offline
Joined: 09/10/2008
Points: 82
Re: Blown bl-36 controller at 48v - twice :(

Well if I recall engr_scotty is running an older BL-36 with the hall sensors. Just to be clear I am using the new (1 month old) BL-36 that only has three wires. The controller that comes with it is black and fairly large. It does have 50v caps, which could potentially be in jeopardy with a fully charged 48v battery. My NiCads average 53-54 volts when fully charged. I have not concluded what happened to mine yet.

I'm starting to wonder why they call this a 50amp controller as well. My Cycle Analyst has never shown anything more than 20-22 amps under load for this stock controller.

-Whome

wakataka
Offline
Joined: 08/14/2008
Points: 29
Re: Blown bl-36 controller at 48v - twice :(

Interesting. I have a BL-36 with the new model "50 amp" controller purchased in late July. It has 72v caps. I haven't tried to run it on anything more than 36v yet.

I also never see anything much over 23 amps draw.

ahough
Offline
Joined: 10/08/2008
Points: 4
Re: Blown bl-36 controller at 48v - twice :(

Hmm. Both of my controllers are supposedly the 50 amp version. In both the big caps are 63V and don't look damaged. My impression was that
when electrolytic capacitors went you got a big mess. There are a bunch of smaller 50v caps, which also look okay. I've been assuming these were on the "low voltage" side of the controller. It would help if I had a schematic, but it sounds like there are a lot of different BL-36 controllers out there.

I've seen it draw 23 amps for a few seconds. The CycleAnalyst routinely records peaks of 30 amps, but I never see that on the display.

I don't know what the blinking green light is supposed to mean.

I don't think I have a warrantly claim because I'm running it out-of-spec at 48v. It would be
different if WE sold it as a 48V controller.

I've been looking at different controllers that I might use. One issue is that the BL-36 has no hall-effect sensors. I think it uses back-emf on the motor leads to figure out where the wheel is in its rotation. The crystalite controllers mostly expect the wheel to have hall sensors. I'd have to go with a pedal-first (sensorless) one.

The other concern with the Crystalite controllers is the current capacity of the FETs. Although I can find a crystalite controller that is 48v, it could easily be expecting a higher resistance in the motor windings than the BL-36 motor gives. This could draw a lot of current through the FETs and kill them. My guess is that the only safe controllers from crystalite would be the ones for the 5000 series. Those seem to all require hall effect sensors. I'd be interested if anyone had sucessfully used a crystalite controller with a bl-36 motor.

engr_scotty
engr_scotty's picture
Offline
Joined: 07/01/2008
Points: 68
Re: Blown bl-36 controller at 48v - twice :(

whome wrote:

Well if I recall engr_scotty is running an older BL-36 with the hall sensors. Just to be clear I am using the new (1 month old) BL-36 that only has three wires. The controller that comes with it is black and fairly large. It does have 50v caps, which could potentially be in jeopardy with a fully charged 48v battery. My NiCads average 53-54 volts when fully charged. I have not concluded what happened to mine yet.

I'm starting to wonder why they call this a 50amp controller as well. My Cycle Analyst has never shown anything more than 20-22 amps under load for this stock controller.

-Whome

I have an older pedal-first (no hall sensors)controller. I think the new controllers use a back-emf method of phase control, so no hall sensors are needed for immediate start. But I digress...

I have not put the 48V Ping to it, so I'm not sure what will happen. I'm not sure if I want to find out, either. Considering buying a brushless controller from ebikes.ca (model C3620PF):

http://www.ebikes.ca/store/store_controllers.php

Justin has assured me it will work with the BL throttle (minus one of the pins..see their hookup diagram).

I've heard in other threads that he newer controllers have 63V caps in them, which should be fine with 48V LifePO4s. You can always pop it open to be sure. I don't know why you guys are having controller failures running overvoltage, I'm just saying that it could be related to the voltage.

--Scotty

ahough
Offline
Joined: 10/08/2008
Points: 4
Re: Blown bl-36 controller at 48v - twice :(

I too am starting to wonder if I didn't really get the 50 amp controllers I ordered, but instead have the older 20 amp version. Does anyone know of a way to tell? In use in with either the 36V or 48V battery packs (3 and 4 12V 12amp-hour SLA batteries, respectively), it would occasionally draw 22amps, but mostly would draw about 18 amps at full throttle.

In mine, the big capacitors are 63V and a bunch of the little ones are 50v.

This would go a long way towards understanding the mystery. At least I'd have a reason to ask WE to replace the controller :)

wakataka
Offline
Joined: 08/14/2008
Points: 29
Re: Blown bl-36 controller at 48v - twice :(

I think the 20 amp controllers were pedal first rather than instant start. If yours is instant start, it should be the 50 amp model.

My BL-36 just doesn't draw anymore than 22 amps at 36v. It averages around 20 amps overall. It's almost exactly 30% more efficient than my BD-36 at the same speed / load, which is just what WE claims. It's performance is very close to the BD-36 in terms of top speed and acceleration. I don't really think the controller is limiting it, at least not at 36v.

hairybrew
hairybrew's picture
Offline
Joined: 08/13/2008
Points: 9
Re: Blown bl-36 controller at 48v - twice :(

@ahough So were you ever able to resolve your problem? End up getting a replacement controller?

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.
eZip 500 Electric Scooter The E-500 electric scooter is ideal for speedy neighborhood transportation, or simply having some fun cruising around the block.
How to Live Well Without Owning a Car Save Money, Breathe Easier, and Get More Mileage Out of Life
Juiced Hybrid Accessories and upgrades for hybrid cars
Who Killed the Electric Car? Essential documentary explaining what happened the last time electric cars were killed
Customize This