Topic open for Discussion. Burnt Out Controller with Regenerative Braking

[stl_recum]

You must have a SLA battery pack for this to work.

Following another thread on this forum, if you have a LIFEPO4 pack the BMS stops the reverse flow from the diode.

http://goldenmotor.com/SMF/index.php?topic=1068.0

[Gregte]

You must have a SLA battery pack for this to work.

Following another thread on this forum, if you have a LIFEPO4 pack the BMS stops the reverse flow from the diode.

http://goldenmotor.com/SMF/index.php?topic=1068.0

I have a Golden Motor brushless front hub motor with a GM Cruise Controller. I also have a LiMn 36v battery and a LiFePO4 battery. The regenerative braking works with both batteries. It will also work without the key switch turned on but it will burn out the controller if you are going fast enough.

If you cross the keyswitch with a diode in the manner shown in the diagram shown in this thread the regen braking will work with the key off and will not burn out the controller. I know this to be true with the equipment I have as I  have done it.

[GoldenMotor]

We have recently enhanced the cruise controller to detect if the battery pack is in place. If the battery is switched off, or is not connected at all, the controller will check the back EMF voltage, if it exceeds the preset limit, the controller will disable the regenerative braking to protect controller from being damaged. Now our new version of cruise controller is much more reliable than before. I'd like to take this opportunity to thank all contributors who gave us feedback and suggestions, to help improve the quality and reliability of GM products.  

The regenerative braking function will be resumed automatically when the battery is switched back on.

[GM Canada]

My 48v system was shipped on july 13 2009. It was promised this diode would be installed in all systems shipped after july 6 2009. Does this mean my system has the diode? is there a way of checking it?

[GoldenMotor]

We do need a diode anymore, read the post.

[GM Canada]

We do need a diode anymore, read the post.

I assume you mean "we do not need the diode anymore" and yes I did read the post, it was written on july 25th. If you read my post you will see my system was shipped on july 13th. Does "recently enhanced" mean before july 13th or after. I'm just looking for some clarity or a way of telling what I have. So i'll ask again, how do I know if I have the new "enhanced controller' a diode fix or no fix at all.

[rolf_w]

lately my colleague has also totally grilled is BAC controller by simply trying to recharge the battery on a downhill after the BMS has switched off the GM battery pack:
. The 'diode solution' offered in this thread will not solve this problem since the BMS will keep the battery disconnected and the FETs will burn out. Solutions could be to disable the controller (as implemented recently by GM) or adding a breaking resistor (which could be the motor wiring?) - both require reprogramming the controller (that's why I'd like to see a USB connector for firmware updates). r

[Perbear]

I have a Golden Motor brushless front hub motor with a GM Cruise Controller. I also have a LiMn 36v battery and a LiFePO4 battery. The regenerative braking works with both batteries. It will also work without the key switch turned on but it will burn out the controller if you are going fast enough.

This is quite interesting, does your batteries have BMS, and if so, is it from GM?

[Gregte]

This is quite interesting, does your batteries have BMS, and if so, is it from GM?

Yes, both batteries have BMS circuits and one of them, the LiMn is from Golden Motor.
But the fact that the regen braking supplies a high voltage current to the controller with the key turned OFF does not have anything to do with the type of battery you are using because the key is OFF, meaning the battery is completely out of the circuit.

[TheKid]

I was told by Li Ping that the BMS on his batteries will prevent regen braking to protect the battery from the higher than 5a regen current. I assumed that was also correct for the GM LiFePo4 batteries as well. When I use the GM battery, regen kicks in for a split second, then stops, and the wheel continues to spin. When I installed an SLA pack, the regen worked fine for a while, but then it started doing the same thing as with the LiFePo4 pack. Then I discovered this only happens with a fully charged battery. It seems as though the controller stops the regen from working with a fully charged battery. I also have one of the older GM regen controllers, and the same thing happens. With the LiFePo4 battery, no matter if it's fully charged or not, regen doesn't work with either controller, but it does work with a less than fully charged SLA pack.

[liared]

This may be regarded as a dumb question but I just want to be sure:
The problem with burned controller from generative breaking is only present if you have both a "magic controller" and a regenative braking controller installed together (regenative braking controller = the black controller box on the web site).
If you only have the "magic controller" installed then there is no risk of burning it from regenerative braking...right!?

[Bikemad]

This may be regarded as a dumb question but I just want to be sure:
The problem with burned controller from generative breaking is only present if you have both a "magic controller" and a regenative braking controller installed together (regenative braking controller = the black controller box on the web site).
If you only have the "magic controller" installed then there is no risk of burning it from regenerative braking...right!?

Sorry Bengt,

But unfortunately it's not right.

Only one of the above mentioned controllers would usually be fitted, not both.

Two controllers would only be used if two separate hubmotors were fitted. (One controller for each motor)

As far as I am aware, unless you have a very recent controller, there is still a risk that the controller may be damaged by the regenerative braking current generated at higher speeds while the battery is either turned off or disconnected.

As of today, 22/7/2009, the day of the eclipse, all GoldenMotor controllers have a new function to deal with the issue of regen braking burning out the controller while battery is off.

Alan
 

[liared]

I bought a 36V 250 Watt MiniMotor kit in June 2009 with  "Magic Controller" (to be installed next week)
So I am apparently at risk of burning it.
Suppose I happen to ride the bike until the battery cuts out (forgot to recharge).
Is the battery in this case defined as "unconnected" (although it is physically connected).
Will the battery in this state absorb the current created from "regenerative braking" or will the controller be at risk of burning if I continue pedalling home without support from the battery? Will I have to walk home leading the bike by hand???
Can I disable the generative braking function  by a command to the "magic" controller - or unplug a wire there - thus avoiding this potential problem?
I see that there is a diode solution that can be applied to my "non-fixed" controller but I am an electric novice not knowing how to fix that or what components to get (and where).
I think that this "add-on" solution for nonfixed controllers should be available to order (with detailed instructions how to install it) from Golden Motor website at reasonable cost.
Additional information added:
I have the 36V 16ah Golden Motor battery.

[Helgeo]

Liared,
The mini motor has a freewheeling hub so it will never generate any power during braking. So you have nothing to worry about.
Actually I think the mini motor is one of the best solutions available for a hassle free moderate powered eBike.

Good luck with your new bike!

Helge

[liared]

Liared,
The mini motor has a freewheeling hub so it will never generate any power during braking. So you have nothing to worry about.
Actually I think the mini motor is one of the best solutions available for a hassle free moderate powered eBike.

Good luck with your new bike!

Helge

Thank you Helge!
I feel really relieved.
For a electric bike novice user like me, participating on this forum is a great learning experience.
I am grateful that you more knowledgeable people have the patience and will to answer an guide a non expert !!