Golden Motor Regen BLDC 48V controller

[Knuckles]

I use several in parallel on my workbench for a constant current circuit (in between hot meals of course).

But obviously I do not use stove-heating elements on an e bike for regen (braking) as heat dissipation.

But the idea is the same. Use a heating element at the correct ohm value and watt rating to dissipate excess braking (electrical) energy if the bats are full.

(This is also known as the "Hot Lunch Waiting at the Bottom of Long Hill" braking effect. )

 

[biohazardman]

if your FETs were 100V I'd be in trouble. but since there are no reports of busted 48V regen controllers I think I'm ok, specially taking into account that my power bus will be much better decoupled than yours.

your controller will fry if the bus hits a critical voltage somewhere between 58.9V and 65.1V. if you use it as non-regen, you'll be safe if you keep *max* voltage below 58V. however when you regen, the bus will be higher than the batt by an amount that's difficult to predict. 16 lifepo4 cells ("nominal" 48V) have a max voltage of around 57.6V, and that's dangerously close to your max. so I'd go very easy on the regen with a fully charged 16-cell pack. going beyond 16 cells would be dangerous, and I'd only risk 16 cells with cells of very good quality (low internal resistance) such as A123s. but maybe I'm being a bit paranoid. (again, without regen you'd have no problem with batt resistance.)

I would like to report a fried 48v GM controller. It died for no apparent reason about 50 miles after the install. I was running a 36v 10ah lifepo4 in series with a couple of parallel smallish 12v SLAs. Wanted to make sure the SLAs could keep up and they were a near perfect match for draw and useful miles with the lifepo4s. Batteries should have been getting low a few miles after I blew my 30 amp fuse and the controller at the same time. I had managed over 18 miles mostly unassisted from the combo a couple of times without LVC kicking in. I found continuity in both directions when checking at both ends of the resister diode pairs on the back of the board. Expect the FETs would fry first and it is them that are giving me the short that I see. My 36v fried after 1200+ miles with regen enabled and well used so I probably have the right parts to fix the 48v unit. Maybe later today I will give it my best. If I have more problems I will have to crack the motor open. OH did I forgets to say that 48v is the only way to go with one of these? Lots of torque and hardly even slows down for the hills. Top speed only 23MPH though. Good regen to slow you down also.

 

[Lanchon]

> I would like to report a fried 48v GM controller.

I'm sorry to hear that, and thanks for reporting. (for other readers: he refers to a 48V regen; the non-regens don't have the diode resistor pair he talks about.)

I'd only use that controller at 48V with very low impedance batteries. the small lead-acids probably have a very hard time accepting charge during regen; voltage might go up and fry the controller easily.

please tell us what components are fried of the FETs, resistors and TVS diodes. assuming that you have enough good FETs to resurrect one controller and you want to use them, and that you want to continue using your current battery setup, I would recommend some changes: remove the resistors and diodes and strongly decouple the bus instead. the FETs would be overvolted but they'd probably survive. if you want I'll tell you what components I'd use in your case.

 

[Knuckles]

YES. SLA has high discharge amps but very low amp charge ability.

NiMH or LiFePo4 is a much better choice to accept lots of regen amps.

-K

 

[biohazardman]

> I would like to report a fried 48v GM controller.

I'm sorry to hear that, and thanks for reporting. (for other readers: he refers to a 48V regen; the non-regens don't have the diode resistor pair he talks about.)

I'd only use that controller at 48V with very low impedance batteries. the small lead-acids probably have a very hard time accepting charge during regen; voltage might go up and fry the controller easily.

please tell us what components are fried of the FETs, resistors and TVS diodes. assuming that you have enough good FETs to resurrect one controller and you want to use them, and that you want to continue using your current battery setup, I would recommend some changes: remove the resistors and diodes and strongly decouple the bus instead. the FETs would be overvolted but they'd probably survive. if you want I'll tell you what components I'd use in your case.

It was a couple of the large diodes on the back of the board connected to the resistors, see pics in link, that fried. Not sure why they fried on the 36v. What a mess these boards are to solder on!!! While rewiring for the 48v controller I put a 14-16 gauge terminal on a 12 gauge wire OOOPS. It came off in my hand while I was upgrading the wiring, after the problems, to crimped and soldered connections. Also found one of the motor power wires had a terminal that would back out easy when connected to it's counterpart so fixed that too. Re-soldered one of the questionable joints on the yellow motor wire on the board as well. Ran it out and about today for 12 miles and it was good. Had another nail in my tire and a flat when I got off werq and broke spoke #4 while heading to the bike shope, with a leaking tire, for a pactch kit. New spokes are on the way I will build the new wheel myself this time hopefully I can do better. Still after all that the bike is down again. Lots of torque but still limited to 23mph tops though do you know anything about this limit?
Thanks for the info I turned off my regen although not sure if it was the problem or the connections. Really don't care to find out just yet. Will wait till the other bike is up and running before I mess with this problem again.

http://goldenmotor.com/SMF/index.php?topic=279.msg3696#msg3696

 

[Lanchon]

> It was a couple of the large diodes on the back of the board connected to the resistors, see pics in link, that fried. Not sure why they fried on the 36v.

this means that the bus voltage went over about 62V with enough energy to fry the TVS'es, even when using the 36V battery. there are two possible causes that could act at the same time contributing to the bus voltage during regen:

-the batt can't accept the charge current. this means that the voltage on the batt terminals will temporarily go up and less current will flow in. this effect has to do with charge distribution and mobility of ions inside the cells. lead-acid cells are particularly bad accepting charge and that's why they can't be fast-charged.

-impedance (resistance and inductance) seen between the bus conductors at the FETs. it comes from the battery (internal batt impedance), the wiring, the shunt, the PCB traces, etc. (bad wiring (like a momentary batt disconnection) can send the voltage through the roof during regen if the controller doesn't abort quickly enough.) the long circuit to the battery is necessarily inductive and so high impedance will be seen in the high frequency range. this means that when the FETs switch, for a very brief period the voltage will go up in a spike. to avoid this the bus is decoupled (caps are added across it).

the problem with that controller is that the bus seems to be decoupled with an alu electrolytic cap (from what I see on the posted pics) and those caps are inductive in the high freq range. so a high voltage spike is to be expected on the bus with every switch cycle, which is a bad thing for TVS'es and FETs alike.

I wouldn't run that controller in regen without better decoupling. with proper decoupling, the TVS'es could be considered optional (but better if they are there nonetheless).

 

[biohazardman]

> It was a couple of the large diodes on the back of the board connected to the resistors, see pics in link, that fried. Not sure why they fried on the 36v.

this means that the bus voltage went over about 62V with enough energy to fry the TVS'es, even when using the 36V battery. there are two possible causes that could act at the same time contributing to the bus voltage during regen:

-the batt can't accept the charge current. this means that the voltage on the batt terminals will temporarily go up and less current will flow in. this effect has to do with charge distribution and mobility of ions inside the cells. lead-acid cells are particularly bad accepting charge and that's why they can't be fast-charged.

-impedance (resistance and inductance) seen between the bus conductors at the FETs. it comes from the battery (internal batt impedance), the wiring, the shunt, the PCB traces, etc. (bad wiring (like a momentary batt disconnection) can send the voltage through the roof during regen if the controller doesn't abort quickly enough.) the long circuit to the battery is necessarily inductive and so high impedance will be seen in the high frequency range. this means that when the FETs switch, for a very brief period the voltage will go up in a spike. to avoid this the bus is decoupled (caps are added across it).

the problem with that controller is that the bus seems to be decoupled with an alu electrolytic cap (from what I see on the posted pics) and those caps are inductive in the high freq range. so a high voltage spike is to be expected on the bus with every switch cycle, which is a bad thing for TVS'es and FETs alike.

I wouldn't run that controller in regen without better decoupling. with proper decoupling, the TVS'es could be considered optional (but better if they are there nonetheless).

Can you explain the decoupling you speak of. I did not want the spike at start up so installed a switch it's not as bad but still there. A relay might werq better but then they use juice to run them. What are some options to get rid of the arc/spike at power up?

 

[Lanchon]

> when the FETs switch, for a very brief period the voltage will go up in a spike

I'm referring to PWM switching some tens of thousands of times per second, not about turning the controller on or off.

> What are some options to get rid of the arc/spike at power up?

1) an inductor in series with the battery, but it'll worsen peak voltage during regen and turn on.

or 2) use a second switch with a series resistor. first activate the second switch to "slowly" bring the caps up to the batt voltage, and then activate the main switch. the second switch could be a button or you could use a 3 position power switch, in which the middle position activates the cap precharge. or you could use a 3-way connector in which one terminal is recessed so that it makes contact last and the other two precharge during fraction of a second. ideally you'd use a 2-way sequenced switch but I doubt you'll find something like that.

 

[biohazardman]

Lanchon

Thank you for the information I will see about making something to stop the damage to my switch at power up.

 

[electrobent]

I was so happy when I first read your all's responses to my pictures of my GM controller. The bearings went out on my 36V hub and I replaced it with a 48V GM wheel. I could not get the controller and the wheel to sync up right and did exhaustive tests which lead to the conclusion that the hub motor was at fault. The instructions given for the controller did not jibe with it's behavior. The instructions said to flip the power switch to cycle through the phasing options while what actually did that was bumping the throttle (to use a gas burning phrase). It only ran on two phases and it was the same disconnected wheel side wire when you connected the three phase wires miss-matching the colors.

I threw a fit and GM finally sent me a new wheel that was not centered. I got it installed and again could not dial it right--it behaved just the first one (which was nice and centered and true but not close to round. By this time the warranty on my controller expired and they no longer sell the 48V version of the regen controller (they do have 36V and 24V models though) so I bought their "cruise controller" which allegedly has cruise control AND regen and is plug and play so having the wrong instructions is not an issue. It came and it seems to have plugged and played though I have not tried it on the ground yet.

So I have the controller pictured earlier in this thread. If anyone wants to cover my shipping costs and give me a few bucks for my time, I'll pack it up and send it to you. I also have the 36V non-regen controller that smoked but I don't think totally died when the bearings gave out that I can throw in. Hell, how about a G3 mac?

I am in Southern Kalifornia, USA

 

[amberwolf]

pm'd