Over volting an Ultramotor A2B Metro hub controller

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Hillhater   100 GW

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Over volting an Ultramotor A2B Metro hub controller

Post by Hillhater » May 04 2015 6:26pm

Knowing that these A2B hub controllers are "soft start" and current limiting to ~25 Amps max, and seeing that it is fitted with 63 volt caps (and assume other components have similar 63v rating ?)....is there any reason this unit would not run on a 55-60 v battery ?.. Just looking for more cruising speed.
The idea is to run normally on the 36v internal "A" battery, but when up to speed on the open road, switch over to the "B" battery at 60v (15s LiPo) to boost the speed up.
I guess it might have some over voltage protection, and the extra watts ( 60v @25A= 1500 watts ) may cause a heat problem , but I believe there is a thermal cut out / protection included.
I know folk have run these at 50 ish volts, but how close to that 63 v component rating can it go before becoming a smoke generator.
Anyone tried these internal controllers at higher voltages ?
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fechter   100 GW

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Re: Over volting an Ultramotor A2B Metro hub controller

Post by fechter » May 04 2015 7:34pm

Yes I have one I run a 16s LiFePO4 battery with. Near 60v hot off the charger but typically settles around 52v. Doesn't do much for the takeoff but definitely gets the top speed up. Mine does around 28mph on flat ground. You can't really pedal that fast, so no human assist.

About the only thing I did was place a resistor in series with the relay coil on the B battery. I measured the coil resistance at 560 ohms. They are rated for 24v. For a 48v pack, I think adding some resistance in series with the coil might be a good idea. A small dc-dc converter would be better, but there is not much room to stuff one in the hairball. A 300 ohm 10W resistor in series with the coil should be good for my packs that top out around 58V.
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Re: Over volting an Ultramotor A2B Metro hub controller

Post by Hillhater » May 04 2015 8:01pm

Thanks Fetcher, That gives me some comfort, Normally i don't mind blowing/replacing a controller, but on this it's a whole different ball game if the smoke starts ! :lol:
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Re: Over volting an Ultramotor A2B Metro hub controller

Post by fechter » May 05 2015 6:51pm

I've racked up quite a few miles at 52v with no problems. I'm still planning to go with an external controller to push a few more amps.
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Re: Over volting an Ultramotor A2B Metro hub controller

Post by Hillhater » May 05 2015 7:57pm

Do you have any issues with the thermal protection in the motor ?
Mine seems to kill the motor even though it still only feels slightly warm ? ( I guess the core is hotter)
(.. Though admittedly after a steep, slow hill that needs max pedal assistance !)
I feel pushing more power through here will only aggravate any thermal problems.
Do you happen to know if the UM Excel motor ( external controller) is very different ?
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Re: Over volting an Ultramotor A2B Metro hub controller

Post by fechter » May 07 2015 7:05pm

Yes, the controller goes into thermal limiting if I try any kind of steep hill. Does fine on flat or mild slopes. One of the reasons I'm going for an external controller. The really weak startup is also kind of annoying.

I have not heard any reports on the Excel motor.
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Re: Over volting an Ultramotor A2B Metro hub controller

Post by Metro_E-cart » May 25 2015 5:06pm

Hello,
I got an A2B Metro about 2 years ago, mainly as a vehicle to do in-town grocery shopping and the occasional trip to Costco. Everything was fine and dandy until about 2 months ago, when I noticed that the frame battery range had fallen from 18 miles to about 8-9 miles with pedaling.
After reading various threads I decided to get a 48V 20AH battery pack to use as my B battery. I connected the battery pack to the XLR connector under the rear rack using the front plate of an original rear battery case. The LCD battery display shows a fully charged battery, but the throttle doesn't work, i.e. no motor movement. Pins 1and 2 are minus, 4 and 5 are plus, 3 has an orange cable, 6 has a yellow cable. 3 and 6 are not connected to anything at the moment. Any ideas what could be wrong ?
Any advice, hints, tips, lectures would be greatly appreciated.
Thanks

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Re: Over volting an Ultramotor A2B Metro hub controller

Post by fechter » May 26 2015 6:43pm

I just used the big black and red wires coming out of the connector. I'm not sure what the other ones do but I just cut them off and it works OK.

I did have a problem similar to yours. It was working but suddenly died but the A side still worked. I traced the problem to a bad connection down in the rat's nest under the frame pack. It was a cheesy bullet style connector that lost tension. I unplugged it and used pliers to squeeze the socket end tighter and plugged it in again. It's been working since, but I plan to completely redo the wiring at some point.

Can you hear the relay click when you turn the key to B?
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Re: Over volting an Ultramotor A2B Metro hub controller

Post by Metro_E-cart » May 26 2015 9:02pm

Yes, the relay clicks when I switch to B, I even exchanged A and B in the hellhole, same result though. Frame battery works fine, auxiliary makes only the speedometer happy. I forgot to mention that my Metro is a Gen 2 with the controller potted in the removable bottom shell of the frame.
I left the 2 thin wires open ended, so just using red and black for the power. The voltage at the controller input connector shows that the relays are switching fine. Still wondering why this doesn't work since the power is going to the controller.

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Re: Over volting an Ultramotor A2B Metro hub controller

Post by Metro_E-cart » May 27 2015 5:26pm

I did some testing today with a bunch of 26650 flash light cells. Up do 47V input throttle works fine. Add another cell and get 50.8V throttle goes non-responsive.
Looks to me like the controller has been programmed to shut itself off. Any ideas on how to get around this without gutting and Lyen controller?

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Re: Over volting an Ultramotor A2B Metro hub controller

Post by fechter » May 27 2015 7:00pm

Yes, that was my next thought. I don't have any experience with that version of controller. Being potted makes it hard to modify. Going with a Lyen controller will have other benefits, but you may lose some of the speedometer functions.
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Re: Over volting an Ultramotor A2B Metro hub controller

Post by Metro_E-cart » May 27 2015 7:44pm

Thank you Fechter. Speedometer function can be taken over by a CA, no big deal. Gutting this controller would be a pity because the FETs are 100V, the relays go up to 75V, so with some, probably software, mods one could run with 72V and not have any externally visible modifications. I am hoping my dealer can extort some know how from A2B :D

If it comes to gutting then more questions arise like where do I mount the controller?
I also would like to have flexibility with regards to speed and range. Normally I would use the frame battery and my external pack sequentially to get more range. But I can imagine scenarios where I would like speed (off road only of course 8) ) and would like to put the 36V frame battery in series with my 48V external pack. Ideally I would like to rebuild the frame battery with 48V as well so I could run 96V for speed or something around 30AH at 48V for range. Do you know which Lyen controller would be flexible enough to handle 36 - 96V and around 35 - 40A ?

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Re: Over volting an Ultramotor A2B Metro hub controller

Post by Metro_E-cart » May 28 2015 4:18pm

Did some more voltage testing on the bike by charging my 26650 cells. Got to 49.5V (12S) and throttle was working. However, the controller also seems to limit the maximum speed to 21mph. I reached 21 mph with about 3/4 throttle and then no more speed increase to full throttle. Voltage dropped to 48.5V. This was with no load. :cry:

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Re: Over volting an Ultramotor A2B Metro hub controller

Post by fechter » May 28 2015 8:52pm

Definitely needs some reprogramming to be fun. There may be a way to access the software through one of the connectors, but they might do that on the board and pot the whole thing. Somebody would know.

I'm planning to mount my controller to the bottom of the rear rack. The wires get sort of long, but it was the only place that looked good.
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Re: Over volting an Ultramotor A2B Metro hub controller

Post by velooman99 » Sep 30 2015 6:04pm

hello, I am the owner of a bike A2B Metro, these batteries are 36v, but you said that you used with a 48v battery, I do not have a 48v battery, for soon I would have against a bicycle with a battery to 72v, the engine is able to supported this tension? (It's a bike used second hand, I do not know what engine)

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fechter   100 GW

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Re: Over volting an Ultramotor A2B Metro hub controller

Post by fechter » Sep 30 2015 7:21pm

velooman99 wrote:hello, I am the owner of a bike A2B Metro, these batteries are 36v, but you said that you used with a 48v battery, I do not have a 48v battery, for soon I would have against a bicycle with a battery to 72v, the engine is able to supported this tension? (It's a bike used second hand, I do not know what engine)
No, not with the stock controller that's located inside the motor. 48V (actually almost 60V hot off the charger) is pushing it.
If you take apart the motor, remove the controller and wire it for an external controller, the motor itself will handle 72V.
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Re: Over volting an Ultramotor A2B Metro hub controller

Post by EastCanMan » Apr 07 2016 7:18am

Just wanted to say that after weeks of searching this topic on A2B (I have older 2 wire controller in hub motor) I am glad to find this site. Great work guys and appreciate the pics and info, answers most of my questions.
I drove the pi$$ out of my bike even in the winter and except for wiring getting wet and corroding away below the internal battery this bike took it all!!! The original cheap wide tires handle great innsnow but the new Shinko SR740 tires do not and are heavier for the motor to power. I'm going to put studs in my old tires for next winter.
If the key wasn't in such a bad place but I sit low and this bike is a dream in snow! Just watch out for slush, and I need some short ski,s so I can drag my feet so I don't lose control if I hit a patch of heavy stuff. I wiped out a few times but just hang onto the handle bars right and go down with the bike and never got hurt! I do want to go faster so appreciate all the details you bike builders have submitted here.
I have pics and will post soon of my adventures, trials, and tribulations.
Thanks again and hopefully I can get more details on A2B upgrades. Woohoo!

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Re: Over volting an Ultramotor A2B Metro hub controller

Post by fechter » Apr 07 2016 2:54pm

What size Shinko tires did you use?
I wanted to try some 244 knobbies but I think they would be just barely too wide to fit in the frame.
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Re: Over volting an Ultramotor A2B Metro hub controller

Post by EastCanMan » Apr 26 2016 4:58am

Shinko SR714 is 2.25-16" 4ply nylon and are directional. Note the motorcycle tire scale differs from that of a bike wheel.

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Re: Over volting an Ultramotor A2B Metro hub controller

Post by fechter » Apr 30 2016 9:23am

I'm using a 2.25x16 moped tire on the front. I have one for the rear but not mounted yet.
We don't get snow here, but the tread on these is much deeper than the stock tires.


The tread looks similar to this:
moped tire.jpg
moped tire.jpg (9.99 KiB) Viewed 1498 times
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Re: Over volting an Ultramotor A2B Metro hub controller

Post by Zarok » Aug 08 2016 10:51am

Hi guys
I'v bought a2b Hybrid 26
My seller told me that I have 450w engine In The wheel
Does anyone knows is this The same engine with controler inside as In Metro model?
My ebike is "New but old" and its very difficult to find any information about It.
There's writing on The cover of engine ultra motor and i Think its The same as Yours.
Can anyone confirm?
Thanks In advance

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