Ampedbikes double standard

[gearhead]

Hello everybody,

I´m not happy as to how Ampedbikes handled the situation created when I fried my controller. On their website they urge us, customers, to be honest and forthcoming with the description of our problems but they don´t feel bound to act in the same way toward us. Read the following email exchange and form your own opinion about their integrity.

Regards,
Diego Calut

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Name of sender: Diego Calut
Email of sender: dmcalut@gmail.com

On 10/17/2011 7:20 AM, Diego Calut wrote:

Hi there,
I installed one of your motors about four months ago and had it working nicely until yesterday when it suddenly stopped. The motor doesn´t respond to the thumb throttle and my CycleAnalist shows that no juice is flowing. The symptoms at the time of failure were a sudden deceleration and a stiffening of the motor. It hasn´t locked up but I had to pedal hard to get out of the way. Lifting the bike off the ground the wheel (it´s a rear 36V 26" rear wheel motor) I can turn it by hand but it is definitely dragging, as if the brake were lightly applied. The free wheel is working OK and I must have rode the bike about 200 miles altogether, using the motor mainly as a help in headwinds and very slight slopes. Again, the failure was sudden with absolutely no warning. Please walk me through the repair! Thanks, Diego.

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On Mon, Oct 17, 2011 at 7:39 PM, Support@ampedbikes.com <Support@ampedbikes.com> wrote:

You will need to check all connections to see if there is a loose connnector, besides that it sounds like you may have fried the speed controller which you can buy a new one off of our website. Or you can send it to us in for repair if youd like

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From: Diego Calut <dmcalut@gmail.com>
Date: Tue, Oct 18, 2011 at 8:41 AM
Subject: Re: Ampedbikes feedback
To: Support@ampedbikes.com

Hi Bud,
Quoting from my original message: "Lifting the bike off the ground the wheel (it´s a rear 36V 26" rear wheel motor) I can turn it by hand but it is definitely dragging, as if the brake were lightly applied." So, can we agree that the problem is basically mechanical and INSIDE the motor and go on from here? Thanks, Diego.

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On 10/19/2011 4:36 PM, Diego Calut wrote:

Oops, I was wrong and you are right. I unplugged the phase wires and the wheel turns freely. I measured the resistance between each of the phase wires and the controller's input wires and one of the phases is shorted. By what I've learned thru the net it seems that the phase's FETs have blown, right?
If so the fix would be to replace them and here I have a few questions: Why did they blow up, given that I very seldom use full throttle? Replacing them by the same model won't prevent another blow up, so should I replace all FETs with higher rated ones? By the way, I'm in Argentina so sending the unit back isn't going to work for me.
Regards, Diego

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On Fri, Oct 21, 2011 at 4:42 PM, Support@ampedbikes.com <Support@ampedbikes.com> wrote:

Which FETs are you talking about? the motor wires or something else? We can sell you a replacement if youd like

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Date: Mon, 24 Oct 2011 09:16:47 -0300
From: Diego Calut <dmcalut@gmail.com>
To: Support@ampedbikes.com

Hi, I´m talking about the FETs inside the controller. One phase (green wire) is shorted to negative input from battery, the other two read 10Kohms. I will buy a replacement but I´m concerned that it may fail within 200 miles, too, not to mention the shipping charges, the custom duties, the paperwork and the fact that I can´t ride the bike. So, in addition to getting a new controller, I´d like to fix the one that got fried with uprated FETs. The ones´ on my controller are marked P75NF758 (or &) CZ OF 7 5 MAR 007. What FETs do you use for repairs?

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On Mon, Oct 24, 2011 at 8:53 PM, Danny L. Ray II <support@ampedbikes.com> wrote:

Heya Diego. We don't replace fets. It is not cost effective to replace them.Also you shouldn't burn a controller unless you were running at 72V. The only controllers that have ever been returned are ones that have been connected in reverse polarity to the battery or electric engineers that run it on an oscilloscope or test various internal parts. I did burn one myself when we were first testing the geared motors at 72V. You can avoid burning at 72V if it is well ventilated and it is shunted internally.

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Reply |Diego Calut to support
show details Oct 25 (6 days ago)

Hi there,
I thought you replaced fets since your first response was "Or you can send it to us in for repair if youd like". No problem, I´ll source them thru Mouser or DigiKey.
Now, let´s get this straight; I´m not asking for a replacement under warranty or anything like that. I just want to fix my bike and get to ride it again. However, I live in Argentina, a third rate country where everything is made complicated by the government and this means that getting a new controller thru customs is neither easy, nor fast, nor cheap. Just to give you an idea of how bad it is; I bought the kit from you in November 2010, I shipped it from Miami in January 2011, and I finally got it in May 2011. I hope to be luckier with the new controller but my BIG concern is with its reliability.
I´m not about starting a big debate on this issue but my installation has been properly done using Anderson power pole connectors and it has worked satisfactorily until now connected to a 36V 15Ah Ping battery, monitored with a Cycle Analyst. So, this may be a first for you guys; somebody (me) managed to fry a properly connected controller while using it within its ratings. I don´t know that the manufacturing date stamped on the FETs, MAR 007, might be a clue to your supplier using overstock or reject components but I´m concerned that this might happen again to me. As you already know this would be a huge inconvenience and that´s why I´m intent on fixing the old controller too.
Thank you for your patience and would you please advise me as to the shipping costs for a controller and a half-twist throttle to Buenos Aires, Argentina?
Regards, Diego Calut

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No response from Ampedbikes as of 10/31/2011
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P.S.: I replaced the blown FETs with locally sourced IRF 2807s and the bike is on the road again.

 

[Icewrench]

Why did they blow up, given that I very seldom use full throttle? Replacing them by the same model won't prevent another blow up, so should I replace all FETs with higher rated ones....



Part throttle puts a higher load on the fets.

 

[neptronix]

How many volts were you running on their controller, sir?

 

[oatnet]

Greetings Diego,

You bought a discount ebike kit, which is a great way to get into the hobby, but not a lifetime investment. Your controller failed because it is cheap crap made in China. Don't feel bad, that describes most of what everyone is running here, and I have a box full of fried controllers myself. Get a Lyen/Steveo/methods/kelly controller and will probably last a little longer.

Then you will start breaking spokes. Then the throttle will fail. Then the BMS. This hobby is working through a series of failure modes until you eliminate them all. IMO the most impressive builders here are not the ones winning races or going the fastest, but the ones who have worked through these failure modes and made a build they can get on and ride, day after day, without messing with it at all.

-JD

 

[nicobie]

Hi Diego,

Not a good idea to tell Amped that you replaced the crap stock connectors with good ones. All warranties are VOID if you change their connectors. If you can't repair what you have, don't buy another from them, get a good one from ebikes.ca or Lyen.

 

[ohzee]

I would recommend buying a controller from someone active on this board and give up on any quality support from amped.

Good Luck.

 

[gearhead]

Hi guys,

Thank you for your messages. Interesting comment, Icewrench, about fets getting a higher load at part throttle. I thought otherwise but anyways, they are rated at 75V 80A, I have a 36V battery and I´ve never seen more than 25A on the CA. Shouldn´t have blown. Maybe an early life failure? I hope so

Thank you!

 

[amberwolf]

Unfortunatley the way that controllers work with motors, the battery currents you see dont' have much to do with the motor currents. There's a few threads that discuss how that all works if you're interested in the details (in the Motor Technology subforum, and the Ebike Technical subforum, and probalby in the Technical Reference Area).

But basically non-full-throttle is good for the motor, and bad for the controller, under load. Controller gets hot, motor stays cooler. Capacitors in the controller die from the heat, electrolyte boiling off, and stop filtering the voltage spikes that then can reach the FETs and blow them up. Sometimes poor heatsinking or counterfeit FETs cause the problem, or something else that causes a current spike when the FETs are already under stress.


That said, I'd recommend checking with Lyen here on ES, or http://ebikes.ca, if you do end up needing a new controller.

Otherwise, for pretty good robustness (though nothing is failure-proof), IRFB4110 FETs are the ones you would ideally want on your controller as replacements (replace *all* of the existing ones with them at the same time).

Also replace the electrolytic caps with low-ESR caps rated for at least 105C, from a known good brand like Rubycon, Panasonic, etc. Preferably with a version that is rated for tens of thousands of hours rather than the more common ones rated for a few hundred to a few thousand hours, if you can find ones in the size and type you need.

Then if it's possible in the environment you ride in, ventilate the controller at both ends, so that air can flow thru it. Even without a fan pulling air thru, just a little bit of cooling air could help a lot. A small fan pulling air thru is much better.


All those things aren't "necessary", but they all help.

 

[dnmun]

start a new thread if you wanna repair your controller. a lot of us have parts we can mail you. so open it up and read what the mosfets have printed on them. i never have seen one opened up.

 

[Joseph C.]

start a new thread if you wanna repair your controller. a lot of us have parts we can mail you. so open it up and read what the mosfets have printed on them. i never have seen one opened up.

S/he already fixed it.

 

[yopappamon]

While they have a good product, Amped seems to take an adversarial position against their customers when there is a problem. Other US venders seem to be a lot more helpful and forgiving of mistakes. It's a shame since I'm only a few miles from Amped. :|

 

[ohzee]

When I complained about my tube battery only putting out 9.4ah on my watt meter the owner blamed it on the
charger and said it was not charging the battery enough. New charger came free of charge which was nice , but
the volts were still the same as was the results.

To me that was smoke and mirrors. Just one of my probably 5 silly stories about this company I had happen to me
in a 3 month period which left me with a sour taste in my mouth.

 

[gearhead]

Thank you so much guys!

I´m really learning a lot from you. I already fixed the controller so I can´t show you the innards, but the FETs specs are on my original post. Anyways, I´ll buy another controller, not from Ampedbikes, in case mine blows up again.

Thank you also for getting me off the hook. This is nature´s way of telling me not to exercise too much; lean on the throttle, rest your legs.

Cheers,
Diego