Why does my bike shut down when I hold down the throttle too long?

[Adh247]

I have an A2B Metro and I use it almost every day, and lately the bike will just shut off when I hold down the throttle for like 5-10 seconds. So now, basically I can't go fast because it will shut off, and when it happens, I have to turn the key off and then turn it back on, and everything will work fine again as long as I don't hold the throttle down...

At first i thought, oh yeah that's probably a battery problem, so I bought a new battery, put it in and it still does it! Then, I was thinking too that maybe it's was just a wire short somewhere but it's too consistent for that I think. I have also

I basically have to feather the throttle so it won't go faster and shut off.

I even switched the A to B connection around and it still does it.

. Any ideas what could cause it to shut off?

 

[Adh247]

How many miles on your odometer?

I don't have one but probably about 500 miles.

 

[Adh247]

That bike is around 10 years old or more, and both it and the battery are long out of production? That throttle response would not be unexpected/ on an old pack. Where did you get a new battery? Hope it's not something that sat on a shelf for 10 years.

No it's brand new. I'm on my 4th battery. That's why I know it's not the battery. Gonna take the bike apart and look for loose connections.

 

[PedalUma]

Thermostats on cars go bad. It might have something like a thermal shut off that has become overly sensitive.

 

[Adh247]

I don't know what you're going on about. Yes, it is that A2B Metro. Yes it's 10 years old, and yes I just put a band new battery in it. Can we get back on topic or should I just delete this thread due to all the rambling.

I have maintained this bike thoroughly and has never given me any problems. I'm going to just go through all of the connections, but other than that, I am asking if anyone who might own an A2B Metro if they have ever experienced the posted topic and what the cause was.

Thank You.

 

[Losna]

I do not have the bike.

If you haven't already, you could check the electrical system according to the manual:

Connector Identification - Ultra motor A2B Metro Service Manual [Page 41]

Ultra motor A2B Metro Manual Online: Connector Identification. Figure 1 identifies the connectors found within the battery compartment, which is inside frame downtube. Remove the bat- tery cap to access these connectors. A I H G FIG. 1 A. Brake switch connector B. Main battery...

www.manualslib.com

 

[Kmart]

Please let me know if you figure it out. I have the exact same problem on my Prodeco Phantom 3.

 

[Adh247]

I think I might have fixed it but I haven't done enough testing. it appeared to be a worn out connector that wasn't making enough contact to put power through.

 

[Adh247]

If your battery is old it could possibly be a bad cell creating it as well. It will read as full charge but not work properly when put through higher performance

 

[FiremarshallDave]

Having built and ridden many Ebikes I will give you my 2 cents worth. Batteries have and amp flow limit. A single cell in a string has a discharge rating that can range from 8A and some are as high as 35A (Molicel brand) Above that number is really expensive and then we start to get into the fraudulent claims of overseas sellers claiming crazy numbers that are unachievable currently. No battery has 9999mah as I have seen advertised. I think we are pushing 4000mah in an 18650 right now. A larger cell will have more Mah but will use less cells. I digress.... A 20AH battery will last longer at full throttle than a 13AH battery, as you will have 7strings of 14 cells as opposed to 5 strings of 14 cells. both of these have 52V (14 cells). You can hammer longer as you have more strings thus more mah (amperage flow). The cell closest to the output to the BMS (battery management system) may tap out first even though some batteries down the string will still have plenty to give. If you let off the throttle a re-balancing occurs. and the battery seems to come back. The 10A discharge was exceeded (usually heat) and the pcb cap shuts down the individual cell. This cap also prevents over discharge below a certain voltage. The BMS also has a flow control some are 30A and if you spend over $600 on a battery you can get one with a 50A BMS. I had a fat tire bike with a 20AH battery and a 30A bms that tapped out after 5 min of hard use. Same battery in my tadpole it was hard to get a tap out (lower rolling resistance). I opted for a 36AH batt with a 50A BMS for the fat tire (problem solved). I don't care if the battery is new it has to have enough cell strings and a BMS system to match to not overheat and tap out. Again mah and discharge rate are two different numbers one is energy contained in a cell and the other is the maximum rate at which energy can be extracted (i.e. 8A). Your answer if your controller and wiring will handle it is a larger battery. Wiring too small will overheat. Your controller is usually listed online and the specs should be there. EM3ev custom built my 20AH batteries with the cells I wanted. The 36AH was an Amazon seller with a niche listing. I knew what I wanted and needed to compensate for the high rolling resistance. I hope this helps some of you. P.S. I use a rear rack for my batteries and add aluminum supports back to the frame. The triangle 36AH didn't fit in my frame as intended and ended up on a rear rack as well. The fat tire is front wheel drive and balances the weight. It works for me My favorite bike right now... The electric Tadpole is a dream to ride as well. My newest build Is an electric 29er and on today's ride it tapped out at 29miles as I forgot to charge the battery this season (put away in fall not fully charged) and Wisconsin had temps near 60 yesterday so I rode 15 miles and then 66 deg today(29 miles then a few more after tap out).