48v Battery issue

[rkraider]

To start i am new with battery technology. I have an ebike kit from ampedbikes, and had a 36v battery recently go bad on me, so i decided to up the voltage to 48v. I got the battery from china on ebay, I have been able to charge the battery, but once its hooked up to the ebike the volts go from 55v(not hooked up) to 5v hooked. What would cause this? I have charged the battery for about 10hrs, do i need to charge longer?

Any help would be appreciated


Thanks,

Ryan

 

[Icewrench]

Check connections. Did the battery come with a bms? Is there good voltage into the bms and not much out?
What battery is it? Who was the seller? pics always help us.

Welcome to the sphere!

 

[rkraider]

Here is the link to the battery. Connections are fine I have a spare 36v and it works fine on the bike. I am testing the leads that hook up to the speed controller, once hooked up is when the battery shows 5v to 0v. Not hooked up 56v

http://www.ebay.com/itm/260835074501?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2648#ht_6446wt_812

 

[rkraider]

So another test. 57v are going into the bms, and once hooked up the volts went to 1.5 coming out of the bms

So lost here. Help is much appreciated....I'm thinking if I have a low cell or cells the bms is shutting off the power to protect? Should I charge for 24hrs?

 

[dogman dan]

Likely one of two things, the bms is simply faulty. or there is a reason the bms is detecting 0v from one cell. check to see if all balance wires are still connected, and if so, then start looking at individual cell voltage.

Possibly a cell group has gone bad already for some reason, such as it's not connected to the rest of the pack. Shipping can bust up batteries where they were connected.

 

[rkraider]

Ok, so i tested each cell. and every cell is at 3.5v with 2 at 3.6v. the bms shows 56v from leads coming out that are to connect to the speed controller, once hooked up to the speed controller the voltage drops to 1.5v, any possibility this is the speed controller?, Im lost!!!! amped bikes says that it can handle a 48v battery

 

[999zip999]

Is there one bms with 16 small balance wires or as in the website picture, One bms for each parelle group ? Picture of bms please. What is the voltage of the charger ?

 

[rkraider]

Uploaded with ImageShack.us

here is a link to image

 

[rkraider]

also here is what the manufacturer told me to do. this makes no sense to me what so ever


HI !

In the test of time, or you find voltage is 0V when the battery is connected electric vehicles?

I mean, if you want to restore the BMS system, you can disconnect the electric car and battery connection cable, this is called: off charge can be restored to normal load .

Because BMS sometimes need to disconnect the cable connection of electric cars, charging can be resumed after

You can like the battery from the electric car down, pay attention to the battery cable can not come into contact with any cable electric cars, then you try to charge, about 1 minute test voltage is reached BMS 55V?

Thanks

- yaping19992010
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[thedarlington]

dude thats a really cheap 15ah battery right there, something must be off, could you keep us up to date how you like it? it looks like a vpower but i dont think even those go that cheap, or conhis, let us know please

 

[OlderThanDirt]

Your battery looks OK since the individual cell groups are correct. The BMS may be at fault. Can you disconnect the BMS and then try hooking up the battery to the controller?

Another thought: do you get a big spark when you connect the battery to the controller? That means a large momentary current has gone into charging the controller capacitors. Most BMSs don't react since the current pulse is very short, but perhaps your BMS is sensing this and shutting down. Try momentarily hooking up the charger to the battery power leads; sometimes this will reset the BMS if it has shut off due to a perceived short.

 

[Jason27]

Lessons learned here people, stop buying batteries from unknown vendors in China....

 

[Gordo]

Lessons learned here people, stop buying batteries from unknown vendors in China....

Jason,
You have just renewed my faith in mankind. Many ES members try to view every post and respond quickly, especially to new members with questions on purchases. Many of us have learned a painful lesson, buying from unknown online vendors. There is always the exception as with the Hua Tong Controller, but 99% of the time, cheap is often the most expensive way to go. Low cost solutions are like lead batteries. A bright first idea which most often turns into a disaster and a black mark for EV's. Many people are bright enough to see they made a mistake and go on to the next build while asking lots of questions. Depending on experience, there should be a 1,2,3 on how to build a first bike;
No experience = buy a complete kit from a know supplier.
Some experience and electro/mechanical knowledge = buy parts from know sources you know will PLUG TOGETHER and work together.
More knowledge = go for parts, cells, expensive bikes and build.