New Ebike kit blowing fuse in battery.

[gilsh]

Hello,

I was hoping for some help with what I'm assuming are a couple of novice questions:

Here's what I know: I bought a 48V 1200W "Ebikeling" rear hub motor kit that I have installed on the cheapest bike I could find at target. I also bought a 48V 10AH Lithium Ion Battery from Vpower. The battery came with 3 10A 250V fuses. The first one burnt out due to me accidentally wiring the positive and negative cables backwards (I'm very much a novice ) The second fuse burnt out after my pedal-assist engaged the motor for about 3 seconds. The third fuse lasted a bit longer; I installed it, lifted the tire off the ground and hit the throttle-- it worked fine, I then hopped on the bike and I was able to use the throttle a couple times for short bursts before the fuse burnt out when I tried to hold the throttle for more than 4 seconds.

I'm wondering if I can just install a bigger fuse and solve my problem without risking major damage to either my motor or my battery... but I'm assuming that the fuse is there for a reason.

The controller that came with the motor is apparently a 25 amp controller so does that mean that I would need a 25 amp fuse? (http://www.ebay.com/itm/272213065352?_trksid=p2057872.m2749.l2649&var=571018571518&ssPageName=STRK%3AMEBIDX%3AIT)

The battery apparently has a maximum continuous discharge rate of 20 A, so does this mean that I should use a 20 am fuse or risk damaging the battery? (http://www.ebay.com/itm/281775651807?euid=83409bfd71ca4ddc883a8a036b54d184&cp=1)

I'll admit that I'm a complete novice so all these questions may already be answered for me somewhere on this forum, but I don't know whether I'm even asking the correct questions to solve my problem. I really appreciate any help you can give.

I have one last, probably unrelated question: why is there a ground wire coming from the battery if the only thing for me to ground the battery to is the bike which is insulated by rubber tires?

 

[nutnspecial]

They rate the cells at 2c max cont discharge (20a) but gave 10a fuse and holder with the kit? Yes, your controller is pulling up to 25a so your fuse needs to be bigger than that.

I don't use a fuse. You could bypass it (for testing purposes ) at least (carefully of course not to cross polarity!). And I guess maybe a 30a fuse would be an appropriate size should you want one.

Keep in mind if the battery is 20a cont, and the controller 25a cont, it will be stressing the battery a little bit @ full draw. If batt doesn't get hot though you should be fine. I doubt you can program the controller down, a fuse won't help protect the battery in that way, and you already have the battery for a good price.

I'd probably just not thrash it too much too often to be kind to the battery.

 

[DAND214]

You can start with a 30 but I think your gonna need a 40 at least. If the battery can put out more you might need the 40 or more. A fuse is to protect you from mistakes. I don't get why they would send 10 amp fuses, they know motors pull a lot more than that on start up.

Dan

 

[d8veh]

I doubt that your battery can supply enough power for the motor/controller. If the fuse doesn't blow, the BMS will cut out if you're lucky. If you're unlucky, the battery will be killed in a few short journeys.

To solve your problem, you need either a higher discharge rate battery or a controller with lower maximum current. You could try shaving or crimping the shunt in your controller to reduce the current. ideally, you need a wattmeter to measure the current, so that you can see the change. If you're good with DIY, you can make measuring device out of a piece of battery cable and a voltmeter.

 

[dilkes]

See this thread
http://www.bikeforums.net/electric-bikes/1052302-fuses-snapping.html.

Same battery, same issue. He ended up going with a 20 amp fuse which worked for him. You may need a larger one. As mentioned, potentially more strain than what battery is designed for,

 

[Voltron]

Maybe there's an internal fuse for the charging circuit in the battery case that the 10s are for...total guess tho of course