Replacing a fuse that is soldered on, 48v 13ah ebike battery.

[firetv2097]

Hi all,

I have an Engwe m20 battery that has failed due to what looks like a failed battery level indicator. I heard a "pop" when i pressed the indicator panel. Which then caused my battery mount plate to fail.


Below are pics of the discharge cable (i think) that has two fuses attached. One is ok, the other has clearly blown.

My question is, should i disconnect the red or black wires from the bms before attempting to solder on a new section of wire with new fuse attached. Is it safe to just cut the wires?

I woud love some help/guidance of this.

many thanks

 

[AGS]

The job of a fuse is to protect the wiring and prevent a fire.

That looks like a 40 amp blade fuse for the output wiring. The other fuse is probably a much smaller one for the charger.

If the wiring and fuse holder haven’t been damaged you can just pull the old fuse out and press in a new one.

The bigger issue is finding out why the fuse blew in the first place.

Something has gone short circuit on the output for it to blow.

 

[AGS]

Having said that, this video suggests that they haven’t fitted a fuse holder and have soldered the blade fuse directly to the wires.

This is a Yose Battery with fuse holders, so you don’t need to do any soldering if the fuse needs to be replaced.

 

[firetv2097]

Hi, thanks for the quick reply

I should have inlcuded the other image of the battery indicator board burned out.

To be clearer, the fuse is just soldered on with no fuse holder present. (cheap Engwe) ,and the fuse is completely blown. I have purchased a new fuse holder and fuses, and i want to be safe before i go ahead with this fix. Also, as the battery level indicator board is dead too, and i doubt i will find a replacement. Should i disconnect it permanently?

I appreciate any help on this.

 

[firetv2097]

Having said that, this video suggests that they haven’t fitted a fuse holder and have soldered the blade fuse directly to the wires.

This is a Yose Battery with fuse holders, so you don’t need to do any soldering if the fuse needs to be replaced.

Amazing, yes you chose the right video example for my situation. I would love to buy one of those white fuse holders, but i cant seem to find them anywhere. Any ideas?

 

[AGS]

Halfords sell maxi fuse holders rated at 80 amps and also sell 40mph (orange) maxi fuses. There are also plenty on eBay. Although everything only has a 24v rating.

 

[E-HP]

I should have inlcuded the other image of the battery indicator board burned out.

What keeps you from posting the pic?

The reason those fuses are soldered is that they’re expected to never blow. If you’re expecting it to blow the fuse regularly enough to have a holder, you should consider a more capable battery.

 

[Diggs]

Just something to keep in mind. 40 amps is really starting to push these blade holders and fuses. Even when I run them at 25-30 amps they start getting warm in this type of fuse holder. (Could also be why they were soldered?)

 

[E-HP]

Just something to keep in mind. 40 amps is really starting to push these blade holders and fuses. Even when I run them at 25-30 amps they start getting warm in this type of fuse holder. (Could also be why they were soldered?)

Half of the “fuse failures” I’ve seen on this forum have had fuses intact and melted holders.

 

[firetv2097]

What keeps you from posting the pic?

The reason those fuses are soldered is that they’re expected to never blow. If you’re expecting it to blow the fuse regularly enough to have a holder, you should consider a more capable battery.

Thanks for the comment, but forgive me, i though the whole point of a fuse is to act as a fail-safe to prevent further damage. This could be caused by any number of failures. In my case it seemed to be that the power indicator was a weak point, but i cant verify. I guess i should have spent over £350.00 to get a "more capable" battery. I dont believe there are any batteries that won't fail at some point.. Chinese made or not. Iv'e heard of a couple of good brands from USA, but sadly i don't live there.

 

[firetv2097]

Half of the “fuse failures” I’ve seen on this forum have had fuses intact and melted holders.

Hi,

Thanks for the info,

I agree that these fuse holders kinda suck. Would you recomment i just use a couple of blade holders, and skip the holder idea?

 

[E-HP]

Thanks for the comment, but forgive me, i though the whole point of a fuse is to act as a fail-safe to prevent further damage. This could be caused by any number of failures

Not really. The fuse is the last line of defense. The battery BMS should have tripped first under most circumstances. The fuse will blow if there’s a short circuit. That picture isn’t useful, but I’d be cautious working around that board if that’s the location of the short. Do you have a shop that you could bring it to?

 

[Papa]

Half of the “fuse failures” I’ve seen on this forum have had fuses intact and melted holders.

Then upgrade the damn holder. For a measly 12 bucks and 10 minutes of your time. If the manufacture thought a fuse wouldn't be needed in the first place, they'd save a few bucks by omitting them completely.

Marine Grade Fuse Holder 8-GA, Fuses Included

Shop online DS18 HYDRO MFH8 Marine Water resistant Fuse Holder 8-GA. . FREE SHIPPING ON ALL US ORDERS.

ds18.com

 

[E-HP]

Then upgrade the damn holder. For a measly 12 bucks and 10 minutes of your time. If the manufacture thought a fuse wouldn't be needed in the first place, they'd save a few bucks by omitting them completely.

Marine Grade Fuse Holder 8-GA, Fuses Included

Shop online DS18 HYDRO MFH8 Marine Water resistant Fuse Holder 8-GA. . FREE SHIPPING ON ALL US ORDERS.

ds18.com

Seems the OP has bigger problems. He has a 40A fuse blowing on what appears to be a short internal to the battery. I wouldn't even attempt to replace the fuse until fully diagnosing that first.

 

[Papa]

Seems the OP has bigger problems. He has a 40A fuse blowing on what appears to be a short internal to the battery. I wouldn't even attempt to replace the fuse until fully diagnosing that first.

I agree.
I was just addressing the crappy fuse holder issue.