I have a trike which I purchased with a 250w motor. Last year I bought a 1000w kit and upgraded. The controller is 36v/ 48v and for nearly a year I used the 36v 15 ah battery, that came with the original bike, without issue. I have recently bought 2 36v 25ah batteries hoping to get a little more range. One of the batteries is fine, the other however fuses if I go up a hill. I have spoken with the vendor who tells me I need a bigger battery., but one works absolutely fine. Am I being fobbed off?
Battery fusing
- Thread starter Debbie Lomax
- Start date
30 +1 amp. The batteries original fuse was a 20amp, but, I put a 30 amp in the first time it fused.
D
Deleted member 25121
Guest
What do you mean by "30 +1 amp"?
What's the maximum current rating of the battery packs, it needs to be greater than the current provided by the controller as does the fuse rating?
Note that "25ah" refers to the capacity of the battery ie how much energy it can store, and doesn't reflect its maximum current rating.
It's possible that the battery that isn't blowing the fuse has a higher internal impedance and isn't as good ass the battery that is blowing fuses.
What's the maximum current rating of the battery packs, it needs to be greater than the current provided by the controller as does the fuse rating?
Note that "25ah" refers to the capacity of the battery ie how much energy it can store, and doesn't reflect its maximum current rating.
It's possible that the battery that isn't blowing the fuse has a higher internal impedance and isn't as good ass the battery that is blowing fuses.
I have supplied the specs of battery and controller as I am not sure what you need to know . Thanks in advance for your help .
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Deleted member 25121
Guest
The important numbers there are that the controller can draw 30 +/-1A and that the battery can supply a continuous discharge current of (only) 20-25A.
That explains why the 20A fuse blew and also why a 30A fuse could also blow.
In my opinion, and I hope somebody says otherwise, it's unsafe to use a 30A because you risk having the battery catch fire. I'm sorry to say that i think your vendor was right in saying that you need a bigger battery.
That explains why the 20A fuse blew and also why a 30A fuse could also blow.
In my opinion, and I hope somebody says otherwise, it's unsafe to use a 30A because you risk having the battery catch fire. I'm sorry to say that i think your vendor was right in saying that you need a bigger battery.
Thankyou, that makes sense. I would need a battery with a continuous discharge of at least 30 A to be safe.
D
Deleted member 25121
Guest
The battery needs to have a discharge rating above that of the controller rating by at least 5amps.
This the problem with illegal 1kw D/D hubs and power hungry controllers , vendors sell batteries that are not up to the job and they continue to use crappy 5a rated cells instead of good 10 - 20a rated cells.
No matter what the battery capacity they just are big enough or have enough cells in parallel to cope with higher current demand.
This the problem with illegal 1kw D/D hubs and power hungry controllers , vendors sell batteries that are not up to the job and they continue to use crappy 5a rated cells instead of good 10 - 20a rated cells.
No matter what the battery capacity they just are big enough or have enough cells in parallel to cope with higher current demand.
If the two batteries were connected in parallel they then become one, the capacity and discharge rate doubles then use a 30amp fuse, though a 30a fuse may still pop as it is at just under the max draw of the controller.
Tbh for single battery you will likely need a battery built to be able to cope with 30/35a continuous draw.
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Deleted member 25121
Guest
The battery can supply a continuous discharge current of only 20-25A so fitting a 30A fuse would be risky, at the extreme it could catch fire. Putting the 2 batteries in parallel with a 20A fuse in each could work but it's far from ideal.
Paralleling the batteries will double the continuous discharge rate and capacity, a single 30a fuse inline just before the controller connection will suffice for protection.
If the draw of 30a keeps popping the fuse then use a 35a one for a bit of headway so the limit isn't being bounced all the time.
Paralleling will be easier on the batteries then as single entities.
If the draw of 30a keeps popping the fuse then use a 35a one for a bit of headway so the limit isn't being bounced all the time.
Paralleling will be easier on the batteries then as single entities.
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D
Deleted member 25121
Guest
From what the OP implied there's a fuse in each battery pack, if they are 20A fuses they why add an additional external 30A fuse?
We don't know what type of batteries are being use, if they are soft packs they will have an external fuse.
D
Deleted member 25121
Guest
You're right, I've re-read the original post. Using a single 30A external fuse is dodgy though, what if one of the batteries went open circuit, the other one would be having to provide up to 31A?
The individual BMS should back up and should limit the current draw, though agree a single battery with correct discharge specs would be better for anyone who doesn't understand or know what they are trying to achieve.
I myself have had no issue paralleling multiple packs to achieve a specific capacity/ discharge need.
I myself have had no issue paralleling multiple packs to achieve a specific capacity/ discharge need.
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