Phew, just a fuse. leading to con-fuse-ion.

Joined
Mar 22, 2015
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90
Location
Rochester, NY.
I had some trouble on my 3 mile ride this AM.

I started with what should have been a fully charged battery (Calibike 48v 15AH). Bike ran fine until the end, when It was suddenly out of juice. Red light on bottom of hand throttle blinking.

When I got back home (pedaling only).. I checked battery voltage...it was 48v climbing to 50+. I found that if I disconnected the battery for a second and hooked it back up I would have all the light's back up on the handgrip like everything was normal. But one twist of the hand grip and back to a dim pulsing red light.

I noticed that along with the pulsing light their was a tiny spark visible in the plastic fuse holder case, sparking in time with the red light.

I have the battery on the charger now. I checked for loose connections. and didn't find any. I did see one small dark spot on the red wire coming from the battery. Perhaps a heat discoloration? I can't tell for sure.

What preceded this? Last weekend I finished my mileage test. the week before that I rode 15 miles and the battery was in the yellow on the hand grip. I didn't check the voltage. I never recharged it. The next weekend I was able to finish the test. Before I started I took a voltage test and was surprised to see a reading of 72volts?? I rode it and it seemed fine, performed great for 9 more miles. I got to 24 miles before I felt the battery was to weak to continue using. It had some life but power was way down and hill's weren't happening any more. Final voltage was under 48volt's.

I left it as is until last night when I recharged it. About 5 days. Since I popped the tire, there was no reason to charge it. It took right about 3 hour's to recharge it.

I just hooked it up to recharge now that I'm home , and it only took 30 min to get a green light. which is consistent with the battery being charged and functioning right....

Did I kill some cell's? Fry a controller? Burn out my motor on an uphill? I always assist it. Despite the arcing the fuse tests out fine.

whats next?

I just hooked up a voltmeter and I read 55.6 volt's after charging. The voltage is rising as it was in previous check's. This time it's hanging out pretty stable, maybe slowly dropping in voltage.
 
Half of the story sounds right and half sounds way off.72v :shock: -3 hr charge sounds about right.what connectors do you have? is your battery throttle meter from a battery kit?
 
Repeating sparks, of any size, is not normal.
investigate that.
 
beast775 said:
Half of the story sounds right and half sounds way off.72v :shock: -3 hr charge sounds about right.what connectors do you have? is your battery throttle meter from a battery kit?

No I use a cheap multimeter. The throttle meter I spoke of is the 3 lights on the cheap twist throttle. I was shocked at 72v myself..? but thats what the readout said. It's reading 56 volt's right now, but as it stands I'm now getting nothing at all when I turn the power button on the throttle. Everything hooked together as it should.

Connector's... Anderson Powerpole connectors at the battery. through a fuse and through a computer style plug to the harness connector on the controller.

I just plugged it all back together and gave it a test... got all 3 light's lit up bright like the bike was back to normal. Gave the throttle a twist and it went dead again with only the red light pulsing and dim.. Tried again, only to get a spark show in the fuse holder. :( :?: I'll post a pic of that in bit.
 
Ok here's the latest. Some better news. I bypassed clumsy fuse wiring and connected the powerpoles directly to the controller and everything seems to work as intended... PHEW! 8)
motomech said:
Repeating sparks, of any size, is not normal.
investigate that.

Thanks for the tip to start at the spark. The cheap fuse has separated. Not sure if the sparks did that, but the fusible part is intact and it passed initial continuity checks.. But now one end is totally falling off.

Here is a question. Could the demise of the fuse be due to my new taller mountainbike tire? 26 x 1.75 roadbike tire, vs 1.95 mountainbike tire. Is it probably causing a greater amp draw? And how safe is it to operate the bike without a fuse? Seems to be more lively without all that clumsy wiring. I'm going to modify this connector next. Better fuse holder. Shorter wires, for a more direct current path.

The andersons are the quick disconnect, no need for the computer style plug as I see it.
 
this

And why do I need all this..CAM00935.jpg
 
Ok, so... After this random con -FUSE-ion which just stole away the first awesome riding afternoon of the season.. :x

I just took it for a mile long test and it rocked as it should :mrgreen: ... and I felt better than ever. The bike feels 'right' again with it's original tire. and it had a little boot in the pants feel for me when I'd give the throttle a good twist. Crisp and responsive. So good I don't want to add any more connectors or fuse holders. But I'll probably add in the right controller harness connector to some power poles with a better fuse spliced inline.

So I guess for now, issue resolved! Hope the hurdles keep staying this simple.
 
if your battery has a BMS then you do not need a fuse. if you do use a fuse, then use two of the 20A auto spade fuses and solder them on each side of the wire to make one 40A fuse. do not use those little fuse holders for major current. that is for charging or for lights.
 
no, a BMS is an electronic switch which turns off instantly when the current exceeds the overcurrent rating.

a BMS will shut off faster than a fuse can blow.

i have shorted big batteries directly across the output and nothing happened because the BMS shut off faster than i could notice what i had done. only time i ever had problems was when i bypassed the BMS. but i was able to cut the 10AWG wire with some dikes as the insulation was melting off of it.
 
Yes most fuse holders suck. I have had similar problems and since I run a BMS I got rid of the fuse and got rid of these intermittent problems.
otherDoc
 
Thanks for the added thought's. News to me about the BMS. Stands to reason. I'm sure, in the end, a properly rated and wired fuse wouldn't be terrible as an idea. But I fell good knowing I'm not running unprotected while running on with a much simpler and direct connection from battery to controller. Bike runs crisp and feels like a happy, lively machine. And the connectors stay together just fine, yet disconnect easily.

Time to reconfigure my stock grip shifter's onto some bar extensions. And source a more progressive throttle.
 
If you want to use a fuse, solder the fuse in. Keep pre-stripped pigtails a couple of inches long soldered to the spares you carry, so you can just twist the wires together off the connection to the (now cut off) blown one on a ride (carry wire strippers or whatever to help you strip back just enough to twist together, and a little tape to put over the twists, or a tube just larger than the fuse to slide over the whole thing to keep it from shorting to anything).


No more worries about the fuseholders causing problems with high reistance conenctions and problems with the bike. :)
 
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