Capacitor as emergency battery backup?

bnschroder

2014 Super Tenere ES
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Last Sunday I almost got stranded in the middle of the Cohutta Wilderness in Northwest Georgia with a dead battery on my CRF250L. I was 20 miles away from the nearest paved road and further from any gas station or auto store. Bike has started happily all day and all of a sudden dead display, no lights, dead!
My buddy fortunately had a jump pack but the bike wasn't running well (had to keep revs up at all times, and it would stall often and then needed to be bumped) and eventually I couldn't even bump it anymore. But at that point we had fortunately reached civilization again.
Someone on the ADVRider CRF250L thread suggested packing a capacitor as emergency backup to put in place instead of a battery when your battery dies. You can't start the bike with it, but apparently it lets it run smoothly and protects the charging system. But unfortunately the guy didn't know details because he wasn't speaking from own experience. Since then I found a YouTube video of a guy bumping his Tenere 700 with a 25V 10,000 Microfarad capacitor that then ran happily.
I figured this forum has some of the most savy MC technicians with real electrical engineering experience, so I would pop the question here:
Anybody packing a capacitor as emergency battery backup and what specs you use?
Thank you
 

Checkswrecks

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Yes, it can and has been done but big caps have big issues. I think I saw a thread at ADV about this once so you might have better luck over there, just remember that starting the big twin takes a heck of a grunt.

As gunslinger implied, there are so many booster packs available, I don't see why anybody would experiment with big capacitors but if you do, we'd love to hear about it.
 

bnschroder

2014 Super Tenere ES
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Yeah - this is not about a super capacitor that replaces the battery or a replacement for a starter pack (which you can’t run the bike on), but merely an emergency solution to bridge the battery to make it out of the wild when you battery completely craps out like mine did.
This was not a case of “too weak to crank”, but sudden death, i.e. the voltage went from 12.48 to 2 when hitting the starter.


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Thrasherg

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I would be looking for someway to temporarily connect an external battery pack to your bike rather than a capacitor, thebattery will be far more forgiving and practical than a capacitor and will probably run the engine for longer..
 

Cycledude

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I know nothing about capacitors but do believe a jump pack would be very capable of running your bike for 25 miles to get you back to civilization, I would remove the fuses for the lights.
 

gunslinger_006

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I know nothing about capacitors but do believe a jump pack would be very capable of running your bike for 25 miles to get you back to civilization, I would remove the fuses for the lights.
Depends on the jump pack. If its the “dumb” kind that just gives you 12-14v...yes.

If its got a chip in it, like the antigravity xp10, it doesn’t give you voltage until it measures your battery at less than i think 9v but check the manual.


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Don in Lodi

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I think the scenario was an internal dead shorted battery. No matter how you boost a shorted battery the dead short will kill everything around it, booster packs, chargers, alternators, etc. The operating system needs somewhere north of 10 volts, the short won't give it. The idea of the capacitor in place of a shorted battery is to give the charging system something other than a dead short to push against on a bump started bike, not to start it. A lot of work. Most systems will work with a dead battery and a good charging system, a shorted battery is a no go. Out in the wilderness, maybe worth while. Anyplace close to a Wally World or a Napa, or a tow, not worth it.
 

DamonS

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Bump starting a CRF 250L Honda or a Tenere 700 is one thing, but a Super Tenere?
had to do it this past week. its possible, but not for the feint of heart and definitely not a flat ground experience.
3rd gear, clutch in, get her rolling relatively fast, clutch out and the motor starts to spin, then quickly drop to 2nd gear (quick clutch pull) to get the motor spinning faster and away she goes.

in my case, I had my son on his CRF250L, strapped to me with a bungee style recovery strap.. half a dozen bad ideas, but when you are stuck in the bush with only an uphill climb to get you out, dumb ideas don't always look as dumb until you reflect back on it
 
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