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Bike to Bike Jumper

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Kiwi_Roy:
A few weeks back I took my Convert to coffee and left the key On
I came out and the battery was as dead as a Dodo, Of course you cannot push start a Convert
I looked around for someone to give me a jump start but none of the car drivers I spoke to had jumper cables.
A guy came along on a Triumph Tiger and we jumped the bike using a couple of lengths of 16 gauge wire I was carrying just by holding the wires on the battery posts with his motor running  after about 5 minutes the Voltage in my Convert was sufficient for it to crank crank over and it started.
This incident got me to thinking how could this have been done easier.
The solution would be if we could have connected between the charging pigtails,
From a previous time trying to start via jumping the charging pigtails I knew that the fuse would blow
But with a larger fuse its possible, I had previously jump started a Super Tenere from my 72 Eldorado

SO I fabled up a cable
4 feet of speaker wire
2 male Bullet connectors
2 female bullet connectors 
Standard bullet connectors may be a little loose in the oversize ones of the tender cable but they will make contact if forced
2 30 Amp blade fuses
I added a small 12 Volt lamp to one end of the jumper wires  to Verify the Tender fuse, this will test the battery connection at either end just unplug from one bike, I used a 12 Volt AC lamp but a simple diode and resistor would work just as well
I tested this out today by leaving the Converts light on until the battery dropped below 11 Volts
I started up the V7 III and within a couple of minutes the convert battery was up over 12 Volts
Note I have 20 Amp fuses in my battery tender cables hense the 2 30 Amp blade fuses I carry to replace any blown ones
The whole thing fits in a small sandwich bag so its no problem to store.

Instruction sheet (put in sandwich bag)
Bike to bike Jumpier Cable
Connects the battery tender cables of two bikes together, No crossover.
Incorporates an LED to display either end status
Battery tender leads should have at least 20 Amp fuses
As cable will carry a heavy current if the bike with flat battery is cranked
Plug bikes together then run donor bike for several minutes to build up charge in flat battery

The cable as shown is only 4 feet long, it was adequate for my purposes but make it 6 Feet and add a couple of clips and it will allow you to jump from and to a car
Yes, you can easily jump a car using your bike, 10 Amps from your bike will soon boost a flat battery to where it can crank a car or truck.

nc43bsa:
I would use a minimum of 8ga wire.

Using less will charge the battery over time, but it won't start the bike.

cliffrod:
What about using a pair of 30 amp non-cycling breakers instead of regular fuses?  If tripped, they will reset when circuit is disconnected.  Not as cheap as fuses, but cheaper than a tow if no spare fuses can easily be had.  One of the better “crude” aspects of older Harley Davidsons is the use of a breakers in place of fuses.  A regular cycling breaker is connected to the positive terminal for the majority of the circuits.  It makes getting a bike back in service or onto the road with no spare fuses much easier.

Fwiw, I still have my set of “official” Moto Guzzi jumper cables that I bought for my V7 Sport from Harper’s at Daytona Bike Week in 1994.  Pretty sure the plastic bag labeling is even in Italian.  Maybe they still sell them?

Kiwi_Roy:

--- Quote from: nc43bsa on December 02, 2022, 05:44:26 PM ---I would use a minimum of 8ga wire.

Using less will charge the battery over time, but it won't start the bike.

--- End quote ---

Sorry, I appended the instruction to my post after your post.
No, we aren't trying to crank through the cables just transfer a charge so the bikes own battery can provide the 100+ Amps the starter will draw.
2 16 gauge wires did it for me in about 5 minutes.
14 gauge twin speaker wire is very flexible and readily available

Both my bikes have Voltmeters so I could see it doing the work the V7 was putting out about 15 Volts and the Convert was up to 14 in no time.

pehayes:
Actually, you can 'push start' a Convert.  Its in the book.  Requires something like 35mph.  NOT ME!  Recent discussion on the Convert Forum IIRC.

Get creative.  Only one piece of wire like a fence wire.  Be careful.  Lean the two bikes together metal to metal.  (Crash bars against each other?)  There's your ground.  Wear your gloves. Jam the fence wire +ve to +ve and away we go.

Patrick Hayes
Fremont CA

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