Bike to Bike Jumper

[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]

I would use a minimum of 8ga wire.

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

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

[Kiwi_Roy]

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?

Breakers would be cheaper than a tow, I was quoted $85 for a tow truck to come and Jump me but you would have to install them ahead of time there's nothing wrong with old fashion fuses
I threw a couple of 30 Amp blade fuses in the bag to replace the fuse in Doner bike when its wimpy fuse blows.
I learned this fuses blow when I jumped my 72 Eldorado to a Super Tennere , thats the reason I added the lamp so I can tell if either fuse is blown, unplug from either bike and the light is checking the fuse in the other bike
I added a photo and schematic to the original post.

[n3303j]

FWIW:
Ran into a guy in a parking lot with a dead jeep and a set of standard jumper cables. STARTED him up with my T3 (Odyssey 925). Surprised both of us.

[Kiwi_Roy]

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

I think it would take quite a while to get enough electrons through a piece of steel fence wire, the resistance would be higher than the 16 gauge copper I used.
The Convert will still crank over when its battery has dropped to 11.4 (read with my Voltmeter at the park light bulb) Cranking Voltage 10.4
Probably quicker to put the flat battery into the other bike that could be push started.

I wonder how many owners have tried to push start a convert, I suppose it would be easy enough to try on a hill.

N3303j said,
FWIW:
Ran into a guy in a parking lot with a dead jeep and a set of standard jumper cables. STARTED him up with my T3 (Odyssey 925). Surprised both of us.

I jump started a car from my Eldorado once, I can't remember if we had jumper cables, I think the car must have been carrying them.
I had my motor running
Once the bike battery is charged the amps are available to charge a second battery in parallel.
BTW
I have a battery tester,
A while back I tested all my batteries, the one in the Honda SUV tested worst the bike batteries all had +100 CCA
The SUV would often run flat with the radio on.

[Kiwi_Roy]

Im currently tending the battery on a high end BMW SUV with my motorcycle tender, it just takes a lot longer for the light to go green.

[Wayne Orwig]

I carry a set of simple cables made using heavy speaker wire. Not sure what the gauge is, but I have started a couple of cars from my bike using them. The speaker wire is a lot more flexible than normal jumper cables. Those people are obsessed with getting as many thin strands of wire in there as you can for skin effect and such.

[guzziownr]

"I jump started a car from my Eldorado once, I can't remember if we had jumper cables,..."

My wife's car had a dead battery, nose-in to our narrow one car garage. Just enough room to slip in the '75 Eldorado and hook up the cables.

[Frenchfrog]

I think one of these might well be a better but more expensive answer
https://www.amazon.com/Best-Sellers-Jump-Starters/zgbs/automotive/318336011

[usedtobefast]

I guess I'm the "buy it" vs "built it" kind of guy.   

I carry these on long trips:  https://www.amazon.com/gp/product/B000WMRO3M/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 





Pics look big, but they are smaller jumper cables designed for motos. 

My thinking, if I am riding solo, and end up with a dead battery, getting a jump from a moto person or car/truck/suv person ... these look very normal and most people understand a jump start and normal looking jumper cables.    So far they have been carried around for maybe 10,000 miles and never used.   

[Kiwi_Roy]

I guess I'm the "buy it" vs "built it" kind of guy.   

I carry these on long trips:  https://www.amazon.com/gp/product/B000WMRO3M/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 





Pics look big, but they are smaller jumper cables designed for motos. 

My thinking, if I am riding solo, and end up with a dead battery, getting a jump from a moto person or car/truck/suv person ... these look very normal and most people understand a jump start and normal looking jumper cables.    So far they have been carried around for maybe 10,000 miles and never used.   

Yes, if you are standing there looking forlorn with those in your hand someone will soon stop and offer you a jump, I have proven this several times with the cables I carry in my Honda SUV.

[LowRyter]

Dave,  a related question for you.

I have a Ducati with a full fairing on it, the battery is buried in it.  I have an SAE connector (7 amp) that I use to trickle charge and a cigarette plug that I can use to run a compressor, etc.

I'm most concerned about needing a jump.  Since the battery is buried f I rigged a direct wire with a post, 1) What gauge of wire and type of post,  2) do I need to hook a ground wire too?

[Wayne Orwig]

Dave,  a related question for you.

I have a Ducati with a full fairing on it, the battery is buried in it.  I have an SAE connector (7 amp) that I use to trickle charge and a cigarette plug that I can use to run a compressor, etc.

I'm most concerned about needing a jump.  Since the battery is buried f I rigged a direct wire with a post, 1) What gauge of wire and type of post,  2) do I need to hook a ground wire too?

You should be able to find a good ground on the engine block somewhere.
Is there a cable on the starter that you can access? If you attach any wire to the battery long term, you really need to fuse it at the battery.

[JediMasterII]

I think one of these might well be a better but more expensive answer
https://www.amazon.com/Best-Sellers-Jump-Starters/zgbs/automotive/318336011

I agree with Frenchfrog.  We have carried a NOCO Boost jump starter on motorcycle trips and in my personal and company vehicles for many years.

I have used it for jumping bikes many times - all successfully.

[OldMojo]

I agree with Frenchfrog.  We have carried a NOCO Boost jump starter on motorcycle trips and in my personal and company vehicles for many years.

I have used it for jumping bikes many times - all successfully.

This and this. Starter boxes are way smaller and have far better shelf life than they used to. Plus they frequently have a USB charge port for your phone, GPS or whatever.

[LowRyter]

You should be able to find a good ground on the engine block somewhere.
Is there a cable on the starter that you can access? If you attach any wire to the battery long term, you really need to fuse it at the battery.

It would go straight to the battery.  what size fuse & wire gauge to you recommend?

The engine would provide enough ground to despite being aluminum and painted?

[Wayne Orwig]

It would go straight to the battery.  what size fuse & wire gauge to you recommend?

The engine would provide enough ground to despite being aluminum and painted?

The aluminum block is a very good conductor. Even the steel in the frame is a great conductor, because it is so large.

[LowRyter]

The aluminum block is a very good conductor. Even the steel in the frame is a great conductor, because it is so large.

Thanks.   Appreciate the info, the frame on my Duc is largely the engine.  The trellis streeting head frame, seat frame and swing arm attach to the motor. 

[n3303j]

....but the paint is a perfect insulator. Any connection must be on bare metal.

[LowRyter]

....but the oaint is a perfect insulator. Any connection must be on bare metal.

I'll probably need to wire both posts

[Kiwi_Roy]

Dave,  a related question for you.

I have a Ducati with a full fairing on it, the battery is buried in it.  I have an SAE connector (7 amp) that I use to trickle charge and a cigarette plug that I can use to run a compressor, etc.

I'm most concerned about needing a jump.  Since the battery is buried f I rigged a direct wire with a post, 1) What gauge of wire and type of post,  2) do I need to hook a ground wire too?

As I have proven by jumping from a Triumph Tiger and by jumping a Super Tenere from my Eldorado a pair of 16 gauge wires will work simply hold the two wires onto the battery posts at either end and the donor machine will soon boost your flat battery up to a point where it will crank the bike.
LowRyter, The 7 Amp fuse will blow as soon as you try to crank the bike, put a 20 or 30 in its place, the larger fuse will still protect the pigtail in a short situation but won't blow when you try to crank
The twin speaker wire I carry is 14 gauge. I installed a male spade connector on each battery post of my convert and regular clips on the other end so I can quickly connect onto the battery and clip onto whatever battery I happen to come across, I haven't used these yet but I'm confident they will work if I ever need them.
I took a picture of several I carry.

From Left to right
The pair of individual wires I used to resurrect my convert from Triumph Tiger ( I don't know how I was able to talk the owner into letting me try this), it took about 5 minutes until the Convert Lawn Tractor battery was charged enough.
My bike to bike plug in cable which I proved works from V7III to Convert (tested in Garage)
A cable I made following the Triumph Tiger Resurrection incident but as yet unproven (14 gauge speaker wire with clips and spades to connect to battery of Convert.), I'm sure these will Jumper to or from a car by Wayne's experience, I might try these out today, I can easily reproduce some conditions in the garage.
Any thoughts on this Wayne, is it a valid test to flatten a battery by leaving the lights on then charging it back up using the jumpers?