Jump Starter used as replacement for Battery

Joined
Jun 16, 2007
Messages
591
Age
77
Location
Massillon, Ohio
Bike
2005 BMW RT
I carry a jump starter as many of us do now. I am not having any trouble but if one had total battery failure could the battery be removed and the jump starter as the battery be used to get home or to a new battery?
 
Yes. I've done exactly that. In fact, if you face that situation it's probably -better- to disconnect the battery and use the jump-box in lieu as the problem may be an internally-shorted battery.

Mind you, jump packs often don't -like- being used that way, and you may be frying your jumper by doing so. But getting to service/home at the cost of having to buy a new (pretty cheap) jump-pack isn't so bad.

Having said that, if your bike is running properly, it should run with NO battery or jumper attached, once started... If it doesn't, then you need to look to the charging system vs. the battery as your issue, IMHO.
 
If the battery is a dead short then it will likely drain your jumper pack, maybe even before you could get the bike started. So disconnecting the battery and using the jumper pack to get the bike running is a fine idea. But using the jumper pack instead of a battery is a sure way to fry your jumper pack. It would be better that once the bike is running to put the battery back on and ride home keeping the idle above 1500.
 
Dave.David said:
It would be better that once the bike is running to put the battery back on and ride home keeping the idle above 1500.

That's what I'd do. A low idle draws on the battery and a jump starter wouldn't last long if you're in traffic without consciously keeping the idle up.

If the battery were absolutely internally shorted it would probably kill your alternator unless there is some protection against that. I'd like that to be in the form of something that doesn't have to sacrifice itself for the sake of the alternator (except for a fuse).

I don't think a complete short is all that common in a battery that was working a few minutes ago not that it couldn't happen.
 
I like the idea of a capacitor that the not quite dead battery charges up To start the engine. The capacitor never needs charging!
 
Since a completely shorted battery is unlikely, why not just get the bike started with the charging pack, and don't shutdown until home or at a battery seller. The packs can be used for multiple starts.
 
Having said that, if your bike is running properly, it should run with NO battery or jumper attached, once started... If it doesn't, then you need to look to the charging system vs. the battery as your issue, IMHO.

Can this be done with no harm to the bike? I thought the battery was necessary to absorb juice produced by the alternator that was not used by the bike.

On second thought, this cannot be completely true since on a long, high speed run, your battery would be topped up. I'd guess in that condition, the field coils get less juice and therefore the alternator cranks out less. But, absent said battery, what happens?
 
Sort of what the voltage regulator does, I thought. A completely "dead" battery that won't ever charge up can cause the alternator to put out full charge and work hard/hot.

I recall on the Concours forum a member would buy a certain jump start model because it had the same size battery as the Concours and was less expensive and lasted as well as typical aftermarket replacements.
 
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Jet is correct. Leave the failed or weak battery in place and use the jumper to get it started. Do not run it without a battery in place as you not only could do damage to the alternator or regulator, but bulbs in the system as they could potentially face the surge power that the battery normally would buffer. That is the worst case scenario, but really the regulator will guard your system until you can get a new battery. I wouldnt put the jumper in place of the battery as I would think that could potentially damage your charging system.
 
I'm not sure if those jump packs are designed to be charged via the jump leads, which is what would happen if installed as a battery replacement. Most have a separate jack for a much lower current charger. Overcharging Li batteries can be hazardous.


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Quick question on a related topic, we have an MT07 that won't start, battery is showing 12.5 volts, so it's charged fully I think, turn the bike on, it primes sometimes but there is no crank, just a clicking noise from somewhere under the seat near the battery, is the battery dead? or is it some other simple issue, bike was running fine before, last ran the engine about 6 weeks ago.
 
Quick question on a related topic, we have an MT07 that won't start, battery is showing 12.5 volts, so it's charged fully I think, turn the bike on, it primes sometimes but there is no crank, just a clicking noise from somewhere under the seat near the battery, is the battery dead? or is it some other simple issue, bike was running fine before, last ran the engine about 6 weeks ago.

Sounds suspiciously like a battery issue to me. What matters as much as the voltage is the current-production capacity ("cold cranking amps"). Voltage and current are analogous to a waterfall: voltage is the height of the falls, amperage is the volume of water cascading over the lip. The total force of water at the bottom of the falls (or the power the battery can produce) is the product of those two factors.

Your measurement indicates you have not changed the height of the falls, but the battery can only send a trickle of juice. The starter motor needs a gusher.
 
Unless below freezing it's just amperage, not cca. Batteries can measure differently between cold and warm cranking capacity.

First, check your battery cable connections are clean and tight.

If they are, in this case it sounds like a broken plate so your batteries capacity is there but you can only pull a small bit at a time. Measure voltage with everything off and while headlights are on, probably a big drop.

Also measure while starting bike. If it drops below 10v, time to replace.

Did the clock and trip odometer reset? A sure sign of low voltage.
 
I carry a jump starter as many of us do now. I am not having any trouble but if one had total battery failure could the battery be removed and the jump starter as the battery be used to get home or to a new battery?


A good non-bike-specific question!
 
Do those mini jumpers have diodes to /prevent back charging? I don't know if they could handle the charge rate of an alternator. The problem with running anything without a battery is reference voltage, without the battery to soften the load variables the regulator has to follow actual load from power usage. They will do it but not really made for that...….my jumper has an indicator to acknowledge "jump condition" of a battery ie...green light....if it allows the jump I would leave the battery in and head to nearest Auto store.
 
I remember reading a ride report of someone doing a Lake Superior circle route on an older motorcycle and the stator failed. She got a car battery, charger and an extension cord. She strapped the battery to the luggage rack and connected it to the electrical system. She charged it overnight by running an extension cord to the charger. She had to get a ground floor room! One of the older style large jump starters with a spring loaded terminal clamp would probably be a better choice. Batteries are fairly easy to get replaced on the road. A stator is another matter.
 
Quick question on a related topic, we have an MT07 that won't start, battery is showing 12.5 volts, so it's charged fully I think, turn the bike on, it primes sometimes but there is no crank, just a clicking noise from somewhere under the seat near the battery, is the battery dead? or is it some other simple issue, bike was running fine before, last ran the engine about 6 weeks ago.

Transmission in gear?


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No bike is not in gear, I ran the bike down the driveway and jump started it in 2nd gear, started ok, bike wouldn't restart on the button as normal so I took the battery out and it's showing as fully charged on the bench, plugged into my battery charger,
anyway connected the bikes battery leads to my jeep with jumper cables, same as before, bikes dash is lighting up, but it will bot crank over when pressing the starter, just that clicking noise from under the seat same as before, so I think it must be the handlebar starter switch that's the issue, or I've read it could be the starter relay wherever that is,
this is a 2017 MT07, FZ07 in the USA, very low mileage bike always stored in a dry garage, the dipped headlights on these bikes nowadays are always on, the only control you have over the lights is the hi beam switch, the low beam light isn't on now when I switch the bike on, so I'm thinking maybe somethings gone wrong inside the starter switch assembly, I know on my vstrom I fitted a headlight relay kit because these switches can go on the vstroms, all the power when starting goes through the starter switch, the headlights dim for a second when you press the starter.
 
anyway connected the bikes battery leads to my jeep with jumper cables, same as before, bikes dash is lighting up, but it will bot crank over when pressing the starter, just that clicking noise from under the seat same as before, so I think it must be the handlebar starter switch that's the issue, or I've read it could be the starter relay wherever that is,
If you hear the relay clicking, then its likely that the handlebar switch is OK, its only job for the starting circuit is to energize the relay. One failure mode could be the relay itself is bad across the high current switch bar. Another failure mode could be excess resistance somewhere in the path from the battery to the starter relay, or starter relay to the starter motor. The high current draw from the starter motor will cause large voltage drops across any small resistance in the path. Once the voltage drop goes beyond a certain point, the motor won't turn. Corroded wires/connectors are the most likely culprit, unless the relay has somehow self destructed.

Also, make sure the jumper cables are well connected to the battery terminals, or they'll cause the same voltage drop issue. In my experience though, motorcycles are pretty easy to jump start from a car battery if you have the cables connected reasonably well, they don't have to necessarily be perfect.
 
Thinking it must be the starter relay so, I think I've located it near the battery, it's got 2 30amp fuses either side, I checked both of these fuses and they are fine, I'm a bit stumped now what to do, have to ring a Yamaha dealers tomorrow maybe.
 
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