Jump Starting Moto with Car....?

[thevoyager]

Left main beam on  

Have read conflicting advice online.. 

I expect conflicting advice here. 

 

But is this safe to do or are car amperages too high for a bike.

 

I have a 2006 CBR1000rr.

[dynax]

You can do it, but you must NOT have the car engine running as this could cause serious damage. It will be safer though to take it off and charge it for an hour or so.

 

[Bender]

Don't have car running and trying to charge, battery to battery OK  for starting and disconnect soon as started. 

[Mississippi Bullfrog]

As above, so long as the car engine isn't running it's fine. Car alternators put out a higher rate than bikes can handle. But a battery alone is fine. 

 

Use a trickle charger to recharge your battery. The charging system won't fully charge it from flat.

Edited May 8, 2022 by Mississippi Bullfrog

[billy sugger]

I blew my reg/rec by jumpstarting my bike from my brothers car because we left the engine running 

[thevoyager]

NOTED - ENGINE OFF - 

 

So someone said riding it alone won't fully charge it back up?

 

I don't have a charger at the moment, obviously I can buy one but is a cost I could do without at this moment. 

[bud]

It should do unless there is an underlying problem with the battery.  Did you leave the ignition on then?

Sometimes it a battery goes very flat it can kill one of the cells. It will still register a good voltage, but won't have the cranking amps it had before.

[Bender]

Once running if you go for a good ride and it don't charge you have either a charging issue or a duff battery, not to be confused with duff beer  

[Mississippi Bullfrog]

1 hour ago, thevoyager said:

 

 

So someone said riding it alone won't fully charge it back up?

That is true. The battery will get some charge but it won't be fully charged. It is a common misconception because the old dynamos would fully charge a flat battery, but modern charging systems don't. 

 

To fully charge a battery from flat you are better off using a charger. 

 

It's not urgent as if you can get it started and give it a decent run it will get enough charge to restart the engine. Many people run their bikes this way all the time.

[Old-codger]

Lidl have one of their Battery chargers on sale this week for a very reasonably price Ultimate Speed Car Battery Charger - at Lidl UK - www.lidl.co.uk

[thevoyager]

Cheers all, LIDL charger looks ok, will see if they have it in local tomorrow.

[Stu]

1 hour ago, Mississippi Bullfrog said:

That is true. The battery will get some charge but it won't be fully charged. It is a common misconception because the old dynamos would fully charge a flat battery, but modern charging systems don't. 

 

To fully charge a battery from flat you are better off using a charger. 

 

It's not urgent as if you can get it started and give it a decent run it will get enough charge to restart the engine. Many people run their bikes this way all the time.

 

I have seen you mention this a few times and I always pull the face of 

 

I am going to be that annoying kid! Why? Why? Why? Why? Why? Why?

 

I was always under the impression that the reg/recs job was to charge the battery fully and once fully charged pump the rest out as heat! so why won't it fully charge a battery? 

 

Oh and to @thevoyager car not running if you haven't guessed  

[Mississippi Bullfrog]

18 minutes ago, Stu said:

 

I have seen you mention this a few times and I always pull the face of 

 

I am going to be that annoying kid! Why? Why? Why? Why? Why? Why?

 

I was always under the impression that the reg/recs job was to charge the battery fully and once fully charged pump the rest out as heat! so why won't it fully charge a battery? 

 

Oh and to @thevoyager car not running if you haven't guessed  

The charging system will charge a flat battery but not to its full capacity. You'd never know unless you checked the electrolyte with a specific gravity float. These days most batteries are sealed so we can't do this. But back in the day I used to measure the level of charge and when a battery was flat the only way to get it to full charge was by using a trickle charger.

 

I remember having issues with a battery that had run down and I'd bump started it. Then I read an article in a technical journal which went into a lot of stuff that frankly went over my head, but when I checked with someone who knew their stuff he said it was the case. Mostly we rely on the charging system to replace the charge uses to start the engine and there's enough juice in the battery to fire the engine so why worry about checking?

 

My Honda has an alarm that drains the battery. I have a battery monitor fitted. If I use the bike every day the monitor shows around 80% charge, it only goes up to full charge when it's connected to the trickle charger. 

[Bender]

Specific gravity changes with the level of fluid in a cell also, a low level cell will have higher reading than a full one, I stopped using sg when you couldn't get to the cells, a good run on a healthy charging system with a good battery will charge the battery, I bump started mine last year  after some edjit left the ignition on cough cough, it's never seen the charger. 

 

Idling and short runs won't.