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Discussion Starter #1
I have a dead 12V bike battery for a 1998 Yamaha Razz scooter.

I saw this video, and figured if it's good enough for a mercedes, then why not?

https://www.youtube.com/watch?v=gMPuzmhYCQc

Yet, I'm not going to risk it. Without good enough proof first...

I digress...

I want to take a newly charged 12V car battery I have, and hook it up to a tiny (12V) scooter battery.

Legend has it that if I hook up the car battery to it for an hour, then I can use a battery charger on the old scooter battery afterwards.

But my three issues with this are:

1) I haven't seen anybody else do it (so sending me a youtube link would help)

2) In all the videos I've seen of car to motorcycle battery, the negative is grounded out

3) I don't know if there would be any amperage issues. The scooter battery says 4Ah on it. (can't see anything saying Ah on the car battery, which is for a Honda Civic)

Before the trolls come out to play:

Yes. I know that I shouldn't be running the car while I'm hooked up to the motorcycle battery.

LONG STORY SHORT: What can I do with my car battery and charger to get this tiny scooter battery enough juice to start trikle charging it?
 

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Still crazy after all these years
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A car battery will probably deliver somewhere around 35 to 50 Ah. If I recall correctly, my Audi (A3 TDI 2.0) had a 55 Ah battery in it.

I've used my car to jump-start my bike a couple of times - it's not recommended, but in an emergency, it works. I've also jump-started other motorcycles from my bike.

Question - why not just buy a trickle-charger for the scooter? It shouldn't cost you more than about $35 ...
 

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Scooter batteries aren't pricey either. You've got to invest a few bucks if you want to own a motored vehicle.
 

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LONG STORY SHORT: What can I do with my car battery and charger to get this tiny scooter battery enough juice to start trikle charging it?
Borrow a larger charger from someone else. Something in the neighborhood of 10 amps should give it a good boost......unless it is beyond help.
And the bigger charger can be left attached for a couple of hours if anything is happening.

Since your little battery has an unknown fault......DO NOT HOOK IT UP TO A GOOD BIGGER BATTERY.
A car battery is capable of several hundred amps for a short shot and can cook a 4 amp battery to the point of explosion in a few seconds.

If you can't get a larger charger, just buy a new battery. A 4 AH one can't be over $50.
 

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Discussion Starter #5
All you Americans and germans with your effeciently independant economy telling me how much stuff is worth in Canada.

I'm just kidding.

You guys are all right. the thing was that as per my mentioned video, the guy says that there are "smart" battery chargers that can't charge a COMPLETELY dead battery.

this little scooter battery is so dead, it's not something EVEN I would joke about.

I guess I'll have to buy a new one regardless, and maybe hope I can use the new one to give the old one a slight charge before hooking it up toa battery charger.
 

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I guess I'll have to buy a new one regardless, and maybe hope I can use the new one to give the old one a slight charge before hooking it up toa battery charger.
That won't accomplish anything useful. You can't keep a spare battery long term. Even if you put it on a tender it will "wear out" about the same time the one in daily use does probably.

Yes most really small tender type chargers will not charge a battery that is completely dead but........have you actually tried it with your charger and your battery ??

And finally, your new battery will need a full charge before putting it into service. That will give you a chance to test your charger.
 

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Easy's right. A "dead" dead battery is worthless. Use it for a core exchange. My M50 battery would hold enough charge last spring for me to charge and ride, but after sitting in the hot garage last summer due to the fact that the 50 isn't my go to bike, it finally gave out and wouldn't start the bike even on the charger.
 

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Is this a lead acid type battery or an AGM(absorbed glass matte) battery? A dead lead acid battery might be functional if u checked it with hydrometer and found what it was low on. if its sulfated, then junk it. if it needs a shot of acid, give it a little. AGM or maintenance free batteries can sometimes be revived by quick charging for very short periods of time at high amp rates (25-30 amps) and sometimes not. U may want to collect some aluminum cans for recycle value and save for a new battery.
 
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