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Jeff Policky
Jeff Policky, Motorcycle Mechanic
Category: Motorcycle
Satisfied Customers: 2425
Experience:  Yamaha Gold, Suzuki Gold, Honda Bronze, Polaris Bronze, BRP
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Battery keeps going down when not in use few days. yamaha

Customer Question

battery keeps going down when not in use for a few days. yamaha 650
Submitted: 1 year ago.
Category: Motorcycle
Expert:  RSRBOB replied 1 year ago.

Hi and thank you for your question.

I would like some more details on this symptom if you don't mind.

First, this is NOT normal, so we can fix it, we just need to find it first. There really aren't too many variables here either.

My first question is, how old is the battery, and what brand is the battery and what size (designation on the side) ?

Have you put a load tester on the battery to see what condition it is actually in? This could be a battery issue or a key off drain issue. Both produce the same symptoms.

Now we need an ammeter. Most VOM (volt Ohm meter) have a 10 amp scale which is plenty for what we need.

Disconnect the negative cable from the battery and connect the ammeter in series (use the meter between the negative cable and the negative battery terminal) and take a reading, key off. Let me know what it shows for amp draw. You do NOT want to start the bike with the meter installed between the cable and the battery. It will draw too many amps and damage the meter. You can hold the cable against the battery to start it however, and once it is running, then the amp flow is small enough that it will be less than the 10 amp max of the meter.

Let me know about those points and we can go from there.


Customer: replied 1 year ago.
Battery is new. Also had it tested at American battery. You said something about the key position could be an issue. When I store the bike what key position should I use? I have tried all positions and removed the key, still it runs down over time.
My credit card company called me about the charge, I see you have charged $29 already, I haven't solved the problem yet.
I will do the amp checks and get back.
Expert:  RSRBOB replied 1 year ago.

What brand is the battery and what is the size designation on the battery? I don't know who American Battery is and don't know how they tested it. Putting a volt meter across an open battery doesn't tell us much. We can do our own type of battery test by fully charging the battery on a trickle charger, then installing it back in the bike and doing a voltage drop test. It is key to remove the battery, or disconnect it completely from the bike's electrical system, so it can fully charge. A good battery should not drop more than about 1 volt while trying to start the bike. If it drops more than that, the battery is no good. New batteries can be damaged from not being properly serviced and/or charged prior to being put into use.

Your key should be in the off or locked position. Avoid the "park" position because that turns the tail light on and obviously would drain the battery.

For the record, I don't charge you anything, nor do I get paid anything, until you accept my answer and agree to pay. The dynamics of how the web site handles deposits and transactions are never disclosed to us. If there are questions about that, I cannot answer them for you.


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