How can I charge a depleted motorcycle battery?

Question

I left my motorcycle too long without using it and now it won't start. The last time it happened I brought the bike to a shop, and they were like there is nothing wrong with your bike, it's just out of battery. Here is the bill ($$$) BTW.

This time I'd like to fix the problem by myself. My battery tender (Battery Tender® Junior) won't recharge the battery because it doesn't have enough charge (if it can't pick up at least 3V it won't start the charge, as it's not able to evaluate the state of the battery). Is there an alternative battery charger I can use? Don't want to shop and (try to) return if possible. My local bike shop couldn't recommend a better charger, but they suggested replacing the battery instead. Is this a simple procedure?

Answer 1

If the battery will take a charge, the easiest way to get the tender to charge it is to fake it into seeing the voltage. To do this, you need another 12v source. I personally use an old battery back up batteries like you'd find in use on garage door openers. Put the 12v source in parallel with the motorcycle battery, then hook the tender up to it. It will charge both batteries.

If you go the route of changing the battery, a beginner DIYer should be able to accomplish this with a basic hand tool set.

On a side note ... the tender is designed to be kept plugged in on your battery. It will keep the battery topped off. They are designed to only charge the battery as much as it needs, then keep it there, ready for use when you want it. Even for extended periods of time. If you aren't using it like this, you're wasting your money and your time.