Cyclepsycho's take on

Maintaining your motorcycle battery (on the cheap):

Many riders are not able to ride their bike year round or their bikes are subject to long periods of storage. A battery that sits for long periods of time, especially in cold environments, will not last nearly as long as one that is properly maintained. I'll try and give you some options on how to maintain your battery and you can decide which one will work best for you and your money.  

By far, the best device for maintaining your battery is the Battery Tender brand charger.

Click on the image to go to the Battery Tender web site.

Now, some of us are just too damn cheap to part with $60 for the above product.  If that's the case, you will still want something to
maintain your battery so you don't have to buy a new one every year.  Considering that the cost of  some motorcycle batteries runs into
three figures, you'd think that $60 on a Battery Tender would be cheap insurance.  You'd think that, and you'd be right, but there are still
some cheap bastards who just won't do it.  Well I'm here to help you.  Here's what this cheap bastard uses:

(Click any pic to enlarge)

Here is an inexpensive float charger from Harbor Freight Tools.  When they are on sale, they sell for about $8.
They come with large clips for the battery, but as you can see I have modified this one with a cigarette lighter plug
on the end.  This way, I can plug it into the cigarette lighter socket (if the bike is so equipped).  Then, I took the clips and
attached them to a cigarette lighter jack, so I could use this charger with batteries that were not equipped with the cigarette
lighter jack.

Now, here's another idea I've used with great success.  Take a regular old 12 volt, 500 milliamp (that's 1/2 an amp) power supply. You may have one sitting
around from an old pair of computer speakers, answering machine or some other electronic device you no longer have or use.  Just make sure that the output is 12 volts DC (NOT AC) and no more than 500-600 milliamps.  Cut the plug off the end of the wire than comes out of the power supply and install clips.  Usually, the wire with the stripe is the positive wire but you should check it with a volt meter to make sure.  Since having metal clips on the ends of the wires make it easier to short circuit the power supply if they contact each other, I go one extra and install an inline fuse on the positive side.  You may have an inline fuse holder sitting around on an old car radio you no longer use.  Now plug the power supply into an ordinary lamp timer and set it to come on for about 2 hours a day.  Depending on the size of your battery, you may want it to come on longer.  Remember, this device is being used to maintain a fully charged battery, not charge up a dead one.  Back in the days when I had to park my bike outside, I would hook it to this device.  I set the timer to come on at about 2:00 A.M., when it was coldest outside.  Using this method, I was able to maintain the same battery for 5 years.  That's pretty damn good for a motorcycle battery.
Additionally, you can hook multiple power supplies to a power strip and run the power strip through the timer.  This way you can maintain several batteries at the same time.

An easy way to connect your charger to your bike is to use a two conductor trailer plug;

You can get a set of these at any auto parts store for under $2.  Wire one end to the battery, and one end to your charger.
It is important that when you wire one of these connectors to your bike, that you wire the shielded end (the one with the black rubber around it) to the
positive side of the battery so that it does not short against the frame of the bike when you tuck it under the seat.

By installing one of these plugs on your bike, you can also use it to power an electric vest or other accessory or an easy place to attach a volt meter to when troubleshooting the electrical system on the fly.

Speaking of troubleshooting the electrical system on the fly, here's a super cheap way to add (if only temporarily) a digital volt meter to your bike:

Watch for the sale flyers from Harbor Freight Tools.  They regularly sell these digital volt meters for $3.99 on sale.  Attach a strong magnet to the back
and a trailer harness to it like this:  (put some tape over the magnet so it won't scratch the paint on your tank)  I take the magnets out of old computer
hard drives.  They are small but very very strong.  If you are a real cheap bastard, just duct tape it to the tank!

Attach it under the seat with the other end of your trailer connector like this:

Then slap the seat back on and stick the meter on the tank.  You can now monitor the voltage output of your charging system under real riding
conditions.  This can be extremely useful when troubleshooting motorcycle electrical systems.

And finally:
Unless you are using one of the new sealed gel cell type batteries, you will need to keep an eye on the fluid level in you battery.  Do it at least every time you change your oil, or more if you ride a lot.  Use a syringe or small funnel to add distilled water.  Tap water sometimes contains additives or minerals that will reduce the life of your battery.  You can buy a whole gallon of distilled water for about $1 at the grocery store.  I've had the same jug for about 5 years and it's only half gone (and I have at least 5 bikes that I run regularly).  Sometimes, just getting to the battery to check the level can be a royal pain in the ass.  I have some bikes that are a real chore to check and require the battery to be completely removed to do so.  Keeping the fluid level maintained will make the battery last a lot longer so even if it's a pain to get to the battery to check the levels, it's worth it in the long run.  Promise me you'll at least do it once a year.
A battery can be almost completely dry and still work for a while. Sometimes you'll have no idea that anything is wrong and all of a sudden, the bike won't start.  Adding water and throwing it on a trickle charger can sometimes bring it back to life, although you should probably order a new one 'cause that one won't be around much longer.

The stuff I did on this page was possible partly because I am an Electronics Technician by trade and partly because I have a lot of this crap sitting around my shop.  If you have to go all over town to buy enough parts to make a cobbled battery charging system like mine, you are probably better off just pulling out your credit card and ordering a Battery Tender.

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