Smallest Battery I can get for 78 KZ650?

I want to relocate all of the stuff until the tail to under the seat and open that up. What is the smallest battery that will work with my charging system? Does it matter what battery I use as long as it's 12v? (Wondering of only certain specifications will work with my charging system.)

I'm kick start only btw. Headlight, tail, and igniter are about all that get power.

Let me know!

Not knowing your specific space requirements,here's two websites to look at:

Motorcycle Batteries
www.yuasabatteries.com/
www.ballisticparts.com/products/batteries/12cell.html

When my bike was kick only I ran a small 12V scooter battery (12vx4-LB) and that was fine - same load just running lights and ignition. I re-installed the starter last year and now have the Ballistic, it cranks the starter quicker than the Busa gel battery I was using previously.

Your battery should approximately match your charging system. If you have the standard 12A charging system you should use a 12A +- battery. This will eliminate any undue loads on the electrical system and minimize the chance of burning anything in it. your system is designed to run from the battery and not from the alternator this means that the wiring is accordingly designed.

Google "A123 motorcycle battery", they are Lithium Polymer batteries made from individual cells. Getting rather popular. I'm about to build one myself. You can buy them pre-assembled, but I prefer doing my own electrical work.

The smallest would be no battery. That would have a capacitor in place of the battery. That's what I run on one of my 550's.

The next size up would be the one Dutch suggests. The one I commonly use on other people's bikes (who cannot use the capacitor) is the one from a Honda Spree 50cc scooter. You can get them at auto parts stores.

Basically, if you are kickstart-only, the battery is just acting as a big capacitor. Even if the battery is dead, it should still run. My friend used a dead Spree battery for years. It didn't have enough power to to even light the headlight by itself, but when he kicked it, it would start and run fine every time.

By the way, for anyone else reading this, the 77 KZ 650 cannot use the capacitor method... only 78 and up charging systems will work for that. The 77 will need the scooter battery at least (12v of course), or a later charging system.

As Tbird mentioned, there are the Li-Po type batteries. But their charging systems need to be a lot more precise, or they can catch fire. I don't have experience with them, but it's what I've heard. Maybe Bountyhunter can expand on that... he's worked with them.

loudhvx wrote: As Tbird mentioned, there are the Li-Po type batteries. But their charging systems need to be a lot more precise, or they can catch fire. I don't have experience with them, but it's what I've heard. Maybe Bountyhunter can expand on that... he's worked with them.

I have been running the Ballistic battery which is a LiPo for over a month now without catching on fire :laugh:
I had some concerns myself but took the plunge after doing some research. I have rewired my bike from scratch a few years back and I have a modern reg/rec combo unit (some kind of ninja). No known charging issues. From what I understand these batteries are pretty tough so unless the reg/rec takes a crap it should be fine.

The main problem with Lithium technology is that it has a limited amount of charging cycles (about 1K). Every time you start your bike counts as a charge cycle. For the price of them I am not sure that they are worth the cycle life. There should be a charging/overcharge/discharge circuit built into these commercial batteries. If someone wants to build a 3 cell battery them selves this circuit would have to be installed. I have been working with Li-Po/Li-Ion batteries for about 6 years now and you DON'T want to get one burning. It is just like a Magnesium fire. Or like lighting a flair. It is next to impossible to put the fire out. It will burn under water and it will also burn inside an oil bath. Sand is the only way to contain the heat. Even a dry chemical extinguisher will not put out this fire. You just have to contain the heat and let it burn it self out. This is one reason you do not find lithium batteries in hybrids you don't want a lithium fire anywhere near gasoline. This is why they still use NiMH in these cars. Lithium batteries are coming into their own in pure electric cars though. The Ballistic Performance Component Batteries are a LiFeSo4 technology which is a bit different than the LiPo batteries people solder together and are also in your cell phones. These you just must make sure that your charging system is not putting out more than 14.5V if it is than goodbye battery.

I've only recently started running a sealed lead acid (AGM type) this year. I was tired of the little bit of acid schmutz near the vent hose on the wet cells. Apparently there differing quality levels on those. My friend tried a couple brands. He says the one from Batterystuff was the best he's used. That's the one I got.

So far so good, but it's only been a few months. When it's charged it cranks fast. I let it sit for a month with no trickle or anything, and it started, but was noticeably slower. After a short ride it was back to starting fast again.

loudhvx wrote: The smallest would be no battery. That would have a capacitor in place of the battery. That's what I run on one of my 550's.

The next size up would be the one Dutch suggests. The one I commonly use on other people's bikes (who cannot use the capacitor) is the one from a Honda Spree 50cc scooter. You can get them at auto parts stores.

Basically, if you are kickstart-only, the battery is just acting as a big capacitor. Even if the battery is dead, it should still run. My friend used a dead Spree battery for years. It didn't have enough power to to even light the headlight by itself, but when he kicked it, it would start and run fine every time.

By the way, for anyone else reading this, the 77 KZ 650 cannot use the capacitor method... only 78 and up charging systems will work for that. The 77 will need the scooter battery at least (12v of course), or a later charging system.

As Tbird mentioned, there are the Li-Po type batteries. But their charging systems need to be a lot more precise, or they can catch fire. I don't have experience with them, but it's what I've heard. Maybe Bountyhunter can expand on that... he's worked with them.

What is this capacitor you speak of? Do you have any brands and/or reading material on it? Sounds like the simplest and smallest way to go.

They call it a "battery eliminator" you can find them on the web. They only work on systems that have a permanent magnet charging system. Some 650s did not. I am not sure about yours.

A battery eliminator is just a capacitor, as Otakar says.

The 78 KZ 650 uses 1-phase, permanent-magnet alternator, so it can go without a battery. It's the smallest, lightest option, but maybe not the simplest.

The capacitor size you're looking for is anywhere from about 3000 to maybe 12,000 micro-Farad. That is usually abbreviated as uF or uFd. THe voltage rating needs to be 50v or higher. It will be electrolytic, so there is polarity. You hook it up just like a battery, but with smaller wires. I recommend the screw terminals.

The 78 650 has a 4-wire regulator/rectifier, with no voltage-sensor line. This means the capacitor can be hooked up with no other changes. Other KZ's with voltage sense lines need a slight wiring modification.

The bike will not start with any lights on. There must be a switch wired in for turning all lights and accesories off. This is because there is no energy stored in the capacitor for any length of time. One kick has to simultaneously charge the capacitor and power the ignition. I run a relay system to automatically turn the lights off any time the bike stops.

Because of this, a more efficient ignition makes it much easier to start. Points can work. Dyna S is harder to start, if at all. The factory electronic ignition is best for this.

Here's the big thing... the bike has to be pretty well tuned so it can almost always start in one kick with a battery. If not, then I would not get rid of the battery.