Battery Diagnostics

Even with a float charger, the battery is not strong enough to start the bike. I can kickstart it just fine, but no amount of riding or charging seems to get the battery up to snuff. I am fairly certain that I need a new battery, but I want to be sure that I wont fry the new one if there are other electrical problems. If I test the battery it reads 12.6 volts when the bike is off. If I turn the key in the ignition, it drops to 11.5 volts, and when I switch the right hand control to "run" it drops to 10.6 volts. This seems odd to have such a drop in voltage without actually placing the battery under a load (other than the headlight and neutral lamp). What say you all?

79 650 with Dyna coils and ignition.

It means one or more of the cells is degraded either by "wear" or sulphation. Lead acid batteries lose capacity over time as the coating on the plates wears of and falls down into the bottom. Sulphation happens if the battery sits uncharged too long. Whatever the cause, you have weak cells which is why the battery voltage drops so quickly under slight load current.

Agree - battery is probably "history!"

A 12 volt battery in good condition offload (ie open circuit) should read around 13.4V. If the battery is low after it's been on the bike and running for a while (ie below this voltage) it may be ok but not being charged by the bike's charging circuit. Place the battery on on a known good external charger for 24 hours and if it doesn't come up to 13.4v (or thereabouts) on a voltmeter, it's cactus. If it does and you still have a problem when the battery is fitted to the bike, then you may have a problem with the charging system on your bike. Also a load test on your battery can be done at any auto-electrical shop, this will confirm battery condition.

Interesting that you have a 79 Kz650 with a Dyna ignition... and now are having battery issues. Your battery is likely bad, but you will want to monitor charging voltage very closely when you get the new battery. The 78 and 79 Kz650's have a higher percentage of charging problems when using a Dyna S. Whenever a charging problem seems to come up, with a Dyna S, where the charging system is not quite able to keep up, it's more often a 78 or 79 Kz650, than any other KZ.

It's not that the charging system is weak from the factory, but it was apparently not designed with enough extra output to handle the much greater load the Dyna S with 3 ohm coils puts on the charging system. When you turn the ignition on, the Dyna S is designed to put full current to one or both coils, so there is not just a headlight load, but you may have more than double the ignition load (than a stock ignition), even when the motor is not turning. Don't do this for too long because the coils will be heating up.

Not all 78/79 Kz650's have this problem with the Dyna S. Some apparently were made with enough extra output to handle this extra load.

The best (but not easiest or cheapest) solution is to convert the charging system to a 3-phase system from a later 650 or 750-4. It is a bolt-on swap, so it's not too hard.

Another option is to convert the ignition to a Kawasaki factory electronic ignition from a later model 550/650/700/750 using a 650 advancer. (You can use the Dyna 3 ohm coils with this.) This would reduce the load by more than half (getting it back to near the stock load).

Another option would be to use 5 ohm coils instead of 3 ohm coils. That would reduce the load a small amount.

A battery with a dead or shorted cell can suck extra power from the charging system. It can read 11 v but go down to 10 or 9v which means there are no AMPs behind it. There are battery suppliers suggested here. I wouldn't buy one at AZ, OR or the others with a 90 day warranty. The good ones offer a 1 year.
Steve

loudhvx wrote: The best (but not easiest or cheapest) solution is to convert the charging system to a 3-phase system from a later 650 or 750-4. It is a bolt-on swap, so it's not too hard.

This could be an interesting option. What years used the 3-phase system and were the same parts used for the 650's and the 750-4?

It sounds like it is unanimous that a new battery is needed, which is what I expected. With a new and fully charged battery, what amount of drop should I expect with the ignition on and the switch to "run"? I am trying to get a feel for what some of the acceptable tolerances are so I will know if I am killing the new battery.

Also are then any battery types that are less susceptible to problems from these older charging systems? AGM vs gel vs lead acid...

Kawasaki Kz650 Charging Upgrade

Looked here? KZ650.info www.kz650.info/


Read this also:

1979 650 B2 Charging Upgrade

From the KZrider.com - Home www.kzrider.com
website)

Ok, I had a problem with the battery discharging instead if charging after I fitted a Dyna s ignition, charging system was coping marginally with the power needed to run the extra relays, ecu, fuel pump and heated WBO2 setup that I use for the EFI that I have on my 650.

If I used the headlights the voltage on the palm pilot display dropped to around 12 volts or less and at traffic lights it would drop to high 10 to low 11 volts.
After searching for info on this site and KZ650.info I found that the single phase stator that the 650b2 uses has the same dimensions as the 3 phase stator used in later 650s and early 750's. I found that electrosports make a high output stator ( approx 20%) more output than the late model 650 , early 750 models which had 21% more power than the B2 single phase unit.

This works out to between 40 to 50% increase.
Lou and told me that I would need the 3 phase regulator/rectifier as well as the new stator. I got these parts from Pacific motorsports ebay shop and used the original 1phase rotor.
When the parts arrived I removed the 1 phase stator (2 wire) and fitted the 3 phase one ( 3 wire) with the original rubber grommet that seals the housing.

There is a dimple where the 3rd wire goes, so I drilled the hole with a battery drill and a drill the same size as the stator wire.
I ran the 3 yellow stator wires to the one side of the 6 pin connector that I bought at the local car spares shop (which luckily enough turned out to be the same as the one on the electrosport regulator/rectifier), but I will have to cut the wires and put bullet connector in the wires when I remove the engine or the stator cover in the future.

The white wire is the output to the battery, I connected this one to the white and red one that was used with the original 1 phase regulator and the same with the black wire that connects to ground. The brown wire is the regulator load wire (connects to the 12v switched wire that i traced back from the rear brake light positive wire)
and that was it.
Used the bike for about 300KM now and the charging is all good

Parts were:-
1 x Electrosport ESR370 Regulator/Rectifier $89.95 from Pacific motorsports
1 x Electrosport ESG010 Heavy duty 3 phase Stator $109.99 from Pacific Motorsports
http://sto...-Powersports-Accessories
Hope this info is useful for anyone else with a 650B2 that is converting from ! phase to 3 phase charging system. Special thanks to Lou (loudhvx) and Bo (onkelb)and incognito0160 as well as all the other guys who gave advise and ideas.
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Hello -- Newbie here. I just wanted to state that I did the upgrade as described and it seems to have allevioated the charging problem. I had narrowed down the problem to the dyna ignition drawing too much power. I decided to try this and it worked. Woo-Hoo! Thanks guys.

Here is what I can find on the alternator systems that came stock on the 650s.

There were basically 5 different types of charging systems used on the kz650s.

The 1977 models used a 3 phase excited field system, with a field coil, rotor, yoke and separate voltage regulator and rectifier. This system uses a switched sense wire to the regulator to indicate system voltage and then either energize the field to increase or decrease the voltage created by the system.

For 1978 and 1979 the system was changed to a single phase permanent magnet type system. This system made use of a magneto/flywheel and stator and the regulator and rectifier were combined in a single unit. No sense wire on this system.

For 1980 a single phase permanent magnet was again used, it is much like the systems used for the 1978 and 1979 systems, but the combo regulator/rectifier changed, it has a switched sense wire to indicate system voltage.

For 1981, 1982 and 1983 the system changed to a 3 phase permanent magnet system. The magneto/flywheel and stator changed and the combo regulator/rectifier also changed. There was an additional change for the later 1983 H3 model after engine# KZ650DE052651 where a different magneto/flywheel was used. The sense wire was used on all of these systems


I have often wondered if the issue the early single phase systems have with the Dyna is related to the fact that it does not make use of a sense wire, but rather shunts to ground at a fixed level. You might try changing to the later single phase regulator/rectifier that makes use of a sense wire to determine when to shunt to ground. I have not done this so have not way of knowing if it will solve the issue or not. But for some reason it makes sense to me.

The sense-less system actually senses the system voltage at the output wire. But this is connected all the time and has the possibility of using a tiny bit of current when the bike is turned off. Using a dedicated sense line allows it to be switched off to ensure there is no leakage of current in the sense circuit. But the functionality, while running, is basically the same, and should not affect output level.

I believe the lower output is purely the result of using a 1-phase stator. This can be tested by simply installing a sense-wire reg/rec onto the 78/79 bike. But I doubt it's going to give any more output. I guess we might know if the stator and rotor part numbers were the same for '78 through '80.

Here are the part#s I can find. They do use the same part#s other than the reg/rect unit.

650 in Vegas wrote: It sounds like it is unanimous that a new battery is needed, which is what I expected. With a new and fully charged battery, what amount of drop should I expect with the ignition on and the switch to "run"? I am trying to get a feel for what some of the acceptable tolerances are so I will know if I am killing the new battery.

Also are then any battery types that are less susceptible to problems from these older charging systems? AGM vs gel vs lead acid...

I think AGM is the best value for the buck.