Total Loss Ignition for Racing

I have some info on converting to a total loss ignition for racing, but I'm wondering if someone can help me figure out how to calculate a good battery size to use in the system. This will be on a Kz650 with a Dyna-S ignition. For now I think I will be using the standard coils. No lights, sensors, starter, etc. It will be for road racing and will likely never run much more than 20-30 minutes at a time (no endurance races). Battery will be charged by external charger between races - no stator/rectifier.

Anyone know how to estimate the draw on the battery from such a system so that I can size out a battery?

Also, I'm assuming some sort of voltage regulator would still be necessary/desirable?

DoubleDub wrote: I have some info on converting to a total loss ignition for racing, but I'm wondering if someone can help me figure out how to calculate a good battery size to use in the system. This will be on a Kz650 with a Dyna-S ignition. For now I think I will be using the standard coils. No lights, sensors, starter, etc. It will be for road racing and will likely never run much more than 20-30 minutes at a time (no endurance races). Battery will be charged by external charger between races - no stator/rectifier.

Anyone know how to estimate the draw on the battery from such a system so that I can size out a battery?

Also, I'm assuming some sort of voltage regulator would still be necessary/desirable?

Am thinking that a voltage regulator serves no useful purpose on a total loss system.

And that a good stock size fully charged battery would be okay for a thirty minute road race.

But I don't know how much smaller than stock a battery could be and continue providing full performance throughout a thirty minute road race.

Good Fortune!

That's what I was hoping to be able to calculate.

So looking into this more, I may stay with points and standard coils.

I found someone on the XS650 sites saying that their coils use about 2 amps. Anyone know what the coils on the Kz's use?

Their math was similar to the following:

12v 4Ah battery, losing 2 amp drain from coils goes flat in approx 2 hours. Spark won't be made around 9v (or 75% of peak voltage) so 25% of 2 hours is about 30 minutes of usable runtime.

I'm not sure this math is accurate, or even if it is whether or not 2 amps is a good estimate for the Kz stock coils - I'm looking for input here. Also interested if anyone knows the draw of the green Dyna coils.

Also saw Loudhvx post in another thread on total loss that he had heard of a 14v battery being used as that is what the charging system runs at. Nobody responded to that post - anybody have input on this?

Also thinking that I need a deep cycle type battery. Aren't most lead acid batteries meant to be kept topped-up rather than being allowed to drain considerably?

This site claims that the Dyna Green coils draw over 4 amps.

sohc4shop.com/catalog/product_info.php?products_id=44

And this post states that they draw around 5 amps.

kzrider.com/forum/4-electrical/361165-he...t=20&start=20#367829

Am thinking the issue about Dyna-S having a larger current draw than points, or the oem Kawasaki electronic ignition, has less to do with the minimal power needed to operate the Dyna-S, and is mostly applicable during low rpm speeds where Dyna-S consumes more power.

At racing speeds, the Dyna-S may not consume enough additional power to warrant significant consideration.

Here are some informative links on the subject:

xs650temp.proboards.com/index.cgi?board=...on=print&thread=7861

bsac10c11c12.co.uk/smf/index.php?topic=3031.0

loudhvx wrote: The Dyna III and Dyna S are not recommended for use with the stock electronic ignition coils. They require 3 ohms or higher, according to Dyna. (Although, some have used them with 2.5 ohm coils.)

The other problem with the Dyna III or Dyna S is that they both use about 3 times as much power, (wasted as heat at lower RPMs), as the stock electronic ignition. This is not good if you are going total-loss.

If you plan on keeping the Dyna III, you'll probably want to get the charging system working well.

Loudhvx's above quote is included in the thread accessed by the following link:
kzrider.com/forum/4-electrical/251955-to...loss-ignition-set-up

Good Fortune!

Yep, that was the XS650 page that I got the math from and the forum post where I got the info from Loudhvx from. The other link was interesting. I guess I'll have to get an ammeter to find out what the ignition draws, but I won't be able to run the bike for quite a while. I was hoping someone knew what the draw of the ignition system would be.

Thanks, Patton!

These links go to sites with some mathematical formulas, and some allow number plug-in with the calculations performed automatically.

As known, the difficulty lies in ascertaining the correct numbers to plug-in.
Not to mention the other variables such as battery condition, track conditions, etc.

Anyhow, here they are:

www.gizmology.net/batteries.htm

easycalculation.com/physics/classical-physics/battery-life.php

www.csgnetwork.com/batterylifecalc.html

batteryuniversity.com/learn/article/calc..._the_battery_runtime

Am also recollecting additional more specific info having been provided in other threads by loudhvx with regard to actual current draw comparisons among the different ignitions at various rpms.

Good Fortune!

Found this post from the archives: www.kzrider.com/archive/viewthread.php?tid=29813#pid252945

Looks like RonKz650 did the ammeter testing.
It looks to me from this info like the Dyna-S and 3-ohm coils suck about 4.2a without sparking.
As I understand things (not very well), once Ron started his bike the information for my purposes becomes somewhat meaningless as I won't have a stator supplying juice.
I'd need to run the tests myself without the charging system connected.
I think I'll have to do this just to make sure I don't run dry mid-race.