Topic: Battery and coil questions.

[vonvendetta]

I'm looking into getting another battery. I've used the search function but still feel unsure.

http://www.dimecitycycles.com/vintage-cafe-racer-caferacer-bobber-brat-chopper-custom-custom-motorcycle-electronics-parts-small-12v-sealed-trugel-battery-78-0531.html

I read that I should go with an 8-cell battery and was thinking ballistic but have read things on trugell and the prices sure vary. Will this battery be sufficient for push button start?

Also looking at replacing the coils. I was just going to go with the Dyna coils but now am wondering if they are worth it. Why not just get the regular coils?

Dyna 3ohm
http://www.dimecitycycles.com/vintage-cafe-racer-caferacer-bobber-brat-chopper-custom-motorcycle-dyna-high-performance-ignition-coils-217411.html

Vs

Old school version
http://www.dimecitycycles.com/vintage-cafe-racer-caferacer-bobber-brat-chopper-custom-motorcycle-electronic-ignition-parts-universal-12-volt-ignition-coil-si-165-2.html

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[strynboen]

the old school type are dohc type,,i use them on my cbx from 1978..they are not for points but elektronic egnision...the ohm are too low for points...but some are using them anyvay..
they are used on cb 650. and forvard types./modells

http://manuals.sohc4.net/CB500/HSM500550_4.pdf


link are for cb 550!
think DS have some more spefic for honda sohc

[Black 750K8]

What bike and are you using the stock location? Here is a good place to start. I like the AGM type Scorpion or Yuasa.
http://www.batterystuff.com/batteries/motorcycle/?gclid=COmWhL7BnLwCFZJxOgodJmwAyQ

[TwoTired]

Regarding batteries, the electric start option requires a CCA (Cold Cranking Amps) rating of about 180 amps or higher.
If you are determined to go for the lithium type, best to also add a voltage display for the bike operator.  Such batteries are damaged of the voltage goes higher than 14.8V or lower than 10V.  The operator assumes the responsibility of constraining the voltage between those limits, as there are no automatic devices available for a motorcycle, (that I am aware of).  A voltmeter therefore supplies battery survival information.

Regarding coils...
Dime city appears mightily confused.  The 3 ohm link displays a picture of 5 ohm coils.  And the "old school" link doesn't even tell you the coil primary resistance!

The stock coils were just under 5 ohm primary devices.  I don't know what bike or ignition trigger you are matching the coils to.  But, low ohm coils take more power to operate than standard coils, and a Dyna-s with double any increased consumption again.  It's pretty easy to overwhelm the CB500/550 alternator capability.  Which usually results in frequent dead or depleted batteries.  Imo, it's kind of silly to go lean on battery, and go hog on coils/ignition system.

Unless you are changing engine compression values or using exotic spark plugs, there is little to no advantage having low ohm coils, beyond "it looks different".

[vonvendetta]

What bike and are you using the stock location? Here is a good place to start. I like the AGM type Scorpion or Yuasa.
http://www.batterystuff.com/batteries/motorcycle/?gclid=COmWhL7BnLwCFZJxOgodJmwAyQ

I'm stupid, cb500 72. Under seat.

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[bjbuchanan]

If you want to replace the coils, even tho they rarely if ever go bad, just get stock replacement. They are plenty good and most of the aftermarket ($$$) don't have any advantage anyway. You won't have stiff crappy wires for another 35 years anyway

Like TT said, lithium don't tolerate abuse like lead acid does. I would suggest that if you do want one that your bike is sorted out well before running it so it doesnt get damaged

[TwoTired]

TT - are you stating that an essentially "stock"550 should be using 5 ohm coils? Especially if running a Dyna-S electronic ignition?

Yes.  I've run the numbers many times in prior threads.  There is only 150 watts peak available from the alternator.  Due to production variances, some examples could put out a little more.  But, it is best to design to minimum specs rather than average or best output.
Points turn the coils on for 190 degrees of crank rotation (dwell),  The Dyna-s leaves the coil(s) on and drawing power, except for 30 degrees of crank rotation (330 degrees of dwell).

Would a rebuilt stator/field coil and Solid state Reg/Rec modify that recommendation?

No, unless the stator and field coil were built to other than stock specs.

There have been some that reported better charging between idle and the alternators break even point on the charging vs rpm curve.  But, the stock regulator directly connects the battery voltage to the field coil (electromagnet) when required.   Most, if not all, solid state units will drive the field coil with at least .6 or .7 V less due to the nature of an electronic switch.
Less electro magnet strength = less alternator output power availability.

All the stock CB550s can deplete the battery during idle, and moreso when lighting is on, ~120 watts, vs the alternator's idle output of about 50-60 watts.