Kawi2strokes.com Forum

Happy 4th everybody!
I was doing some battery research today and noticed that the spec for my H1D calls for a 9Ah battery. The specs for my H2 and S2A call for a 6Ah battery. Why did Kawasaki spec the H1D for 9Ah? I've been using a 5.5 Ah Yuasa in that bike. How important is the Amp Hour rating and should I upgrade to 9Ah?

Thanks!

Use whichever one you like. 9 Ah will give you more time with the headlight on and the engine not running, but I don't do that very often. The charging system is voltage regulated, so it doesn't matter to the battery. I use a 1223W AGM battery in my H2, and it's rated at 5 Ah.

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If it surges, that's normal, upshift.

Thanks Jim!
I was hoping you would reply

Some bikes employ DC ignition systems (points or CDI) drawing from the battery circuit. Some utilise an AC supplied CDI which reduces the battery load, especially at lower rpms. The type of alternator plays a role too since some with field coils and brushes are energised by the battery. The charging systems are marginal on these bikes so having a larger DC storage is reasoned due to higher peak demands or more DC electrical load. H2s can get by with a smaller battery, half the size of stock as they have no field coil for producing power and have an independent magneto CDI. Points ignition systems draw the most load at lower rpms due to longer ignition coil saturation times which just happens to be the weakest charging or DC production situation. Points or DC powered ignition also need a battery to start. My H1B battery is much larger than that of my H2s. That is my take on why it matters.

The question was about an H1D, which has the same electrical system as an H2. The 9 Ah spec may have been a holdover from previous H1 models that had more need for higher battery capacity.

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If it surges, that's normal, upshift.

Jim, Since it is the H2 electrical system a smaller battery can be used. Actually guys have been known to use capacitors to replace the battery, not my personal choice though. I just attempted to explain why and when you can get away with lesser.

The battery was a carry over from 69-76 same battery for the H1. They mustve just thought it'd be easier just to keep with it

Bottom line

It fits-3/5/7/9 amp hours do not matter unless parking lites are on for more than 2 pints.

cliff