What battery to use for 650SS 1963

The minimum is 5ahr which would go in the Nortoin Battery box quite easy. 7 Ahr or 9Ahr if you can get it in. Traditional lead acid is what the machine was designed for, there is several new battery manufacture types, as long as the seller can confirm the battery is fit for Automotive use then you have some guarantee. What is not recommended is any battery from the alarm world, sealed with very square corners and flat spade terminals, these will tend to overcharge and dry out.

Hello Chris,

You can use a 12 volt 9 ahr battery. More Ahr is better.

The standard type is 12n9-4B-1, dimesions 135 x 75 x 139 mm. Yuasa has a better than standard type which is YB9-B.

My bracket for the battery is non standard

Gents, Coming in late on this one as I'm looking for a battery for my 67 650SS. My trusty Haynes manual suggests the battery rating should be 12Ah, the Yuasa YB9-B is only 9Ah.

The Yuasa YB12A-A is 12Ah rated, is 135Lx80Wx160H and would seem to fit my battery box (just quickly running a tape over it). It is slightly more expensive.

Any comments on the required Ah argument or other experience?

Cheers,

Len

Len, your bike is a 12V capacitor coil ignition type whereas Chris's Dad's is a 6v magneto ignition.  Hence the different power needs.  Cheers, Howard

Hi Howard, Thanks for your help, as always. However, mine is pre coil - 12V with mag, Zener diode, rectifier, alternator. I guess it was an early 67, possibly transition, build. I guess I'm just questioning the Haynes data which, under 'Battery' gives the 12 Ah spec for the 6V Lucas MLZ9E, then gives alternative (without giving specs):

- Lucas PUZ5A for P11 and P12 models only

- Lucas PUZ7E - early machines,  standard models

- Excide 3EV9 - early machines, de-luxe models.

It does mention elsewhere (not under 'battery') that the Zener diode type is 12V and one of the circuit diagrams shows 2x6V batteries = 12V. Nowhere else does it mention the Ah  spec of thhe battery. Typical Haynes,  I guess?

If I'm getting a new battery I may as well get the most suitable one. If a 12Ah fits, why not get it instead of 9Ah. However if 9 Ah is adequate with my charging system, I would be happy to go with that and save £20 on the battery cost. Hence the call for opinions.

Cheers,

Len

Hi Len - I owned a '66 650SS like yours with a mag and 12v Zener diode set up.  That had two 6v Exide batteries in series tucked neatly in the standard battery box.  It also had a neatly designed clamping arrangement to stop the batteries chafing.   One of the terminals came very close to the bracket as I recall and I had to keep it greased up to stop it causing a short circuit. It did work very well and I would say more reliably than later bikes with a huge blue- topped Lucas 12v offering.  I'd go for a Yuasa and I'd say 9Ah is adequate unless you're running heated gloves, suit, seat, coffee machine etc.   Cheers, Howard    

That's what I'll do.

Cheers,

Len

As Al said, 5Ah minimum. Maximum depends on available space and how much weight you want to have. What's needed depends on consumption and riding habits. Coil ignition consumes.Lamps too. The alternator output depends on rpm. Low revving with lights on will drain the battery, more Ah will get you running a bit longer. High rpm and no lamps will keep the battery charged. LED lamps need less.

Remade the electrical system on a 350 BSA. Probably the original RM21 120W alternator. Replaced rectifier and zener with an regulator/rectifier. Boyer ignition. H4 headlamp. 5Ah battery. Capacitor for emergency starting with dead battery. Battery at 12.6V before run. One hour gentle mostly green lane ride at low to medium revs. Headlamp on. Charged at anything above idle. Battery voltage after ride over 13V.

Conclusion. On a bike in good condition a 5Ah battery is enough.  Alan is right as usual.