Smallest non-lithium 12V battery?

[stinkwheel]

On an ongoing search for the smallest 12V lead acid/AGM/gel motorcycle battery I can find.

Doesn't need to be big, just needs to be there and can be holding a minimal amount of charge, just needs to have enough to get the points sparking initially (and for reference, a PP3 9v battery will actually do this, it just wont cope with being charged at 12V). I've used capacitors and they function in a pinch but a dinky battery seems much more reliable.

Not lithium because the nature of the charging system is such I think it would kill them in short order, the alternator output is just too "dirty".

Smallest I have to-date is a FB4L-B which is 120L x 70W x 92H. I bet we can go smaller.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[virus]

Fire alarm batteries for the win I reckon.

Quick google finds this one https://www.fireprotectiononline.co.uk/yuasa-np2.8-12-vrla-battery#product-details-tab-Technical-Specification but i bet theres a yuasa smaller somewhere.
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own: 81 xs1100g...
owned: 85 rat CG (sold), 91 GS500e (stolen), 84 gsx400f (scrapped), 81 z250 (siezed, siezed, scrapped), 83 cb250rs (sold), 84 gpz750r ratfighter (killed) 84gpz400 (sold), '80 cb650 ratfighter (wrote off) 95gsx6/12f ratfighter (killed) 91 xj900 (sold)
stinkwheel Well I just had my hands up a pigs fanny. Which makes your concerns pale into insignificance.

[WD Forte]

I have a Yuasa YTZ7S 12v 6.3 aH battery
here which is 110L x 70W and100H so a wee bit shorter

I wouldn't go too obscure and go for cheap and easily available over
ludicrously small.
Also, bear in mind the applied voltage, load and charge rate it will be subject too so an alarm battery may not like it up em where a scooty
battery will cope better.

A weeny scooty battery would probably be best IMO
for instance a Yamaha Aerox Q50 battery
ENTX4L-BS 113L x 69W x 87H AGM 12V 4Ah 85A
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bikers smell of wee

[stinkwheel]

I've used an alarm/UPS battery before and they don't seem to cope well with the vibration. I don't think the plates are as firmly supported.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[jeffyjeff]

I've seen some really small batteries on an old school Honda 90 or a Cub 50, but when I looked it up I was reminded that those are 6V. Still, if they are more than 50% smaller than what you got, you might connect two in series. just a thought.
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History shows again and again how nature points out the folly of men - BOC

[stinkwheel]

[Robby]

Looking around, it looks like the generic 4ah scooter battery is your best bet. Smaller than that and things start to get unusual and entirely the wrong application - like a small cluster of li-ion or nimh cells which won't play nice with your charging system or vibrations.

If you need it to work, I would compromise on size.

[alains]

look for YUASA they make YUCEL 1,2 Ah 12V size (Lxlxh)97x47x51 mm
YUCEL 2,1 Ah .....................178x35x60 mm
price around £25
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the worst day fishing is better than the best day working

[The Artist]

https://www.amazon.co.uk/LiCB-23A-Alkaline-Battery-5PCS/dp/B07V26VLQ1

[Nobby the Bastard]

[The Artist]

[Nobby the Bastard]