How strong battery do I need for electric start?

[lingeringstin...]

I'm rewiring my bike to fit an electric start, electronic ignition 250 twin engine.

Previously I could run with any 12v battery that would fit in the hole because the bike was kick start and was easy to get going. But now I'll be needing a battery to turn a starter and my first impressions are to try to buy the biggest, most powerful but cheapest battery I can find that will fit the box.

There are loads of batteries that MIGHT fit in the box but really I have no idea what amps and shit would be best. And I might want to fit some fancy pants bright lights or something at some point.

Any clues?

[doggone]

Provided it's not a reluctant starter any 12V bike battery should be fine with that smallish engine.
You're probably more likely to find charging system is not up to running the extras mentioned for very long.

[RhynoCZ]

It's all about the starting current. If you get an average 8Ah (and more) battery, the starting current will be more than sufficient.

What would be the best? Well, the highest starting current obviously, with reasonable capacity. Higher the capacity, bigger the battery though.

I'd try something like 10Ah, 150A (more, means ''better''). I'm not familiar with your motorcycle though, and maybe a smaller battery would do the job as well.

Have a look at YTZ10S, that's what I would try first.
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'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[redeem ouzzer]

Do you need it? Electric start is weight and drag. Fuck it off and use a house alarm battery.
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Be a REAL MAN!

[Teflon-Mike]

Some of the Chinky bikes make do with a 6 or 7 Ah battery, I think the Super-Dreams, which were hugely over-rated for belt and braces 'you can rely on THIS e-start' honda thinking, is only a 9Ah....
If you are pondering equipment upgrades, the starter's out such an issue, as the out-put of the genny.... which has to keep the battery full.
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My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'

[lingeringstin...]

The biggest problem I've got is the funny shape of the MZ battery box on my bike. Originally it was a 6v system with kick start so it didn't have a very big battery. I used to get by with things like house alarm batteries. For at least the last 10 years I've been using two Maplin's 6v batteries wired up for 12v because they usually have them on sale for half price every winter.

So far the only thing I've found that will fit the battery box is about 5 or 6 amps at most, which will probably be OK for this 250 twin engine.

[temeluchus]

There are very small lithium starter batteries that weigh next to nothing.

https://www.tayna.co.uk/YTX4L-BS-Shido-Lithium-Motorcycle-Battery-LiFePO4-LTX4L-BS-P10440.html

you could remove the gubbins,thats mostly a plastic housing to make it fit a battery box. Lithium cells can discharge much greater current for a given capacity compared to lead acid batteries.
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Some shite cruiser. Now with guns and FREEDOM!

[MCN]

[temeluchus]