commando battery mk2.A

A 9 amp hour battery should be adequate as you are not running an electric start. Your lights should not be relying on a battery but the charge from your generator. Think of the battery as a bucket of power that is being filled by the generator. the hole in the bucket supplies power to the ignition, lights, and any accessories you have switched on (heated grips, sat nav etc) Your generator should keep the bucket full of power. If you stop the engine then the bucket will empty. A bigger bucket will take longer to empty than a small one. What that means is, if your generator quits then a bigger battery will keep you going for longer than a small one. I run an 8 Amp/hour sealed lead acid battery (numax) It is physically smaller than the 14 amp/hour battery and obviously lighter and cheaper. you could buy several of these for the price of some of the high tech batteries

Electric starters need a bigger battery to supply a lot of current for cranking.

Previously anthony_williams wrote:

has anyone had experience with the dry [mat] batterys.

there are some about the right size but only 9amp hour.

i am not sure if this would be ok to run the lights on a long run.

there are some at 14amps and above.would it be wise to purchase one with more amps hour ?.....tony

I run a YTX12BS in my mk2a, a YTX14BS is the same length and width but is higher this may also fit?

I have run a 7 amp and as long as you change the flasher unit to a modern one (see the electrics section for details of the one I use), that does not rely on a piece of hot metal, your flashers will not stop flashing when sitting at a junction waiting to turn.