I notice that newer cars with stop/start features are using super capacitor banks to assist the battery.
Strikes me that this would be a very useful addition for a diesel bike as it would allow the use of a smaller battery whilst allowing the large current draw needed to turn the starter motor.
You can buy 'off the shelf' units sold as assist starters such as the Sealey Electrostart
![Image](https://i.imgur.com/ZZ8DsWT.png)
Now clearly this is a tad expensive to use as a bolt on booster, however there are cheaper alternatives such as:
![Image](https://i.imgur.com/6sF9QKt.png)
But as I'm a cheapskate I shall go with:
![Image](https://i.imgur.com/cDelJ63.png)
Hopefully this will save me buying a new battery every year.