Super capacitor Starter Booster

[Diesel Dave]

Gents,

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



Now clearly this is a tad expensive to use as a bolt on booster, however there are cheaper alternatives such as:



But as I'm a cheapskate I shall go with:



Hopefully this will save me buying a new battery every year.

[pietenpol2002]

So Dave, here's another related question for you that will highlight my ignorance of electrics. Could one use the capacitors for the glow plugs and thus dramatically reduce the battery size with the use of kick start and LEDs?

[Diesel Dave]

I doubt it, glowplugs will draw about 50 amps for up to 30 seconds and that’s a lot of juice to store in a capacitor array.

The problem with capacitors is they self discharge quickly so you can’t leave them connected to the battery all the time. Similar to a glowplug setup the capacitors will need to be connected to the battery and allowed time to charge before cranking the motor.

[coachgeo]

some petrol bike guys have replaced their whole bike battery with units like that if I recall right. Had not thought about combining them. Not a bad idea.

[BertTrack]

On my normal fuel bikes i've put a capacitor across the battery. As large as i can fit somewhere on the bike with thick wires. Theory behind it is that when the rpm is low the capacitor assists the battery in the low voltage region (low rpm) when the ignition coil draws amps.

But in practise i've also found that the start relay connects "sharper" with a more definite click especially when you do this with an almost low battery. It causes the battery to be useable for starting even when it's almost done giving.