Here we go again

[b'knighted]

Fired up the Vincent Comet same petrol in the tank over winter (last of the Esso zero ethanol perhaps) you have to love the lithium battery still charged after 5 months in an unheated garage all that power in an old black Lucas battery shell one push of the starter button no valve lifter and away she went magic! good run round the lanes.
Only when I got back I remembered I had even forgotten to drain the sump :-0

Hi Tim,

I'm about to buy a starter battery for a Comet. Please could you remind us of the spec of your magic lithium battery and whether it is safe with the Walkernator.

 

[timetraveller]

There are several members who have used Lithium batteries with a Walkernator. All those who I have spoken to have been happy and had no long term problems. I hope that they will raise their heads here. I actually do not understand why this seems to work as if one buys a modern battery charger it has different settings for lead acid or lion batteries. However, in the real world it seems to work. The good side of Lion batteries is that they hold a charge for a year or more and can be drained down to about 10% of their fully charged state without problems. Doing that to a lead acid battery would shorten its life dramatically.

 

[oexing]

Norman, the LiFePo4 cells are 3.4 V, so in a 6 V system you just get two of them and be happy with around 7 V charge. Or have 4 each in a 12 V system that got 14 V charging voltage, no troubles from this. Don´t just look at one cell for comparing lead and LiFePo4 accus in respect to charging them on the bike. I did replacements in more than two bikes already after the gel lead accus died, never again lead for me.
Don´t confuse the explosive Li-Ion types with the LiFePo4 at 3.4 V per cell.

Vic

 

[timetraveller]

Thanks Vic.

 

[BigEd]

You will find more information in this thread:-

https://www.vincentownersclub.co.uk/threads/grosset-electric-starter-installation.10801/post-168903

I bought the largest Shorai battery that just fitted inside a dummy battery box. A Comet should work fine with a smaller one. They can be fitted any way up as they have no acid to leak. This type of battery is expensive so it may be worth looking to see if there are cheaper similar batteries from other manufacturers.

 

[vibrac]

I think there is a difference between a battery on a comet and a battery on a comet with electric start mine is a lithium one not a (Shorai) and it recharges to a minimum (Alton) within 3 miles of being used to start the bike. It sits on end in a black 'exide' box. My plan is to buy another for my E start twin when built
I have heard stories of Lithium batteries still showing charging after a long time riding and thus getting 'warm' but battery technology is always improving so those stories may be of earlier versions of Lithium batteries

 

[Keith Martin]

We have used this battery on electric start twins many times. It is the smallest battery I could find with the most cranking amps. It will fit in some of the battery cases with thinner sides. The thicker rubber cases make it a tight fit.

AG-1201 Small Case Lithium Battery

Antigravity Batteries AG-1201 is an extremely versatile Hi-Power, lightweight Lithium Motorcycle/Motorsports battery in a tiny format, perfect for custom builds

antigravitybatteries.com

 

[Speedtwin]

Last Sunday run out on Comet 1 drained sump two pints of oil hmmmm.
Very fresh motor all new and tight.
Comet 2 friends bike I fettled over the winter tea cup full came out.
Very well used motor.
Both fired up and performed lovely, fell in love with my comet again was still smiling on Sunday night.
Plan an electric start so my other half can enjoy the comet.

Al

 

[BigEd]

I think there is a difference between a battery on a comet and a battery on a comet with electric start mine is a lithium one not a (Shorai) and it recharges to a minimum (Alton) within 3 miles of being used to start the bike. It sits on end in a black 'exide' box. My plan is to buy another for my E start twin when built
I have heard stories of Lithium batteries still showing charging after a long time riding and thus getting 'warm' but battery technology is always improving so those stories may be of earlier versions of Lithium batteries

What make\size of battery are you using?

 

[oexing]

Now that is serious money for electric start accus.
Sorry I was wrong about cell voltage of two different types of Lithium cells:
The good mannered type is LiFePo4 with 3.2 V per cell
The explosive type is LiIon and 3.7 V per cell.
I certainly want the first type in my bikes at 3.2 V, so two of them - or 4 when parallel wired for more capacity - can be charged by standard dynamos/generators that are correctly set for 7 V resp. 14 V in 12 V systems.
The LiIOn will be too high in serial wiring with added voltage so will not get charged up to specification.
So far I hope for no need for electric kickstart leg and just have some low price cells soldered up in gutted battery cases.

Vic
LiFePo4 cell