Sunday 22 March 2015

Odyssey Extreme PC680 Battery with Carbon Cage and Fitting Guide

A couple of months ago a friend said that he'd recently ordered and fitted a new lightweight battery to his R500.  Lightweight - that's right up my street, so I had to buy one.  I purchased the battery on next day delivery and it has sat in the garage since the day it was delivered.  

There is a reason for the lengthy fitment time though.  I ordered the Odyssey Extreme PC680 Battery from Powervamp racing and this included an alloy cage to  fit the battery to the scuttle.  Having spoken to one of the chaps at Powervamp at the time of placing my order, I enquired if they had a carbon version of the mounting bracket, and he suggested they were having one made, but it wasn't available just yet.

That got me thinking... and researching - I as I now had some NEED for that carbon battery holder.  I called some carbon manufacturers to see if they could make me one, and it turned out after a few calls that I stumbled upon the guy who had made the mould already - perfect what a result.  Anyway, he was reluctant to make it for me as it was quite a long job for a small part.  The carbon cage arrived earlier this week, and so this weekend was the first opportunity to fit everything.

Onto the Battery Swap and Fitting Guide:-
This fitting guide is the easiest solution I could come up with as I have a heater, a 12V master switch (which means less slack on the +/-ve leads) and I didn't want to drill holes into my scuttle.  I'm not saying this is the way everyone should do it, but it seemed the most logical for my requirements.

The first step was to ensure the track day master switch was off, remove the negative, then the positive lead and the top of the cage holding the battery in place.
OEM Banner battery in Caterham R500D engine bay.
OEM Banner battery in Caterham R500D engine bay.
With the battery removed - now remove the four cap head bolts holding the lower half of the battery tray in place.
Standard Battery Tray in Caterham R500.
Standard Battery Tray in Caterham R500.
I thought it would be a good idea to see how much lightness I was adding with this new battery, so weighed the cage - which weight nearly half a kilo - 464g to be exact.
Battery Cage removed and weighed in at 464g
Battery Cage removed and weighed in at 464g
I had to use our suitcase scales to weigh the banner battery, and the readings varied from 8.2kg to 9.2kg, so I took a picture of the lowest weight.
Banner Battery weighing in at 9.2kg
Banner Battery weighing in at 9.2kg
I then figured out that the cage to hold the battery was really suited for mounting the battery on horizontally on the scuttle (which I didn't want to do) so I measured up and figured out that if I made a bracket to attach the cage to, I could get the battery into the standard location without drilling any extra holes, so for the lightest solution I decided to make a carbon bracket.

Manufacturing the carbon bracket:-
Firstly, I purchased an all in one carbon fibre laminating starter kit from easy composites link here for around £40.

I then needed a mould to lay my carbon fibre onto, so measured up a rough template and got Nigel from Specialist Sheet Metal in Stevenage link here to make me one.
Carbon Fibre bracket template
Carbon Fibre bracket template
The kit arrived, and there was a link to download the instructions from their site in the box, but the link didn't work which was annoying.  As I've never made anything out of Carbon Fibre before I was kinda stuck without the instructions and it was late on Friday night, so I couldn't call their helpdesk to ask the questions I needed answering.
Carbon Fibre Laminating Starter Kit from Easy Composites
Carbon Fibre Laminating Starter Kit from Easy Composites
Nevertheless, a search on youtube found the video below from their sister company Carbon Mods (who sell pre-made Caterham Carbon Fibre part).  So I watched the video a couple of times to familiarise myself with the process and began work.

First thing is to cover your mould with their supplied release agent with a thin, but even coat, then alloy it to dry for around 20 minutes.
Release agent
Release agent
Then it was time to cover your mould with the first coat of export, mixed 100g resin to 30g hardener (and this has to be accurately measured otherwise it won't harden properly).  It was also suggested on the video to really spend a lot of time mixing the resin and hardener too.
Epoxy Resin and Hardener being weighed
Epoxy Resin and Hardener being weighed
Once the mixture had been properly stirred, it was then onto the mould in a thin but even layer.  This must then be allowed to harden for around three hours otherwise the carbon sheet wouldn't stick properly to the mould.
Mould covered with one coat of the adhesive solution
Mould covered with one coat of the adhesive solution
After the adhesive solution was allowed to dry, it was then time to cut the supplied carbon sheet (Supplied in 100cm x 30cm roll) into 30cm x 30cm squares and then to lay the first sheet.  You had to get the weave lined up as the first layer will be the one that's visible, so it was worth trying to lay this out as best as I could. It was quite tricky as the adhesive was very tacky and it was my first time ever making something like this.  Then another batch of the adhesive solution was mixed up and blobbed on top of the first sheet of carbon fibre in stippling action so as not to move the weave.
First sheet of carbon laid onto mould, with another coat of adhesive solution
First sheet of carbon laid onto mould, with another coat of adhesive solution
Then straight after that the second sheet of carbon was laid on top of the first sheet and another coat of the adhesive solution applied.
Second coat of carbon fibre sheet laid with another coat of adhesive solution
Second coat of carbon fibre sheet laid with another coat of adhesive solution
Then it was time to lay the third and final sheet of carbon and apply another smaller amount of adhesive solution, as a lot of the solution would soak through the sheets.  On the vertical section in the picture below I used the remaining 10cm of sheet and built up a small profile so that the outer cage would fit snugly.
Third and final sheet of carbon fibre laid
Third and final sheet of carbon fibre laid
Now it was time to kick back and do something else on the car (fit the carbon headlights!) whilst the carbon fibre part hardened.  It was pretty hard after the suggested eight hours, but I left it overnight before attempting to remove the part from the template.

With the part completely hardened, I could out the cardboard I'd used to protect my flooring (as the adhesive went everywhere this was a good idea!) and then gently prised the part I'd made away from the template using a wall paper scraper.
My first carbon fibre part ready for removing from it's mould
My first carbon fibre part ready for removing from it's mould
Next it was a case of placing the battery into the (professionally made) carbon cage and lining it up against the (home made) carbon bracket and marking out where to trim.  I marked this using a blue paint marker, but it may have been better using a black permanent marker, as it was near impossible to get the paint marker off!
Battery, cage and bracket in place and marked ready for cutting
Battery, cage and bracket in place and marked ready for cutting
With the bracket roughly cut, I decided to weigh the holder which came in at 282g - 182g lighter than the standard alloy cage.
Carbon battery cage and bracket weighed in at just 282g
Carbon battery cage and bracket weighed in at just 282g
Then it was a case of screwing the cage and the bracket together and fitting the holder to the existing battery holes in the scuttle.  I also took the opportunity to fit the CTEK charging lead.
Odyssey Extreme Battery with Bespoke Cage and Housing in Caterham R500
Odyssey Extreme Battery with Bespoke Cage and Housing in Caterham R500
I'm pleased with the end result - it was very time consuming to make the part, and the total cost including the battery for this upgrade was around £200 - I did also weigh the new battery, but I can't seem to find the picture?  Anyway... It was 5.7kg which combined with cage weight saving is a total of 2.7kg of 'lightness added' and at 13p per gram saved that's pretty good value.

4 comments:

  1. Surely a carbon top to the pedal box is next... Or chuck away the heater and invest in some Damart long johns. That will save a kilo or two!

    ReplyDelete
    Replies
    1. Believe it or not - I have tried to find a carbon top to the pedal box... I found one months ago, but can't remember who sells / manufactures them... Let me know if you who does!

      And the long johns are a highly doubtful addition to the weight saving strategy!

      Delete
  2. I know this is an old post, but if you'd used the other side of your mould, you'd have got a much better looking finished product.

    ReplyDelete
    Replies
    1. Yes that is correct, but that would've made the outside of the carbon battery casing poor... I'd prefer the imperfections on the inside as that's the bit you rarely see... Thanks for your comment nevertheless. Best wishes.

      Delete

Thanks for your comments, I'll check out what you've written and add it provided it's useful informative and not spam.