Thanks thamesmud for the info on charging the batteries.  As mentioned in a previous post the club has minimal experience of electric power, so we will need to update the handbook and regs at some point. 

We will also need to update our Hazard Log and the Risk Management Plan.  Consequently, at some point could you detail the hazards regarding the various types of batteries and the hazards involved when charging them (especially in the paddock)?

I couldn't agree more Andy, I learnt more about my kart in the first 2 laps of Whilton Mill than any of the research I did before I started.  It was a huge amount of fun with masses of grins per lap.  I'd say its more fun than regular karting and I've done quite a bit of that.

Whats more, it has spurred me on to get it finished.  Can't wait for the first kitcar show and Brooklands.

Hours of fun

WESTONZOYLAND UPDATE

Ian Lang is going to be the event lead for this event.

He will need the support of other members.  Volunteers are required for Clerk of Course, deputy Clerk of Course, Event Secretary and marshals.  The club has a proven procedure for organising and managing events, and the Events Co-ordinator is there to assist anyone carrying out these tasks.  Training and experience can also be provided for the various roles at our events at:

• "Race the Waves"
  The National Kit Car Show
  Brooklands

I met Thamesmud and his wife on Tuesday evening to collect the LiFePO4 cells. We had a meal and a good cyclekart chat. They had come over to this side of the country for a short break, which was fortunate timing for me.

So now I have almost all of the components needed to make up my basic electrical system, I'm just waiting for a few little items for the wiring - solder tags, heavy duty cable and terminals etc. Hopefully, I might get a chance to connect everything up and see that the motor turns (or not) in the next week.

I haven't settled how many of the 56 cells I am going to use in my battery pack. The simple solution that I had intended was to use 48 to make three parallel strings of 16 cells giving me a 45Ah battery which would give me about 30-35 minutes of racing. That would be draining it down to 20% charged. It would probably take a little over an hour to charge which could be a real nuisance. Depending on the event, there might be time between heats/races to partially recharge and to avoid a full recharge.

But I am now considering making 3 smaller batteries of 16 cells each. The smaller batteries would provide about 10 minutes of racing each and I could swap them each heat/session and have two on charge while I'm driving with the third. The smaller battery would experience a greater voltage drop under load, which would reduce its power output a little (about 7%) but the cyclekart and driver would be 15kg lighter (also about 7%) so the performance might be identical. The drawback of smaller batteries is that they would limit me to 10 minutes of racing.

A third option would be to make 2 batteries - a small one with 16 cells and a medium one with 32 cells. They would give 10 and 20 minutes of racing, respectively. This would allow some flexibility for different types of events and would be a compromise.

For today, I favour the two battery solution. I expect that will change just as soon as I get the cyclekart together and actually drive it and see how it goes and how long the batteries actually last. Everything might change and need redesign - but that's what winter is for, right?

Charging a group of cells to get them to the same voltage as the others [ Guests cannot view attachments ] This is prior to assembling them into a battery with a BMS. I need them to be at the same voltage in order to pair them up in parallel.

This is a trial assembly of a 32 cell battery. [ Guests cannot view attachments ] I don't like the physical shape as it will be difficult to fit into the cyclekart, so I will have to take it all apart again. I think that half that height (and twice the depth) would fit under my seat and leave space in the engine compartment for a fake petrol engine.