Battery Vehicle Society

Things have moved on since I posted this in December. I passed MSVA (a detailed MOT) about a month ago and after the usual nightmare with registration my number arrived today. I'll add to the thread below with all the excitng information about my early drives, but for now I'm just reaching the end of my recharge after 4.5 miles of undulating roads.

Today I picked up the drive chain that I'd ordered, took it home, cut it to length, fitted it, pushed the trike (known as Sparky) outside and drove up our quiet cul-de-sac. Naughty I know but if you ever build a self designed, self built vehicle you will do the same. It's one of those great moments in life like.............well I'm sure you can fill in the blanks for yourself! It felt torquey, was almost silent and very smooth. I could have done with some air in the two front tyres to make the steering lighter and better at self centring, but the steering was accurate and predictable. I'm slightly concerned that the front shock absorbers might be too soft for the battery weight which totals over 150Kg. However the drive side of things was perfect. I have not yet programmed the Alltrax 7234 controller so it's on the default settings,whatever they may be, but I should get a cable that I've ordered within the next few days to connect to the laptop. After that I just need to finish a few items and I'll be ready for the MSVA test at Oldham. It's about 25 miles of mixed town and country driving away so it looks like I'll need a trailer. (Offers of trailer loans from anyone in the North West would be very gratefully received, (I do have a tow bar)). I can't find a way to show a photo on the forum or a link to a web page because I'm useless at that sort of thing, but if anyone would like to see my work in progress they could e mail me and I would send them some photos that I took a couple of weeks ago. I would have no objection to them being made available for anyone to see if someone can find a way to do this. I'm just going back into the garage now to relive the moment, I may be some time.

Andrew Kirk.

Well done always nice to throw the final switch!



My creation lives! (Insert mad scientist laugh here!)

I researched an EV project in 2007 but didn't start to build. It was when I saw the claims of the Vectrix scooter in September 2008 that I really started to regain faith in EVs. I saw that with a small battery capacity of only 3750Wh Vectrix claimed a range of 35-55 miles.

This got me thinking again and I so designed a new EV trike which I hoped would be able to get me to work (cheaply) and give me a chance to try out an anti roll suspension system which I had invented. (It works very well but is not EV specific so I won't go into it.)

I got some metal delivered in October 2008 and started to build my chassis.

I had it ready to paint in July 2009 and standing on it's wheels by about October.

My first drive was on the afternoon of 17th December. I did a quater of a mile, it snowed and stayed cold for a very long time.

I still worked in a freezing garage and had it ready for MSVA test in February-It failed! It took me until March and a third test to completely redesign the front brakes and get a pass. Interestingly to comply with the rules I have ended up with a braking system which is less competent and less safe than the one I origionally presented.

The DVLA then did nothing to assist me in getting it registered. You can't phone them directly and when you do they have usually done nothing at all. Still it's done now and I can advise Mr. Cameron where the axe should fall. It takes 3 people to answer each phone call so thats a 66% reduction in staffing straight away!

Enough moaning! I had done about 20 miles of testing at my "private test facilties" (less said the better!)
but today I could legally drive. I took an undulating route of 4.5 miles first. It accelerates slowly for the first 10 mph but is quite good by the time you reach 25mph. I kept it down to 30mph on the long gradient of half a mile and it climbed well. Then a flat turning to downhill part where I reached 41mph!
I turned round an returned via the same route. Motor temperature reached 44C. I recharged in 20 minutes.

Later I did another 3.6 miles but this time I tackled a 10 % gradient. I have reduced the output current to 180 from a max. of 300 amps for my early testing and had wondered if I could maintain a decent speed. My calculations showed that I could have slowed to 14mph! Fortunately I approached the hill at 36mph and dropped to 29mph at the steepest point, though I think my speed may have continued to fall if the gradient had remained as steep.

My motor terminal reached 55 C and the insulation within the brushholder reached 65C.

What testing would you advise to ensure reliability.

How can I calculate my Wh/mile? I currently only have a voltmeter as a fuel guage, a multimeter for general testing and I can record the recharge times of my PFC 1500 72V charger.

Tommorow I hope to do 10 miles, at least.

Any advice at this stage would be gratefully received.

The best source of details about my trike is at EV Albums where I am listed as a Kirk EV, aka. Sparky.

Andrew.

Woo-hoo! Congratulations Andrew. Long time coming for you.

Use something like this http://www.reuk.co.uk/Kill-a-Watt.htm

Once you know the miles driven and how many kwh it took to recharge the rest is easy.

Greg,
thanks for the advice, I saw similar for £12.95, about £20 in P and P and VAT so I will get one. In the meantime I have studied my charger profile and, although my conclusions may be somewhat out, I am calculating about 125-130 Wh/mile at low 30s cruising speeds.

Sorry if I bore anyone but today I did something I've dreamt of since before I started my Ev project. I drove the "27" miles to work! I had done 26.17 miles yesterday whilst getting lost in Preston. Voltage sag was never worrying, never getting below 65V and then only momentarily.

Today I thought I had better keep the speed down to low 30s cruising speeds again, after all \i wanted to get there! Due to the accuracy of my MTB speedo compared to that on my scooter I recorded only 24.67 miles and recharged slightly quicker than yesterday. Max. speed was 37mph as I took a run at a hill. My average was 25.05mph. I recharged in 3h 14mins.

The return journey had me a little anxious. This time the steepest hills are at the end of the trip. It went well. I averaged 26mph and celebrated with 47mph down the "Myles Standish Way" in the last mile. Voltage drop was not a problem.

What do those with knowledge of LA think is an acceptable voltage sag?

Alltrax suggest that 48V for a 72V system is about the limit. I have read elsewhere that 10.8V per 12V battery is a sensible limit for long battery life (64.8V in total). Any opinions?

Andrew.

Alas Andrew,
Having read your evalbum.
http://www.evalbum.com/3061

If you omit the lead for LI*'s you will halve the weight and have 3x the charge. They suffer considerably less voltage sag, work hard as h*ll until there is next to no charge and will last you years upon years over thousands of recharges....... if you do not overcharge or discharge them.

They make ev's practical.

Beemer, Andrew's given up on EVs and sold his trike.

I suppose at a weight of 725lbs with 340 lbs lead batteries he was headed for a spanking

Such irony. It's what we aspire to without the loopholes.