48v battery pack

Hi Royce, hi Paul, everybody.
Picture of my new LIFEP04 cells for my project, as a reference, the pack is 20" long 10.5" and 8.5" high and the cells are 90ah and after initial charging, it will be set up as picture but only as a 48v pack, as specs are far more relaxed at this time, each cell weighs in at 2KG and total capacity is approx 8.2KW. The purple 18650 cell is one of several thousand new cells I have also just purchased, and have a higher energy density, and will be used further down the road. With regards location, whichever type of cell I use, from the outset I had planned to fit as many as possible in the keel, and eventually just bolt a front and rear end onto the stressed battery box/frame. Regards waiting for a crashed Zero or similar, I think you are wasting your time, unless you are trying to bypass SVA approval, then its fine, that said I am scouring salvage yards every week in the hope of finding one, but unless they sell at a reasonable price, I feel its actually a retrograde step. Yes you have everything you want in one package, but that's the problem, the package itself, as soon as you try to reconfigure to what you want or need, nothing fits its all been designed as is, everything will be in the wrong position, and every plug /connector will not stretch to where you want it to, and every lug and fixture will be in the way, and most chassis are now Alloy making welding a more expensive option, not to mention, most chassis are heat treated, and any welding will reduce this. Anything can be done, but I think it would be far easier to convert several existing steel rolling chassis that you prefer, or already have, or even start from scratch, but purchase a motor straight off the shelf, and a controller to suit, lots are available, and you don't need to go far from our site, and use one of Cedrics offerings, the electronics side has to be easy because I can do it, and although you will still have to build or buy a battery pack, unless you drop very lucky, will end up with a bigger compromise than you wanted. BUT if anybody has a bent or bashed electric, circa £3000 ime all ears. Yours Dave Arthur

battery pack 004.jpg3.39 MB

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Good stuff!

Good to hear from an electronics person who does vehicles! I absolutely agree about the problems of re-packaging other peoples powertrains, invariably a struggle with everything in the wrong place. As a result I've been hanging about waiting for the E-powertrain that I can fit into an FF. The C-Evo has the performance package. but cannot be fitted in the FF box - and it's far too integrated (for me)to re-model. So I've been looking at equivelent power trains (Torque, KW/hrs.) that aren't so well integrated, where you can see the separate battery box, and the controller and the motor. The Zero is in that window so I thought I'd see if it would fit this spec.*

In theory I could buy all the bits and learn how to do it myself, but what I want to do is focus on the vehicle design, See what's possible. I don't have any money, so doing the design work is a way of making progress until I do, Really I just need to know the size of the boxes, motor dimensions etc.

The keel seems an obvious place for batteries but it's actually quite a small and constricted area. It's really important, aerodynamically that the space below the wheel spindles, what could be called the keel, be as narrow as possible, more or less a wheel fairing filling the gap between the wheels. Then you need the leg cut-outs to prevent trapping the riders leg if they fall over - and enough space over the top to easily step over the cover. It doesn't leave a lot of simple space. I've got a CAD of the box somewhere.

So I moved to looking at this 'rear-engined' layout as a way of densely packaging the entire power train in the simplest box, where it wouldn't intrude on the vehicle design. The space behind the rider is the one place where you can use all the safe available width - like 600mm) - where the pack weight can be easily managed and will ensure good rear wheel loading.

*Specification. Seek to exceed C-Evo benchmark for performance (100 mph), management etc. Uncompromising single seat FF, with rear-mounted powertrain. Exploring aerodynamic and ergonomic improvements. Technology demonstrator. Idealy electric, but ICE motor options are also promising and much cleaper (Triumph 675 triple?) ICE version could be quite quick, lets call it "the Malcolm Newell"


I forgot to ask. I was planning to visit the SVA test site with FJ and some drawings abd see if there were any E-FF issues. Are there specific EV's regulations? I expect I need a proper sparky to sign it off and stuff. I have built complete new vehicles around an engine and a number plate. But it's more difficult to insure "Modifieds" now and the MOT centre can get trouble. Perfect paperwork is always the best place to start...

Maximum voltage

Having been looking into the issue of voltage myself some while ago, I seem to remember that there is an upper limit of 75v for vehicles before needing all sorts of electrical sign offs or professional installation. Generally anything under 50v is seen as reasonably safe.

Safety, performance? Reality intrudes again

I'm pretty good at your basic vehicle electrics - 12v. DC, very comfortable. But I've been close to E-vehicle power management for a few years - I'm married to the person that verified the Infineon power management chip and know the person who wrote most of the software. 500 volts @ 400 Amps, DC. I'm not even going in the room when the lid is off the box. We discovered during the E-championship attempt that it's theoretically illegal to even connect that shit to the mains... So if I do an E-FF the powertrain will indeed be designed, built and signed off by an appropriately qualified person - and SVA registered.

E-'bicycles' (speed/power limited PTWs) are great, probably more relevent to mass transport needs than anything else in the speed-restricted cities of the future. And there's a host of people capable and willing to develop them - like Peter. I just want to go on developing (FF) PTW's that are fully traffic compatible*, a vehicle design issue. Of course it should be E-powered, but that's a problem for E-power specialists. I'm hopful that eventually there'll be a box, with a shaft sticking out somewhere that spins - and uses electricity rather than petrol. The C-Evo box is a perfect example, but regrettably the wrong shape - otherwise I'd be building an FF using it.

Maybe I should be looking for someone prepared to re-box the C-evo powertrain... I've got a big enough space and making boxes is easy (steel, alloy, GRP whatever). I think in the meantime I may have to go and measure up something like that 675 Triumph Triple "box". No-one lives forever and I fancy that rear-engined, single-seat option. Maybe someone else will fit the E-power box after burning petrol in the open air is banned.

*At it's simplest, 80 MPH cruise 100Mph max. 1g. plus braking, and all the usual comfort, handling, safety and efficiency.

Speed criteria

Why do you need 80 mph cruise and 100 mph top speed for traffic compatibility? Trucks are traffic compatible at much lower speeds.