Topic: Starting to take shape...

[Karl]

you got a lot of us slobbering after this new box.....

...you're not the only ones slobbering, I've been drooling over it as well ...must be the thought of running a reliable max power 24v, "voodoo" will have a new lease of life 

[techytype]

24v volt Karl  where's your ambition man?

36v more like 

regs
alan

[Karl]

I'm happy with 24v    Carrying just the two lead/acid batteries suits me just fine  ,  couldn't really justify the expense of Li-ion power packs to get up to 36v - and three lead/acid batteries would be too heavy.

Besides, a maxed out 24v c5 is plenty quick enough - as the one c5Martin and I sorted for Jason Bradbury proved. If this gearbox conversion works, I'll be very happy.

Does anyone know where to find details of the power curve/characteristics of the standard c5 motor ? Can't seem to find it listed anywhere or even a Polymotor site  

[minimin]

Is it in here?
http://www.c5alive.co.uk/pub/downloads/C5-UnofficialServiceManual.pdf

[techytype]

i know it's favoured to use a single 12v leisure batt, and for longer journey stamina that's fine.

from what i see on the run in Brighton, it's rarely most are going to use the high speed option for more than short bursts or for climbing steeper inclines.

i wonder if 3 x M/C batt's to give 36 volts were used for these bursts, perhaps using an electrical contactor (heavy duty relay) to switch between the two battery power sources, you could get the best of both worlds without the higher battery costs. if initial starts were on 12 volts switching to higher volts once moving above say 6 mph thayt would help reduce 'stall' current from dumping the smaller amp hr batts.

the original cell was very small, and i'd be real curious to know how long the modern day M/C batts would actually last if they were the sole power source, although you will have less amps available the higher grunt offered by 36 volts imo will go a fair way to balance out that 'loss' to be a fair compromise of the higher speed.

several configurations might be worked out based on the above, but you can get the gist of my theory, so now just hurry up with them darn boxes  .


regs
alan

[Karl]

Is it in here?
http://www.c5alive.co.uk/pub/downloads/C5-UnofficialServiceManual.pdf

...you're right, there are a few graphs etc in there - but not what we need . I'm after the power curve that gives torque figures at given revs etc.

[techytype]

Is it in here?
http://www.c5alive.co.uk/pub/downloads/C5-UnofficialServiceManual.pdf

...you're right, there are a few graphs etc in there - but not what we need . I'm after the power curve that gives torque figures at given revs etc.

tbh Karl, think you will have problems with getting this info, Hoover would be the ones or perhaps Adam.

but i'd wonder at the value of it even if available, the original setup has the motor is running via a reduction gearbox @ 12v, so we can work out the reduction ratio, we also know this setup has very little grunt running at this voltage especially at lower revs and soon runs out of puff on inclines.

if you again lower te ratio then you will have more grunt but lower top speed

my 2pth , i think you have to make a decision whether to run with 12 volts and same gear ratio as original, or go for 24v allowing marginally higher gearing.

if you go this route you might have to do some experiments on what damage might be done if the motor is stalled.

you already have a machine running 24v so you know how effective it is with original gearing which seemed very sprightly to me. you can't please all the people all the time so now you need to decide if that performance is enough for most, personally i think it is as these machines were never designed to be quick  .

if anything my advice would be make the standard ratio box as i'm sure these will sell in bigger quantities, then make a 'MKII' performance option with a higher ratio.

i've seen mods using sturmy archer hub gears, might be another way forward later on.

regs
alan