Recent content by robinfisichel

I want to do a quick example of this, just to see how worthwile regen breaking would be. If the car brakes from 40-0mph in 4 seconds (about 0.4g) the change in energy is 95925 J for a 600kg car. Assuming 31% efficiency this makes available 29736 J. In terms of power this is producing 7.4kW...

Thanks i think i get it now, there's a company called thunderstruck motors who do batteries for 100 Ah 3.3v for about $150 dollars a piece or something, so a lot of cash for sure, but that's my least concern. Tesla uses something like 6000 batteries, and has a tonne of power and torque, but...

Thanks, makes more sense now, though I am using 3.3v batteries so i guess its 0.25v per battery instead. I am confused about the difference between Wh and Ah..

Cool, nice info, i think that's what i hear as wel. Control systems are way beyond me as well! My design is really hypothetical so I am not worrying about this too much. One problem with the drive cycle i used for the EV is its aimed at emmissions testing (as are most) so doesn't incorporate...

Another EV related question from me, I would like to know a few things about regen braking... 1. For typical cars, how efficent are regen systems, I've seen 31% quoted http://engineering.wikia.com/wiki/Regenerative_braking as in how much of the kinetic energy of a vehicle is recoverable 2...

I have another problem! I was calculating how much extra capacity i would need to run the standard onboard systems, (radio and headlamps) and calculated: Radio Power = 10w Light power = (2x50w) + (2x35w) for 4 lights breaking and headlamps. If the lights run on 12v then the current...

Actually from reading the wiki on this it looks like the equation is meant for lead acid only, so probably that's why i can't find a number. I would like to find a general alogorithm just to make things simpler in my spreadsheet!

Thanks mshelp! You seem to be answering a lot of my questions lately! I am not sure i completely understand but I get the idea now, C is NOT coulombs!

http://evcomponents.com/cscart/index.php?dispatch=products.view&product_id=29862 for example I thought Coulombs SI units was A.s so for 1 second 4C = 4A, am i wrong?

I am designing an electric vehicle and choosing the batteries. For this i want to model some inefficiencys into the batteries. I came across the formulae T=C/I^n where T=battery life C = capacitence I= current n= Peukert's number would 1.1 for n be ok for lithium ion, it seems to take quite...

Great!

I take it i would have to have a specialised motor for this kind of application, i.e. not the one i am using.

Another question, again very basic; If i want say 110 Ah, is this something along the lines of n/(110) = 1/100 + 1/100 ... 1/Cx + etc where x is some value greater than 110 (like 200 maybe) n = number of batteries in order to bring the total Capacity up to 110 Ah?

Simple? You would think so , see if you agree with my approach... I have a car, I know its power at certain Rpm's and I know the magnitude of resitive forces. So 1. I calculate the power loss due to resitive forces 2. I calculate the net power by subtracting this from motive power. 3. I...