48 volt system for budge EV. Opinions wanted!

I’ve been reading on this forum and a couple of places online about budget EVs. Its seems that some EVs maybe be using 48v systems from fork lifts. I’ve also looked at some kits online. It looks like a big jump from 48v to 72v since many of the golf cart parts, cheap ebay motors, and fork lift parts max out at 48v.

clutch question. If I dont use a clutch will I be able to coast? I’m guessing if I have a clutch I can coast which will save the batteries I assume.

Current Parts list
8 - 6volt flooded lead that everyone else uses
Controller will be a kelly
KD48400 36V-48V 400A $289

I’m trying to get an old porsche as a donar car, but I doubt that will come through.

My requirements for my Daily Driver
30 mile range (includes 20% overage)
at least 45mph

Budget conversions are some of the most rewarding.
I suspect that 72volts will be the bare minimum for reliable 45mph speeds. Unless your are on a really tight budget (used parts only) the prices of controllers really start to go up after 72v, but below this the prices are pretty fair.
Most 48volt motors are able to be run at higher voltages (within reason) They are rated for continuous 48v use. If you use it at 72, but for only 50% of the time or less, this should not be a problem. Voltage everything to do with speed, so you will be using higher voltage to go faster, this would be a problem for steady higher speed use, except that most of the time, when you are at “cruise” you are using low amps, reducing heat build up. You can also duct air to the motor, or fan cool it.
Pretty much as long as you are not facing long steady climbs, you can get away with running the motor a little higher voltage, without too much trouble.
Just my two cents, Eric

OK whats the deal with Voltage. There is so little USER READABLE information on EV’s its driving me insane.

I NEED to go as low in voltage as possible. I was thinking I would have to go with 96v but the idea of rigging 400 cells is daunting. 48v would be SO much nicer. I could go with 200 cells OR stick with 400cells and twice the capacity.

My needs are pretty stringent. I need a 70 mile drip dead range (ie worst conditions) and I need 55mph reliably. I do not care if it takes 30 seconds to GET to 55mph thats fine but I need to maintain that 55mph for 45 minutes! My commute is 54 miles EACH way (charging at work NOT a problem) so anything less than 70 miles gets dangerous. I would prefer 110 miles as a “just in case” something goes wrong with the charge at work but I have enough petro cars that I can leave one at work just in case (family business) Thankfully its all level roads no real hills to speak of (Levittown PA 19057 to Egg Harbor City NJ 08215)

I take all surface roads so I average 50-55mph MAX

My plan is to use D cell 10amp NIMH batteries. (lead acid is just not an option too expensive too heavy too short a range) and to actually mount every one of them in a consumer IC smart charger. THis solves the charger issue and the charging individual cells to full issue. Not sure how to solve the discharge problem yet.

being able to go 48v would be nice. that would mean only 40 cells “per pack” instead of 80 cells.

I have seen golf carts do 30mph. is 20mph more so difficult? I figured it would simply be a trade off or Speed Versus Acceleartion. Smaller wheels better accel poorer top end but LARGER wheels (or higher gearing) would get me the top speed at the price of acceleration. Like I said 0-55 in 30 seconds PERFECTLY acceptable to me :slight_smile:

If I can get an EV together to replace my car for the daily commute I would save over $3,000 a year. I WANT a damned EV (I hate you chevron)

PLUS if nano solar can get there 90cent a watt solar panels to the consumer market I could put a $500 panel on the roof and a $1600 grid tie in in the garage and NEVER PAY A PENNY every again for my driving needs (that $500 panel would produce more power each month sold back to the utility than the EV would use in a month) IE driving would be free and 100% pollution free.



[QUOTE=nerys;1744]There is so little USER READABLE information on EV’s its driving me insane.[/QUOTE]


Know exactly what you mean, I’m looking for a 17mile each way commute.
I want to mount SOMETHING onto a 2 seater all fibreglass kit car i plan on making (weight without motor/batteries should end up around 500kgs)

But its the SOMETHING im having trouble with, just cant seem to find a motor that sounds suitable for a fair price, if anyone could suggest an industrial-found motor alternative i’d be happy (an ebay.co.uk listing would make me even happier :wink: )
I dont want to risk big money on a prototype

my commute only involves 10mins of town driving, the rst is cruising on dual carriages, id happily be stuck with 60mph, could charge at work no problem so a 25-30 mile range would be ideal, im also considering a removable generator to boost range if feasible, but i just want to find a motor :mad:

Some of you guys are wanting a whole lot for whats out there.

One thing you want to consider is to look into the practicality of getting a drive with REGEN ability. That is the ability to capture forward motion when you’re slowing to a stop. If you’re able to use this to your advantage, you can likely get by with less batteries, saving money and weight while improving performance due to the decreased weight!

Any DC motor or Servo motor turns into a generator upon release of applied power so you may as well make use of it if you’re high % city driving. The Regen drive allows the system to capture the energy generated. This generation also slows the motor in turn slowing your vehicle. This way you’re able to use regen to brake versus actual brakes, saving them for the final few feet of stopping or for emergency braking.

Regen is explained here