Newbie to EV's Hello

[mcharles13]

Hello all.

I'm Mike from Big E-RC. I was referred to this board by Xyster and Reid Welch. I first heard of ev's from them and a couple others interested in my packs and decided it's something i really need to research.

I'm interested in learning more about electric bikes and cars. Kits, systems, everything. I'm an information sponge and tend to learn fast so hit me with it !

Also on a more personal note. Has anyone created an electric go kart? I'd love to build a couple of these one day for my fam and i.

I look forward to learning.

,mike

[Lessss]

Nothing to it really.
Batteries, Contoller, motor and gears. The rest is just a frame.

[xyster]

Hi Mike. It's great to see you here! Reid, me and a number of others have sure learned much -- especially about batteries -- from the RC forums where I first learned of bigerc:
http://www.rcgroups.com/forums/index.php

I'm an information sponge and tend to learn fast so hit me with it !

Anything in particular? Despite Lesss's assertion, there sure seems to be a lot of info to get hit with (at least there was and still is for me ) Of course with your background, it's really just a matter of scaling up to EV size that which you already know, plus some basic bike/scooter mechanics.

[mcharles13]

I probably just have a lot of reading to do. When i went from small e-planes to big ones, there was a learning curve and new hardware used. Also when i went from planes to monster trucks.

Do you guys use brushless or brushed? Also where do you buy your motors,esc's, etc. Those places usually have good technical information and gives me a reference point cost wise.

When i was still in DC an e-bike would have been great but now i'm in MD and live too far from work to e-commute. Well technically i do since i take the metro and that runs on electricity. An e-go kart would be more suitable now for goofing off and having fun with the kids.

Also another topic i've been meaning to research. The new hybrid vehicles can they be converted to electric only or is that too large of an undertaking? Is there an electric only coming out any time soon?

I'm bout sick of gas prices. they are still hovering at $2.60ish in my area and steadily rising. During the big price jump we were well above $3/ gallon. Stupid dc/metro area.

[Ypedal]

Yep.. Brushed.. Brushless.. Geared.. Gearless... Axle driven or Chain/Gear driven...

Controllers are Sensorless or HALL sensor controllers....

Power Meters.. LVC ( Low voltage cutoff )

we got all that fun stuff....... just bigger and badder..

welcome aboard !!!

[xyster]

Do you guys use brushless or brushed? Also where do you buy your motors,esc's, etc. Those places usually have good technical information and gives me a reference point cost wise.

Most scooters are 36 or 48 volts and use brushed motors, and most ebikes are 36 to 72 volts and use brushless motors w/sensors. Many cheap ebikes use 24 or 36 volt brushed motors connected through a chain and gears:
http://thesuperkids.com/electricbikes.html

Good ebike kit and battery vendor:
http://www.ebikes.ca (lots of info)
http://www.ebikes.ca/store/ (their store)
http://www.ebikes.ca/simulator/ (an awesome hubmotor simulator)
another:
http://www.poweridestore.com/

One of the few kits that drives through the chain:
http://www.cyclone-usa.com/index.php

Also another topic i've been meaning to research. The new hybrid vehicles can they be converted to electric only or is that too large of an undertaking? Is there an electric only coming out any time soon?

There's a couple companies selling hybrid car to plug-in hybrid conversions:
http://www.calcars.org/priusplus.html
http://www.greencarcongress.com/2006/02 ... nveil.html
I don't know much else about that.

[jondoh]

Hi Mike,

I understand you work with the e-moli's and A123 batteries. I've got e-moli's on my brushless cyclone and crystalyte e-bikes and they're great. I'm using the stock milwaukee battery packs and connector blocks but I was thinking if i wanted to build a bigger pack, i'd have to take the cells out of the case and bundle them more densly-- something you already do. I checked out your site and you don't seem to have packs for 56v. is this only because rc folks don't need such high voltage or is there a technical reason? do you know of a way of conveniently charging a high voltage pack without having to separate them back into 28v?

[Toorbough ULL-Zeveigh]

Which is you're personal preference for a large capacity lithium pack. The A's or the E's?

[mcharles13]

Hi Mike,

I understand you work with the e-moli's and A123 batteries. I've got e-moli's on my brushless cyclone and crystalyte e-bikes and they're great. I'm using the stock milwaukee battery packs and connector blocks but I was thinking if i wanted to build a bigger pack, i'd have to take the cells out of the case and bundle them more densly-- something you already do. I checked out your site and you don't seem to have packs for 56v. is this only because rc folks don't need such high voltage or is there a technical reason? do you know of a way of conveniently charging a high voltage pack without having to separate them back into 28v?

The only reason a certain pack is not on my site is because no one has requested it yet. I run a very flexible configuration system. When someone requests a new shape i add it to the site. (if i can physically make it) I just added 2 new pack shapes to the site yesterday.

I can build out the pack shape you need. I'll have to do a little research on charging solutions and post it. I know there are chargers out there that will do 14s (14 cells) but i dont know them off the top of my head. Most of us in the RC plane field stop at 10-12s. Personally i've not used more than 4s emoli and 5s a123. This summer i'll be building an either 7s or 8s a123 plane.

When you say 56v are you talking (2) v28packs in series? If so that is actually not a 56v pack. It's 14s which is actually a 51.8v pack (nominal). Under a full charge it is 58.8v but under load it will come down. Emoli's are actually 3.7v per cell nominal and 4.2v full.

An alternate method of charging the (2) 7s packs (v28) is to seperate them and charge them parallel at the same time. If your charger and power supply can handle it just double the amount of amps you pump into the system and you'll save time but still be able to retain your current charging solution.

[mcharles13]

:?: Which is you're personal preference for a large capacity lithium pack. The A's or the E's?

If you would have asked me 1 month ago i would have said emoli. But now it's a123 all the way.

The voltage and mah for the a123 cells is lower than emoli but the throughput and voltage retension is awesome.

Also another added benefit is the a123's can be run flat with no damage, provided it's not a slow discharge past 2.5v/cell. With emoli you need to program an LVC of ~3v per cell. Emoli's can be run low but this significantly shortens their lifespan it seems. With a123 just remove the LVC or set it to Nimh setting and let it rock.

I abuse the life out of my a123's and they just keep coming back for more. I put the full 2300mah back in each time. With my emoli's i never used more than 2600mah by the time i hit LVC and the power is weak at that point. I absolutely love running full power until the very last second where it stops completely. You dont feel a gradual power loss. It's full bore till the end and then nothing.

In a bike application i can see this being an easy method of creating a "fuel" gauge. A simple wattmeter can be hooked up in series with your system and just watch the elapsed mah. When you get to your packs mAh rating your empty. Hook it back up to the charger and in 15min your full and ready to go again. (again provided your charger and power supply can provide enough amps for fast charges)

Some real world numbers on a123. On a 5s1p (5 cells in series) in my rc truck i pull 81A @ 955W. In that same truck on a 5s2p (2 sets in parallel of 5 cells in series) i pull 90A @ 1300W

For you guys depending on how many lvls of parallel you run will see very little voltage drop. The more mAh the less drop AND you'll be able to use the full mah rating.

[jondoh]

1300 watt from an RC truck???

sounds like an electric car to me-- you sure you can't ride on top?

Right now compared to electric cars, bikes are where things are at because they're a relatively cheap and easy way of getting involved with EVs. The efficiency and relatively low power requirements of a bicycle makes them well suited to take full advantage of the latest battery technologies. They can also be pretty stealthy so you won't be hassled all the time by cops.

Not to be down on the electric car but batteries are a problem. An electric car needs lots of batteries which are expensive and/or heavy. I would be really interested in a car from this company though:

http://www.venturevehicles.com/

Regarding electrifying a go-kart I believe the folks at thunderstruckev did electrify a dune buggy once... if you want to electrify something for the kids, maybe a tadpole trike like here:

http://www.kmxus.com/product.php?ProdID=6

[fechter]

I remember a couple of killer go karts on the old V.com forum.
Etek powered, a go kart should be able to eat gassers for lunch. Until the batteries go dead anyway. Of course you could use a smaller motor if it's for the kids and you don't need tire burning power.

[mcharles13]

LOL it would be for my wife and i first, and the kids later. they are only 3 and 2 years old. I dont think it will be any time soon for them.

what's v.com

i tried to go to it but nothing pops up.

[jondoh]

actually it was visforvoltage.com but it got hacked and destroyed last year. there is visforvoltage.net but most ebike folks moved here. too bad about visforvoltage since it had a lot of very good info, pictures and stuff.

quick question about the milwaukee packs. you spoke of the e-moli bms needing a low voltage cut-off to prolong the life of the batteries. i believe the milwaukee batteries have this but i want to confirm this with you. I ran the batteries down completely about twice. when i measured the output voltage, my dvm read around 8.5 ~ 9 volts. I'm hoping i got this reading because the BMS stepped in and said, "no way! charge me first! ".

[Toorbough ULL-Zeveigh]

:?: Which is you're personal preference for a large capacity lithium pack. The A's or the E's?

If you would have asked me 1 month ago i would have said emoli. But now it's a123 all the way.

Thanx 4 that!

I was leaning that way, based only on paper. It's great to have someone's direct experience confirm what the specs would seem to indicate.

[mcharles13]

actually it was visforvoltage.com but it got hacked and destroyed last year. there is visforvoltage.net but most ebike folks moved here. too bad about visforvoltage since it had a lot of very good info, pictures and stuff.

quick question about the milwaukee packs. you spoke of the e-moli bms needing a low voltage cut-off to prolong the life of the batteries. i believe the milwaukee batteries have this but i want to confirm this with you. I ran the batteries down completely about twice. when i measured the output voltage, my dvm read around 8.5 ~ 9 volts. I'm hoping i got this reading because the BMS stepped in and said, "no way! charge me first! ".

I haven't used the ones salvaged from packs. My cells come from the factory unused so i dont have the circuit that comes with the v28 packs. From what i understand the v28's do have protection built in.

[bobmcree]

i just bought 8 dewalt 36v packs to get the A123 cells, since it would have cost almost twice as much to buy the cells from A123. I am figuring on building a 16S4P setup for my bike that should give me 53V 9.2 Ah with a cell weight of 10 pounds. i was glad to hear about your rc experience; i have been running 8 NiMH sC cells in my RC10T at about 800W and the motors usually last 2 4 minute races. I was planning on trying some of the cells in my rc truck as well.

has anybody disassembled the DeWalt packs and can you provide me a link to any info available? i understand i might need a special tool to properly disassemble the packs. i will not see them for a few days. any links to using these packs and details on the bms would be appreciated.

[mcharles13]

http://www.rcgroups.com/forums/showthre ... ght=dewalt

That's how to dissasemble a dewalt pack.

[knoxie]

wow

Great link on splitting those packs!! warm up that soldering iron Bob and tell the dog he may have to go walk himself for a few days!!! you are going to be busy

Knoxie

[Lowell]

$1.20/Watt hour is sounding a lot more reasonable, however the energy density on the A123 cells isn't that great. Not even 50Wh/lb