Building an EV motorcycle. Batteries: Need opinions.

[P-hack]

EVTV sold a bunch of them, AFAIK folks are using ~$1000 chargers with a constant current phase (till a predicted voltage achieved) followed by constant voltage phase (till a predicted current is achieved), charging them in a string. Might find some discussions about it.

Some specs at the bottom of this page:
EVTV Motor Verks Store: 1 Renault Influenza Battery Packs, NEW ADDITIONS - THIS JUST IN!, Betterplace

[TurnNBurn]

Originally Posted by P-hack

EVTV sold a bunch of them, AFAIK folks are using ~$1000 chargers with a constant current phase (till a predicted voltage achieved) followed by constant current phase (till a predicted voltage is achieved), charging them in a string. Might find some discussions about it.

I threw up a little in mouth, but let me clarify. The chargers cost $1000?

I'm going to research these constant current chargers when I get home tonight.

[P-hack]

Yah, I'm seriously looking at the lithium charging/balancing kits/options too. FYI I picked up a $300 ac24ls, and a $300 controller kit, so these batteries would be a great fit price/capacity wise if I can figure out a cost effective way to charge them. Onboard 115v preferred, but need >156 volts so it will be interesting.

[P-hack]

Also FYI I'm considering the juicebox kit @ $179 FYI. 15kw @ 240v. at 115v it is limited to 1.5kw but that is plenty for a bike. Probably tap into the J1772 protocol to control it or something, don't know about several hundred in special cables/plugs though. And balancing is still an issue.

Electric Motor Werks, Inc. - CUSTOMIZABLE JuiceBox - an Open Source Level 2 (15kW) EV Charging Station

[P-hack]

edit, not sure what the juicebox adds... looks like J1772 is kinda dumb. Maybe it can be modified into an actual charger, dunno. here is a schematic http://emotorwerks.com/JuiceBox_Publ...Schematics.pdf looking like glorified ac/dc passthrough, handy if you already have a leaf.

[TurnNBurn]

Alright, got the controller programming stuff setup.

I've been studying some wiring diagrams. Question: what's the purpose of the contactor/solenoid? The alltrax 7245 comes with a fuse I plan to use and I'm going to use the key start that came with the bike (on/off switch). I see the Allbright SW200 would be the choice for my bike, as that's what most people recommend. But what is the purpose of this on the bike?

An update on the batteries, I'm looking at getting the leaf batteries in possibly a 4kw/h pack and an Elcon PFC 2500 charger.

[P-hack]

fyi, fairly cheap but useable looking diy charger:
$200 Build your own intelligent charger. - DIY Electric Car Forums

Also a lot of folks don't worry about a bms, but they will install something very simple like this so they know it is time to balance the cells manually (i.e. once a week max), it isn't perfect but it is better than nothing and very cheap (even number of cells in pack required, never a problem with leaf modules):
And pack voltage/current of course. And the consensus (in the absence of active balancing) seems to be to bottom balance when you do need to.

The contactor allows key control of the pack, the controller might suck a lot of juice when idle. Sometimes it a safety thing I guess, the controller can open the contactor in some situations, don't know what those are off the top of my head, but if it doesn't then a manual switch will do too(thinking it should be at ground level but not sure, certainly it should be of the big red easy to press button variety).

[TurnNBurn]

I'm still confused as to what the contactor is used for since it just seems like a switch. Which I already have.

[P-hack]

Convenience for one.
Your key switch probably cannot handle hundreds of amps (or many volts either). So you use the key switch low power/voltage signal plus your small 12 volt battery to power the coil on the contactor and close the circuit on the large battery pack. The Allbright SW200 has a 12v coil.

They have some wiring diagrams for the controller, you are going to have a separate 72 to 12v dc-dc converter and 12v battery for accessories? I'm just the messenger

FYI, the alltrax documents for the axe seem to be using a 72v contactor and accessory relay. It gets rid of the need for a 12v battery, but you expose your key switch to 72v, so maybe that is a reason to have an interlock.

i.e. these two mixed together, the vehicle key is in the second one
http://www.alltraxinc.com/files/Doc1...e-wire-dia.pdf
http://www.alltraxinc.com/files/Doc1...y-wire-dia.pdf

I would probably have done it differently.

[TurnNBurn]

Originally Posted by P-hack

They have some wiring diagrams for the controller, you are going to have a separate 72 to 12v dc-dc converter and 12v battery for accessories? I'm just the messenger

I'm up in the air about this. I have a bunch of small 12v lead acid batteries (nice small ones). So I was contemplating using the larger batteries just for the drive system and have everything else run on a separate 12v battery.

$0 for batteries I already have, or $80+ for a 72v to 12v DC converter? Hmm....


So what I'm gathering is the contactor is the same function as the key switch except it's built for more volts and more amps.