BMS for the XM-3500

I also just received an XM-3500li. For a BMS, I chose the pre-built goodrum-fechter one from Rechargeable Lithium Power. I bought an additional 4 cells to add to my bike, so I went with the 24 cell version, but they also have 20 cell versions available. Because these are prismatic batteries, you want a 2.7v low voltage cutoff. And because you're using 40AH batteries, the smallest shunts (250mA) will work fine. I haven't attached mine yet (getting the panels off the bike to expose the batteries took a couple hours), but I'm planning on using computer-style 4-pin Molex connectors so that I can remove the BMS if necessary.

Also, FYI, the VIN is behind a pop-off panel, engraved in metal, under the seat. You'll probably need that to get your bill of sale.

i saw a 20cell PCM of similar design, but i cant seem to find it atm.

that type of BMS is fine for charge, and monitoring, but don't put it in the traction circuit, as it wont handle the current.
you can use it to sound a buzzer, or open a contactor if a cell goes low.

even better, you could have it signal the controller a cell is going low, so it cuts in and out, the same way a pack level low voltage cut out works.

my favourite BMS is this:
http://www.evworks.com.au/index.php?product=BMS-CM060-V6
http://www.evworks.com.au/index.php?product=BMS-MCU-TS90-EV2

it does the same thing as the PCMs, but i have found it to be far more reliable (i have way to many crispified PCm boards floating around).

Matt

this is the 100amp bms from battery space. THIS is the one you need, not the 60A smaller version.
http://www.batteryspace.com/pcmwithequilibriumfunctionfor24cells768vlifepo4batterypackat100alimited.aspx
$259
I have an extra one for $250 pre-soldered w 75A Anderson connectors
www.falconev.com/batteries ( see the difference here )
for 20 cells, just use 20 wires instead of the 24
contact me if interested

Matt, are you using the TS90 now? How was installation and performance with the system?

back when i was running Lithium i used the TS90
i found it very reliable and modular (makes increasing/decreasing cell count much easier).

installation is a bit time consuming, as each module has to be bolted to each cell, then the sense lines between modules soldered together.
you will also need to find somewhere for the master module to go.

Matt

Curious, with the 4 extra batteries, will you need to upgrade anything else?

I'm upgrading the bike to an "XM-4500". I purchased a Kelly KBL72201 (72 volts, 200 amps, 1=Regen braking), and a 4.5KW hub motor. In addition to that I'm completely redoing the dashboard with a large-display digital Cycle Analyst. I probably also need a 72 volt DC-DC converter.

Right now my moped is in pieces and the wires have been taken out so that I can trace where each one goes and what it does. I'll be posting more information them later. Right now I can tell you that all 60 volts come off the battery in an ~8 gauge red wire and go through the key ignition switch to become a yellow ~8 gauge wire that runs all the 12 volt DC systems. It also tells the motor controller to start. This yellow wire is what you need to hook the Cycle Analyst up to.

Anyway, in about a week I'll be putting together a wiring diagram of all the known wires. At the moment, however, I'm having trouble getting the plastic case off that fits around the handle bars.

Does anyone know how to take it off. Better yet, does anyone have a service manual?

Take a glance at this Topic. http://visforvoltage.org/forum/5910-skinning-xm5000li This is going to help you a lot.

Best

Curious, I made that conversion myself except I'm still using the stock hub motor and have upgraded to 28 cells. It's really nice having the variable regen braking. My cycle analyst confirms 7% average range gain and up to 14% in city driving. I used a wuxing thumb throttle mounted to the left rear veiw mirror post. You mount it so it is like a trigger right in front of the left brake handle. so you wind up with three fingers on the brake lever and your index finger on the brake "trigger" the more you pull the more brake you get, it's very natural. I tried using the throttle and other combinations and I think this works best. I would like to hear others experiences. I'll try to find my old post with the picture and post it.

Iccarus - your post was my inspiration. I also ordered a thumb throttle for the variable regen and am going to mount it on the left-hand mirror stem. Since I'm changing out the hub motor I discovered the axle nuts are 26 or 27mm. I bought a 1-inch socket at first and that was too small. The 27mm socket that I exchanged it for will work just fine, but there is a little play in it, so probably 26mm would work. I wish I had a caliper!

Back to the original topic, I just installed the extra four batteries and I'm using ring terminal connectors to attach the BMS sense wires to the batteries. I still need to solder the wires to the board. Pictures tonight. The ring terminals can be picked up from Home Depot and you can buy one of those wire strippers/crimpers for $4 which makes the cable making process a breeze. Yes, you will need to undo some terminal bolts from the batteries, but It put my mind at ease to know that I re-tightened each connection myself. This way I also don't have to worry about soldering wires directly to the battery interconnects.

I also picked up some spiral loom for cable management and some numbered wire label stickers. There's plenty of space under the seat, just forward of the storage area where the batteries fit easily, standing upright.

I've chosen the space directly under the storage compartment as the mounting place for the 24-cell BMS. With a 20-cell you would have more mounting options, but the 24-cell just barely fits between the bike's frame. But even with the 20-cell I believe this location is still the best. You should be able to open up the hatch with the three screws in the bottom of the storage area if you want to view the diagnostic LEDs on the BMS.

I'm interested in any problems with the mounting of the motor. I have one too I just haven't mounted it yet. I figured I'd see if I burned up the stock one first. You'll have a nice machine when your done. Have fun with your project, be careful, take your time. BTW, I just wrapped electrical tape around the mirror post till it was the right diameter for the throttle, kind of primative but it worked and was easy. Then just put a little a little Goop in the boot and slide it over the tape. Goop is a good flexible adhiesive. Then just thighten the throttle onto the boot. A dab of goop will hold it in place if it tends to move on you. Enjoy your ride.

Bill