XM 3500 (continued)

Hey Guys- Here is the latest news from Seattle:

I talked to my new scooter guy today and we are ordering a new controller that will go anywhere from 48V to 220V programmable and a new DC/DC converter that will be good up to 120Volts. I suppose a new circuit breaker will be in order too. He is going to charge me $1300 for all of that equipment, including installation and testing, and the only question now is how the motor will handle all of this? We will start out with the 24cell mod and then run it for a month or so. I hope to get up to a 28 cells and run somewhere between 90V and 105V. That should be some good power. He also checked up on a 6000watt brushless hub motor for me at 72Volts, in case I do blow the 3500watt stock hub motor. The 6000watt is on a 10" rim but that can be changed to. The other question I have then would be a charger for 28 cells but I think elite can help me with that....

I also want to check into at least upgrading the rear braking system, buying all new components for the rear brake especially if I am going to increase the speed to 50-55mph. My intention is to get a scooter that will be reliable and safe and can go at least +40 miles in distance, (I weigh 230lbs and so the most I can get now is 30miles) I also really believe in what we are doing and I may not know all the technical stuff but I am will to be the guinea pig for progress. I cannot tell you how much fun it is to ride this baby and know in my heart that I am helping in some small way to be the change that I want to happen....

All of this new mod action will be happening in next week or two and I will keep you all abreast of the progress. Best to you all....Mikie

when you start heading beyond 72v, you can start buying car sized chargers such as zivans.
28cells will get you 84v under 1C load.

Matt

Hey Matt-- thanks for the great info on Zivan, with 28 cells I would get about 90volts average and max out at maybe 105volts at full charge---these are my uneducated figures, are they about right?

I did some research with my non-electro-educated mind and it looks like the NG1 72-120volt is the ticket & here is the link where I found the best price:

http://www.electricmotorsport.com/store/ems_ev_parts_chargers_zivan.php

I can have them(or I will)program it for the Lithium Batteries which is great. By the way I am not sure what you meant by 1C so I did some research and now I understand but in the surfing I found some controversy, please read the basic info below and then go to the link that comes after where the mystery resides:

Lithium-ion typically discharges to 3.0V/cell. The spinel and coke versions can be discharged to 2.5V/cell to gain a few extra percentage points. Since the equipment manufacturers do not specify the battery type, most equipment is designed for a 3-volt cut-off.A discharge below 2.5V/cell may put the battery's protection circuit to sleep, preventing a recharge with a regular charger. These batteries can be restored with the Boost program available on the Cadex C7000 Series battery analyzers.
Manufacturers rate the lithium-ion battery at an 80% depth of discharge. Repeated full (100%) discharges would lower the specified cycle count. It is therefore recommended to charge lithium-ion more often rather than letting it discharge down too low. Periodic full discharges are not needed because lithium-ion is not affected by memory.

Now the controversy, what do you think this guy is up to?

http://www.buysellcommunity.com/sale/WOXNVZAA/

He seems serious about the occasional major damage to batteries with this brand of charger....Best Mikie

ps I suppose another thread for this subject might be good here but I do not know how to do that, sorry still learning....M

when they refer to 3v cut off, they mean for Lithium cobalt cells.

the cells we are dealing with here LiFePO4, a very different bread of lithium cell.

2.5vpc is the cut off.

at 90% SOC (ie almost fully charged) a 1C load (or 40A for a 40AH cell) will result in 3vpc for a TS cell.

so 40A from your 28 cell pack you will see 84v.

Matt

as far as the zivan cooking your batteries, if you have a BMS, the BMS should prevent this.

just make sure no one cell goes over 4.2v, and under 2.5v

Matt

It is not a good idea to upgrade 28cell with nowaday XM3500li,the motor will overheated.

Pls wait for our 2nd generation motor with 1/3 thickness copper winding and bigger capacity next month.

Mountain Chen-- thank you for contacting me/us about your upcoming motor, I would like to order one as soon as possible, direct from the factory or you. I am wondering about what the electrical values will be for this new brushless hub motor? How many volts, amps and what the wattage will be? Also will it still be on a 13" rim size that is 130X60x13? Thank you again for letting us know what you are doing and all of the details. Mikie

No problem,new motor is the same size,but thicker inner winding,bear 80V and 100A current !

Definitely keep us informed about that, Mountain. I'm highly interested in hearing how your expreimenting comes out as well, Mikie. I'm not satisfied with the 39 mph top I'm I'm getting on my XM-3500Li, and if it makes a big enough difference replacing that hub motor with a controller/DC/DC converter/battery set-up that can give me a significant boost could very much be worth digging into.

Hey Lenny-- it is interesting how we guys think the same in solving some of these problems, I too(I believe I heard it somewhere here also) put the breaker down underneath the seat compartment with access from the screwed on plastic door and for the same reasons.

I called the scooter shop today and they now have the new controller and DC/DC converter in the shop--- the tech will call me when his work schedule clears up early next week. I am looking forward to getting it in there.

Here is the #1 plan, install all the new equipment and then hook up the extra 4 cells, giving me 24cells & about 80volts. Run that while I order the next 6 batteries and wait for them to come in. While I run the 24 cells I will get one of those infrared thermometers and keep a close eye on the temperature, as well as speed and power going up a nearby steep hill. Does anybody want to give me a guesstimate about what range of external hub temperature would be in the yellow zone? & then the red zone? Sparky, can you measure your mod at 80volts and give me any numbers? (I know you are busy busy but....)

Plan #2 install the other 6 cells and then purchase a zivan charger (and during charging make sure I closely monitor the voltages of the 30 cells). Now I must Very Very closely monitor the external hub temperature, I should have some good stats from the 24 cell mod to fall back & to compare to the 2 different modifications and consequently what kind of heat production I will get.

Plan #3 install Mt Chens new 80volt 100amp hub motor which should easily handle the 88v-96volts I will be getting from the 30celll pack. At this point I will STOP with the modifications for both power and speed. This scooter is just not built to go faster than 55mph and be safe, actually I feel that 50mph should be the top end for safety.

The GreenBMS will be inserted in any of the above steps because the BMS will make, not only worry free charging, but the most efficient use of the 24-30 cell pack. Go Sparky.

Take care guys it is nice to know you are interested and willing to give support....Mikie

Hey Guys, well the above sure looks like a fire sale to me, making room for the spring 2009(XM5000) models. Here is the latest and I know this has all been words but this major mod is really happening just slow cooking like any good soup. Yesterday I ordered a 6kw 72V brushless hub motor 13" rim with tire and disc brake + shipping= $708 from Steve at Kelly Controllers. Thanks John for the great referral.

http://www.kellycontroller.com/

I feel that this motor will be the best solution to get the 52+mph and distance for my needs. Once I get the new motor(2 weeks) then off we go to the scooter shop for the complete mod. Final price should be about $2000. I also have decided to put the extra 6 batteries under the seat. The under seat storage is pretty useless and now that I have the good sized Givi I will use Givi for all my storage needs. So I will cut out the bottom of the storage bucket under the seat and some of the sides. That will give me a real under the hood kind of situation for the 6 batteries(30cells) and for the Green BMS I/WE are getting for Xmas. Just pop up the seat and all the goodies will be right there accessible! Take care....Mikie

So, you're going with 30 cells? Eek! :jawdrop:

That should definitely get you over 52 mph - it should get you over 60mph

Our "XM-4500" using a 4.5kW motor and 24 cells gets a solid 53mph.

John-- that is good information, my stats were just uneducated guesses. You have given me food for thought. Maybe I will start with the
24 cells I already have. Play around with that and see what happens with the 6kw. I can always add more. Also one day I will come across a much more solid frame and suspension than the XM3500 has and then I can move over all of these components and then feel more comfortable
with 55-60mph. Thanks again John you always seem to give this forum some good juju. Mikie

Lenny-what's up?

I'm keeping up, just watching this all with interest (including John's "XM-4500" mod over in my thread if you want more details on what he's put together.) The one thing that got me was John was saying something over there about a 20 mile range or so. Which makes me wonder what method might be used to tradeoff some of your top-end speed with that many batteries for a little extra range. I think I would need a comfortable 30mph on the range, but 50-55mph on the top end would be plenty, overall. I'm sure the answer can be found on the DIY forums, but those guys talk 6 miles over my head on most of this stuff.

I'm also interested in the width of your motor, since John mentioned having to bend out the frame a little for his.

Also I was wondering, if you're going to cut out the botton of the seat, why not just take out that piece completely? Although looking at it again I suppose the lip of that part does make a bit of a "seal" for where the seat meets the bike... still, you could look at yanking it and seeing what effect that has if it saves you some modification time. Plus later if you wanted to have that underseat storage and we got a better battery technology that was smaller you'd still have it all there. Not that I would rely on that, mind you.

John was saying something over there about a 20 mile range or so.

If at 53 mph we're drawing 100A and we have a 40Ah battery. Then, assuming an 80% DOD we have 0.8 * 40Ah = 32Ah available to us. Drawing 100A would give us a theoretical max run time of 32/100 = 0.32 hours. 0.32 hours * 53mph = 17 miles. Now, drawing 100A from a 40Ah battery is a 2.5C rate - at that rate the battery will likely provide less than 32Ah. OTOH, some folks will run their batteries closer to 90% DOD. So, let's say 17 miles plus or minus 10%. Now bear in mind that I don't know anyone who would jump on the bike and ride at Vmax until the batteries were drained. You'll have various speeds - most of them below Vmax. That's why I said "about 20 miles".

As clear as mud, right?

Which makes me wonder what method might be used to tradeoff some of your top-end speed with that many batteries for a little extra range.

Not easily. To get more range you need more amp-hours. To get more amp-hours you need bigger batteries or to add more batteries in parallel to your existing pack. By adding more cells in series you get more speed (and speed is fun, but it costs you less range). If you want more range either (a) sell the TS40LFPs and buy TS60LFPs or (b) add a string of 20 TS20LFPs in parallel with your 40LFPs.

I'm also interested in the width of your motor, since John mentioned having to bend out the frame a little for his.

We didn't have to bend it much - but that's hardly a resounding endorsement of the affect we made to structural integrity. IMO, I'm fine with it - but I can't in good conscience say "you won't have a problem" - I just don't know.

why not just take out that piece completely?

That's what we did - but we're not going for aesthetics (it's just our test mule). If I get a chance I'll take some photos and post them here.

Hey John and Lenny- yes I would keep the outside of the under seat storage box for sealing and looks. John great information. The "new" XM5000's coming have 60 amp hour batteries. If I have 20 batteries in series (like a stock XM3500) and I want to go parallel [to get a larger gas tank for more distance] do I have to put all 20 in parallel or can I just do a few or half(10cells)? Best M

All twenty. The parallel packs must have the same overall voltage (otherwise bad things will happen).

in my experience,
TS batteries aren't good for any more than 1.2C continuous.
at 100A, my cells sag to 2.7vpc, and by the time ive pulled 20AH, they sag to 2.5vpc.

If operating at 100A continuous, sag is likely to be greater.
If you are drawing 100A continuous, lfp90s are probably a better fit.

Matt

Does anyone know what the real operating temperature range is for the batteries? (i.e At what temperature will the range be significantly reduced?) I am currently getting approximate 30 miles per charge. At what temperature would I get less than 20 miles per charge?

Also, I read (somewhere) that the batteries should be stored at 40% capacity. Does that mean 2.94 volts?