XM-3000 LiFePO4 upgrade

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jdh2550_1
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Current Motor Company received their first inventory shipment of batteries on Friday (as opposed to the smaller R&D orders). So, I "liberated" 20 of the 40Ah cells to see how easy it would be to upgrade my XM-3000 from SLA to LiFe.

The answer is - very easy. Packaging the 20 cells in five "4-packs" they are almost a drop in replacement for the pre-existing Greensaver batteries. They're ever so slightly wider (maybe 1/4 inch or less?) - and that's with the two end plates on. So it's a snug fit - but that's no bad thing. The 4-pack is also thinner - so there's some space that could be filled with a simple spacer. The cells are taller so I will need to cut away some of the under-seat tub - haven't done that yet. The bolt size on the LiFe is bigger than on the GS so I also had to put new lugs on the cables.

I don't have the specs on me but the bike is now significantly lighter - which helps with accel. Top speed is the same - 41mph actual (46mph indicated). Range is also better (not sure what the 1C Ah rate on the GS's were - but certainly not 40Ah). I plan on adding the CuMoCo BMS to this set up. I'll report back when I do.

If CuMoCo were to sell DIY upgrade kits for 5 x SLA to 20 x 40Ah LiFe with a per-cell BMS would folks be interested in purchasing these? Cost would likely be in the $1750 to $2000 range (that's my best guess at the moment).

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Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas. No Worries." - JDH, CuMoCo || "Make Volts Not War" - anon.

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jhg
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Re: XM-3000 LiFePO4 upgrade

I'm absolutely interested--especially as my GS batteries are starting to show signs of old age. Here's what I would desire in a DIY upgrade package:

* Cost closer to $1500 if possible (can these be safely shipped at a reasonable cost?)
* Complete package, maybe including spacers, lugs and extra wire?
* Step-by-step instructions
* Photos of each step, showing battery placement, etc.
* Some sort of warranty on batteries and BMS
* Advice on how to recycle the old batts?

This sounds like an exciting project, especially if the bike will weigh less! Thanks John!

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jdh2550_1
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Re: XM-3000 LiFePO4 upgrade

Hi Joe,

* Cost closer to $1500 if possible (can these be safely shipped at a reasonable cost?)

We'll try to keep the cost competitive but I think the prices quoted above represent pretty good value for money. A key thing to remember is that most LiFePO4 BMS solutions out there right now are significantly more expensive. Watch this space as we crunch the numbers.

Another way to save a significant amount of money would be to go with 20Ah cells. This would take at least $500 off the price, maybe more. Obviously you'll have less range and different packaging options - one thing I need to do is determine the max amp draw to confirm that the 20Ah cells won't be pushed too hard in this situation.

Would anyone be interested in a 20Ah pack rather than a 40Ah pack? Or would this be too small?

* Complete package, maybe including spacers, lugs and extra wire?

Yes, I envision the pack will be complete. One of the issues I'm considering is the fact that these packs have a bigger bolt size than the GS's. This means crimping new lugs - and crimping lugs this size need a special tool. So, would we just supply the lugs or would it be better to supply replacement cables? We can provide cables for the interconnect between battery packs and the cable from the most positive battery to the circuit breaker. However, the cable from the most negative terminal goes straight to the motor. I'm going to ask the folks at CuMoCo if there's a good option for a high quality "no tool" connection we could make between the motor wire and the most negative terminal. Not sure it's worth shipping "spacers" to you - actually, we may recommend simply using the dense foam packing around the batteries as spacers. These spacers in the battery boxes aren't critical because the fit is snug. The one exception is the battery that sits on top of the bottom three. We could go with the factory approach and supply "industrial strength" double sided tape - or we might see about providing appropriate strapping. On my "quick and dirty" conversion I simply laid the battery on it's side.

* Step-by-step instructions
* Photos of each step, showing battery placement, etc.

Yup, for sure on this.

* Some sort of warranty on batteries and BMS

I'm hoping we will be able to provide a 12 month warranty. It depends on how concerned we might be with mistakes on installation causing failures.

* Advice on how to recycle the old batts?

Good point - hadn't thought of this. However, in a lot of cities it's likely as simple as putting the batteries out on the curb with your other recyclable material. Alternatively taking the batteries to any store that sells lead acid and they can likely take them from you (when buying a battery they give you a trade in value for the dead batteries - but they probably won't want to do that if you're just turning them in).

Thanks for your feedback.

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John H. Founder of Current Motor Company - opinions on this site belong to me; not to my employer
Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas. No Worries." - JDH, CuMoCo || "Make Volts Not War" - anon.

garygid
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Re: XM-3000 LiFePO4 upgrade

John,
Consider threaded inserts and then smaller bolts in the (2, 4, 6, or 8?) cell "posts" where existing smaller-hole connections are used.

Also, there might be enough metal around the hole on the existing lug to just drill out the hole?

Cheers, Gary

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Cheers, Gary
XM-5000Li, wired for cell voltage measuring and logging.

Mikie
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Re: XM-3000 LiFePO4 upgrade

I posted this in the battery section of this forum but I will place it here also....this offer on EBay is considerably cheaper than what you are talking about in the above posts....Mikie

http://cgi.ebay.com/ebaymotors/72-volts-lithium-iron-ion-battery-for-EV-electric-car_W0QQcmdZViewItemQQ_trkparmsZ65Q3a3Q7c39Q3a1...

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jdh2550_1
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Re: XM-3000 LiFePO4 upgrade

garygid wrote:

John,
Consider threaded inserts and then smaller bolts in the (2, 4, 6, or 8?) cell "posts" where existing smaller-hole connections are used.

Also, there might be enough metal around the hole on the existing lug to just drill out the hole?

Cheers, Gary

Gary - threaded inserts sounds like a good idea - thanks! Not enough material to drill out existing lugs.

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John H. Founder of Current Motor Company - opinions on this site belong to me; not to my employer
Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas. No Worries." - JDH, CuMoCo || "Make Volts Not War" - anon.

jdh2550_1
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Re: XM-3000 LiFePO4 upgrade

Mikie wrote:

I posted this in the battery section of this forum but I will place it here also....this offer on EBay is considerably cheaper than what you are talking about in the above posts....Mikie

http://cgi.ebay.com/ebaymotors/72-volts-lithium-iron-ion-battery-for-EV-electric-car_W0QQcmdZViewItemQQ_trkparmsZ65Q3a3Q7c39Q3a1Q7c240Q3a1318QQ_trksidZp4506Q2ec0Q2em245QQhashZitem3ef53f95d6QQitemZ270402557398QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessoriesQQsalenotsupported

Hi Mikie,

Thanks - I might look into buying this setup for testing and then I'll be able to compare.

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John H. Founder of Current Motor Company - opinions on this site belong to me; not to my employer
Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas. No Worries." - JDH, CuMoCo || "Make Volts Not War" - anon.

reikiman
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Re: XM-3000 LiFePO4 upgrade

A couple cents worth of observation on that pack. It's a 72b 40ah pack from Hi-Power, no BMS, but with a "balancing charger". The beginning price on the auction is $999 and there is a reserve price which hasn't been disclosed. Therefore the beginning price is not the price, the reserve price is the price. It's not fair to John's suggested price to compare it with a non-price on an ebay auction.

In questions he quoted $10,000 for a pack using 200 ah cells.

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reikiman
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Re: XM-3000 LiFePO4 upgrade

He finally disclosed the reserve price:- $2499

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Mikie
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Re: XM-3000 LiFePO4 upgrade

Wow-- nice catch man, you caught him and called him out! John is still my main man, I just need business to turn around and in a major large way before I can upgrade. Mikie

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jdh2550_1
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Re: XM-3000 LiFePO4 upgrade

Thanks David. Good luck with the saving Mikie.

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John H. Founder of Current Motor Company - opinions on this site belong to me; not to my employer
Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas. No Worries." - JDH, CuMoCo || "Make Volts Not War" - anon.

jhg
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Getting the old batteries out

Before I can upgrade, I obviously need to get the old Greensaver SLA's out. I need some tips here--I know they're stuck in with industrial double-sided tape. I tug and tug, but can't get them to budge, especially the rear-most one in the lower tray, which needs to come out first. Any hints?

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Mikie
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Re: Getting the old batteries out

Hi -- I had trouble getting mine out too, but it was a long time ago. If you can get a scissors jack to spread apart the housing some that would help you get ahold. Another way would be to take some wire and screw it into the + &- posts, making a kind of lifting loop then you would really be able to get some leverage to take it out. Good Luck....Mikie

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garygid
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Re: Getting the old batteries out

Lifting loop of wire + to - posts ... CAUTION do NOT short the battery ... DANGEROUS.

Also, pulling on the terminal posts MIGHT rip them right out of the battery top, destroying the cell, hazardous, and DANGEROUS.

Have you removed all the hardware and wires from all of the cell posts?
And, have you duct-taped (cloth type, double layer) over each post to help avoid dangerous accidental contact?

ARE these cells only held down by the tape?
Is there a solvent (again DANGEROUS) that will loosen the tape?
Maybe a little solvent, carefully used in a well-ventilated space, would be effective?

Are the cells banded into packs of maybe 3?
Or, are they individually placed?

If banded, can one "hook" onto the band on either side. On the TS 3-cell packs in the 5000Li, the compression bands have lifting "straps" (heavy string) installed, but the string-connection is a bit weak.

Does the "grip" of the tape weaken when it gets hotter?

Are the cells wedged into the battery box?
When replacing the battery, will you be able to re-use the same battery box?

Is there a drain hole at the bottom edge of the battery box?

How does the manufacturer recommend removing the cells?

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Cheers, Gary
XM-5000Li, wired for cell voltage measuring and logging.

Mikie
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Re: Getting the old batteries out

Gary--you are absolutely right sorry for being so stupid! But you can use a non conductive rope or even duct tape squished up is very strong. Spray a little WD-40 along side of the outside of the battery packs and then try the rope or tape, it will come out and you can move forward with your mod. Best....Mikie

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jhg
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Re: XM-3000 LiFePO4 upgrade

Thanks, guys, for the ideas...As you know, the battery tray is pretty tight, and doesn't have any openings in the bottom...I might be able to pry the sides open a bit, however. Another idea is to take a wire coat hanger and make a small prong on the end...if I could snake this down the sides of the battery, I might be able to get the prong underneath to help pull it up...

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Joe G. -- Commuting on XM-3000

jdh2550_1
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Re: XM-3000 LiFePO4 upgrade

The Greensavers already have handles - so no problem there. I find that rocking them from side to side as much as possible while also pulling upwards helps to break the hold that the tape has. If lifting straight up I can actually lift the bike off the center stand before the tape gives way - but by rocking it side to side and lifting up I got them out.

It is certainly a PITA!

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John H. Founder of Current Motor Company - opinions on this site belong to me; not to my employer
Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas. No Worries." - JDH, CuMoCo || "Make Volts Not War" - anon.

jhg
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Re: XM-3000 LiFePO4 upgrade

Woo Hoo, got the Greensavers out! Sprayed plenty of wd-40 down the sides between the batteries and the metal tray, and let it sit overnight...seems to have loosened the tape's grip sufficiently that I could rock the batteries out. Thanks for the advice, everyone!

Joe

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Joe G. -- Commuting on XM-3000

Mikie
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Re: XM-3000 LiFePO4 upgrade

Joe-- glad to help, and enjoy the lithium batteries I know you will be happy....Mikie

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Iccarus
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Re: XM-3000 LiFePO4 upgrade

For anti corrosion try ACF-50 that stuff is incredible. I have tried every anti corrosion formula out there and that stuff is amazing and doesn't leave a waxy residue like some of the other higher quality stuff.

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PJD
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Re: XM-3000 LiFePO4 upgrade

John,

A few things I've learned form my experience with Thundersky LiFePO4's so far. This is all, of course, "anecdotal" so take it for what it is worth.

When new, the cells have free liquid electrolyte that can be heard sloshing around when shaken. This free liquid electrolyte goes away after the first one or two charge/discharge cycles. I have since learned that this is due to a portion of the organic solvent electrolyte breaking down electrolytically during the first few charge cycles and forming a "solid electrolyte interphase" on the anodes. This interphase then prevents the remaining electrolyte from breaking down.

The above has two important implications:

1. The proper formation of this electrolyte interphase is important for good cell life and keeping the internal resistance low. This may be the purpose for the Thundersky-recommended procedure (page 31 of the manual) of initially "conditioning" each cell, by charging it at 1/3C, discharging it at 1/3C (to a minimum of 2.5 V but I'd stay higher), then recharging at 1/3C. Unfortunately, due to the confusing bad English in the manual, many people miss or mis-interpret this recommendation and think it is referring to kind of optimum procedure for regular use.

2. The cells should be mounted upright, for at least the first few charge cycles, (in my opinion, all the time) or some of the anode and cathode material may not be submerged in the electrolyte, inhibiting proper interphase formation.

My experience with my two scooter conversions so far supports conditioning the cells. The first set of cells were bought unconditioned and simply charged with my available .2C charger - then discharged (at much faster than 1/3C) during first use of the scooter with the new pack. The second set of cells were conditioned using the Thundersky procedure before I bought them. With about the same number of cycles and about 3500 to 4000 km on each pack, the unconditioned pack shows about 5% more warm-weather internal resistance, worse in cold temperatures, and I even had to replace a couple cells that started refusing to balance with the rest of the pack. The conditioned pack has been performing flawlessly.

Hope this helps with the current motor scooter project.

Paul D.

PS - Should you have any spares, what would you sell just bare cells for? Thanks.

jdh2550_1
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Re: XM-3000 LiFePO4 upgrade

Hi Paul,

Thanks for the info and the explanation! I much prefer to know the why behind the conditioning rather than the "thou must condition". :-)

We haven't decided on a price for bare cells yet - but I'll drop you a message and we can maybe figure something out.

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John H. Founder of Current Motor Company - opinions on this site belong to me; not to my employer
Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas. No Worries." - JDH, CuMoCo || "Make Volts Not War" - anon.

MikeB
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Re: XM-3000 LiFePO4 upgrade

John, do you think you'll be able to do a round of conditioning of the batteries on the bikes you are building? Getting a slow discharge doesn't seem too difficult (though it'll be annoying to leave the bike parked with the headlights on for a week once it's delivered), but the slow charge would seem to require using something other than the standard charger, which most customers won't have.

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jdh2550_1
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Re: XM-3000 LiFePO4 upgrade

Mike - yes, we will be conditioning the batteries before installing them.

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John H. Founder of Current Motor Company - opinions on this site belong to me; not to my employer
Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas. No Worries." - JDH, CuMoCo || "Make Volts Not War" - anon.

MikeB
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Re: XM-3000 LiFePO4 upgrade

jdh2550_1 wrote:

Mike - yes, we will be conditioning the batteries before installing them.

Make sure you mention that on your website.
"We run all batteries through a controlled charge/discharge/charge cycle to detect factory defects and provide initial conditioning." (or something like that)

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