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Thread: 1980 Kawasaki 440 LTD 8kW conversion-Workin' toward the conclusion

  1. #1
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    1980 Kawasaki 440 LTD 8kW conversion-Workin' toward the conclusion

    When I got my El Moto out this spring, she was totally dead.

    Not just dead, "really" totally dead.

    Nothing lit up, buzzed, clicked or anything.
    ...so, I grabbed the MM

    The 48V battery pack showed 6.2V

    Then, I checked them individually
    ...battery #1 (@ the positive output connection) showed 1.5V
    ...#2 showed 3.3V
    ...#3 showed 5.4V
    ...#4 (@ the negative out put connection) showed -3.9V
    (seriously, it showed a minus)
    (negative voltage, that's a new one on me)

    So, yup
    ...I think I killed 'em

    I had the main cut-off, turned off while it was in storage for the winter
    ...but, it seems that I didn't wire the DC to DC inverter to the cut-off switch
    ...I wired it straight to the battery pack
    ...it must have been drawin' a small amount of power all winter long

    So, I'm guessin' (Naw, I'm pretty sure)
    ...that was a fatal (for the battery pack anyways) mistake

    Well, can't get shook about it
    ...grandma always said "things happen for a reason"

    * Note to self:
    Don't do that again

    Learning as I go

    Moving on, I figured maybe this is a good opportunity to up grade to Lithium.
    I have been doin' lots of research on 'em & so far, I'm likin' the Chevy Volt lithium battery packs
    A 2Kwh section is
    ...45V (nominal) so, I would only need (1)
    ...~47AH (2Kwh)
    …only weighs ~45 lbs.
    …& they seem to be plentiful in the ~$300.00 range

    According to my research, going from a 48V 35AH "Lead" battery pack to a 45V 47AH "lithium Ion" battery pack

    I should have "roughly" double the "available" power (actual usable battery capacity)
    ...at about half of the weight
    ...& it should recharge in "roughly" 1/2 of the time that the lead battery pack took

    But, I have been reluctant to "pull the trigger"
    ...because there's a lot of "Very Important Details" to them
    ...like monitoring the balance, discharge & recharge rates & even worrying about the levels (per cell) of discharge & recharge

    That's why I did all of the research & work on them "stupid" Batt-Bridge's

    Well, I did it
    I am the proud owner of a 2kWh section of a Chevrolet Volt lithium Ion battery
    ...45V 47AH ($400.00 delivered)
    ...as opposed to (~$300.00) for (4) 12V 35 AH SLA batteries

    It's only ~9 1/2" wide x 9 1/2" deep x 10 1/2" tall
    ...as opposed to the ~15" wide x 10" deep x 7" tall of the SLA batteries
    ...so, it should fit nicely on the bike

    It only weighs ~45 lbs.
    ...as opposed to the ~80 lbs. that the SLA batteries weighed
    ...so, the bike should handle better & get better "mileage"


    When I sat the battery pack on the bike, it fits in & looks great & I can't even see it while sitting on the bike
    For mounting, I used a couple pieces of 1/2" x 1'2" angle steel to mount the battery pack to the bike

    Now, for some of the stuff I did wrong.
    First, I removed the on/off switch, (for the speed controller) that I previously mounted under the seat & ran the wires up to a relay switch (under the "tank") that's controlled by the motorcycles ignition switch

    Then, I removed
    ...the "extra" battery cables, connecting the "main" power cut-off switch
    ...the cut-off switch (itself)
    …& the 500A "main" power fuse

    I'm gonna try a 150A circuit breaker, as a test
    ...as the "main" power cut-off switch
    …& as the "main" power fuse too

    It should be the "weakest link" so, if it's "incompatible", I "think" it should continuously "trip" the breaker
    ...but, (hopefully) not harm the system

    Next we needed to find a place to mount the circuit breaker, so it's easily accessible while riding
    ...& we need to mount a shunt ...somewhere, for the Amp/Volt meter (to help keep an "eye" on what's happening inside of this thing)

    As for mounting the Circuit breaker & the shunt, nothing can really be mounted "to" or "on" the battery cover because there is not much room (~1/2")
    ...& there are open terminals (cell/pouch welds)

    Then, I thought, "hey" what about...them "new" plastic drill boxes @ Harbor Freight?

    Yeah, the red ones
    ...they'll even match the bike

    Hmmmmm, that just might work
    ...probably, have to go on the sides, not much room on top

    I think these drill boxes (~2" thick x ~4" tall x ~6" wide) will work, I'ma gonna give 'em a try anyways

    I can mount the circuit breaker, in (1) box
    ...& the shunt (a part of the meter circuit) in the other

    If I mount (1) box on each side they'll look, kinda like, (mini) saddle bags

    For mounting, first, I tried a big (36") Zip Tie, that went all of the way around the battery, thru each box & back to itself
    ...it kept them on but, they still "moved around" a bit

    I don't want to just "glue them on"
    ...how about some "Industrial Velcro" (the extra heavy duty kind)

    This way, I can "glue them in place" & they'll still removable (if ever necessary)

    So, I used both
    ...the Velcro locks them in place (no movin' around)
    …& the Zip Tie is a "safety strap" (just in case)


    To hook 'er up

    The power starts @ the battery packs positive (+) terminal, so I attached a piece of 4g. cable to the battery's positive terminal via 1/4" x 4g. lug & 10mm nut
    …& connected the other end to the in "BATT" side of the circuit breaker via another 1/4" x 4g. lug & a 7/16" nut

    Then, the power comes out of the "AUX" side of the circuit breaker thru another piece of 4g. cable via 1/4" lug x 4g. lug & a 7/16" nut & then connects to the contactor with a 3/8" x 4g. lug & a 17mm nut & finally, the power comes out of the contactor via a 3/8" x 4g. lug & a 17mm nut & then connects to the B+ "bar" on the speed controller, using another 1/4" x 4g. lug & a 10mm nut-n-bolt

    Now, to complete the circuit the negative (-) connects to the speed controllers B- "bar" (1/4" x 4g. lug) thru a piece of 4g. cable
    …& then connects to the P- side of the "shunt" (3/8" x 4g. lug)(mounted in the other "saddle bag" & finally, another piece of cable connects the B- side of the shunt (3/8" x 4g.) to the negative terminal on the battery pack using a 10mm nut

    * tip on cuttin' battery cables
    ...a cut-off tool can/will slice thru it like butter without smashing/deforming the end of the cable
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  2. #2
    Senior Member Ted Dillard's Avatar
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    Just a tip for noobs. See the little icon up in the toolbar that looks like a piece of film, next to the Picture icon?

    Screen shot 2018-09-11 at 5.31.39 AM.png

    If you click that you can add your YouTube movies directly to the page, like this:

    That way, people don't have to navigate to your YouTube page to see the clips, and they can continue to read your thread where they left off. Unless, of course, you want to re-direct them to the YouTube page for clicks. Makes the forum a lot more readable (not sure if you care about that).

    As far as cutting cables goes (just caught my eye, because it's at the end), this thing cuts cables like buttah: https://amzn.to/2QjqAn7 Snip snip, no crushed wires, clean cut.


    I've used it for everything right up to 4/0.

    Also, (adding this here so as to cause minimal disturbance to "your" thread), I see you haven't posted to Endless Sphere, at least near as I can tell. https://endless-sphere.com/forums/ You ought to consider it, they're doing all sorts of interesting EVs - not just cars or motocycles. One caveat, though, you're going to get a lot of advice there, lots of very experienced people, so you'll have to toughen up a little. You'll get loads of clicks on your YouTube channel there.
    Last edited by Ted Dillard; 11 September 2018 at 0328.
    Power in Flux: The History of Electric Motorcycles

  3. #3
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    Before I put this battery pack to use, I want/need to know what's goin on "inside", so we need some kind of monitors or meters
    There are many types of monitors available but, I wanted to "try" to build a lower cost a DIY monitor/meter.

    Here is what I came up with, I call it a Tri-Quad. It costs less than $25.00 & simply uses an Amp/Volt meter (~$15.00 delivered) to monitor the power consumption & battery pack capacity (Amp: displays the amperage drawn by the motor & Voltage: displays the "total" battery pack voltage)
    …& (2) individual Volt meters (~$3.00 ea. delivered) is to monitor the balance of the battery pack (One will display the voltage reading of 1/2 of the battery pack & the other will display the voltage reading in the other 1/2)

    As long as they both show the same reading, the battery is "in balance" or "balanced"

    I kinda wanted the Amp/Volt meter on top (to show total capacity)
    …& the (2) 1/2 pack meters next to each other (to show the voltage of the left 1/2 & the right 1/2)
    ...but, they are too wide side by side so I stacked 'em up in a row

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    Last edited by Functional Artist; 11 September 2018 at 0957.

  4. #4
    Senior Member Ted Dillard's Avatar
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    Power in Flux: The History of Electric Motorcycles

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    Links have been repaired. They must have been outdated.

    Super bummed! I think, I burned out balance monitor meter #2

    I got the Tri-Quad mounted on the bike & everything connected. Then, double checked ALL connections before final hook up (plugging the BMS plug in to the battery) & everything looked good.

    So, I plugged 'er in & everything still looks good.

    Went to turn the key on to "power up" the system & turn the meters on & noticed Balance Monitor Meter #1 is kinda flickering
    (how can it do that? they should be off) Weird/NOT GOOD

    Then, I turned the key on & most everything worked, as designed
    ...the Amp/Volt meter "lit up" & displayed 45.9V
    ...the battery balance meter #1 "lit up" & displayed 22.5V
    ...but, meter #2 didn't do nuthin', nuthin', nuthin'

    I went thru everything (3) times
    ...WTF everything looks "right"

    So, (as a test) I got out (2) other Volt meters & connected them in place of the (2) meters that are in the Tri-Quad & it seems to work "as designed".

    What could of went wrong?

    While connecting the wiring harness that goes from the Tri-Quad to the battery pack, I was thinkin', the Amp/Volt meter is switched on/off thru it's 12V power wires
    ...but, the (plain) voltage meters are powered, thru the monitor wires, right from the "source"

    So, I figured we gotta add a switch, to be able to turn the meters on/off.

    Hmmm, if I added/wired a relay into the "center tap" connection
    ...by breaking that single connection, would turn both meters on/off
    (This way I could use the bikes 12V system to switch the "higher" voltage stuff on/off)

    Now, I'm thinkin' that, ...well basically, I had the (2) meters wired in series
    ...maybe with the "center tap" connection off (disconnected)
    ...instead of ~22V goin thru each meter, there was the whole "pack voltage" (~45V) goin thru them

    They should of been able to handle it
    ...the specs say DC5.0V - 120.0V (input voltage limit 132.0V)

    But, when I look at other voltage meters
    ...like this one


    I notice, there is no decimal point (like on mine)

    They are not labeled so, (maybe) did they send me "smaller" meters?
    ...how could I tell?
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    Last edited by Functional Artist; 11 September 2018 at 1051.

  6. #6
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    It looks like you're combining and condensing old posts from the DIY forum. This is progress! Keep going! Keep going! Keep combining and condensing along with editing out the not useful to the reader information. I think you can get these posts to a point that they will be a pleasure for the reader to behold. Have another adult in the household(or, maybe the kids) read through them for clarity of content. Remember, good writing is an art too!

  7. #7
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    A not to much more expensive option may be to use 2x cell logs to monitor each of your 12 cells. 6 per logger. I did a similar setup with my bike before I got a more expensive balance controller.
    Here is one: https://www.amazon.com/Tenergy-Batte...ll+meter&psc=1
    Caveat is that they typically use power and will slowly drain cells at different rates. You can get away with bulk charging for a long time but eventually your cells may drift. You can decide to bottom balance them one at a time to a specific low voltage or top balance them to a specific high voltage. A cheap way to do this is with a variable DC load, like this: https://www.amazon.com/Constant-Curr...t+current+load
    I don't know about your bike but I hope your charger cuts off at a specific voltage so as to not overcharge your pack. I charge my Volt cells to 4.15V Max so that would be 49.8V for your 48V pack. A 48V Lead acid charger might do 55V which may damage your cells/ cause a fire.

    All in all probably cheaper to just wire in a 12s balance controller to just keep the batteries all level and not worry. https://www.ebay.com/itm/12S-30A-44-...YAAOSwC19bEXJP
    It's not a great one but better then nothing. It would be used to just keep the batteries level. Then you can just use your 3$ Volt / Amp meter to tell whole pack voltage and current draw.

    Good luck.

  8. #8
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    Thank you cmcnall, those are some great suggestions & don't worry, I am definitely NOT just "hooking up" a generic charger.

    If I may, here is a little "background info"

    As I said, I have done "tons" of research on lithium batteries. I specifically chose this Chevy Volt battery because they are professionally designed & manufactured. (DIY lithium battery's "scare" me, too many variables (Ohm's, capacities, connections, construction etc.)

    The Chevy Volt cells were specifically matched to very close tolerances & the quality control was set at such a very high level (probably due to a zillion dollar contract with General Motors) that they are very stable & maintain their "balance" very well.

    During research I came across several DIY'ers (do-it-yourself) that are using this same battery pack to power go karts, golf carts, scooters, motorcycles, boats & some are even "drag racing" but, as for an "affordable/quality" BMS or a "proper" charger the results are scattered.

    The "stock" Chevrolet BMS is for the whole pack (370V) & not really "hackable" to be used on individual (45V) sections. There are some "quality" aftermarket BMS's available but, many cost (~$500.00 & up) more than the battery ($400.00) they are protecting does.

    Many folks have tried some of the "low cost" options with varying success but, I have read many stories where someone used/relied upon a BMS & it actually "killed" the battery instead of protecting it. The suspected "issues" vary from incompatibility to installation errors to component failure to even the "parasitic draw" of the BMS itself trying to maintain the "balance" of the battery.

    So, I'm trying a different approach to using lithium battery's.

    Start off with a "high quality" professionally manufactured battery pack

    Monitor pack balance using (3) digital voltage monitors (1) that monitors the entire pack & (2) others (1) monitoring each 1/2 of the pack

    Protect the battery from being "drained" too low, the speed controller is set for a 39V low voltage cut-off
    …& I will manually monitor while in use.

    To protect the battery from being overcharged I will use a lithium charger with the "top charge" preset to ~49V cut off.

    A manual BMS (I am the BMS) so to speak

    * I, personally would NOT use & do not recommend, this "manual BMS" concept on ANY other type of battery pack.

  9. #9
    Empulse R #24 frodus's Avatar
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    That is the single best written post by you since you got here (and even of all the ones on DIY Electric Car). Thanks for taking a few minutes to write it. It was clear and concise and not as hard for me to understand as other posts of yours.

    I too have had a problem finding a good middle of the road BMS that isn't over $800. I have recently begun to work with the Zeva BMS. I'm going to start selling them soon, just finishing some testing and going to put in an order for a small batch of them. They're great BMS so far and can be used for stationary or mobile applications. Maybe look into it a bit and let me know.

    (BTW, I've worked for Manzanita Micro and Elithion as a consultant, and build a BMS with some guys in Portland a while back and consulted on a couple projects involving Orion BMS, to give you a frame of reference).

    Your half-pack monitoring is the next best thing to cell-level monitoring. At least if it goes under on the half pack, you can figure out where to look. Maybe go even more granular than that, and do 1/4 pack. Whatever is the best cost benefit to you. And yes, you're the BMS, but at least you have an idea of what you're looking for.

  10. #10
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    Quote Originally Posted by frodus View Post

    That is the single best written post by you since you got here (and even of all the ones on DIY Electric Car). Thanks for taking a few minutes to write it. It was clear and concise and not as hard for me to understand as other posts of yours.
    Yes! Reading it was like getting a breath of fresh air. Or, a fresh charge on a battery bank. The information was all there and ready to go. Keep it up man.

    Speaking of keeping it up, you do not want to leave these batteries unattended over the winter like your last lead acid set. Keep checking them for phantom loads and the self-discharge rate. I recall you isolated the problem last winter to the DC to DC being left on?
    Last edited by Electro Flyers; 11 September 2018 at 2123.

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