here is some info on 20v yardworks lithium ion

[strbmx]

I just did the 80V 6ah test on a 5304 with a 20ah 72V Controller.

I pulled 69.79KM/H Top Speed.

10KM Ride

7km in to the ride @ 80% Full Throttle, the Controller shut down, After a 2 minute wait, the controller turned back on and only worked for a few seconds, I turned it into a 60V pack and and then a 40V pack and the same thing still happend.

I just ordered a SUCTEAM 72V 28A Controller, will do the LVC Mod and see how it works.

I will keep you guys posted.

 

[Anonymous]

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[mikereidis]

let's get Mikey, he'll try it. He likes it, hey Mikey"

Sitting here watching my cheap ass charger actually appear to function, extinguisher and phone at ready, gas cans removed from garage.

Two 1N5404 3a, 400v diodes in parallel (yeah I know ) for half-wave, heater, fan to cool it all, and thats about it except meters and wires and a plug. No capacitor. I decided BMS logic probably uses battery itself so half wave would be cool, at half the full wave amperage, on average every 1/60th of a second.

I ran around the blocks a few times to deplete my 2s. Open circuit voltage was 34.68, started charging at 4 amps, now after 47 minutes it's at 41.0 volts and 3.59 amps.

It worked ! After 65 minutes I shut it down as one batt was showing 20.87v. But after 6 minutes rest, they were 20.37v and 20.36v, and after 16 minutes 20.34 and 20.33. Pretty close in balance, but not really finished with CC mode yet. I'd have thought they would take 98 minutes, not 65, in half-wave.

So now they're on the YW chargers topping up; will see how long to top.

EDIT: Took another 1.5 hours on official YW charger. That seems about right: 65 minutes on CA (Cheap Ass) charger was equivalent to first 2 hours on YW charger. Two amps nominal versus 3.8 amps nominal should be a 1.9 ratio equivalent to about 120:63; off by 2 minutes. So this was a 0.63c charge. I think my battery voltage measuring was off because of the large AC component there; DC range probably doesn't do RMS. Manual solution is to switch CA charger off for a few seconds to get accurate battery voltage.

Wonderful ! Time to buy a pair of beefy full wave bridges and a pair of basic utility heaters, on separate 15 amp circuits and add switches on negative battery bus too. I think this could charge a pair of 4s's in 1.5 hours with one 4 pin connection, instead of my current 10.5 hours with way to many connections/disconnections.

Oh yeah, time to get 2 more YW batts to upgrade my 2s aux to full 4s status. Symmetry you know... And range, with the unexpected 33% decrease in range with an extra 105 pounds on trailer.

Think I'll ditch the battery bag. Interferes too easily with under seat steering and wheel if seat set low like I like. I think I can make 8 bats fit better than 6 in the bag when semi-loose and "duct tape" moldable.

EDIT: nice biking weather expected next few days. Taking daughter on ebike trailer to daycare, and son and I will ebike to Ottawa for more bike stuff. Time to check online inventory of YW batteries for my next 2.

 

[pwbset]

I just did the 80V 6ah test on a 5304 with a 20ah 72V Controller. 7km in to the ride @ 80% Full Throttle, the Controller shut down

Was that a Clyte controller by chance? I'm running 87v hot off the charger and have soldered the shunt of my Clyte 72v20a pedal first controller for 30-40 amps and I'm noticing some really odd behavior now like it's sending bad voltages to my CA (100+v) and the text of the CA fades above 90v. For the first time also the controller is noticeably warm to the touch after a high power ride. Wondering if this controller is have difficulty at higher power ratings despite it's 100v caps/fets. The subsystems/boards/traces etc. likely aren't designed to handle these multi kW power levels. Duh. :lol:

Wish someone (ANYONE) would make a pedal first controller higher than 20 amps.

 

[strbmx]

Yes its a Clyte. I am getting a new one this week. I will only be running 60V from now on...

How have people found the 60V 12ah Setup with Yardworks?

 

[mikereidis]

Yes its a Clyte. I am getting a new one this week. I will only be running 60V from now on...

How have people found the 60V 12ah Setup with Yardworks?

Hmmm. Mines a CLyte, 72v, 20a, PF, and 4s no problem so far, BUT I really don't push the 4s for more than a few seconds at a time. Even up 10% incline I've only gone 20 KMH for maybe 1 minute or so, although I have power to go up to 32 KMH / 20 MPH (1150 watts). I've tested this for 10 seconds or so, and yes 30+ KMH up 8-10% incline is easy to achieve.

Seems the 2 busted controllers here pop from heat, IMO, not from voltage itself. If it was just voltage, pop would happen at start with fresh batteries. I'm hoping to get a cheap backup controller soon. When I do, I will try really pushing 4s up the Gatineaus, while my ebikes warranty is still good. That said, perhaps I should wait until ebikes has these controllers in stock again, if they ever do. After Olympics ?


AFAICS, only 3 of us here running these batts. (?) Nuts And Volts (3s2p), yourself, and myself (4s + 2s). If anyone else, please delurk/speak up and share your experiences.

I drained all 6 batteries yesterday with the kids on a trailer again. About 25% at 350 pounds, and 75% at 330 (sans daughter left at daycare while son and I went to Ottawa for bike stuff at Bushtakah). When my 4s died just over half-way I knew I would have to slow down and do a bunch of pedaling. I did and batts finally died a few KM from home. Need. More. Batts.

At least bike can't tell the difference between electrons from YW vs. "Dangerous Cheap Ass Charger" (DCAC).

For whatever reason, batt 1 was showing 18.80v, while 2-4 were showing around 16.7 - 17.3v. Hmmm, I still suspect the battery that came with trimmer is better than other 5 batts. Since trimmer was first product, perhaps this was the first higher quality run to get QA approval from CTire.

Charged 2s from YW in 3.5 hours (One YW was 1.81 amps, other was 1.83, a bit lower than spec of 2a). Charged 4s from DCAC in 2 hours from full discharge to 21.11v indicated on top battery (Maybe about 20.99v real?). From 20.95 or so indicated voltage increased pretty fast. Yes, this is the point to switch from CC to CV, but I pushed it a bit because as soon as DCAC disconnected voltage would drop about 0.12v (was 0.20v earlier), and the batts wouldn't be fully charged and would have to top up on YW.

Same thing, more or less happens with YW. Pull the batt as soon as charger goes green, let them rest for a few minutes, put back on YW and LED would be red again for a while.

I think these batts have overcharge protection, because at 21.11v indicated, battery suddenly dropped to about 7v, so I disconnected DCAC. After 20 minutes or so, batteries had dropped about 0.2v from their post DCAC open circuit voltages. At this point the battery voltages were reasonably matched; all about 20.6 - 20.7v. I put them on YW to top and all topped to green in about 30 minutes.


Been pondering a "production quality" DCAC (for me, not manufacture.) Thought about 240vac connection and $75 CTire 240v, 20a heater for 4s2p or even 8s charging. (Maybe later for heavy, home charger.) Thought about dual 120v chargers on separate circuits to do two 4s packs at once.

For now, have settled on idea for a single 120v, 4s DCAC. If I get a small, light heater, I can mount DCAC, a 120vac plug, and 120vac outlet on bike, and carry heater when needed and when my runs include access to 120v outlet. I could have lunch or shop, or let the kids play at the park for an hour or so, and refill one 2s pack or about 40% of a 4s pack. With properly polarized plugs, and strategically placed 120v contacts on handle bars, I won't even need to lock the bike.

Outlet will allow me to test various heaters, or other high amp loads, like powerful lights. Heat in garage (and even on bike) will be nice when it gets colder, but might be nice to use amps for something useful, rather than wasting as heat when warmer out.

Light switches, plug, outlet, heater; bike will look more like a mobile appliance than transportation. I think I may go back to 1s-4s switchable, for charging convenience when each battery gets 21v full. If battery 1 stays better, I could use 1s on that batt to get home. Might go with non-light switch toggles for DPDT instead of SPDT with 3 way light switches.

Forget solar cells. An outlet, an outlet, my kingdom for an outdoor outlet.

 

[Anonymous]

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[Anonymous]

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[wasp]

 

[mikereidis]

I did a 27 KM commute to work test tonight. Top speed: 52 KMH on flat, probably higher. Bike paths are fine for touristy stuff, but the smooth commuter streets gave me the confidence to run 30-40 KMH, with several runs to 50 KMH (30 MPH) chasing cars and motorcycles...

The 4s pack gave me 39 KM before cutting out at full throttle up a 3-4% incline.. Later it gave me another 1 KM at light throttle downhill. About 5-6 runs to 50, 30-40 KMH about 70% of way, and 20% 20-30 and 10% 15-20 on dark paths. It helped that this wasn't a complete round trip, and there were still long, 3% or so inclines to climb to return home. My 2s ran at or close to full throttle for remaining 13 KM uphill generally, and batts were showing about 19.0v open circuit each on return home.

I'm sure it helped that I had used lower current and manual higher current pulsing with the DCAC on the 4s to top up the batts. I got the top batt to 21.00v pretty steady, but dropped to 20.99v later... Rest were at or above 20.93.

Unless my DCAC blows up my batts, I'm ebiking to work Friday... Wait till people see what I'm hauling up on the elevator... And how fast can I get it going down a 50 foot hallway before desperately braking...

Will take CSA approved chargers to work. I have the range to return home, but I want some extra for fun/insurance. Can't go STRAIGHT home after work now...

 

[mikereidis]

Special $99.99 deal on these batts may be available until CTire corrects their price database. (I presume it's a central database.)

Bought two more batteries for 4s x 2. Price scanned as old price: $129.99, even though I bought there before for $109.99. I invoked the "Scanning code of practice" and asked the perplexed cash guy for the maximum $10 off of each battery. He gave me the first battery, as per the code. If I had only bought 1 battery at a time, I imagine I could get $10 off each battery.

Also got one $9, 600v, 40a, full-wave bridge rectifier for DCACv1. Wonder if the batts will charge at 30a / 5c in 15 minutes ? Also got a $25 ceramic heater I plan to mount on bike (for longer runs with access to 120vac) and plug into standard 120vac outlet on bike. DCACv1 will be on bike; just the big-ass "rectal-fire", some switches, a plug, an outlet and some wires, without heater. This should help solve my connector issues; IE all the hassle of connecting/disconnecting chargers.

New 1s-4s times 2 bank switch system, and some DMMs will help me to charge, top-up and discharge for test or by bike by just throwing switches. At the end of a run I can just throw switches and hit throttle as needed to try and equalize the open circuit voltages on each battery. While charging I can also equalize voltage/charge with switch throws.

2 outlets will be for heater, and another heater or any other appropriate load. Eg. I have a small "hotplate" two burner stove with one dual element I'm using now to modify charging current. Switches will also allow each load to be series or parallel connected. System will work for discharge testing as well as charging. Hmmm, bike seat warmer, hot meals/drinks AND charging will taking e-bike breaks. Will be good in colder weather.

Battery system will become modular with 2 batts (bank A and B) for each "module". Module will include 2 switches, (1) a 21v or 0v bypass switch, and (2) an A/B bank switch. Module will have 2 wires (or 3 if I ever do full time voltage monitoring for each module.) I could run with a single module giving 1s x 2 for low weight when I'm only going a short distance. Can add modules until 4s x 2. Could also use modules on another bike, or remove a batt from a removed module if I ever decide to trim the grass again.

I THINK I'm getting at least about 110 WH (maybe full 6ah almost?) from these batteries at high current rates now, where I used to get only 100 WH from my best battery. Part or all of this is due to my topping up the batteries to 21.00v or near. (Saw a batt today at 21.24v ! but dropped under 21v when I stopped the DCAC.) It's possible these batts also work better after a few cycles. I read something at an RC site about this helping with LiMn. Looking at the figures and graphs I saw though, I'm not sure it really helped much, if at all.

Also got various diodes and a $20 DMM with a backlight, for voltage readings at night. Fun to be doing hands-on electric/electronic stuff again...

 

[wasp]

Special $99.99 deal on these batts may be available until CTire corrects their price database. (I presume it's a central database.)

Bought two more batteries for 4s x 2. Price scanned as old price: $129.99, even though I bought there before for $109.99. I invoked the "Scanning code of practice" and asked the perplexed cash guy for the maximum $10 off of each battery. He gave me the first battery, as per the code. If I had only bought 1 battery at a time, I imagine I could get $10 off each battery.

Also got one $9, 600v, 40a, full-wave bridge rectifier for DCACv1. Wonder if the batts will charge at 30a / 5c in 15 minutes ? Also got a $25 ceramic heater I plan to mount on bike (for longer runs with access to 120vac) and plug into standard 120vac outlet on bike. DCACv1 will be on bike; just the big-ass "rectal-fire", some switches, a plug, an outlet and some wires, without heater. This should help solve my connector issues; IE all the hassle of connecting/disconnecting chargers.

New 1s-4s times 2 bank switch system, and some DMMs will help me to charge, top-up and discharge for test or by bike by just throwing switches. At the end of a run I can just throw switches and hit throttle as needed to try and equalize the open circuit voltages on each battery. While charging I can also equalize voltage/charge with switch throws.

2 outlets will be for heater, and another heater or any other appropriate load. Eg. I have a small "hotplate" two burner stove with one dual element I'm using now to modify charging current. Switches will also allow each load to be series or parallel connected. System will work for discharge testing as well as charging. Hmmm, bike seat warmer, hot meals/drinks AND charging will taking e-bike breaks. Will be good in colder weather.

Battery system will become modular with 2 batts (bank A and B) for each "module". Module will include 2 switches, (1) a 21v or 0v bypass switch, and (2) an A/B bank switch. Module will have 2 wires (or 3 if I ever do full time voltage monitoring for each module.) I could run with a single module giving 1s x 2 for low weight when I'm only going a short distance. Can add modules until 4s x 2. Could also use modules on another bike, or remove a batt from a removed module if I ever decide to trim the grass again.

I THINK I'm getting at least about 110 WH (maybe full 6ah almost?) from these batteries at high current rates now, where I used to get only 100 WH from my best battery. Part or all of this is due to my topping up the batteries to 21.00v or near. (Saw a batt today at 21.24v ! but dropped under 21v when I stopped the DCAC.) It's possible these batts also work better after a few cycles. I read something at an RC site about this helping with LiMn. Looking at the figures and graphs I saw though, I'm not sure it really helped much, if at all.

Also got various diodes and a $20 DMM with a backlight, for voltage readings at night. Fun to be doing hands-on electric/electronic stuff again...

nice i'll be curious to see how fast you can charge these yw bats they should be good for 2c charging,even if you fry one during testing
they have a great return policy...i never new about the scanning thing...and my ex worked there for more than 10 years, were did you come by this?
or is it universal?
loving all the info from your posts...thx
peace wasp

 

[mikereidis]

nice i'll be curious to see how fast you can charge these yw bats they should be good for 2c charging,even if you fry one during testing
they have a great return policy...

i never new about the scanning thing...and my ex worked there for more than 10 years, were did you come by this?
or is it universal?
loving all the info from your posts...thx
peace wasp

Scanning code of practice is a standard policy that many big, reputable retailers have. Don't recall if it's Canadian or NorthAmerican or what. Idea is to help protect us from unscrupulous retailers that leave out 1/2 price signs and ring up full price and many people don't notice. Every 2nd or 3rd trip to IGA and many grocers years ago I would catch a scanning "error".

Look for signs around the cash register, at any big chain retailer or grocers especially. At this CTire, the sign/paper was prominently displayed right on the sorting surface. Sometimes it's on a pole or the register itself.

Yeah, I'd bet the cells inside the batts are good for 10c, with some loss of life, like maybe 10-50% when always charged at that rate as a WAG. There's a chart I saw somewhere indicating number of cycles for different C rates of both charge and discharge. I think I recall something like 50% loss as the max cycles lost shown.

The batts can be discharged at over 5c, so why couldn't they be charged at that rate also ? CTire just keeps charge rate low to lower problems and especially to keep charger cheap at $30. BTW it's what is called a switching charger, it appears to me, which is much like a switching power supply hooked to a CC (Constant Current) mode, and I think a "lazy" (low cost, low rate)
CV (Constant voltage more or less) mode. I was checking out the chips and main components, and taking higher res photos, when I decided there was probably little useful information to glean from the charger other than what you could get with a voltmeter and ampmeter, and that info doesn't really help when trying to build a high amp charger.

I'd also bet there is some BMS limit on the charge rate, but I haven't hit it yet at 4 amps, only 0.66c.

120v-2v-21v = 97v

97v / 6.86 ohms (1500w parallel 600w) = 14.15a = 2.36c

I think that's worth a shot with one of the new batteries; I guess the $109.99 one.

I got 2 CTire/Airworks heaters. One's a normal $20 with 2 speeds: 230 ohms fan, 15 ohms low power, 9 ohms high power. No thermostat.

The other is a $25 Ceramic. Resistance is pretty high, but I imagine it drops a lot when warming, perhaps giving it a slow start, but the resistance may change a lot depending on Ss and other load. I read that ceramic is actually supposed to be self regulating and resistance goes up when hotter, but perhaps there are different curves for room temp and when the thing gets really hot. They both feel like they weigh about the same, for carrying on bike.

On with the DCACv1 production model, with full wave rectification and bigger amps, integrated into the bike.

But first, I think I'll go drain the batts with a run to the Gatineau Hills. Cheers...

Hey nuts&v, are you ready for a race over the Gatineau's ? I figure you'll one up me with 3s3p at least, after you scoop up as many $99.99 specials as you can.

And yes I know the reckoning, may even have heard/read the mogambo guru, and there are many who deem certain crazy ideas worthy of an acronym. Dangerous $40 high amp chargers, all parts available at CTire except rectifire, for thrill seeking e-bikers would be worthy IMO. (I'll repent if somebody gets a Darwin.)

I wonder how many of these batts you could series for one of CTires e-bikes that were on sale for $350 or $450 for brushless folding, before making a warranty claim ? Been watching them to go on sale again for a possible second e-bike. Gee, everything at CTire except the diodes, and those could probably be scavenged from something there in a pinch. Like something with a switching 120vac PS, but beefier than the YW chargers main bridge, which only has to handle 0.75 amp or so. More like a computer PS.

 

[karma]

has anyone found the casing hot under heavy load? just wondering im working on my battery case, and i was thinking on adding a heatsink on the outside of the case and bolting it to the bms.

i dont have them yet i get paid friday :x

 

[Anonymous]

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[karma]

good saves me some work :wink:

cheers

 

[mikereidis]

They don't get hot but they get warm. I have them wrapped in duct tape, covered with cardboard (for cushion) then polypropylene tarp material (to keep rain out), all inside nylon pannier type bags, and no problems with heat.

Yep, the internal resistance of the batts is low enough that they warm up very little. Charging at 2a / 0.33c is nothing. Discharge at up to BMS limit of 31a is probably OK, but the lower the better. Perhaps they even have temp protection inside.

I checked with my infrared temp meter and never saw a case temp over about 83F, with ambient in the 70s.


Charger:
There is now a fully functional 120vac power cord on the back of my bike. I'm prepared for extension cord length jokes (Actually it could work at 30-35 MPH continuous, with a superlong and carbon nano-tube light extension cord. Maybe I'll try with a short cord for fun with a discharged battery. )

Downside is bike is less stealth now, and NCC might grab me.

Batteries charged at average of 9 amps, full wave rectified or 1.5c no problem. I ran them at 12a or 2c for 5 minutes with a run to 13.5a for a few seconds. It works but my pseudo constant voltage phase is a pain to do manually, switching loads around. Will have to automate. In theory a 21.0v zener that can handle 6a (126w) would do it simply, but if such a zener existed, it would be very expensive. I'll look at PCM like solutions. Wonder if a standard light dimmer (5a = 600w ?) would work for an infinitely variable pseudo-load ?

With full wave and the heaters on the AC side, the fans now work, which is good for getting rid of the heat, and helping to draw a little air across the bridge rectifier. Bridge got hotter than I expected with no air and no heatsink. I pointed my CanFan at it and duct-taped it (! ) to a computer power supply case and it stayed pretty cool. Need good heatsink and maybe fan for charging I think.

Will probably never be CSA or UL certifiable, but will ground bike frame, to 120vac ground only (Not batt's or anything else.) Should remove some of the danger, and more with a GFCI.

Did a "tourist run" early this AM with 2s x 2. Bike feels MUCH lighter with 7 pounds / 2 batts removed. Might be worth it to run battery light for short runs. Having switches mounted on 2 batt "modules" with only 2 wires from each module, and chucking battery bag, make this viable. Will wire and mount my other 4 batts today. Duct tape and super bungees are much better than battery bag. Flexibility of placement is letting me put seat all the way down again, with better clearance for under seat steering bars that MUST go under seat to take many curves decently.

Re-calibrated bike computer for bigger ebike tire size. Was 1460 mm per rev, now 1539, so my previous range and speed calcs were low by 5%. I got 25 KM last night on a single pair of batteries, including the nasty hills I have to climb to get back from Ottawa River level to Pink and Klock Road level. Speeds were usually 20 KMH or less, except downhill.

 

[wasp]

They don't get hot but they get warm. I have them wrapped in duct tape, covered with cardboard (for cushion) then polypropylene tarp material (to keep rain out), all inside nylon pannier type bags, and no problems with heat.

Yep, the internal resistance of the batts is low enough that they warm up very little. Charging at 2a / 0.33c is nothing. Discharge at up to BMS limit of 31a is probably OK, but the lower the better. Perhaps they even have temp protection inside.

I checked with my infrared temp meter and never saw a case temp over about 83F, with ambient in the 70s.


Charger:
There is now a fully functional 120vac power cord on the back of my bike. I'm prepared for extension cord length jokes (Actually it could work at 30-35 MPH continuous, with a superlong and carbon nano-tube light extension cord. Maybe I'll try with a short cord for fun with a discharged battery. )

Downside is bike is less stealth now, and NCC might grab me.

Batteries charged at average of 9 amps, full wave rectified or 1.5c no problem. I ran them at 12a or 2c for 5 minutes with a run to 13.5a for a few seconds. It works but my pseudo constant voltage phase is a pain to do manually, switching loads around. Will have to automate. In theory a 21.0v zener that can handle 6a (126w) would do it simply, but if such a zener existed, it would be very expensive. I'll look at PCM like solutions. Wonder if a standard light dimmer (5a = 600w ?) would work for an infinitely variable pseudo-load ?

With full wave and the heaters on the AC side, the fans now work, which is good for getting rid of the heat, and helping to draw a little air across the bridge rectifier. Bridge got hotter than I expected with no air and no heatsink. I pointed my CanFan at it and duct-taped it (! ) to a computer power supply case and it stayed pretty cool. Need good heatsink and maybe fan for charging I think.

Will probably never be CSA or UL certifiable, but will ground bike frame, to 120vac ground only (Not batt's or anything else.) Should remove some of the danger, and more with a GFCI.

Did a "tourist run" early this AM with 2s x 2. Bike feels MUCH lighter with 7 pounds / 2 batts removed. Might be worth it to run battery light for short runs. Having switches mounted on 2 batt "modules" with only 2 wires from each module, and chucking battery bag, make this viable. Will wire and mount my other 4 batts today. Duct tape and super bungees are much better than battery bag. Flexibility of placement is letting me put seat all the way down again, with better clearance for under seat steering bars that MUST go under seat to take many curves decently.

Re-calibrated bike computer for bigger ebike tire size. Was 1460 mm per rev, now 1539, so my previous range and speed calcs were low by 5%. I got 25 KM last night on a single pair of batteries, including the nasty hills I have to climb to get back from Ottawa River level to Pink and Klock Road level. Speeds were usually 20 KMH or less, except downhill.

great info keep it coming...
i'll add some of my findings with my 2 bat set up....
range is droping...latest ride today was 9.7 km
various loads and speeds
bat levels were 15.63 and 16.04v @ lvc
i think they are becoming unbalanced...100km of use
i am charging and discharging using ONLY + and -
i will(tonight) run 2 more wires from my bat box
using these additional wires for c- to see if they balance
so it might not be a good ideal to charge "everyday" with the main -
i will add wires and start charging with c- and report back

peace wasp

 

[Anonymous]

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[wasp]

Do more riding before concluding that range is dropping, and remember that things like wind make a huge difference in watts hours per kilometer. I am over 1500km on these batteries and I'm not seeing any loss of range yet, but if I'm riding into strong head wind, yes range will drop.

are you charging from the negative termanal or c - terminal ?
seeing a .5 volt difference concerns me a little the most i.ve
seen is .11 difference ? it may be nothing but i'd thought i'd
share the info...will report back

 

[wasp]

Do more riding before concluding that range is dropping, and remember that things like wind make a huge difference in watts hours per kilometer. I am over 1500km on these batteries and I'm not seeing any loss of range yet, but if I'm riding into strong head wind, yes range will drop.

are you charging from the negative termanal or c - terminal ?
seeing a .5 volt difference concerns me a little the most i.ve
seen is .11 difference ? it may be nothing but i'd thought i'd
share the info...will report back

as a follow up my bats are going out of balance...
now lvc kicked in bat 1 15.64v bat 2 16.99v
i'll rewire for c- tomorrow...to tired from pedaling(lol)

peace wasp

 

[Anonymous]

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[wasp]

As I said earlier in this post, my batteries have always had varied voltage at end of discharge. Does that really mean they are out of balance? These are not individual cell voltages, to know if the battery pack is out of balance you'd need to measure individual cell voltages. All I care about is: they always charge to approx 20.8V and the range has not dropped, so they are not losing capacity after 1500km. The series connection and resistance of wires and connectors may be related to the pack voltage differences after discharge.

well i measure before and after charging
are you using only + and - to charge
or are you using the c- and + to charge ?
if one bat kicks the lvc out at 15.5 it don't
matter if the other one is at 21v ?
i am losing distance
it may be a bad bat but i think the cells
are not balanced because i'm not using c- to charge.
i will rewire for c- tomorrow and run them a few
times and measure the v's at the end and compare
they built em this way for a reason or why bother with c- ?
i still want to push them but not kill them...
i'll let you know the numbers tomorrow

 

[mikereidis]

As I said earlier in this post, my batteries have always had varied voltage at end of discharge. Does that really mean they are out of balance? These are not individual cell voltages, to know if the battery pack is out of balance you'd need to measure individual cell voltages. All I care about is: they always charge to approx 20.8V and the range has not dropped, so they are not losing capacity after 1500km. The series connection and resistance of wires and connectors may be related to the pack voltage differences after discharge.

well i measure before and after charging
are you using only + and - to charge
or are you using the c- and + to charge ?
if one bat kicks the lvc out at 15.5 it don't
matter if the other one is at 21v ?
i am losing distance
it may be a bad bat but i think the cells
are not balanced because i'm not using c- to charge.
i will rewire for c- tomorrow and run them a few
times and measure the v's at the end and compare
they built em this way for a reason or why bother with c- ?
i still want to push them but not kill them...
i'll let you know the numbers tomorrow

I've never used the middle connector (C?). Interesting if it's not directly tied to -, could be a sense line of some sort, but these batts don;t really need that. YW charger and trimmer don't use that extra connection, so I don't either, but I had assumed it was just another negative line. I'll investigate.

I believe the battery internal BMS handles balancing the individual 5 cells inside, so we don't have to worry about that. I think balancing the batts can be a good thing, but it's not essential.

There is nothing inherently wrong with running a battery with 20% charge in series or parallel (with diodes) with another at 100%. (Except LVC will kick in on low batt, before high batt.) Running like this will not damage anything.

I think that you would find that 2 batteries in series, each reading 21.00v at start of run, will tend to stay in sync through most of the run, I tested this last night at the 24 KM mark of a 44 KM run where my 4s bank A lasted 42 KM (20-30 KMH, half on lower speed bike paths, half on street.) All batteries started at 20.99v and at the 24 KM mark they were all 19.9v give or take a few hundredths.

My discharge tests, and common knowledge indicate that voltage drops fast at end of battery cycle. This IMO means that two series batteries, starting at same voltage/charge, could have 1 or 2v difference between them at LVC cutoff time, even though they are pretty closely matched. I.E. The statistically expected differences between the batteries becomes magnified at the end of the battery cycle.

So compare battery voltages at around 18v or higher only, below about 18v you will start to see bigger differences.

I am also looking for marginal or lossy batteries while my warranty is still fresh. Charging in series is easier when all batts are at same voltage. In theory, unless the internal BMS gets in the way for some reason, batteries starting at 18.00v together should charge to 21.00v together, as well as discharging from 21.00v to 18.00v together. If one or more batteries differ by much using a test like this, I'd say there is a problem.


I did my first run with 4s x 2 last night; got 42 KM almost home on 4s bank A; only used bank B for last 2 of 44 KM. This was after using my bike mounted (minus loads) DCACv1 to charge all A bank batts to 20.99v and all B bank to 20.8 or so. Was a lot of hassle to balance the batt voltages; I have an idea for an enhancement to automate the constant voltage phase by shunting unneeded current when a battery hits 21.00v.

I see that NCC huts often have external power outlets. Will see if they can handle 12-15a. Take that NCC ebike clarifiers ! Cheap $20 heater weighs 3 pounds and is preferred portable choice. Temp cutout operates when heater running but fan not spinning fast enough though. Mostly an issue at lower currents, which should be less of an issue for outdoor night-time fillups. Topping up a battery is like topping up a reluctant gas tank, First part is fast, topping up takes too long for time invested versus charge received.

Ceramic heater weighs 4 pounds, may be more fragile and has strange thermal characteristics. As it gets hotter, current goes up and it gets hotter still. So batt current rises for a good time. In theory I think this eventually goes the other way when really hot, but in my app that doesn't seem to happen (except that as batt voltage rises, current tends to go down).

 

[Anonymous]

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