48v 1000w controller shutdown under load

[re-volt]

greetings! this is my first post so i hope i dont embarrass myself too much by revealing my lack of knowledge about things and stuff.
i recently bought a standard cruiser type e bike. australian (qld) law states it has to be limited to pedal assisted 250w with a 25/kph
cutoff. alternatively, we're allowed a 200w twist and go. i got the 250w (36v 10ah)...

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after a couple of months riding about i felt i needed 'more power'. lol so i ordered a cheap-ass generic chinese 1000w, as well as a
cheap-ass generic 12ah 48v battery. i was originally going to install the new kit on a GT Ruckus frame that i obtained for $2 from a
local charity where i occasionally volunteer, and had almost everything i needed to get it done, but because i had to wait a bit to be
able to afford the battery i started raping the GT for parts to put on the cruiser. i ended up replacing every part on the cruiser except
for the frame, seat, rack and chain-guard. and now i think ive built myself a pretty sturdy, mildly powerful e bike.



so now to my problem: if i gun the throttle too quick when im taking off, or even when building momentum, the motor cuts out.
i have to turn the battery key off, then on again, to reset (the controller?) it to start again. my entire knowledge about e bikes,
and dc electricity in general, is limited to what ive read on the interwebs over the past 12 months. ive never even met another e biker yet lol
i inquired at a local auto electrician about my problem and he said -
"yeah, thats what they do mate. so they dont over load the electrics mate. so ya dont cook it. gees mate..."
now, i have nothing against labourers, i am one myself, but this guy just didnt convince me that he knew anything more than what time
he was finishing work and where he was going to buy this evenings discount beer. condescending wankshaft
doesnt he know i soldered my own wiring?
which i assume could also be a possible cause of my dilemma.

so my questions: will excessive wiring lengths, or kinks/joiners/loops/too much solder, not enough solder in the wiring, inhibit power enough
to cause the controller to think the minimum threshold has been breached? maybe the controller is receiving too much juice and overloading?
maybe a battery cell has shorted/glitched/died? its a bit of a hassle. if i build up speed gradually it will max out at about 55kph... which is nice
but at traffic lights, where getting a good jump off the line without stalling is a safety requirement, and much preferable to becoming a hood
ornament on a poorly made korean work truck.
im positive that the motor cutting out under load is not a normal thing, and if it is then mine does it at the wrong time.
maybe somebody here has a suggestion or a simple method of increasing/decreasing the power its getting, as needed.
i have a limited budget these days so the more cost efficient a solution may be, the better it will be for my fund-sack.

anyways, im Jase, the Tasmanian Voltrocket Pilot. im quite approachable and friendly, and im proud to be part of such a helpful and knowledgeable online community.
thanks for reading, and thanks in advance for any help you can give me.

 

[DAND214]

Did you fully charge the new battery? It souds like the BMS is shutting down under load. having to reset the power switch says low battery.
In any case charge the battery at least overnight if not longer. It would also help to know which/where you got the battery. Any pics might help too.

Dan

 

[999zip999]

What's the voltage of your charger and check the battery voltage, please post.

 

[re-volt]

hey thanks for the quick replies guys.

here are the numbers for the battery and charger that were listed on the site:

48V12AH Li-ion Battery Specifications
Type : 48V12Ah Li-ion battery pack (with alu case)
Model: EMC4812001
Nominal voltage: 48V
Weight: about 4.9kg
Standard Charge (0-45 ℃): Use 2A constant current charge to
42V ,and use constant voltage charge to the current less than
100mA
Standard discharge: 2A constant current discharge to 27.5V
Fast discharge: 5A constant current discharge to 27.5V
Nominal capacity: 12Ah (standard discharge)
Cycle life: Standard charge and fast discharge cycle 500
times , the capacity will not less than 60% of the nominal
capacity .
Maximum continuous charging current: 5A
Maximum continuous discharge current: 15A
Maximum instantaneous working current: 30A
Resistance (23 ± 2 ℃): ≤ 250mΩ
Battery case: Whitebait Aluminum Case
Protection system: Internal BMS
Charger: 54.6V / 2A
Size: 385 * 110 * 75mm
Storage conditions: -15 ~ +35 ℃, relative humidity: 45-75%,
atmospheric pressure: 86-106KPa
Use the operating temperature:
Discharge: 0-60 ℃; Charging: 0-45 ℃;



i bought it from an ebay dealer (health.life) based in guangdong, china.

ive painted the silver parts of the battery but its a silverfish style and ive
checked numerous times for any overheating and never noticed anything
warm, let alone hot. the same with the controller.

when the battery first arrived i charged it til the charger automatically shut off,
but unless i unplug the charger from the wall it will continue to start up charging again
every few minutes for about 5 seconds.

i just checked the voltage on the battery with cheap volt meter (on the 200v setting?)
after it 'fully charged' and the reading said 53.1v.
the details on the charger sticker match the details mentioned in the specs above and
the input to the charger is listed as 220v AC/50Hz

 

[DAND214]

Did it ever work or this the first try?

If the charger says 54.x v let it charge. Too many pull the plug the minute the charger stops thinking it's fully charged and balanced. If the charger turns off and back on let it charge for hours so it can balance the cells. All you need is one cell that isn't charged and the rest don't matter. The low one will trigger the BMS and shut down the pack.

The specs

Nominal voltage: 48V
Weight: about 4.9kg
Standard Charge (0-45 ℃): Use 2A constant current charge to
42V ,and use constant voltage charge to the current less than
100mA
Standard discharge: 2A constant current discharge to 27.5V
Fast discharge: 5A constant current discharge to 27.5V

can't be for that battery, 42 charged or 27.5v discharged is for a 36v pack.
It's a 48v pack since you got 53v test, just the specs are wrong.

Dan

 

[re-volt]

Dan that sounds about right. i checked the charger numbers on my
old set-up for the 36v and the charger has the 42v @ 2a. so it would seem i
need to replace the charger for the 48v with a more suitable one, which i like
better than buying another battery or controller.
ive had this new set-up in the bike for about 2 months and ive just been taking
it easy to avoid the inevitable stalls, living with it. but if my only problem is
that im not getting a full charge then thats fairly easily fixed.

i just found one with 'bigger numbers' on ebay for around $110 aussiebux

Output: 54.6V 240W
Charging current: 4A (constant current process)
Off-current: 350mA

i'll shop around for better prices but thats gotta be better ay?

i noticed that in Aus we use a 240v household electricity system, whereas in
china where the charger was made they use a 220v system.
would that make a difference at all?
i'll also give my current charger a red hot go til it stops restarting and see
how that goes.
thanks Dan and everybody else for your help, i think i heard what i wanted to hear

 

[DAND214]

Dan that sounds about right. i checked the charger numbers on my
old set-up for the 36v and the charger has the 42v @ 2a. so it would seem i
need to replace the charger for the 48v with a more suitable one, which i like
better than buying another battery or controller.
ive had this new set-up in the bike for about 2 months and ive just been taking
it easy to avoid the inevitable stalls, living with it. but if my only problem is
that im not getting a full charge then thats fairly easily fixed.

i just found one with 'bigger numbers' on ebay for around $110 aussiebux

Output: 54.6V 240W
Charging current: 4A (constant current process)
Off-current: 350mA

i'll shop around for better prices but thats gotta be better ay?

i noticed that in Aus we use a 240v household electricity system, whereas in
china where the charger was made they use a 220v system.
would that make a difference at all?
i'll also give my current charger a red hot go til it stops restarting and see
how that goes.
thanks Dan and everybody else for your help, i think i heard what i wanted to hear

Before you buy another charger read the specs on it not what was listed online. many vendors from china paste wrong specs or someone elses.

How long does it take to recharge the battery when the charger shuts off? I still think it just needs to be left on the charger longer, not that it is the wrong charger.

So you said that the battery has worked after you got it for a while, so it sounds like I said, Out Of Balance. Let it charge and charge for a day or so if the charger turns off and on. The final voltage when you take it off the charger should be very close to the spec on the charger.

The 220vf and 240v is not a problem. We use 120v but many call it 110, in most cases it's more like 125v. Well at lest here where I live.

dan

 

[d8veh]

Your battery does not have enough power for that motor. You're exceeding the BMS limit current, so the BMS is shutting down.

By opening the throttle slowly, you don't drmand such high current, and as the speed goes up, the vurrent goes down, so the urrent is a lot less at full throttle cruising speed than when starting off.

You need to limit the current at the ontoller or get a new battery.

 

[DrkAngel]

1000w output motor might draw 2000w battery input under full throttle at low speeds.
2000w / 48V = 40A+
Battery has a maximum 30A brief output
30A+ output will likely sag battery voltage below the controller or BMS's ~41V LVC (Low Voltage Cutoff) causing a shut off fault.
Solve with more capable battery or lesser Amp controller or use throttle restraint at low speed.

 

[re-volt]

thanks for the replies guys. unfortunately the bastard thing died. been charging til it stops. after last ride it did the shutdown thing and never started again. charger says charged but meter says 00.00. lights on top of battery say full charge. plug it in, switch it on... nothing. did i wreck the battery? i would think if it was the fuse between batt and controller i would still be getting a charge reading from the battery (just checked fuse, no damage). does exceeding the BMS limit current break stuff? and if i were to get another battery or controller which ones go together to comfortably power a 1000w donk??

 

[DrkAngel]

Most likely a BMS failure.
Some "wrap" opening might be necessary to confirm ...
You should test voltage at leads from individual cells.

You will want a battery with a ~40A continuous (40A+ surge capable) output for your 1000w motor.
Similar battery technology to your failed, should allow adding cells in tandem to new battery for expanded capacity and capability.

 

[re-volt]

ok thank you

 

[re-volt]

hey turns out i found the battery fuse, hiding under the battery handle. yep, im a dufus. i thought it was the one hanging off the controller. thats a good example of how inexperienced with this sort of thing i am, but im learning stuff all the time (the hard way).
it looked pretty bad, the guy at Jaycar didnt seem to know much but said it looks like something very serious is going on lol

popped so hard it cracked the glass.
so, i wasnt able to find a f20al250v 20a fuse in town but a dude said he'd check his workshop this afternoon so maybe one there, or maybe a shop in toowoomba or brisbane will post some.
i cant afford new hardware right now so if i get it going again i'll just take it real easy on the throttle,
or find alternatives using the parts i already have.

which begs more answers to more questions-
1.a)why did it blow a 20a fuse if the 12ah battery is too weak for the 1000w?
b)can the controller pull a power surge from the battery?
2.do fuses pop just one time, or is it possible for them to blow, but remain
in a damaged state that can still carry the current temporarily?
3.can i hook up my 48v battery and controller to my 250w hub motor, turning it into a light 500w or something?
i read somewhere that hub motors can handle a lot more power than theyre sold to..?
if so, what sort of problems can i look forward to if i did it.
4.is there a way to measure the max/min power you can give the motor?
5.can i power the 1000w wheel with the 36v battery and controller,
turning it into a heavy-ass 250w motor? lol
i can see that im going to be into these things for a while, and im hoping a lot of the parts/hardware that i obtain
can be used with other parts.
geez im demanding arent i lol if anyone can answer all these questions in one reply it will be an epic read, so thanks for any time ya spend on it. ill number my Qs for simplicity. CHEERS!
once again, apologies for appearing too lazy to research the tech stuff available everywhere for myself.

 

[DrkAngel]

"Maximum continuous discharge current: 15A
Maximum instantaneous working current: 30A"
1000w motor draws >30A surge (battery pack BMS safety limit) - caused BMS fault
20A slow blow fuse survived brief surges to BMS safety limit (~30A?)

Most hub motors can survive higher voltage and amps, but larger battery controller of same 48V will not affect top speed. Will likely give better acceleration to same top speed. 36V 250w motor @ 48V = ~333w motor output

48v 1000w motor run with a 36V battery can output near to 750w ... but 36V 15A capable battery is restricted to <500w continuous motor output.

 

[re-volt]

awesome, that explains a lot. thanks heaps DrkAngel.

 

[flat tire]

Get rid of the BMS. Those motors like plenty of voltage and you've got room for a more powerful battery, up to around 84 volts, and a Lyen controller. I'm running 19S NCA which is 79V peak and the motor loves it. Gets up to 42 MPH with conservative controller settings.

As far as the law goes, I'm sure you've figured this out but watch vigilantly for cops, and if you see any, slow down and start pedaling