Greenworks 40v G-MAX disassembled- 11C rating?

ggtronic said:
bluovalguy said:
Warning to anyone using these batteries... They have no internal LVC whatsoever. I accidentally left them connected to the bike with controller on for almost a month.
Click to expand...
Not totally true Bluovalguy : they have an LVC and my bike shut down at approximatly 33-34V ... i suspect a wrong custom made battery adapter wich had kept the BMS on for that month ?

everybody buy these Tools with plugged battery wich would ran the company bankrupt it they all discharge to zero !

When you make your own "custom" adapter , you need a switch that will turn off the battery BMS and voltage feed
if you leave it unused for extended time ...
if not, your BMS "standby" current will probably drain your battery in the long term like it happend to you...
Click to expand...

Not sure what you mean by adaptor... I'm just connecting to the main +/- terminals directly with greenworks insert blocks. Full voltage is always available to the main terminals unlike the older version which shuts down when idle.

Was the LVC you were seeing from the controller? I have run down to 31-32v without cut... It just can't deliver much power at thatthat level.
 
i dont own the Gmax... i have the regular 40v as shown above on my pic... and if
i plug to +&- i get nothing... i need to trigger the "BMS" to get power out...

there is something wrong with your setup ! i would not use
these Gmax if your "custom plugging" setup doesnt provide
BatteryManagementSystem=BMS and LVC ! when you use it
while having lower than 33v you are damaging cells !

Your Gmax battery might be defective ? defective bms ?
 
ggtronic said:
i dont own the Gmax... i have the regular 40v as shown above on my pic... and if
i plug to +&- i get nothing... i need to trigger the "BMS" to get power out...

there is something wrong with your setup ! i would not use
these Gmax if your "custom plugging" setup doesnt provide
BatteryManagementSystem=BMS and LVC ! when you use it
while having lower than 33v you are damaging cells !

Your Gmax battery might be defective ? defective bms ?
Click to expand...

This is just how the gmax is designed. Others have noted that the main terminals ar always on as well.

How do you activate your old greenworks 40v? Just jumper pins 4 & 2?
 
So Gmax Tools might have BMS+LVC then ?

With regular 40v battery , i link pin4+ to #3 like this
and then the negative tabs gets "live"

BMS_activation.jpg
 
Hey guys, I was about to order a Gmax battery, as it looked promising from this thread (just perfect when you look for an extra light, high c rate and safe battery pack, and quite cheap too. And it is just below the allowed capacity if you want to take your e-bike kit on planes) . I've just seen your recent update, I feel a bit concerned about not using the bms/lvc...
Have you sorted it out bluovalguy? I don't really get how jumping pins 4 and 3 can avoid long term discharge, and how the bms is triggered. Could you enlighten us a bit ggtronic?
Thanks
 
Kousbk : we cannot presume that Gmax need the same connection
as my regular GreenWork 40v ! ?

you need to analyse what happend at each tabs before and after
plugging it to your tools to determine whats going on with these
Gmax battery and how does the BMS work... because i'm almost
shure that all Gmax have a system to protect its cells from over
discharging !

Gmax user absolutely need to make the BMS+LVC work to use
these or your going to ruin this expensive battery...

i cannot help... i dont own any GMax
 
Yes, sure. We cannot presume, but still I suspect they use the same pins. The only difference being that Gmax let you tap directly from the +/- . And yes ggtronic you are right, the only way is to measure voltage and current when plugged into the tool under tension. That way we can guess which terminals should be jumped and where to put diodes. That's unfortunate, I considered purchasing only the battery, as I already got a gas lawn mower and trimmer and don't really need any blower or chainsaw :-S
Don't you want to try bluovalgguy :-D ?
But ther's stg I don't get, is it harmful for the battery if you have an LVC in your controller, and use the regular charger (with bms then)?
Maybe I'll go for the old battery, if I find it. Do you think it can safely deliver 4c ?
I am building a portable kit that can be plugged on any bike within a few minutes for short commuting rides, and such a light and powerful battery is just perfect!
 
if the Gmax+ - tab are always "live" (i have doubt, maybe Bluovalguy battery become defective?)
, than something else in the tools protect the battery ?

i ran up to 25amp on mine easy and the internal fuse is 50A !
4c mean 16amp or about 600w... no problem at all...but i would not
drain 600w for extended period of time...after all, any regular
bicycle doesnt neet mor than 200w(38v x 5amp) to run approx.
20kmh on flat surface...
 
It seems bluovalguy is right, there are other examples on endless sphere, telling about the "advantage" of being able to -apparently- bypass the bms. Easy connection for sure, but you loose all this battery has to offer. They apparently did not find your trick for the old battery. And greenworks is not really keen on helping.
I think I can check if the pin #3 activates the bms by simply wiring a resistor between the + and - to simulate a working tool, and measure the current between #4 and #3, turning down progressively the sensor's resistor. If there are some mA, means that the bms is working and consuming some current. If there are some Amps, means it's a short! In the former case, I can just jump the 2 pins then, with diodes and a fuse, we never know...
Then I can wait until the LVC is supposed to shut down the main circuit, and conclude. The only thing I have to assume is that the bms operates at the same voltage as the battery, as I won't be able to detect any voltage divider without the tool connected. I think it is reasonable.

Well I already got an off-the-shelf middrive ebike, following EU regulations (i.e. 250w mean, 500w peak), and its main job is to climb 10% slopes with 2 kids in a trailer behind. I can tell you I'd not be against more watts :-D
Anyway good to know for the old battery, but those are becoming quite scarse and thus actually more expensive than the gmax...
 
What if greenworks simply dropped the bms in gmax batteries, as bosch did:
https://endless-sphere.com/forums/viewtopic.php?f=14&t=59480
Looks like a bms is not so necessary after all...
 
VLC is mandatory , or you will destroy the battery after
just 1 or 2 over discharge !...
if the battery doesnt have its own VLC (voltage low cut off),
than each tool should have one ? Gmax must have implement the VLC
Inside the Gmax Tools and many VLC adapt themself to the specifiq number
of cells (i'm an RC airplane/multirotor pilote and all our ESC have
"intelligent" VLC)

if VLC are Inside Gmax tool, than you will have to duplicate
it for your bike !

about BMS...accurate monitoring of each individual cells
is not mandatory but remain a "nice to have" , specially
for users like us wich might make mistake in our connection...

https://en.wikipedia.org/wiki/Battery_management_system
 
agree about difference HillHater... but still... every tools using rechargable Lithium battery
should have BMS/LVC !

We own 3 GoldenMotor wheels thas has internal LVC, so it could protect the Gmax
with appropriate settings :
http://www.goldenmotor.ca/products/Smart-Pie-5-%28VECTOR%29-700c-and-29er-Front-Conversion-Kit.html

we also use this battery that also has internal BMS/LVC
http://www.goldenmotor.ca/products/36V12AH-LiFePO4-Aluminum-Cased-Battery.html

+ my GreenWorks 40 volts 4ah with internal BMS/LVC....

so i have 2 separate LVC system for all our Ebike
 
-UR18650RX cells. From what little I can find, these are 22amp rated (11c), and Greenworks claims up to 2,000 cycles. (44a rating on the 4ah pack sounds about right given a single 2ah battery can power a mower that supposedly is nearly as powerful as a gas mower.)
Click to expand...

From what I've read, no ones proved they are Sanyo RX's.

I was going to buy the Ego 56V from Home Depot, but I need to know what the internal cells are, and therefore their discharge rating.
It'd be nice to know what cells are in the different tool battery packs, and what configuration they are in, otherwise you are just gambling on something that might be this or that cell with no one actually taking it apart, and taking a friggin picture of the cells with the printing on it.

-----------

You know what, why would I pay ~$400 for ~60V and 8Ah for a tool pack cell, when I can spend ~$450 and get ~60V and ~17Ah.
I think I gravitate towards tool packs because there is easy access, no shipping and its plug in and ride.

I've done the calculation on this now 2 or 3 times. And I've come to the same conclusion, I will go with 18650 cells and build my own pack.
 
ggtronic said:
...... but still... every device using rechargable Lithium battery
in the world have some sort of LVC ! either in the battery and/or in the ESC or inside the device power supply
Click to expand...
Nice thought ,..but not true!
There are a few million Ecigs and LED flashlights with no LVC.
Cells with built in protection are generally no use for EV or other high discharge applications.
 
LOL ok i'm sorry ! you might find lipo device witn no LVC at your local dollar store LOL ?
but not with tools company with reputation :roll:

Markz : understand your quest for high power and really do respect your DiY hobby !
... i want "light" & near original bike that provide small helps...i own a 1500w wheel and want to "sell" it
so i can go back to a lighter 750w ... and i dont have time for "custom"
battery pack/BMS/charger built/design...
 
ggtronic said:
LOL ok i'm sorry ! you might find lipo device witn no LVC at your local dollar store LOL ?
but not with tools company with reputation :roll: ...
Click to expand...

Well now you have narrowed down your range quite a lot from .." every device using rechargable Lithium battery"...
..and you obviously dont know the cost of some Ecigs or LED flashlights !
 
markz said:
-UR18650RX cells. From what little I can find, these are 22amp rated (11c), and Greenworks claims up to 2,000 cycles. (44a rating on the 4ah pack sounds about right given a single 2ah battery can power a mower that supposedly is nearly as powerful as a gas mower.)
Click to expand...

From what I've read, no ones proved they are Sanyo RX's.

I was going to buy the Ego 56V from Home Depot, but I need to know what the internal cells are, and therefore their discharge rating.
It'd be nice to know what cells are in the different tool battery packs, and what configuration they are in, otherwise you are just gambling on something that might be this or that cell with no one actually taking it apart, and taking a friggin picture of the cells with the printing on it.

-----------

You know what, why would I pay ~$400 for ~60V and 8Ah for a tool pack cell, when I can spend ~$450 and get ~60V and ~17Ah.
I think I gravitate towards tool packs because there is easy access, no shipping and its plug in and ride.

I've done the calculation on this now 2 or 3 times. And I've come to the same conclusion, I will go with 18650 cells and build my own pack.
Click to expand...

Maybe you missed it in the original post, I did actually disassemble my first gmax battery and identified the cells. Theres a photo half way down the fisrt page (although you probably can't see the cell markings.) Can't say for sure if all of them use these cells, but mine from mid 2013 were marked UR18650RX.
 
Hillhater said:
Well now you have narrowed down your range quite a lot from .." every device using rechargable Lithium battery"...
..and you obviously dont know the cost of some Ecigs or LED flashlights !
Click to expand...
Never say Never... :oops: LVC are
integrated in 99.9% of RC esc used with lipo and should cost less than 1$ ?... if you buy an expensive LED flashlite without LVC ,
it remain a "dollar store" stuf to me LOL http://www.hobbyking.com/hobbyking/store/__81793__DYS_16Amp_Micro_Opto_BLHeli_Multi_Rotor_Electronic_Speed_Controller_BLHeli_Firmware_SN16A.html

This Flashlight would fit with my "quality" device list : soon we might buy them for 20$ on ebay :?:
http://www.plxdevices.com/World-s-First-Intelligent-LED-Flashl-s/122.htm

Thanks BluOvalGuy ! GreenWorks company really like the video i made for
there Facebook page : https://www.facebook.com/hashtag/gasisthepast?source=feed_text&story_id=977699105622652
i win the montly contest and they gave me a free
40v brusheless chainSaw+2 additional 40v battery !

they also used my video on the #8 project here :
http://batterypower.greenworkstools.com/blog/11-little-known-uses-for-your-leaf-blower?utm_content=26342987&utm_medium=social&utm_source=facebook
 
ggtronic said:
So Gmax Tools might have BMS+LVC then ?

With regular 40v battery , i link pin4+ to #3 like this
and then the negative tabs gets "live"

BMS_activation.jpg
Click to expand...


What kind or Diode do you use??
 
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