Best damn 6S lithium monitor on the planet for $15

[methods]

The little ones are the worst... Cut through your skin like a hot-wire through foam.
These big ones flash so fast that it just chars the outer layer, nothing deep.
Those little wires have time to cook deep


-methods

 

[Hyena]

Methods, you're not a very good ambassador for lipo when you keep doing shit like this

This time when i was switching back to 24S I forgot to switch the balance taps.

Oooouch!
I've done that too - I parallel charge 4 banks of 6S and one day accidently left the balance taps all connected when switching the main discharge leads back to series. Luckily I was only just bringing the connectors together when they contacted and vaporised.
I endeavor to only make each mistake once and thus far I still have all my epidermis intact :lol:

 

[flip_normal]

I see the BM-6 on hobbycity. look here, it's only $13: https://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=8927

I got 4 of these from hobbycity and the alarm cell voltage can only be set down to 3.0V when the page they sell them from and the spec sheet clearly states it can be set down to 2.0V, I also asked them if they came with the wiring harness shown in the picture and was told it did...... it didn't. Hobbycity asked me to send photos of what I received (which I did) and that they'd get back to me after doing some testing, that was two weeks ago and still no reply. Jason at chargery says that they are selling the older version still and offered to sell me 4 of the new ones for 60USD delivered. So I've got 4 of these which are no good to me and hobbycity has 3 more days untill I escalate the paypal dispute.
Overall pretty shabby service IMHO.

EDIT: Did anyone else get any of these from hobbycity? If so can you set the alarm cell voltage down to 2.0V?

Regards,

Luke

 

[Hyena]

I ordered one from hobbycity with a bunch of turnigy lipos a few days ago, I'll check when it arrives. Are you planning to use them with something else other than lipos? Taking them below 3v/cell will rapidly shorten their life so you wouldnt want to set it any lower anyway. As for the wiring harness, I think you'll find that what you see in the picture is actually the balance taps lead coming from the battery. They don't actually mention on hobbycity that they come with any plugs/wiring, although they're pictured here in this ebay listing so who knows...

 

[flip_normal]

Hyena - I was hoping to use these with a LiFePO4 pack so being able to set these to 2.5V or 2.1V was the plan. I'll be interested to know what the one you're getting can be set to.

Re. the wiring harness, if they hadn't explicitly told me, when I asked them, that it was included then I could have bought some from them and had them shipped with the order and saved on postage is all.

Cheers,

Luke

 

[jorhyne1]

Did you guys ever resolve whether these monitors could be set low enough to be useful to use with Lifepo4 batteries?

 

[johnrobholmes]

The ones I have go down to 2v on the alarm. Got em direct from chargery.

 

[flip_normal]

Jason Wang at Chargery told me in an email that Hobbycity were selling the older version BM6s. When I told him that the ones I got from them were V2.0 and had LiFe printed on the circuit board and asked him what version the new ones were he ignored my questions and just offered to sell me some of the ones he had. It very much looks like a batch of the newer boards were sent out with the old firmware programmed into them. Either way both Hobbycity and Chargery expected me to pay for their mistake. Why they insisted on behaving in this way is beyond me. In my book they're no better than thieves and I won't be doing any more business with either of 'em.

 

[methods]

woh woh woh... easy now.
What is the problem here?

I have BM6's from years ago that are programmable for both Lipo and LiFeP04.
I bought these like 6 months before Hobby City even carried them.
You are claiming that you recently bought a BM6 from Hobby City and it will not work for LiFePO4?

What range can you set them to?
Are you sure you are flipping between LiPo and LiFe mode?

-methods

 

[flip_normal]

The BM6s I have here have one button. I hold it down and it beeps, I then pess it again and each time it changes the low voltage cell alarm piont from 3.0V to 4.0V in 0.05V increments and then back to 3.0V. I hold the button down for a couple of secs it gives a double beep and the alarm is set. Not sure what you mean by flipping between LiPo and LiFe mode. I bought 4 of these. More details in previous posts in this thread.

- Luke

 

[flip_normal]

Just did a quick vid so you can see what I mean.
[youtube]1l42_iFt2Vc[/youtube]
I'll post copies of my emails with chargery and hobbycity if you want.

- Luke

 

[MitchJi]

Hi,

Is this an 8S version produced by the same company or an 8S product of equal quality?:
http://endless-sphere.com/forums/viewtopic.php?f=14&t=12815
http://www.hillrc.com/EnProductShow.asp?ID=96
http://endless-sphere.com/forums/viewtopic.php?f=14&t=12820

 

[methods]

Since you seem bummed I would like to offer a solution ->
I need 4 more. I will pay you what you paid for them if you will ship them to me for free.

Is that a fair resolution?

I dont want to pay shipping because I would be able to "throw them in" on any one of my other Hobby City orders.

P.M. me if you want to do the deal.

-methods

 

[flip_normal]

Hey methods,

I just thought others would like to know how these companies treat their customers is all. If you want these 4 x BM6s then $50 and they're yours, paypal me when you get them, pm me your contact details and I'll get them in the post tomorrow.

Cheers,

- Luke.

 

[flip_normal]

Hi,

Is this an 8S version produced by the same company or an 8S product of equal quality?:
http://endless-sphere.com/forums/viewtopic.php?f=14&t=12815
http://www.hillrc.com/EnProductShow.asp?ID=96
http://endless-sphere.com/forums/viewtopic.php?f=14&t=12820

I don't think the CellLog 8s is produced by Chargery, no sign of it on their site. Looks damn nice. From the discussion on rcgroups they're still revising the firmware, not sure how easy it is to get working with logview software either, but seems like it's set to be a very cost effective basis for a data logging BMS with a neat little display.

 

[mwkeefer]

Hello everyone,

These BM6 are still all that and the issues I detail can be compensated for, these are still the cheapest simplest off the shelf way I know of to protect Li cells, that said... there are a few issues you should know about.

http://www.designsforbusiness.com/ebikes/videos/BM6-CalibrationIssues/Edited_IMG_0047_BM6_OutOfCalibration_Proof.avi

This video shows the variation and incorrect HVC triggering of the BM6 when testing 4 of them on the same turnigy 6s lipo.

I have edited out the swapping the BM6 units (4 tested and demonstrated on the same 6S pack with nothing connected to it... btw, the fluke and the iCharger show all cells between 4.179 and 4.185 there are .002mv differences between the Fluke and iCharger but that is not of concern... you can see as these 4 BM6 cycle through their various readings they are widly off. You will also hear the HVC beep cut in... look it thinks some of my cells are 4.22+?

The good news here is the error is on the high side, so a cell of 4.18 could read as 4.22+ and trigger HVC alarm... atleast it will prevent overcharge. There are some variations (much more limited scale .010mv) in the LVC detection also... so 3.2 could be 3.21 but... again it's to the side of caution so it's not dangerous but to have finite control and get the most from your packs... you should test / calibrate each BM6 so you know it's offset. This will allow you to select a more appropriate LVC and to determine based on the displayed value if you should ignore the HVC alarm on a particular BM6 unit / cell.

Really, hope this helps!

-Mike

 

[bearing]

I wonder if they have switched to cheaper resistors with higher tolerances.

 

[mwkeefer]

Hey all,

Just to clarify, the BM6 units in the video I shot are all new within the last 2 months and are all the "new version" advertised on Hobby Kings website.

So if your question is in the new units have they swapped em out? Doubt it, we may have better luck ordering direct from Chargery as Methods has done.

I have taken the worst of my BM6 and am trying to "recalibrate" the sense resistor network, I am not sure I will be able to (but probably can) solve the issues but... I might as well try on this one since it always triggers a HVC alarm (the last cell is really off calibration) if I charge past 4.16v or so.

-Mike

 

[MitchJi]

Hi,

It would be nice if someone would test the CellLog 8S battery monitor and logger. Its more expensive but 8s is an advantage and it has logging.
http://www.hillrc.com/Enproducts.asp

【iCharger Products】
10S 10A Balance Charger/Discharger 1010B
6S 10A Balance Charger/Discharger 106B
6S 10A Balance Charger/Discharger 106B Plus
10S 10A Balance Charger/Discharger 1010B Plus
8S 20A Balance Charger/Discharger 208B
350W DC Power Supply P350
CellLog 8S

 

[bearing]

So if your question is in the new units have they swapped em out?

The first reports were saying units are of excellent quality, and "spot on" on voltage. Now they read like 30 mV from each other. Chargery must have changed something. Maybe they are not calibrating each unit anymore (if they were). Or maybe they have changed some components, like resistors or the voltage reference.

 

[webfootguy]

Hello everyone,

These BM6 are still all that and the issues I detail can be compensated for, these are still the cheapest simplest off the shelf way I know of to protect Li cells, that said... there are a few issues you should know about.

http://www.designsforbusiness.com/ebikes/videos/BM6-CalibrationIssues/Edited_IMG_0047_BM6_OutOfCalibration_Proof.avi

This video shows the variation and incorrect HVC triggering of the BM6 when testing 4 of them on the same turnigy 6s lipo.

I have edited out the swapping the BM6 units (4 tested and demonstrated on the same 6S pack with nothing connected to it... btw, the fluke and the iCharger show all cells between 4.179 and 4.185 there are .002mv differences between the Fluke and iCharger but that is not of concern... you can see as these 4 BM6 cycle through their various readings they are widly off. You will also hear the HVC beep cut in... look it thinks some of my cells are 4.22+?

The good news here is the error is on the high side, so a cell of 4.18 could read as 4.22+ and trigger HVC alarm... atleast it will prevent overcharge. There are some variations (much more limited scale .010mv) in the LVC detection also... so 3.2 could be 3.21 but... again it's to the side of caution so it's not dangerous but to have finite control and get the most from your packs... you should test / calibrate each BM6 so you know it's offset. This will allow you to select a more appropriate LVC and to determine based on the displayed value if you should ignore the HVC alarm on a particular BM6 unit / cell.

Really, hope this helps!

-Mike

Any idea how hard it would be to modify them to do things like add shunt bypass on over voltage and add an opto to daisy chain the low voltage cutoff signal?
This might be a cheaper/quicker method to get a working BMS for a large number of cells than a by scratch design or modifying an existing design (and the surface mount parts make the whole thing much smaller as surface mount is harder to do by hand for small runs).

 

[scoot]

Hi,

It would be nice if someone would test the CellLog 8S battery monitor and logger. Its more expensive but 8s is an advantage and it has logging.
http://www.hillrc.com/Enproducts.asp

【iCharger Products】
10S 10A Balance Charger/Discharger 1010B
6S 10A Balance Charger/Discharger 106B
6S 10A Balance Charger/Discharger 106B Plus
10S 10A Balance Charger/Discharger 1010B Plus
8S 20A Balance Charger/Discharger 208B
350W DC Power Supply P350
CellLog 8S

I tried that link but could not get it to work right now... But that is the kind of 8s device I think I am looking for too. I'll try again later :wink:

 

[mwkeefer]

This was an is my initial thinking, I was working on tapping into the BM6 to be used as a sensor module (so 4 for 12S2P pack) interfaced to an Atmega1280 as the primary controller which would be how we would use the signals from the BM6 units. LVC can be handled by interrupting the throttle return +vcc line via a simple transistor based switch (or even a relay)... HVC would do the same.

I have an email (and an order) to Chargery to see if this is a flake issue or serious, I will post my results when I have them (and before I continue this branch of BMS system).

-Mike

 

[methods]

I could not get either of your videos to play.

All I can say is that the BM6's I own are dead on and always have been.
I know that the owner of Chargery (name slips my mind) will do a run of just about anything for you if you are willing to order 100 pieces.
My guess is that now that he is selling to Hobby City they put the squeeze on him and now instead of selling quality is is selling quantity.
If you sell 20,000 of something for only $0.07 more than it costs to make I could see where you would be trying desperately to save a few bucks on each unit...
Maybe running 5% resistors is something he would consider.

Perhaps the new units do have lower quality divider resistors
That would be insanity though - technilogical suicide.
Chargery works closely with the RC community and they clearly understand the importance of accuracy. I find it very hard to believe that they would do this.

Can anyone else report on an error?
All of mine read almost identically give or take 5mV

-methods

 

[mwkeefer]

I just looked into the CellMon8 and it might be a really good fit... but nearly 2x the price even on sale @ 27.79.

Interesting thing about them is they have trigger outputs for multiple condition alarms such as Pack Voltage or Cell Voltage + USB Interface for PC + 16MB of FLASH for logging in logview open format.

I will order a pair to test.

-Mike