Jun 03, 2008, 03:33 PM
Registered User
Joined Feb 2008
183 Posts
Quote:
 Originally Posted by Technical Tim I am just in the process of balance charging a battery with menu 2 set at +20, when I changed it the reading moved up 0.02 V which hopefully give me a slight reduction in max cell charge. Will reply shortly. TT
Ya, my cheapo meter was similar to a Fluke reading too, should be good enough for us.

The play by play is awesome, I'm on the edge of my seat.
 Jun 03, 2008, 03:53 PM Registered User Lancashire, England Joined Jun 2008 6 Posts Okay the charger has finished. Balance charging at 2 amps for a 2250 mah battery. (the amps dont seem to affect balancing accuracy) Charger readings Pack voltage - 12.6 V All Cells 4.16 v x 3 = 12.48 V Meter readings Pack voltage - 12.58 V Cell 1 - 4.22 V Cell 2 - 4.18 V Cell 3 - 4.17 V So no real change apart from a slightly reduced pack voltage as a result of that 0.01 V reduction in cell 1. It does appear my charger always seems to balance cells 2 and 3 within 10mV, with readings are about 20 mV low. I cant understand why cell 1 is so different. I know about the resistor issue, and maybe I just got 2 'good' resistors for cell connections 2 and 3. If cell 1 was as close as the other 2 I wouldnt have a problem, just a pretty accurate charger. Oh well, I will monitor it, and considering the tech specs on some balancers like the blinky state a voltage of 4.25 V before anything happens, I think at this setting I will be okay. Cheers TT
Jun 03, 2008, 04:16 PM
Registered User
Joined Feb 2008
183 Posts
Cool, thanks for the update.
Ya, 4.22 isn't too bad, too close for my tastes, but at least you're below the EVO stated 4.23V maximum voltage, so it shouldn't be causing any damage.

I think cell 1 always has a problem because of the way the circuit is built, cell 1 isn't treated exactly the same as 2 and 3, so resistor variances affect it more than normal. If it were purely resistor error that lead to cell 1 being too high, then it would be random between chargers, but we've both got problems with cell 1 being too high compared to the other cells.

My cheapo charger also sets cell 1 too high. I wonder if other people have a problem with cell 1 being too high.

You're lucky Tim, at least you can use your charger. Mine, even at +20, still overcharges. I got a real bad one.

Quote:
 Originally Posted by Technical Tim Okay the charger has finished. Balance charging at 2 amps for a 2250 mah battery. (the amps dont seem to affect balancing accuracy) Charger readings Pack voltage - 12.6 V All Cells 4.16 v x 3 = 12.48 V Meter readings Pack voltage - 12.58 V Cell 1 - 4.22 V Cell 2 - 4.18 V Cell 3 - 4.17 V So no real change apart from a slightly reduced pack voltage as a result of that 0.01 V reduction in cell 1. It does appear my charger always seems to balance cells 2 and 3 within 10mV, with readings are about 20 mV low. I cant understand why cell 1 is so different. I know about the resistor issue, and maybe I just got 2 'good' resistors for cell connections 2 and 3. If cell 1 was as close as the other 2 I wouldnt have a problem, just a pretty accurate charger. Oh well, I will monitor it, and considering the tech specs on some balancers like the blinky state a voltage of 4.25 V before anything happens, I think at this setting I will be okay. Cheers TT
 Jun 03, 2008, 04:38 PM Registered User Lancashire, England Joined Jun 2008 6 Posts Sorry to hear you got a bad one. If I hear anymore about this charger will post. Cheers TT
 Jul 07, 2008, 08:13 AM Given up counting Bicester, UK Joined Sep 2005 2,372 Posts Has anyone figured out how to get menu 1 back? I got a mystery B6 charger but menu 1 doesn't appear at all. Menu 2 does though.
Jul 13, 2008, 03:34 PM
Registered User
Joined Dec 2007
19 Posts
Quote:
 Originally Posted by bennetje So I think the best way to threat this charger is: 1. use my kit to exchange the bad resistors for good and stable ones 2. Connect 6 accurate 4.20V voltage sources to the balance connector and go to service menu 1 for calibrating (use fully charged perfectly balanced Lipo packs or powersupplies for this). 3. Connect an accurate 12.60V voltage source (Lipo or power supply) to the banana outputs, go to service menu 2 and adjust the voltage reading on the display to 12.60V And like Dusk already said: be very careful when using service menu 1, because after calibrating it is not accessible anymore!! Ben.
I would just like to say that after following the steps above my IMAXB6 finally is worthy of being called a ”balance charger”. I used 2 3S packs, perfectly balanced and connected in series, to do the menu 1 calibration. Prior to this I had used Bens resistor upgrade to replace the 1% resistors.

I wonder if the imax B6 chargers are not calibrated from factory. This would explain why the balancing is so poor with the 1% resistors, why menu 1 is accessible, and why changing to 0,1 resistors alone improves the balancing significantly. Recalibrating using service menu 1 and a balanced Lipo pack was the ultimate cure. After this my B6 always balances the cells to 4,18V. This is a bit odd since it was calibrated to 4,20V/cell, but all cells balances perfectly equal and that is all I ever wanted (accuracy must be within 0,01V now).

I think it is some built in safety function (or software bug) that keeps the charger for reaching 4,2v per cell. In service menu 2 the voltage reading is perfect (matches the connected battery). However when it is charging the displayed voltage is slightly higher then what can be measured with a voltmeter. This makes the charge stop at 4,18V per cell (charger displays 4,2v). I suppose the charger could be programmed so that wile charging it adds a little bit to the voltage reading so that there is no risk to overcharge (perhaps the imax manufacturers lazy fix to accept the original poor balancing).

Anyway I’m finally happy with my Imax B6. It took me a bit more then half a year since I bought it, and in the mean time I have bought a better charger to solve my balancing needs. In the end I did not save any money but I learned a lesson about buying Hobbycity crap.

Thanks Dusk and Bennetje for solving the mysteries.
 Aug 22, 2008, 07:30 AM Registered User Joined Feb 2008 10 Posts I wonder if anyone from iMax (SkyRC) is reading these threads ? Maybe he/she could explain how to reopen the balancing configuration menu once it's been used. After all, its their product and their (non)quality.
 Aug 22, 2008, 10:56 AM Registered User Joined Feb 2006 348 Posts Wouldn't bet on that. They probably copied everything including the software so I don't think they even know how it all works. Ben.
 Sep 04, 2008, 07:22 AM Registered User Joined Sep 2008 112 Posts 1. use my kit to exchange the bad resistors for good and stable ones Ben or any one. Might the kit work for a Mystery B6? Mine comes close to acceptable (4.22, 4.19, 4.18). I am able to access both menus 1 & 2 and did adjust #2 a couple of points with a known accurate source. I used my external Equinox balancer with the Mystery and got 4.20, 4.19 & 4.20. All readings were derived from charging new 2200s. While I'm not opposed to balancing externally the fact remains when you buy a balancing charger that's what one expects to get!
 Sep 04, 2008, 04:23 PM Registered User Joined Feb 2006 348 Posts I don't know. I don't have a Mystery B6 to check. But good chance it is the same as the Imax B6. Ben.
Sep 22, 2008, 10:17 PM
Registered User
Joined Sep 2008
2 Posts
I have a imax B6AC and i was thinking to get Ben's kit, but i saw this Trinity charger thats looks exactly like mind. They should be using the same board and power supply. http://www.redrc.net/2008/07/trinity...gement-system/ http://forums.radiocontrolzone.com/s...d.php?t=250929

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Last edited by lazyray304; Sep 23, 2008 at 08:45 PM.
Sep 29, 2008, 04:54 PM
Registered User
Joined Sep 2008
112 Posts
Quote:
 Originally Posted by lazyray304 I have a imax B6AC and i was thinking to get Ben's kit, but i saw this Trinity charger thats looks exactly like mind. They should be using the same board and power supply. http://www.redrc.net/2008/07/trinity...gement-system/ http://forums.radiocontrolzone.com/s...d.php?t=250929
Sprung for a Turnigy Accucell 6 from HobbyCity and it does the job, balances within .01 and has a cooling fan. At \$39.99 how can one go wrong.
 Nov 22, 2008, 12:38 PM Registered User Ipoh, Perak Malaysia Joined Jul 2006 4,033 Posts Hi Has anyone found a way to reactivate Menu 1 yet? Btw, before I found this thread, I was trying this buy pressing the paired buttons, since I had already known there way something like this when I read something like it some time ago. DO NOT press the Enter and INC key together during switch-on! I did that, and now I could get to charger to even swtich on! Totally dead. Does anyone have any idea how to fix that? Thanks chewy
 Jan 15, 2009, 11:03 AM Registered User Joined Mar 2008 14 Posts Tried service Menu today with a iMax B8. After applying 33.6V exactly (Philips 6.5 digits Calibrator, checked with Keithley 2000), the Menu showed: VOL(33.6V) 4700 IN:21 EX:2 (the Values IN and 4700 were varying for some seconds, then got stable). After this the Menu changed to 096 324 096 096X 096 096 096 096X Does not react to Stop, DEC, INC. I did not try Start/Enter! After that, I switched off. The procedure is repeatable so far... Next, I will get a plug for the Balance port and apply a voltage divider with 7 0.01% Vishay Bulk metal foil resistors... and see what happens ;-) So far, I think the B6 needs 25.2V Input and will show no VOL SET ERR! Thanks to dusk, for his investigation! Sorry for my English... rgds Achim
 Jan 15, 2009, 12:17 PM Registered User Ipoh, Perak Malaysia Joined Jul 2006 4,033 Posts Has anyone found out how to reset the service menu so that we can recalibrate the individual cells? My B6 won't response to the keypress. chewy