sos95714

Hi Tim, I’ve been using an MRC 989 for a few months now and have a few questions I would appreciate you helping me out with. First off, when Auto Cycling 110 mah nicd batteries, during the discharge stop phase the charger is actually charging the batteries at a 0.10 mah rate (aprox 1C) when it should be cooling the batteries down. I’m not sure this is good for the batteries and am wondering if this is normal or if this would be a Warranty issue.

Also, when slow charging new 4200 mah batteries on 1/10 C, after the timer maxxes out at 199 minutes and restarts, it gets stuck and cycles from 00:00 to 00:59 continually so I don’t know how long the batteries take to charge. This isn’t a big deal, and doesn’t seem to effect the charging, but at the same time seems seams kind of weird.

One other thing, Is there somewhere I can find out what the Stop Codes are and what to adjust to get the batteries to stop at the proper code. Right now the batteries are stopping at mostly C 2, and I get C 0’s whenever I top off batteries, and I think I’ve seen a few C 2’s. The problem is that I haven’t a clue what these codes mean (except I seem to remember C 0 being the normal stop code) or what to adjust when I get them. It would be helpful if you would provide a brief description of the stop codes for all us 989 users along with possible adjustments that would allow for a proper charge.


Thanks, Steve

PS. I posted a similar message in another thread but thought it would be more appropriate to ask a fresh question.

Tim@MRC

I saw your post on the other thread, I just haven't had a chance to test my 989 here to experience what you're refering to. Also, I have to get the termination codes from my engineer. As soon as I do, I'll get back to you. I just put a battery on to cycle now.

Tim

sos95714

I’ve been doing a little experimenting with my 4200 mah batteries and this is what I found. When I charge a 4200 mah battery pack at 4.2 amps the charge terminates with a “C-2” at 4722 mah capisity. I then imeadiatly start another charge cycle and the charge terminates with a “C-0” with a 249 mah capisity. Since the second charge cycle delivered 249 additional mah of capisity I went back to the settings area and changed the battery capisity from 4200 to 4500. Now when I charge the battery the charge terminates with a “C-0” at 4945 mah capisity, which I think is a good thing. I’m thinking the actual capisity of the 4200 mah batteries is so much greater than the rated capisity the “Brain” thinks something is wrong and prematurely terminates the charge. What are your thoughts? Do you think I’m on to something here? Maybe when you post the termination codes it will make more sense.

Have you been able to duplicate the charging at 0.1 mah while in discharge-stop mode? This one kinda bugs me.

Steve

Tim@MRC

The only time I've seen the 0.10 amps is after charge and before discharge. In the profile for that battery, adjust the trickle setting to 0.00 amps and see if it goes away. I don't see it after the discharge. I'm still trying to get the codes from my engineer, he's pretty tight lipped about it for some reason, but your assumption does make sense. I'll let you know when I find out what the C-2 means. I know that C-0 is normal peak. I'll get back to you.

Tim

sos95714

OK…I reset the trickle down to 0.00 and ran the Autocycle on the 110 mah 4 cell nicd’s again. I first stated the battery was charging at 0.10 amps during the discharge rest cycle. I was wrong, it seems the battery continues to discharge at the rate of 0.10 to 0.11amps during the discharge rest cycle. I say this because at the start of the 10 minute rest cycle the battery voltage is 4.56 volts and at the end of the rest cycle the voltage droped to 4.52 volts. All the while the current indicates 0.10 to 0.11 amps during the 10 minute discharge rest, increasing the total discharge by 18 mah.

With all other battery configurations I use (1200mah 6 cell nimh, 1100mah 7 cell nimh, 3000mah 6 cell nimh, 4200mah 6 cell nimh) there are no problems in this regard, only when I cycle my three 110 mah batteries. During the discharge rest cycle there should be no charging or discharging activity, right? I wonder if the problem might have something to do with the low mah setting (110 mah).

Steve

Tim@MRC

Sorry for the delay, I was away at the iHobby show for a week and I'm still trying to get caught up. I still haven't been able to reproduce the "trickle" discharge in between the discharge/charge cycles. I would use the charger for now, and when your R/C season slows down and you don't think you'll be using the charger for a week or so, send it in to us so we can take a look at it for you. At this point that's all I can really suggest.

Tim Sandor

sos95714

As you suggested, when the season ends I’ll go ahead and have you guys take a look at it. I did a little experimenting and when I discharge at low rates using the autocycle mode the 989 adds another 100 mah to the total discharge during the 60 minute discharge rest. I am assuming the rest period is to allow the chemicals in the battery to stabilize before the charging starts but I don’t know to what extent the continued discharging during the rest cycle is preventing this stabilization process, or even if it’s a critical issue, but since you can’t duplicate the problem I would guess it’s some kind of problem that can be remedied.

When I send in the 989 should I simply send it to the address on the back of the manual with a reference of our conversation?

Thanks,
Steve

Tim@MRC

Hi Steve,
Yep, send it to address on the back of the manual. Include a note detailing what we spoke about with your name, address, and phone number.

Tim

sos95714

Hi Tim,

I sent in my 989 for repair/replacement on 03/03/2008. Can you provide me with status?

Thanks, SOS