Upgrade MRC 989 for use with A123's
 

Hi Tim,

What are the chances you folks will write code for charging A123’s and let us send in our MRC 989’s for an upgrade? Now that would be cool!

SOS

RE: Upgrade MRC 989 for use with A123's
 

I'd like to see some charger with adjustable voltage termination (by voltage) along with some safety parameter as a double check so the user can simply dial in the correct voltage like a digital power supply.

RE: Upgrade MRC 989 for use with A123's
 

What about the powersuply feature of the 989. In this setting you set the max voltage and max ampreage you want:eek:

RE: Upgrade MRC 989 for use with A123's
 

Hmm, sounds like a good idea, never thought of that.

Actually that's a great idea. I will try it out and see.

RE: Upgrade MRC 989 for use with A123's
 

I wonder if you were to use the power supply for charging, if it would be beneficial to incorporate the “Dapter” as a kind of safety feature. Guver, l'd be interested to know what you discover.

RE: Upgrade MRC 989 for use with A123's
 

I've been thinking about this and will hopefully test it this weekend. I'll post another topic to discuss outside the MRC forum.

Psst, nobody tell Tim yet [sm=47_47.gif] Sounds like a nice marketing feature?

RE: Upgrade MRC 989 for use with A123's
 

Sorry guys, I was away for business for a week and just got back. I did ask my engineer, and he said the power supply mode would be fine for charging the A123 cells. However, I'm not going to officially say "Yes, it will absolutely charge them with no problems." until I get some cells and test it for myself. So for now I would hold off, but if you want to do your own testing, I can't stop you.

RE: Upgrade MRC 989 for use with A123's
 

http://www.rcuniverse.com/forum/m_6600923/tm.htm

I think your engineer is right. Here's what I have so far. A couple of tweaks to the charger and it can be marketed as chargeing any termination voltage, more risk of user mistake though.

RE: Upgrade MRC 989 for use with A123's
 

Is mrc considering a software upgrade so we can charge a123 cells?

RE: Upgrade MRC 989 for use with A123's
 

I've done some testing with the 989 and A123, and we are considering something, but I'm not quite sure yet. The 989 will charge the A123's in Power Supply Mode, but it won't do them in 15 minutes, and it doesn't show capacity or actual voltage, etc... in power supply mode. So that's why we haven't said anything to effect the it will charge them. My engineer tells me that he could program the 989 to show those things in power supply mode, but it still won't be able to charge them in 15 minutes. I haven't had a chance the sit there with a stop watch to see how long it actually takes. Maybe guver has a better idea.
Hey guver, how are you able to graph the charge? What settings did you use when testing the A123s? I've been using 12 amps at 7.2 volts, and I think it's taking almost an hour to fully charge, but I'm not sure. As the voltage in the pack approahes the 7.2 volts, the amperage is dropping, so that's why it's taking longer.
If MRC decides to offer a re-program/upgrade, I'll announce it on this board.

Tim Sandor

RE: Upgrade MRC 989 for use with A123's
 

I used a dvm with pc graphing interface sold by Radio shack. I can't remember the settings and do not have any A123 cells. I used Lipos. I'm going to charge some lipos to a "storage voltage" soon.

Hmm, we have 106 watts available. I thought we were limited to 10 amps as well? If so then a 2S A-123 would start out at 10 amps and taper off like you stated. A 3S might do 10 amps, 4S might do 8 amps , ect.

I'm sure we won't get a 15 minute charge, but would be able to get a 3C (or more) charge at least in the start.

RE: Upgrade MRC 989 for use with A123's
 

I was hoping that MRC would step up and make the 989 capable of doing A123. I know in the present form it will charge A123 in the lipo and power supply mode if done correctly but upgraded specifically to do A123 would be fantastic. I've noticed Astroflight has offered an upgrade to their 109 lithium charger for A123 so it's nice that MRC is looking into it as well. I love my 989 and look forward to charging my 6s1p MEC solderless power tubes when I get them built. Fifteen minutes is an attractive number but isn't the end all be all for someone like myself. As long as it will charge them in a decent amount of time and I don't have to upgrade to another expensive charger right now I'd be happy. I've already dropped over $600 changing to A123 and a charger isn't in my budget right now. The weather outside sucks right now so I'll patiently wait [&o]

RE: Upgrade MRC 989 for use with A123's
 

I now have two 6s1p A123 MEC solderless power tubes built which I have been testing with the 989. I've charged on both the 5s lipo charge and using the power supply mode. The lipo setting charges up as expected to a touch over 21v. The power supply mode has to be set to 21.7v to overcome the slight shortage in the actual output of the charger. The readout of the charger is off by only .04 so it's fairly close and is consistently off by that amount. The charger will allow up to a 5.3-5.8v charge for my packs in parallel in lipo and around 4.8v in power supply mode. In lipo charge the pack will only lose a slight amount of voltage as the pack sits. On the other end if charged in PS mode the pack looses quite a bit and ends up around 20.2v. That's a large loss in voltage from a peak of 21.7. In PS mode the amps gradually taper down till they get to 0. It takes quite awhile to get the amps to 0 and they will bounce up and down. I've not allowed it to do this for very long so I'm not sure if the charger will eventually stop in PS mode. I believe the cells are shedding off power and the charger is flowing a little current as they are doing this hence the current fluctuation at the end. I fly the SPT's in my Align 600 as 12s, sport flying for 7min dead or 6min with some to spare. The packs take around 45-55 min to charge so it's quite a long time.

RE: Upgrade MRC 989 for use with A123's
 

I built a 5s1p A123 pack for my Electristar from a Dewalt 36v tool battery. After reading the posts by guver I thought before buying another charger for A123's (own two 989's) I would try charging with the 989 in power supply mode along with my Hyperion LBA10 balancer. On the first try I set it to 18v and 5.8a (max amps it would allow). The battery charged for about 20min at 5.8amps and then tapered off to 0amps in about an hour. The battery came off the charger at 18v but after 30min dropped down 17.6v. All the cells were perfectly balanced. I discharged the pack and recharged at 18.5v and 5.8amps. After an hour the pack came off the charger at 18.5v and settled down to 18.2v after 30 min. After 12 hours it's still holding at 18.2V. During charging I hooked up my Eagle Tree logger to monitor the amperage and voltage. It appears the Super Brain can charge A-123 cells.[8D] Do so at your own risk.

http://img.photobucket.com/albums/v2...es/A123989.jpg

RE: Upgrade MRC 989 for use with A123's
 

Tim, any info on an upgrade yet? Really would like to see this feature on my 989.