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results - 6/2/2002 5:33:10 PM   
RC Accessory



Posts: 607
Joined: 12/7/2001
From: Tampa, FL, USA
Status: offline 		I do not think so. My next test is to take a 4 cell 2700 and do the same test. This time I will repeat the procedure with the same values. 2700 nimh 4 cell pack. 2.7 amp charge (C/1) and 1 amp discharge.

I think the problem is the SN can't properly peak a large pack at a large charge rate. C/1 is an acceptable charge rate for nimh cells.

Put it this way, if the problem is that the unit can't properly peak charge at a C/1 charge rate, its usefullness as a field charger becomes in questions. C/1 is not that high of a charge rate and is well within the spec's of the battery.

(in reply to DrV)
       Post #: 26

SuperNova vs SuperTurbo - 6/4/2002 6:14:40 AM   
lennyk


 

Posts: 565
Joined: 12/8/2001
From: Port of Spain, FL, USA
Status: offline 		Evan,

I have the problems charging nimh with my Supernova at
100ma.(lowest rate) I have tried 2 packs so far, a 4 cell and a 5 cell AA's
they both end prematurely. I have tried the slow initial charge etc to no avail.

(in reply to DrV)
       Post #: 27

SuperNova vs SuperTurbo - 6/10/2002 9:36:01 PM   
Alastair



Posts: 79
Joined: 6/10/2002
From: FL
Status: offline 		I have the sn charger and have the same problem with getting a full charge into nimh batteries. I find it works fine by just using automatic even though it says not to in the instructions.

(in reply to DrV)
       Post #: 28

SuperNova vs SuperTurbo - 6/10/2002 11:45:46 PM   
EddieWeeks



Posts: 1132
Joined: 12/27/2001
From: Baton Rouge, LA, USA
Status: offline 		I too am having problems with false peeks with
the SN so I did some testing.

I have a few Supernovas and lots of NiMH packs
and the instruction say only use the Auto mode
for NiCD batteries. I have watched the Auto mode
do its thing and it seems quite smart.

Using the Supernova with a 5 cell 1650 NiMH
Auto discharge with a Auto charge.

Charge Discharge
mah mah

1644 1497
1628 1481
1643 1475
1661 1482
1655 1491

The max charge current was around 1.3 amps and
even though the delta peak was set for NiCD, the
Auto mode seems to work fine for this pack.

I also charge a 6 Cell RC-3000 NiMH pack in Automode
and it went right to 5 amps and the pack did not
get any hotter then a manual charge set to NiMH.

I think I am going to just push the Autocharge from now
on.

Eddie Weeks
http://www.corpcomp.com/weeks1/

(in reply to DrV)
       Post #: 29

SuperNova vs SuperTurbo - 6/11/2002 10:22:47 AM   
Jazzy



Posts: 1106
Joined: 1/8/2002
From: Erie, PA, USA
Status: offline 		I E-mailed one of the Marks' brothers to find out the delta-V cutoff for NiMH and NiCD batteries in reference to the SuperNova.
NiMH: 0.07V
NiCD: 0.09V

I was also instructed to use the auto or NiCD programming if false peaks became an issue with the NiMH preprogramming.

By the looks of it I personally don't see a problem using the auto or NiCD preprogrammed presets for NiMH.

_____________________________

Aww $#!^.... I left the )@#& transmitter at home!

(in reply to DrV)
       Post #: 30

Info on fast charging NiMH - 6/5/2003 6:10:36 AM   
hatasaka


 

Posts: 1
Joined: 6/5/2003
From: Menlo Park, CA
Status: offline 		Thanks Evan for all the great info on ST vs. SN.

I can't say with certainty what the problem with the SN is, but it looks to me all the symptoms are related to the termination algorithm. I'd be willing to bet FMA is using a negative delta V (-dV/dt) algorithm.

Here are a couple of links describing various NiMH fast charge topologies and some problems with -dV/dt termination.

http://www.e-insite.net/ednmag/index.asp?layout=article&articleid=CA231590
http://www.powerstream.com/NiMH.htm

All the SN symptoms of early termination with high charge rates and new batteries bespeak -dV/dt.

Incidentally--not to throw gas on the charger flames--but just because the ST doesn't exhibit the same symptoms doesn't necessarily mean it's the superior machine. If it's also using -dV/dt, its specific algorithm may be less sensitive than the SN possibly leading to slight overcharge. Overcharge is much worse than early termination in terms of battery health.

As the Powerstream article states, temperature termination (dT/dt) is more reliable than -dV/dt. My experience with several 4-8 cell chargers tends to bear this out.

Does anyone know the specific termination topology used by ST and SN?

Thanks in advance.

Mark

(in reply to DrV)
       Post #: 31

SuperNova vs SuperTurbo - 6/5/2003 12:36:08 PM   
IronZ



Posts: 219
Joined: 12/27/2001
From: Tipp City, OH, USA
Status: offline 		The problems with the SN not peak detecting properly seem to be due to the break in of the battery. I researched this a bit and after buying my SuperNova found out that with a NEW NiMH battery the SN would false peak, I had to break it in with a C/10 rate three to four times and then the SN worked flawlessly. New batteries don't peak properly on the SN. Since you are supposed to break in new packs anyway, I don't see how this is a real issue. Also, I was advised by FMA to set the battery up as a NiCd (.2 mV diff) and it would function properly, they were right. They also said to NOT use the AUTO mode, as this may be to hard on the NiMH's. Just some info I have.

IronZ

_____________________________

[color=red]IronZ
[/color]

(in reply to DrV)
       Post #: 32

SuperNova vs SuperTurbo - 6/5/2003 6:03:55 PM   
reggles


 

Posts: 3
Joined: 5/30/2003
From: Surrey, England
Status: offline 		Guys,

For what it's worth, I purchased one of the very latest Simprop Intelli-Control chargers, with the new V3 software, when I was over in Dortmund back in April. The Supernova is supposed to be a 'badged' version of the Simprop unit, but I do not think there is a V3 software version of the SuperNova released yet.
I have not had much chance to use my Intelli-Control V3 yet, but I have used it to charge some 8 cell packs of GP 3300 Nimh cells and had no problems at all. However, these packs were initially put through 3 cycles of discharge/charge at the C10 rate, before attempting to fast charge same on the Intelli-Control V3, and then I did charge same using the manual program and a 1C charge rate, as recommended by Simprop in their instruction manual for the charger.
From what I have read here and on other forums, the key to successful charging of Nimh packs, whatever the charger, seems to be this initially cycling the packs at the C10 rate and then fast charging at a 1C - 1.5C maximum rate !

Reggles

(in reply to DrV)
       Post #: 33

SuperNova vs SuperTurbo - 6/5/2003 6:28:27 PM   
jacs



Posts: 394
Joined: 1/27/2003
From: Uddevalla, SWEDEN
Status: offline 		My SuperNova v.2 has no problem putting in 660 mAh in a 600mAh NiMH battery pack or 2000+mAh in a 1500mAh NiCd. The only think that I have notice is that discharge isn't good. So sometimes I discharge my battery pack's with an electric engine.

By the way reggles new Simprop V3 can handle Litium batteries also so that charger will be my next one if I go for litium in my parkflyers.


_____________________________

Jacs

(in reply to DrV)
       Post #: 34

SuperNova vs SuperTurbo - 6/11/2003 8:58:22 AM   
rcgear


 

Posts: 33
Joined: 8/11/2002
From: mary esther, FL, USA
Status: offline 		Eam201, I agree that you are way off base! This is constructive exchange of ideas and information.

rcgear

(in reply to DrV)
       Post #: 35

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