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Old 02-05-2009, 10:25 AM   #1
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Default Much-more CTXD2 .

Hi , i have a MM CTXD2 and a EP 4600 pack , when i discharge on my D2 my pack to 0.9v and when i fully charge the pack , it only peaks at 3800 mah .
But when i dead shorted my pack for 30 mins down to 0.9v on my D2 , my pack peaked at 4418 mah ,im wondering if dead shorting the pack damages the pack .
Could I get peoples advice please , thanks.
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Old 02-05-2009, 10:34 AM   #2
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Hi , i have a MM CTXD2 and a EP 4600 pack , when i discharge on my D2 my pack to 0.9v and when i fully charge the pack , it only peaks at 3800 mah .
But when i dead shorted my pack for 30 mins down to 0.9v on my D2 , my pack peaked at 4418 mah ,im wondering if dead shorting the pack damages the pack .
Could I get peoples advice please , thanks.
Usually it will. In the past, some batteries had a increased in voltage, but at a loss of runtime when they were deadshorted. Modern Ni-mh cells HATE this. It can cause them to do some really odd things. I did try it once and the cells had an ever greater problem with self discharging when not in use. These cells perform their best when you leave about a half to almost a full charge in them for storage.

Don't worry about the "mah" that you are putting into the cells either. It's not a very accurate way of showing how much capacity it has. It relies entirely on how much voltage was originally in the battery pack itself at the start.

But looking at those packs, the capacity has either dropped over time with use or they just havent been cycled in a while. Sometimes when you use the packs a little more it "wakes" them up, and they end up performing a little better.

-Korey
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Old 02-05-2009, 10:36 AM   #3
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Your not really dead shorting it if you discharge it down to 0.9v. The CTX is a great discharger for your cells......... Only one I use!
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Old 02-05-2009, 10:37 AM   #4
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Usually it will. In the past, some batteries had a increased in voltage, but at a loss of runtime when they were deadshorted. Modern Ni-mh cells HATE this. It can cause them to do some really odd things. I did try it once and the cells had an ever greater problem with self discharging when not in use. These cells perform their best when you leave about a half to almost a full charge in them for storage.

Don't worry about the "mah" that you are putting into the cells either. It's not a very accurate way of showing how much capacity it has. It relies entirely on how much voltage was originally in the battery pack itself at the start.

But looking at those packs, the capacity has either dropped over time with use or they just havent been cycled in a while. Sometimes when you use the packs a little more it "wakes" them up, and they end up performing a little better.

-Korey
OK , but doesnt the mah effect the runtime , like a 4400 pack will last longer then a 3800 pack.
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Old 02-05-2009, 10:45 AM   #5
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OK , but doesnt the mah effect the runtime , like a 4400 pack will last longer then a 3800 pack.
Like Korey said, after discharging them regularly and charging them at a proper setting, you will "wake" them up and the MAH will come back. Charging them up past 4400 MAH is not bad..........Don't forget to leave charge in them when your done racing for the day.
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Old 02-05-2009, 10:48 AM   #6
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Your not really dead shorting it if you discharge it down to 0.9v. The CTX is a great discharger for your cells......... Only one I use!
Well i am , first i discharge the pack with linear to 0.9v then i dead short the pack at 0.9v , so what would you recomend ?
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Old 02-05-2009, 10:56 AM   #7
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Once you get the cells down to 0.9v, charge the cells at 6 amps. Set the delta peak at about 10mv. Once the cells are charged, your ready to run.

.........I usually put about 1500 MAH in the battery before I pack up and call it a weeknd of racing.......My packs have lasted me 8 months, so far, and the charges get up to 4600 mah or more.........Good Luck!
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Old 02-05-2009, 11:02 AM   #8
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Try setting the CTX-D to 0.7V cutoff with the 5A linear discharge. This gives a nice balance between energy taken out for effective equalising, and a safe margin to stop the cells getting too close to 0V.
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Old 02-05-2009, 11:04 AM   #9
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Once you get the cells down to 0.9v, charge the cells at 6 amps. Set the delta peak at about 10mv. Once the cells are charged, your ready to run.

.........I usually put about 1500 MAH in the battery before I pack up and call it a weeknd of racing.......My packs have lasted me 8 months, so far, and the charges get up to 4600 mah or more.........Good Luck!
So , i always leave 3000 mah in the pack for storage for 1 month but i remember trying to last a 5 min race with my pack that only peaks at 3800 was hard and even impossible .
If you dont get it , i have 6 packs , 5 of them are able to last 5min ( cuz they peak at 4400 mah but the 6th pack only peaks at 3800 mah and i could only last 4 min 40 sec , so i dead shorted the pack and it peaked at 4400 mah ( lie the other packs and i could last 5 mins , what i want to know is can i dead short my pack ( wich is only 3 weeks old ) to get more runtime to last 5 min ??
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Old 02-05-2009, 11:07 AM   #10
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So , i always leave 3000 mah in the pack for storage for 1 month but i remember trying to last a 5 min race with my pack that only peaks at 3800 was hard and even impossible .
If you dont get it , i have 6 packs , 5 of them are able to last 5min ( cuz they peak at 4400 mah but the 6th pack only peaks at 3800 mah and i could only last 4 min 40 sec , so i dead shorted the pack and it peaked at 4400 mah ( lie the other packs and i could last 5 mins , what i want to know is can i dead short my pack ( wich is only 3 weeks old ) to get more runtime to last 5 min ??
DO NOT dead short a NiMH pack.

I think your runtime issue has been brought up before - the answer is that you are using too hot a motor for your skill level. Run a softer motor. Silly tricks to try and gain a high charge capacity will not make any significant difference on the track and will only serve to damage your cells.
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Old 02-05-2009, 11:09 AM   #11
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I never dead short my packs so I'm not sure what it would do to that pack.
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Old 02-05-2009, 11:11 AM   #12
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OK , so i think i will stop dead shorting my packs and i will set the cut off at 0.7v .
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Old 02-05-2009, 11:20 AM   #13
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Thanks ALOT for the quick replys , i got what i wanted to know in 10 mins , thanks again guys .
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Old 02-05-2009, 01:25 PM   #14
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Could you guys look at this and tell me what you think , because i dont know if they are right or no ?
http://www.petitrc.com/view_news.php?id=5330
Thanks .
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