R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric On-Road

Reply
 
Thread Tools Search this Thread
Old 04-04-2004, 11:44 PM   #1
Tech Champion
 
Still Bill's Avatar
 
Join Date: Jan 2004
Location: Reno, NV
Posts: 7,237
Trader Rating: 12 (100%+)
Default Battery issue

A few hours ago, I charged (@ 5.5 volts with a .04 cutoff) a 6 month old GP3300 matched 1.17+ V battery pack on my GFX and it topped out at about 1600 mahr. The cells on both ends were pretty hot; so, I took temps of each cell in the pack within 20-30 seconds after the charging ended.

The temps were as follows: 180 - 150 - 120 - 120 - 150 - 185 (temps rounded to nearest 5 degrees)

Don't think I've ever had such variances between cells after charging a pack. I would call it warm in the center going towards hot on each end

Anyone have an idea what is wrong?
__________________
Constantly evolving CRC WGT and WGT-R/T...Carpet & Asphalt...All thanks to Team CRC.

And a pair of Associated B6 buggies for turf and clay tracks.
Still Bill is offline   Reply With Quote
Old 04-04-2004, 11:57 PM   #2
Tech Elite
 
fatdoggy's Avatar
R/C Tech Charter Subscriber
 
Join Date: Aug 2001
Location: MD USA
Posts: 3,642
Default

Check each cell with a volt meter to make sure you don't have any dead cells.
fatdoggy is offline   Reply With Quote
Old 04-05-2004, 02:29 AM   #3
Tech Regular
 
Johnny J's Avatar
 
Join Date: Feb 2003
Location: Australia, NSW
Posts: 375
Default

That sounds pretty bad. Try putting it on a tray and deep discharge the individual cells.
Johnny J is offline   Reply With Quote
Old 04-05-2004, 02:42 AM   #4
Tech Elite
 
Join Date: Oct 2003
Location: Green Bay,WI
Posts: 3,006
Trader Rating: 1 (100%+)
Send a message via AIM to R/C Anonymous
Default

get an equalizing tray ....problem solved
__________________
Geoff C.
R/C Anonymous is offline   Reply With Quote
Old 04-05-2004, 03:33 AM   #5
Tech Apprentice
 
Join Date: Jun 2003
Location: Norway
Posts: 70
Default

How long should they rest on the tray for maximum result?
sturla is offline   Reply With Quote
Old 04-05-2004, 04:00 AM   #6
Tech Elite
 
AdR|aN's Avatar
 
Join Date: Jul 2003
Location: Malaysia. Land of Peace.
Posts: 2,445
Send a message via ICQ to AdR|aN
Default

IMHO, cycle them a few times then get a reading again.
It might be caused by maybe 1 or 2 bad cells.
NiMH cells arent suppose to sit in a tray for too long or it will kill them.
AdR|aN is offline   Reply With Quote
Old 04-05-2004, 07:48 AM   #7
Tech Champion
 
Still Bill's Avatar
 
Join Date: Jan 2004
Location: Reno, NV
Posts: 7,237
Trader Rating: 12 (100%+)
Default

Quote:
Originally posted by fatdoggy
Check each cell with a volt meter to make sure you don't have any dead cells.
Hi fatdoggy,

All are 1.24-1.25 V after discharge. Should I give it another charge and measure them that way?

I do tray my batteries weekly. Have an Octane 2. Typically use them twice on race day because they charge better the second time around.

Thanks.
__________________
Constantly evolving CRC WGT and WGT-R/T...Carpet & Asphalt...All thanks to Team CRC.

And a pair of Associated B6 buggies for turf and clay tracks.
Still Bill is offline   Reply With Quote
Old 04-05-2004, 08:07 AM   #8
Tech Elite
 
fatdoggy's Avatar
R/C Tech Charter Subscriber
 
Join Date: Aug 2001
Location: MD USA
Posts: 3,642
Default

If they are all reading 1.24-1.25v then you don't have a dead cell. I'm not sure, weird. Not too much solder on the solder joints?
fatdoggy is offline   Reply With Quote
Old 04-05-2004, 08:25 AM   #9
Tech Master
 
raving-monkey's Avatar
 
Join Date: Apr 2004
Location: yorkshire, england.
Posts: 1,818
Send a message via MSN to raving-monkey
Default

if you deep discharge your cells (to below say 5.4v for the whole pack) they will never recover.

do not discharge at below 0.9v per cell (5.4v per pack)

this is why its better to get an equalising tray that cuts off at 0.9v.

or if you know your circuits make your own with some 0.9 zenna diodes and a couple of resisitors/capacitors...what ever they are
raving-monkey is offline   Reply With Quote
Old 04-05-2004, 08:27 AM   #10
Tech Elite
 
fatdoggy's Avatar
R/C Tech Charter Subscriber
 
Join Date: Aug 2001
Location: MD USA
Posts: 3,642
Default

The integy chargers discharge to .8v per cell (4.8v) and I've never had any problems.
fatdoggy is offline   Reply With Quote
Old 04-05-2004, 09:14 AM   #11
Tech Master
 
raving-monkey's Avatar
 
Join Date: Apr 2004
Location: yorkshire, england.
Posts: 1,818
Send a message via MSN to raving-monkey
Default

well my dad works with this guy and specialises in cells/power etc and wegot him to design us a circuit for an equalsiing tray, and we were gonna get it to cut off at 0.7...but he said that was to low and it will discharge the cells too low. and he said the lowest to go is 0.9v per cell.

once he has finsihed the circuit i will post it if you want.
raving-monkey is offline   Reply With Quote
Old 04-05-2004, 09:45 PM   #12
Tech Champion
 
Still Bill's Avatar
 
Join Date: Jan 2004
Location: Reno, NV
Posts: 7,237
Trader Rating: 12 (100%+)
Default

Quote:
Originally posted by fatdoggy
If they are all reading 1.24-1.25v then you don't have a dead cell. I'm not sure, weird. Not too much solder on the solder joints?
Hi again fatdoggy,

Have a 60W iron and it does a nice job for me. Pretty confident that soldering is not the issue.

So, I charged it again tonight. Not much of a rest. Only went to 2650 mahr; but, it didn't have any high temp issues.

Funny that the temps were basically opposite from the previous. Being 110 - 120 - 130 - 130 - 120 - 115 across the pack. So, for this case, they were warmer in the middle than on the ends.

Then, I charged up its "sister" battery (bought at same time) and it went to virtually the same mahr and temp figures.

Pretty much going to be using these two packs for practice at this point in time. Got new packs on the way.

Going to chalk this whole thing up to a fluke occurence.

Thanks again.
__________________
Constantly evolving CRC WGT and WGT-R/T...Carpet & Asphalt...All thanks to Team CRC.

And a pair of Associated B6 buggies for turf and clay tracks.
Still Bill is offline   Reply With Quote
Old 04-05-2004, 09:58 PM   #13
Tech Champion
 
Still Bill's Avatar
 
Join Date: Jan 2004
Location: Reno, NV
Posts: 7,237
Trader Rating: 12 (100%+)
Default

Quote:
Originally posted by raving-monkey
if you deep discharge your cells (to below say 5.4v for the whole pack) they will never recover.

do not discharge at below 0.9v per cell (5.4v per pack)

this is why its better to get an equalising tray that cuts off at 0.9v.

or if you know your circuits make your own with some 0.9 zenna diodes and a couple of resisitors/capacitors...what ever they are
In concept, I agree. However, there have been multiple times that I have discharged beyond .9v with excellent mahr readings on the following recharge. It's a mixed bag.
__________________
Constantly evolving CRC WGT and WGT-R/T...Carpet & Asphalt...All thanks to Team CRC.

And a pair of Associated B6 buggies for turf and clay tracks.
Still Bill is offline   Reply With Quote
Old 04-05-2004, 10:23 PM   #14
Tech Master
 
raving-monkey's Avatar
 
Join Date: Apr 2004
Location: yorkshire, england.
Posts: 1,818
Send a message via MSN to raving-monkey
Default

yes but maybe that is why your have 2 dodgey packs.

you discharged them lower than 0.9v per cell (not much lower) and they will not recover all the way, but say if you discharged them at 0.7 and down they would never recover.
raving-monkey is offline   Reply With Quote
Old 04-05-2004, 10:40 PM   #15
Tech Elite
 
BigDogRacing's Avatar
R/C Tech Charter Subscriber
 
Join Date: Aug 2001
Location: Memphis, TN
Posts: 2,955
Trader Rating: 12 (100%+)
Send a message via MSN to BigDogRacing
Default

Raving Monkey- please stop telling people how to manage their batteries when you don't know what you are talking about. .9volts is the cutoff for high amperage discharge (10-30 amps). It's perfectly fine for him to discharge his cells in a discharge tray until the lights go out. If they have never been dead shorted I wouldn't leave them in the tray for very long. If you onlt race in stock class you can dead short your new packs after the first cycle. Make sure to deep discharge them in a tray that takes them to 0 volts before you short them.

I'm sorry to be harsh Monkey, but you obviously don't have a clue on what we are doing to the newer GPs. You might try listening more and typing less before you become all knowing....
BigDogRacing is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
HELP!!! ESC Issue Chris__RC Electric Off-Road 6 08-31-2008 01:31 PM
Battery charging issue Weasely Rookie Zone 9 09-29-2007 08:47 AM
AE 18B Battery Issue Staufman Electric Off-Road 0 09-14-2007 06:19 PM
DPD issue Racingfreak6 Electric On-Road 5 01-01-2007 09:56 AM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 08:50 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net