RCCrawler Forums

Tronk · 11-27-2006, 01:23 PM

I made the mistake of placing some new charged homemade battery packs in a container all together. They where placed in the container to seperate them from discharged battery packs. The packs have been in the container for 3 or 4 days. Tonight I found one of the battery cells slightly warm, but the other cells felt cold to the touch. It appears that the battery terminals/bars had made contact with each other for an undetermined amount of time. Around the positive and negative terminals of each battery cell there is a residue of what looks like rust. It is also the same colour as rust.I have removed the residue with a stiff brush and a light sand with sandpaper.

Is it advisable to see if these battery packs will take a charge or in anyones past experience is it wiser to change the batteries. I do not wish to do anything that could be beemed a fire hazard.

The bateries are sub c 4300mah packs that I made 2 weeks ago and each pack has been run twice.

Thanks for any help.

Moondust1950 · 11-27-2006, 01:30 PM

Have you ran them in water i hear salt water can rust your batterys

Tronk · 11-27-2006, 01:37 PM

Yes I have ran them on the beach.

Tronk · 11-28-2006, 12:49 AM

Please can someone advise if they think it is safe to charge the batteries

JohnRobHolmes · 11-28-2006, 11:19 AM

Do you have a voltmeter to test the voltage of each individual cell? If you can manage to balance the pack back out through individual cell discharging (with a small flashlight or car lightbulb), it will be safe to charge again.

Charge it at .4 amps when you do recharge.

Tronk · 11-28-2006, 11:24 AM

Many Many thanks for that.

SammyXp · 11-28-2006, 11:51 AM

There's a good chance the brown residue is just flux from when the pack was soldered together during its build. Are you sure the brown stuff is new? Or is there a chance it was there all along and you just never noticed it?

Tronk · 11-28-2006, 11:55 AM

The brown residue is definately new. They where clean when I made them. The residue did not appear until I placed the batteries all together. I know not to place batteries together with metal objects. On this occasion I just did not think. Think you americans use the term "dumbass".

I am going to do what Mr Holmes. I will put an update as to what happens.

Thanks for the replies guys

Tronk · 11-29-2006, 11:59 AM

I went today and bought a new charger and discharger. It is a BMI Digipeak14 ac/dc 1- 14 cell charger/discharger. The batteries are discharging as I type.

I responce to Mr Holmes stating that the following charge rate is required I would just like confirmation on the following calculation which I believe is correct but I am not totally sure.

Batteries are 4300mah.

Divide the mah by the charge rate of .4amp. =

4300 / .400 = 107 hours and fifty minutes to re-charge the pack.

Thankyou.

EeePee · 11-29-2006, 12:09 PM

Do .4 amps, but for no longer than 16 hours.

K_Willis · 11-29-2006, 12:11 PM

Quote:

Originally Posted by Tronk

I went today and bought a new charger and discharger. It is a BMI Digipeak14 ac/dc 1- 14 cell charger/discharger. The batteries are discharging as I type.

I responce to Mr Holmes stating that the following charge rate is required I would just like confirmation on the following calculation which I believe is correct but I am not totally sure.

Batteries are 4300mah.

Divide the mah by the charge rate of .4amp. =

4300 / .400 = 107 hours and fifty minutes to re-charge the pack.

Thankyou.

mah = milli amp hours...
so divide by 1000
gives you 4.3 amp hours...

so at 4.3/.400 gives you 10.7 hours... add a little extra time for heat loss etc.

JohnRobHolmes · 11-29-2006, 12:14 PM

the batteries are 4.3 amp hours or 4300 milli amp hours. 4.3/ .4 = 10.7 hours. They wont be fully charged in 10 hours though because of heat losses.

Nimh cells peak around 140 degrees F. Either pull them when any individual cell reaches over 150, or wait until 16 hours like EeePee suggests.

JohnRobHolmes · 11-29-2006, 12:15 PM

You type faster than me Willis!

Tronk · 11-29-2006, 12:17 PM

Many Thanks to the both of you.

I am finding all this very challenging.I only ever expected to get a truck, turn it on and drive away. I am finding that I need a lot of skills etc to keep up with what I want out of it. Maths is something I was never very good at. It is suprising though what you learn by doing a search. I always thought it was a bit "off" when you guys just used to answer search. I can understand it better now though as it is a great way to get experience.

I am just glad that you two did not just reply. SEARCH.

Thanks guys

Tronk · 11-29-2006, 12:19 PM

WOW Mr Holmes.

You got two posts in whilst I typed my reply.

Thanks for your help also.

I usually find myself searching through your posts when I get stuck

JohnRobHolmes · 11-29-2006, 12:29 PM

Did you use that new charger to discharge each cell individually, or did you find a bulb that did the trick?

Tronk · 11-29-2006, 12:38 PM

I went on a search and came up with the bulb reference number 1157. The car spares shop did not have a reference for that number. I then went searching deeper and got the bulb reference for a bulb in the UK, reference number 380-R 21/5w 12v1151. this is a bulb that drew 2 amps.The garage said it would be no good as it was a twin filament bulb.This is what I was going to build.

http://www.rccaraction.com/articles/...scharger_1.asp

I then went to the model shop and returned the brass rod that I had bought, and he said i needed the discharger that I bought. It was about 200 of your dollars but I got 60 dollars off. My cells are an on the axle pack that I made. It is made of 6 cells. 3 on either side, and connect with a deans connector to the discharger .I just connected the 6 cells to the discharger and then let it run its cycle. I will be able to post pictures tomorrow as then I get my STAR. [payday]

In answer to your question. No I did not charge each cell individually.

K_Willis · 11-29-2006, 12:55 PM

Quote:

Originally Posted by johnrobholmes

You type faster than me Willis!

Quote:

Originally Posted by K_Willis

mah = milli amp hours...
so divide by 1000
gives you 4.3 amp hours...

so at 4.3/.400 gives you 10.7 hours... add a little extra time for heat loss etc.

Quote:

Originally Posted by johnrobholmes

the batteries are 4.3 amp hours or 4300 milli amp hours. 4.3/ .4 = 10.7 hours. They wont be fully charged in 10 hours though because of heat losses.

Hehe damn... get out of my head

JohnRobHolmes · 11-29-2006, 01:34 PM

The reason I stated to discharge each cell individually it to balance the pack back out. If you had a few warm cells when you found them, there is a strong likelyhood that some of the cells are charged and some are not. When you go to recharge the pack the cells with more charge will likely be ruined from heat, while the empty cells wont even reach full charge.

Dont listen to the guys at the car shop. 2 filaments or one, it still draws power. Just get some alligator clips and hook a bulb up to each cell- use two bulbs in parallel on just one cell and it wont take long to get em all drained evenly. When the bulb dies out, pull it off. Did you test the voltage of each cell yet? It will tell you exactly what happened in that tub.

Tronk · 11-29-2006, 01:43 PM

Hello Mr Holmes.

I have just removed a 12v5w bulb from my trailer brake light. I soldered a positive wire from the terminal underneath and a negative from the bulb casing. I have held the to each end of each battery cell and the bulb filament just manages to glow.

Regarding testing the voltage. I would not know exactly what to buy. I think it requires one of the testing meters that electricians have. If I bought one which I am prepared to do, I would not know how to read it or how to interprit the readings that it gave.

Thankyou for your perciverence [hope that is spelt correctly]

11-27-2006, 01:23 PM	#1
Tronk Quarry Creeper Join Date: Dec 2005 Location: United Kingdom Posts: 234	Brown residue on battery terminals I made the mistake of placing some new charged homemade battery packs in a container all together. They where placed in the container to seperate them from discharged battery packs. The packs have been in the container for 3 or 4 days. Tonight I found one of the battery cells slightly warm, but the other cells felt cold to the touch. It appears that the battery terminals/bars had made contact with each other for an undetermined amount of time. Around the positive and negative terminals of each battery cell there is a residue of what looks like rust. It is also the same colour as rust.I have removed the residue with a stiff brush and a light sand with sandpaper. Is it advisable to see if these battery packs will take a charge or in anyones past experience is it wiser to change the batteries. I do not wish to do anything that could be beemed a fire hazard. The bateries are sub c 4300mah packs that I made 2 weeks ago and each pack has been run twice. Thanks for any help.

11-29-2006, 12:38 PM	#17
Tronk Quarry Creeper Join Date: Dec 2005 Location: United Kingdom Posts: 234	I went on a search and came up with the bulb reference number 1157. The car spares shop did not have a reference for that number. I then went searching deeper and got the bulb reference for a bulb in the UK, reference number 380-R 21/5w 12v1151. this is a bulb that drew 2 amps.The garage said it would be no good as it was a twin filament bulb.This is what I was going to build. http://www.rccaraction.com/articles/...scharger_1.asp I then went to the model shop and returned the brass rod that I had bought, and he said i needed the discharger that I bought. It was about 200 of your dollars but I got 60 dollars off. My cells are an on the axle pack that I made. It is made of 6 cells. 3 on either side, and connect with a deans connector to the discharger .I just connected the 6 cells to the discharger and then let it run its cycle. I will be able to post pictures tomorrow as then I get my STAR. [payday] In answer to your question. No I did not charge each cell individually. Last edited by Tronk; 11-29-2006 at 12:42 PM.

11-27-2006, 01:30 PM	#2
Moondust1950 Rock Crawler Join Date: May 2006 Location: United Kingdom,Scarborough Posts: 563	Have you ran them in water i hear salt water can rust your batterys

11-27-2006, 01:37 PM	#3
Tronk Quarry Creeper Join Date: Dec 2005 Location: United Kingdom Posts: 234	Yes I have ran them on the beach.

11-28-2006, 12:49 AM	#4
Tronk Quarry Creeper Join Date: Dec 2005 Location: United Kingdom Posts: 234	Please can someone advise if they think it is safe to charge the batteries

11-28-2006, 11:19 AM	#5
JohnRobHolmes owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down! Posts: 20,290	Do you have a voltmeter to test the voltage of each individual cell? If you can manage to balance the pack back out through individual cell discharging (with a small flashlight or car lightbulb), it will be safe to charge again. Charge it at .4 amps when you do recharge.

11-28-2006, 11:24 AM	#6
Tronk Quarry Creeper Join Date: Dec 2005 Location: United Kingdom Posts: 234	Many Many thanks for that.

11-28-2006, 11:51 AM	#7
SammyXp Quarry Creeper Join Date: Jan 2006 Location: Winston-Salem Posts: 200	There's a good chance the brown residue is just flux from when the pack was soldered together during its build. Are you sure the brown stuff is new? Or is there a chance it was there all along and you just never noticed it?

11-28-2006, 11:55 AM	#8
Tronk Quarry Creeper Join Date: Dec 2005 Location: United Kingdom Posts: 234	The brown residue is definately new. They where clean when I made them. The residue did not appear until I placed the batteries all together. I know not to place batteries together with metal objects. On this occasion I just did not think. Think you americans use the term "dumbass". I am going to do what Mr Holmes. I will put an update as to what happens. Thanks for the replies guys

11-29-2006, 11:59 AM	#9
Tronk Quarry Creeper Join Date: Dec 2005 Location: United Kingdom Posts: 234	I went today and bought a new charger and discharger. It is a BMI Digipeak14 ac/dc 1- 14 cell charger/discharger. The batteries are discharging as I type. I responce to Mr Holmes stating that the following charge rate is required I would just like confirmation on the following calculation which I believe is correct but I am not totally sure. Batteries are 4300mah. Divide the mah by the charge rate of .4amp. = 4300 / .400 = 107 hours and fifty minutes to re-charge the pack. Thankyou.

11-29-2006, 12:09 PM	#10
EeePee MODERATOR™ Join Date: Jul 2004 Location: Ohio Posts: 18,928	Do .4 amps, but for no longer than 16 hours.

11-29-2006, 12:14 PM	#12
JohnRobHolmes owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down! Posts: 20,290	the batteries are 4.3 amp hours or 4300 milli amp hours. 4.3/ .4 = 10.7 hours. They wont be fully charged in 10 hours though because of heat losses. Nimh cells peak around 140 degrees F. Either pull them when any individual cell reaches over 150, or wait until 16 hours like EeePee suggests.

Sponsored Links

11-29-2006, 12:15 PM	#13
JohnRobHolmes owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down! Posts: 20,290	You type faster than me Willis!

11-29-2006, 12:17 PM	#14
Tronk Quarry Creeper Join Date: Dec 2005 Location: United Kingdom Posts: 234	Many Thanks to the both of you. I am finding all this very challenging.I only ever expected to get a truck, turn it on and drive away. I am finding that I need a lot of skills etc to keep up with what I want out of it. Maths is something I was never very good at. It is suprising though what you learn by doing a search. I always thought it was a bit "off" when you guys just used to answer search. I can understand it better now though as it is a great way to get experience. I am just glad that you two did not just reply. SEARCH. Thanks guys

11-29-2006, 12:19 PM	#15
Tronk Quarry Creeper Join Date: Dec 2005 Location: United Kingdom Posts: 234	WOW Mr Holmes. You got two posts in whilst I typed my reply. Thanks for your help also. I usually find myself searching through your posts when I get stuck

11-29-2006, 12:29 PM	#16
JohnRobHolmes owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down! Posts: 20,290	Did you use that new charger to discharge each cell individually, or did you find a bulb that did the trick?

11-29-2006, 01:34 PM	#19
JohnRobHolmes owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down! Posts: 20,290	The reason I stated to discharge each cell individually it to balance the pack back out. If you had a few warm cells when you found them, there is a strong likelyhood that some of the cells are charged and some are not. When you go to recharge the pack the cells with more charge will likely be ruined from heat, while the empty cells wont even reach full charge. Dont listen to the guys at the car shop. 2 filaments or one, it still draws power. Just get some alligator clips and hook a bulb up to each cell- use two bulbs in parallel on just one cell and it wont take long to get em all drained evenly. When the bulb dies out, pull it off. Did you test the voltage of each cell yet? It will tell you exactly what happened in that tub.

11-29-2006, 01:43 PM	#20
Tronk Quarry Creeper Join Date: Dec 2005 Location: United Kingdom Posts: 234	Hello Mr Holmes. I have just removed a 12v5w bulb from my trailer brake light. I soldered a positive wire from the terminal underneath and a negative from the bulb casing. I have held the to each end of each battery cell and the bulb filament just manages to glow. Regarding testing the voltage. I would not know exactly what to buy. I think it requires one of the testing meters that electricians have. If I bought one which I am prepared to do, I would not know how to read it or how to interprit the readings that it gave. Thankyou for your perciverence [hope that is spelt correctly]

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