a123 batterys

[mid-air]

HELP: i have 5 of 1100ma.2 cell packs, when charged and checked on 3 of the packs with a 1 amp load the packs will increase voltage . the other 2 packs will decrese, all voltage is 6.56 -9. would a bad solder joint do this? i used rosin core solder. thanks for the help in advance AL

[Tomapowa]

... with a 1 amp load the packs will increase voltage...
Not too sure what you mean by the packs increase voltage... explain... :confused:

[mid-air]

Not too sure what you mean by the packs increase voltage... explain... :confused:
Tomapowa: if the voltage is 6.45 it will rise to 6.65 when load is applied.
AL

[beer-man]

this is caused by the cells warming up, A123's like to be run hot, the second flight is always better.

[Dan Baldwin]

HELP: i have 5 of 1100ma.2 cell packs, when charged and checked on 3 of the packs with a 1 amp load the packs will increase voltage . the other 2 packs will decrese, all voltage is 6.56 -9. would a bad solder joint do this? i used rosin core solder. thanks for the help in advance AL

Are you saying that some of your 2 cell A123 packs are at 9 volts?

Dan

[mid-air]

Are you saying that some of your 2 cell A123 packs are at 9 volts?

Dan
no i ment 6.56-6.59. AL

[Tomapowa]

Tomapowa: if the voltage is 6.45 it will rise to 6.65 when load is applied.
AL


Hm... got me on that one.... usually when a load is applied to s battery, it's voltage drops... not increases. How are you measuring this voltage and what type of load are you using? Have you been able to measure the individual cell voltages when you think they have increased? Is one or both cells higher than 3.3v?

As for heat... my A123s hardly ever get warm (<110 degrees F), even under 40-50A continuous and/or occasional 70-100+ amp loads... LiPos are a different story.

[mid-air]

Tomapowa: i am useing these on a fuel airplane and heli. i made the packs useing regular rosin core solder not electronic solder , i cleaned and tined the surface add applyed cheap rosin core to make the connection , i have an idea that is the problem , the conection is heating up and and making a better conection causing the rise, but not corecting the problen of a crappy joint. what do you think? AL

[Tomapowa]

Tomapowa: i am useing these on a fuel airplane and heli. i made the packs useing regular rosin core solder not electronic solder , i cleaned and tined the surface add applyed cheap rosin core to make the connection , i have an idea that is the problem , the conection is heating up and and making a better conection causing the rise, but not corecting the problen of a crappy joint. what do you think? AL
I don't that's it but tell us more about your setup, like what type of wire and connectors are you using and specifically, how are you measuring this voltage and what are you using for a load? Are you directly soldering to the A123 battery or to it's tabs?

[mid-air]

found my problem ! i was useing a hanger 9 volt with load meter and it was off by 1 volt. so the whole meter is false. checked it out with a simson vtvm and thinds are good. AL