Battery Pack Newbie HELP

  • Thread starter ztekneq
  • Start date
  • #1
4
0
I work at a local entertainment venue and wanted to experiment by building my own pack for current laser tag vests. The manuf charge us a FORTUNE!

So the specs are 6 NiMh 3800mah 1.2V 4/3 Panasonic 370a's wired in a block series

there is a small resistor (i think) on the lead but I cannot make out what its specs are..this is where i need some help. What do you guys think it might be?
 

Answers and Replies

  • #2
mgb_phys
Science Advisor
Homework Helper
7,819
13
It's unlikely to be a resistor that would just waste heat, it's more likely to be a fuse which is a good idea if you are strapping the batteries to your body.
 
Last edited:
  • #3
4
0
k

quite possible...... looked like it might have had bands like a resistor though.....

its not on the lead to the connector so to say.. there is a wire (small) soldered to the first positive cap in the series drops down next to the battery and is then connected to the middle lead of the three lead series

http://www.tekneq-design.com/battery.jpg [Broken]
 

Attachments

  • battery.jpg
    battery.jpg
    10 KB · Views: 345
Last edited by a moderator:
  • #4
mgb_phys
Science Advisor
Homework Helper
7,819
13
In that case it's probably a thermistor to monitor temperature of the battery while charging.
A common way to charge NiCd/NiMH is to turn up the charging current until it starts to get hot and then back off a little.
If you aren't worrried about charging speed it is better/safer to just charge for 10-12 hours at 10% of the battery capacity.
 
  • #5
4
0
is there any specifications that one would need to replace such a part?
 
  • #6
mgb_phys
Science Advisor
Homework Helper
7,819
13
You would need to know it's cold resistance which you can measure with a meter, you could estimate the temperature coefficent by putting in warm water and then measuring it's resistance again.
But like I said, it's easier/safer to just trickle charge the batteries, quick charging home made battery packs is a bit dangerous to the battery and you!
 
  • #7
4
0
It is exactly a thermistor! Im actually duplicating an existing pack. What would be the downfalls of hooking in the wrong thermistor? I have an existing intelligent charger that is being used as well. Is there anyway to estimate what thermistor should be used?
 
  • #8
NoTime
Science Advisor
Homework Helper
1,570
0
You might want to try some electonic supply houses.
For instance, Radio Shack sell a 6 cell nicad pack for RC cars with charger for about $20.
They also sell connector adaptors.
 

Related Threads on Battery Pack Newbie HELP

  • Last Post
Replies
18
Views
9K
  • Last Post
4
Replies
79
Views
4K
  • Last Post
Replies
16
Views
1K
  • Last Post
Replies
1
Views
2K
Replies
5
Views
1K
Replies
2
Views
1K
  • Last Post
Replies
5
Views
3K
  • Last Post
Replies
4
Views
838
Replies
6
Views
2K
Replies
7
Views
13K
Top