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General Misc => Misc => Topic started by: Admin on April 15, 2010, 11:38:22 PM

Title: need small ~3.7V battery
Post by: Admin on April 15, 2010, 11:38:22 PM
I'm having trouble finding a particular battery . . .

no less than 3.6V, 150mAh, 100mA peak
no bigger than 0.9"x2.2", flatter the better
preferably with leads already soldered to it
preferably as a complete pack (I don't want to make a custom battery)
can't be Lipo or alkaline
under ~$15

Anyone know of any?
Title: Re: need small ~3.7V battery
Post by: Admin on April 15, 2010, 11:49:22 PM
I just found something that matches here:
http://www.robotmarketplace.com/products/battery_build_main.html (http://www.robotmarketplace.com/products/battery_build_main.html)

But if anyone knows of something cheaper let me know . . .
Title: Re: need small ~3.7V battery
Post by: Razor Concepts on April 16, 2010, 07:37:35 AM
http://www.cheapbatterypacks.com/ (http://www.cheapbatterypacks.com/) does custom packs as well
Title: Re: need small ~3.7V battery
Post by: Admin on April 16, 2010, 10:20:50 AM
http://www.cheapbatterypacks.com/ (http://www.cheapbatterypacks.com/) does custom packs as well
Is it just me, or is it quoting between $3 and $5 for a battery pack? Then simply by reselecting the same cell, it multiplies the price by 10x?
Title: Re: need small ~3.7V battery
Post by: amando96 on April 16, 2010, 12:25:48 PM
http://www.sparkfun.com/commerce/product_info.php?products_id=731 (http://www.sparkfun.com/commerce/product_info.php?products_id=731)

i've been meaning to get that for my weather balloon project
Title: Re: need small ~3.7V battery
Post by: Admin on April 16, 2010, 08:46:18 PM
http://www.sparkfun.com/commerce/product_info.php?products_id=731 (http://www.sparkfun.com/commerce/product_info.php?products_id=731)

i've been meaning to get that for my weather balloon project
but  . . .
Quote
can't be Lipo or alkaline
;D
Title: Re: need small ~3.7V battery
Post by: Razor Concepts on April 17, 2010, 05:02:52 AM
If you are planning a large order, you can contact the guys at CBP directly and they should be able to give you a discount. The custom ordering thing is generally just for a couple packs for RC cars and stuff.
Title: Re: need small ~3.7V battery
Post by: Canabots on April 17, 2010, 09:27:02 AM
I'll just throw in my 2 cents about this...

Have you checked out Hobby King? They have quite the assortment of small lithium batteries for low prices. I don't know if any of them are the right size requirements, but it's worth looking.
Title: Re: need small ~3.7V battery
Post by: Razor Concepts on April 17, 2010, 09:30:38 AM
I'll just throw in my 2 cents about this...

Have you checked out Hobby King? They have quite the assortment of small lithium batteries for low prices. I don't know if any of them are the right size requirements, but it's worth looking.

remember, no lipo  ;)
Title: Re: need small ~3.7V battery
Post by: amando96 on April 17, 2010, 04:19:34 PM
ahh, i read ''lipo, or alkaline'' like you didn't have any preference, daym  :'(
Title: Re: need small ~3.7V battery
Post by: voyager2 on June 19, 2010, 04:56:04 AM
Hi All,
I found these on sparkfun:
http://www.sparkfun.com/commerce/product_info.php?products_id=8818 (http://www.sparkfun.com/commerce/product_info.php?products_id=8818)
Its rechargeable 3.7v Li-Ion @ 150mAh 200mAh
One problem EXACTLY 1 INCH in diameter(2.45mm)
Title: Re: need small ~3.7V battery
Post by: TrickyNekro on June 19, 2010, 05:28:53 AM
I can't really find their list but should be somewhere...
http://www.camelionbattery.com/index.php?option=com_content&view=category&layout=blog&id=29&Itemid=65&lang=en (http://www.camelionbattery.com/index.php?option=com_content&view=category&layout=blog&id=29&Itemid=65&lang=en)

I got a 600mAh pack... but I'm sure there are 150mAh packs too... somewhere... NiMH always...

The 600mAh pack looks like this... It's nice and small... and the 300mAh pack is almost half the size...
The 150mAh is even smaller....

And here is how the 600mAh pack looks ;-)

http://img691.imageshack.us/img691/8352/19062010f.jpg (http://img691.imageshack.us/img691/8352/19062010f.jpg)

Edit: Basically look for cordless phone batteries... Most of them NiMH / NiCd.... The NiMH definitely would do ;-)
Title: Re: need small ~3.7V battery
Post by: Admin on June 19, 2010, 06:17:16 AM
When I said no Lipos, I mean Li-ions, too :P
Quote
can't be Lipo or alkaline

I ended up deciding on the http://www.cheapbatterypacks.com/ (http://www.cheapbatterypacks.com/) website.
Title: Re: need small ~3.7V battery
Post by: madsci1016 on June 19, 2010, 07:10:39 AM
can't be Lipo or alkaline

sounds like this is for work.
Title: Re: need small ~3.7V battery
Post by: Admin on June 19, 2010, 08:02:38 AM
can't be Lipo or alkaline

sounds like this is for work.
Well, although for work I can't/shouldn't really use LiPo (prototype underwater robots + lithium = bad idea), this is actually for a separate project.

At work I just recently bought some LiFe batteries . . . supposedly the same current output as a lipos, similar voltages, but no crazy thermal runaway issues . . .
Title: Re: need small ~3.7V battery
Post by: madsci1016 on June 19, 2010, 08:12:14 AM
true.

I don't know if you have the same rules we do, but for us, the Navy says no to Lithium-anything. It stinks.
Title: Re: need small ~3.7V battery
Post by: Admin on June 19, 2010, 08:38:07 AM
I don't know if you have the same rules we do, but for us, the Navy says no to Lithium-anything. It stinks.
Rules?

I work in a building for biological engineering sciences . . . I have to follow rules for chemical safety, but have been given no rules for robotics related stuff.

For example, I must label every chemical in my lab with a chemical safety label. My big tank of water in my lab has to say "H20 non-hazardous [date][my name]". They got mad when I just labeled it 'water' saying it was a policy violation . . . They do however let me wear shorts, no lab coat, and eat in my (personal) lab, a big no-no for the other labs . . .

Once a guy spilled some sulfuric acid and the entire building was evac'ed for half a day. Dudes with full hazmat suits surrounded the building. The guy who did it also spilled some on himself, so he had to walk around without pants for half a day.

I'd hate to be the guy that does that with a lipo battery . . . apologizing to my boss without pants on is definitely not cool . . .

Hence, I got a LiFe. (hehe bad pun but I always wanted to say that!)
Title: Re: need small ~3.7V battery
Post by: madsci1016 on June 19, 2010, 09:42:07 AM
Yup, anything robotic we work with either has to have SLA batteries or super special permission to use lithium. It's to the point where we are designing the power system around that battery instead of the power needs of the robot.

The supposed story is a few years ago, a 3 KW/hr Li-Poly battery went critical inside a building on a Navy research lab and the fire brought down the building. The department that owned the battery was dissolved, and now the saftey board that approves everything that can be brought onto a Navy owned vessel won't approve Lithium anything, unless under extreme circumstances.