Batteries!

[Xyver]

What is the best kind of batteries to get?  I'm just getting into robotics and plan on doing it for a long time (going to university for mechatronics)  and was hoping to get some nice batteries to use. So... What size/type would be best? 
I heard Lithium ion is good, anything else?

I plan on mostly using it for smallish projects, what voltage do I need?  6? 9? 12?

Price is no problem as I plan on using them for a lonnnnng time.  (but hopefully they're still reasonable,  Im still on a student budget haha)

[SmAsH]

Well, the majority of the community here favor ni-mh batteries, usually 6v for running servos or 7v2 for running both servos and control circuitry.
But many users have been getting into li-on and have reported good results.
The batteries depend on what you are running, if its just some small servos, id go with ni-mh 6/7.2v.

[Xyver]

And most things will be Arduino powered.  But that takes anywhere from 7-12 volts I hear.  Where can I get cet batteries?  I have some rechargable double AA's that Im pretty sure are NiMh.  What amps is best?   Higher=better?

EDIT:: I found some rechargable batteries.  They are as follows:

4x AA Infinicell with 1.2V and 2600mAh

4x AAA infinicell with 1.2V and 850mAh

1x Energizer 9V that says 7.2V-150mAh.

[Razor Concepts]

You will need other batteries for high current applications. 3-cell lipos are great, since they are right around 12 volts.

[Xyver]

Dont Lipos need a special charger?

[SmAsH]

They need a li-po charger.

[z.s.tar.gz]

Don't forget about LiFe!

Advantage: All the features of Li-Ion/Pol + more power and they don't explode
Disadvantage: Needs a special charger different from other lithiums.

[waltr]

Dont Lipos need a special charger?

All batteries need a special charger that is design for that particular battery chemistry and construction.

[Razor Concepts]

Don't forget about LiFe!

Advantage: All the features of Li-Ion/Pol + more power and they don't explode
Disadvantage: Needs a special charger different from other lithiums.

I don't know about more power. Less voltage per cell, more weight, less C rating, takes up more space per mah, etc etc. 70c lipos now exist on the market, too.

[z.s.tar.gz]

Well, they last longer and don't explode. If you want long term, these are them.

[Xyver]

Well, they last longer and don't explode. If you want long term, these are them.

Which ones?  LiFe?

[z.s.tar.gz]

Yep. Lithium Iron Phosphate.

[Xyver]

Ok. Where would I get these batteries?  Ive been googling them with no luck.  I'll probably use what i have for now and then upgrade later.  My friends getting some LiFe batteries for his electric bike but they are really big and and like 500$... I was thinking more small scale.

http://cgi.ebay.com/48V-20AH-LiFePO4-Electric-Scooter-E-Bike-Li-Fe-Battery_W0QQitemZ320475811159QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item4a9dd8cd57#ht_2083wt_941

(actually more expensive then I thought...)

Theres also this
http://www.engadget.com/2010/02/03/horizon-debuts-h-cell-2-0-hydrogen-fuel-cell-system-for-r-c-cars/

[Razor Concepts]

The highest quality LiFes come from A123 systems - but they are pricey.

[nottoooily]

Aren't you afraid that if you commit to some particular battery it'll constrain everything you design? Will your robots really get enough real world use that a few sets of alkalines won't do?

What is the best kind of batteries to get?  I'm just getting into robotics and plan on doing it for a long time (going to university for

[z.s.tar.gz]

All-Battery sells them to, but they can be hit or miss.

[Hertz32]

m uncle uses lipos wi is rc gliders and says as long as you dont over charge em theyre fine i was using 1 with a spectrum reciver and a arduino and sum elcheapo M.A.C.T.H.U (may admin continue to help us ) servos. . . .

[Xyver]

Well I was just getting some advice, I think LiFe's are a little too expensive for me.  I'm going to get a bunch of NiMh batteries and that'll do me fine for now.  Thanks guys!  I really like the battery university link.