Battery for 120LB battlebot?

Currently my team is using two 12V motor cycle SLAs in our battlebot but these are a little too heavy for what we want. What kind of "battle packs" and chargers have you guys had success with? The competition we will be entering has a 24V battery voltage limit.

Where can I purchase the batteries for this then?

What kind of charger would I need to use for the lithium ion batteries then, and how fast would we be able to charge them?

The problem with charging batteries like these, especially lithium, is that the more voltage and amps you feed them at a time, the hotter they get, and the faster they will deteriorate. Personally, I just stick with most instructions saying not to exceed 1C, which i believe is 10% of the mAh in amps to the battery at around 12v from the outlet. This is just a guess based on what I see from my peak charger for my lithium polymer batteries, LiIon's could be different.

Flame war alert-! There is NOT consensus on this issue on this forum---But my advice is: Use LiPos.

Look, the LiFe batteries (aka A123) have been accepted, but even though the tech has advanced people still think that Lithium Polymer batteries (the next level) are dangerous. They really aren't, if you bother to read and follow the instructions. I admit they are more expensive, but are more 'power dense.' With new low internal resistance tech, you can charge a 65C LiPo in FIVE MINUTES. Granted, you would NOT want to do that more than once a day, and it will get hot, but it is within the design specs. More importantly, you can empty a 65C battery SAFELY in less than one minute!! If you need power and energy in a small package Lithium Polymer is the best answer.

HOWEVER--buy the right charger, read the directions, know what demands your bot makes on the batteries (i.e. amp draw), and be prepared to spend the $$. If you want the SMART PERSON"S answer to power, the LiPo is the answer.

Oh, and SLA? Might as well be a dinosaur. Between that technology and LiPo lies NiCd, NiMH, and LiFe. Like everything in fighting robots, you really need to do your research and stay up to date on it.

In other words, definitely replace the SLA with something more current. I actually think NiMH are pretty decent, but NiCd, while definitely cheap are not worth the time, money, and effort you are gonna put into them. And A123/LiFe really do NOT suck, I just think LiPo are superior.

rdubard wrote:

Flame war alert-! There is NOT consensus on this issue on this forum---But my advice is: Use LiPos.

Look, the LiFe batteries (aka A123) have been accepted, but even though the tech has advanced people still think that Lithium Polymer batteries (the next level) are dangerous. They really aren't, if you bother to read and follow the instructions. I admit they are more expensive, but are more 'power dense.' With new low internal resistance tech, you can charge a 65C LiPo in FIVE MINUTES. Granted, you would NOT want to do that more than once a day, and it will get hot, but it is within the design specs. More importantly, you can empty a 65C battery SAFELY in less than one minute!! If you need power and energy in a small package Lithium Polymer is the best answer.

HOWEVER--buy the right charger, read the directions, know what demands your bot makes on the batteries (i.e. amp draw), and be prepared to spend the $$. If you want the SMART PERSON"S answer to power, the LiPo is the answer.

Where do you recommend buying these from? And what kind of chargers do you use on them?

Also, the competition I will be entering specifically does NOT allow Lithium polymer batteries. Lithium-Ion, NiMH, NiCD, and the useless SLA are all allowed.

If you don't mind, what 120 lb competition are you entering? The ones I know of allow LiPo.

SamM wrote:

If you don't mind, what 120 lb competition are you entering? The ones I know of allow LiPo.

The Wisconsin BotsIQ competition.

Aha, BotsIQ and their safety.

froggyman wrote:

Where do you recommend buying these from? And what kind of chargers do you use on them?

Also, the competition I will be entering specifically does NOT allow Lithium polymer batteries. Lithium-Ion, NiMH, NiCD, and the useless SLA are all allowed.

We get LiPo from Robotmarketplace, Horizon Hobbies, or directly from ThunderPower. There are a multitude of good chargers out there--we have used Hyperion and CommonSense RC to good effect.

We used to get the NiMH from Tower Hobbies (many brands--know your specs and shop around), and I loved the Duratrax I.C.E. charger for those batteries (and NiCds too).

Because this is 'grown out of' the RC market, all the chargers need a "12V" (actually 13.5 V) supply and will not simply plug into an AC outlet. We got those from Tower Hobbies too, but there are a LOT of options there.

As for the LiFe/A123, I don't know where to get 'em, cuz I don't use 'em.

Good Luck!

I know it's kind of scary to be getting stuff directly from China but most of Hobbyking's LIPOs are really good. I like the Turnigy Nano-Tech stuff best myself but most of their other ones are good too. In fact, they are better than the stuff I have gotten from Robot Marketplace.

http://www.hobbyking.com/hobbyking/store/index.rc

Koensig wrote:

I know it's kind of scary to be getting stuff directly from China but most of Hobbyking's LIPOs are really good. I like the Turnigy Nano-Tech stuff best myself but most of their other ones are good too. In fact, they are better than the stuff I have gotten from Robot Marketplace.

http://www.hobbyking.com/hobbyking/store/index.rc

I have heard that the HobbyKing batteries are just fine. I have never tried them out, so I simply can't give them my seal of approval, but no reason to diss them either!