Noob alert. Basic question #1....

[tonytiger]

Hello.
New to robot building, and r/c in general. Looking at building a basic featherweight, a la Haynes manual (got to be easier than fixing a knackered old car where everything is rusted and seized, right?!). No intention of entering competition, just getting to grips with the basics for now.

I’m just starting to get materials and components together but have a question over drills as drive motors. Ive bought 12v Argos value drills, but note in the Haynes photos (and elsewhere on internet) that 14.4v drills have been used. Obviously I realise the hammer functionality is of no use, but the 14.4v have 1.3Ah batteries whereas the 12v have only 800mAh. The 12v seem very popular among robot builders - so just after opinion on whether to stick with them, or return and get the 14.4v instead. Is the battery capacity increase worth it?

Thanks for taking the time to read this.
Cheers,
Tony.

[Ocracoke]

Hey there, welcome to the forum!

For a basic featherweight, either voltage is good at this stage (though more is better) and I guess either battery is also fine for this application though 800mAh is fairly small, they can be changed later on if you decide to go further into this and into competition - my Featherweight uses 2.1Ah batteries in series and my Beetleweight uses a 1.5Ah battery. I can't say how long the Beetleweight battery lasts in combat but the Featherweight will run 2 matches before needing a charge and that is with it zipping around everywhere.

[Garfie489]

The good thing about using two drills however is you will double the capacity if in parallel.

1.6Ah would last you a 3 minute fight in the tests i done for the school kits i produce. It depends on other factors such as wheel size, however i found for the setup i use, each battery adds around 2 minutes of fight time to the setup.

[Deathly Hallows]

I am new to this too. End of last year I tried a test with some 14.4v Argos drills on a test rig https://youtu.be/6AJNEDZZX_4 worked fine once unsorted out how to keep wheels attached. I used it as a proof of my skills and I have no intent to use that hardboard chassis, but the drill motors were impressively fast. If I use them for a real robot I would look at taking them out the casing and using a clamp to hold in place the ties suggested in the manual do not allow accurate alignment.

[tonytiger]

Thanks for the quick replies. It sounds like I’ll be best swapping to the 14.4v drills to reduce frustration at too short a run time - especially with an approx 5 hour charge time per battery. It’ll also be cheaper for now than looking at alternative batteries and chargers.

Simon - I’ve already looked at your build thread for that ;-) In a similar fashion, I intend to build a basic model following the Haynes guide, and then refine it once I’ve got the basics sorted and working.

[Theo]

Just remember you can't use the batteries in the new 12v Simple Value Argos drills, they use some weird lithium chemistry that isn't approved yet. You could check with your event organiser, but it might be best to go with Nicads if you plan on using the drill batteries, most lithium ones aren't approved (aside from DeWalts with their a123 LiFes iirc). For reference, My featherweight has a 3.1Ah battery but that's just because I have an abundence of space and weight left.

[Deathly Hallows]

I was surprised at how cheap LiPo's are. They sound a bit scary and it's new terminology 2S 4C etc. but not that complicated, plenty of sites and threads explaining it. Though you are on a budget perhaps they are still worth a look. But you will need a charger (and some on ebay ship without a mains charger) and a safety bag to comply with regulations. Also a fuse is mandatory in a LiPo system (but I'd fit one even if not).

[maddox10]

Theo, for all classes, most LiPo's are approved by the FRA and subsequently the event organisers.
Team RCC used 5000mAh and 8000mAh "el cheapo" Hobbyking LiPo's in Bullfrog, and never had any organiser objections.
Our feathers and raptors , again, cheap Hobbyking LiPo's, and no problems whatsoever.

Just follow the rules on fuses and battery managment, and you can use most commercial/RC LiPo batteries.

[swanaldo]

What Mario said