New bot

hi all

my dad would like to build a bot but just a simple one, and we were wondering when we buy the drills for the motors the batteries that come with them can we use both batteries. i mean will the overall 24v blow the 2 12v motors?

thanks alex/Jerry

hi alex,
i would say no, because even if 24v would blow 12v drills normally, i doubt the drill batteries will give you the current to do that anyway. If in doubt, try shorting the fully charged set across an ammeter for a second (not more) and i imagine youll see 10-12 amps maybe on 24v.

if you are keen to use both sets, run one to each controller and have 12v per side. you need 2 links, but there is no rule that says both controllers must share the same battery.

another option, buy the motor/gearboxes alone from ewan, and get some better batteries with the money you save. 2 x £12.99 = £25.98, 2x ewans drills = £17, leaving you £8.98 to put towards much better batteries than the ones that come with the drills.

another option, if you have electronize controllers, is put the 24v on as you say, and turn the gain (speed) down on the controller to 12v. you can always turn it up again later if you want more performance.

hope this helps

(Message edited by jamesb on July 07, 2006)

And that £8.98 would be roughly enough to get two 6v 4Ah batteries from Maplin. Link them in series and you get the 12v with enough current to last at least a couple of battles. I think the batts are £4.99 each - Ive not tried mine out in any situation more rough than some testing but they seem to be pretty good batteries.

does anyone have pic of a robot which has its motors and wheels not next to each other? i.e. one infront of the other, (slightly)

cheers alex

Try this Alex
http://www.pillowtorque.com/tech.htmhttp://www.pillowtorque.com/tech.htm

My local Woolworths is doing 12 volt drills for 6 quid each, including battery and charger. Start simple and upgrade.

we were planning on get some cheap drills already, but thanks anyway

thanks alex

are these the right speed controllers for what we want to do? on techno bots, speed controllers, electronize and the 11th one down?

cheers

The electronize controllers you describe are the ready built 15 amp ones for £34 each. I cant say if they are right for you without knowing what drill motors you are using (and probably not even then). I think they would probably be OK - perhaps someone who has used them in a drill motor powered bot will read this and comment. I use the 30 amp versions of these with external relays (£46 each) and they are very good. Im currently using them to run 24 volt drill motors and they work well.

I tryed 15amp CPUs in Mr. Happy with 14.4v motors on 14.4v, the fets blew (three times!). I now use the 30amp exsternal relay version and have had no problems,

Ive used the 15amp cpu ones for years and they have been fine, they drove Alpha for about 2 years now theyre in Omega, both use(d) golds but with alot of load on them. Just the relays would give up after a long period of time. But i suppose golds are smoother and cleaner running then drills so would probably be worth adding diodes across brushes (which you should have anyway).

With drill motors I would prefer the 30A versions. Maybe even the 40A upgrades. You might get by on the 15 Amps, but why risk it?

remember that it also depends on your drive train setup as to what will be suitable, gear ratios, friction etc.

I would follow Leos advice to be on the safe side. It will save you in the long run