Cheap speed controller help?

[Flag Captured]

Trying to get HardWired running at long last, after the absolute farce with the ebay speed controllers (they don't even work properly now, brake function keeps kicking in when it shouldn't, completely unusable now and they won't accept returns) I'm looking for some new speed controllers that'll handle a 5000mAh 4S LiPo and a drill motor each, but the problem is that I've now got a very small amount of money for those, a new receiver and wheels, so that puts the BotBitz ones (that I'd prefer to have) out of the question for now... I'd love to reprogram some myself, but my technological incompetence means they'd probably end up as a ball of fire by the time I'm done.

Anyone know of any cheap speed controllers that'll be suitable at all for this? Thanks in advance!

[Ellis]

Finding new speed controllers that will do everything you need for as little as possible is a battle most of us fight. However I don't think you'll find anything new, which has a chance of lasting, backed by competent and helpful people, than a set of the new 30a speedos from Botbitz. 60 quid delivered, and you'll get help at the end of any emails you send.

http://www.botbitz.com/index.php?rou...&product_id=74

I don't know how these have done in combat yet as they haven't been around long, but I would be very surprised if the Botbitz guys put anything up for sale without being 100% sure of its viability.

Other than that, keep an eye on the for sale section, there will be other speedos that can do the job for less than 60 quid, but they'll have the question mark of having seen combat/reliability hanging over them. And if anything which is truly a great deal comes up, chances are it'll be snapped up in minutes.

I'm all ears if anyone has a better suggestion than the new Botbitz, as I said everyone is or has been in this same boat before. :P

[plargen]

as of the moment all the cheap 320a esc on ebay seem to have the brake problem and ive looked at the the boards and there are no variations in components that i can see so it is defiantly to do with software

so the best bet is probably the botbitz esc at the moment

the only other cheap esc i know of are the blue 50a http://www.ebay.co.uk/itm/2310202146...84.m1423.l2649 have used them for testing and they were a bit twitchy

and these http://www.ebay.co.uk/itm/2x-RC-Boat...item2ec9b08912 which i used to run my wheelchair round for a bit on a 14.4v nimh pack so fairly hardy but they were quite warm at the end lol

heres the vid https://www.youtube.com/watch?v=LhXVcjkS1eM

[daveimi]

have you bought the lipo yet?

[Walmsley2012]

Ellis the new 30a esc from botbitz are Brushless though arent they? can they be programmed for brushed drill motors?

[RogueTwoRobots]

All the Botbitz controllers have already been programmed for brushed motors, including the 30A ones. It's the foundation of their business

[marto]

I personally used them in my robots and also did stress tests on them before putting them for sale. I have run them for 3 events with no issues. We do test everything in our own bots in combat before putting them on sale. I ran a pair of drills on 5S A123s.

Here is a recent 3rd party review.
http://servo.texterity.com/servo/201309/?folio=34#pg34

I have done tests @ 30A @ 50% duty cycle for 1.5min and 30A @ 100% duty cycle for 5min+, under controlled conditions.

[Flag Captured]

have you bought the lipo yet?

I have, already been running it with the dodgy eBay controllers... Going to keep a hold of them and see if there's any way I can modify them later down the line (trying to find out who manufactures them, hopefully they'll have a way of reprogramming!) but I think I'll end up going with these BotBitz ones!

Would I need to add any sort of precautionary measure to, say, cut power if the drills were to stall so that the controllers don't toast themselves, or would they handle the amps? And would I be able to step it up to a 5000mAh 5s LiPo (or even 6s?) down the line? I seem to recall A123s being similar chemistry to LiPos, but just double-checking before I get some ordered!

Thanks for the help too everyone, still finding my feet with all the whole combat robotics thing!

[daveimi]

I've heard tales of people putting fuses in line with the positive feed from the battery. I'm not sure how they decide which amerage of fuse they need though. I'm guessing its to find out the maximum draw of your componentry and get a fuse around that.

[marto]

Look if your worried about the controllers then you should just spend the extra $60 and get the 85As, more reliable and tested. The 30As will work, are 1/2 the price and should be fine with your setup but your essentially pushing them to their limits. Which is fine (I do it all the time) but you shouldn't be too pissed off if you burn one out. Has anyone in the UK burnt out a 85A yet?

Steve

[leorcc]

Best practice is to get a fuse that is rated below the maximum current the weakest part of the system is. Suppose the controller is rated for 100A, and the battery is rated for 150A, get a fuse that is rated for 90A to protect both.

[Flag Captured]

Hmm... I think the 85As could be the best bet then, might be worth that little bit extra if I can get the money for them... I have a 80A fuse already linked up to the system, so I think that'd all end up fitting alright.

Just going to stick with the servo-based controllers then I think until I can afford them, or sell some old stuff that I don't need to help raise a bit of cash for it -thanks all for the help!

[suvv]

appologies for butting in on this but wouldent it be possible to build a fanrig to cool the speedos or is that a stupid idea??