Could it be that the prop is too big? and the motor is drawing too many amps with this big prop on and causing the speed controller to overload and shut down? Sounds as though you may have a Chinese speed controller with that size amperage?   Never trust a speed controller ratings from the East – We know all about them and the magic smoke – If there wasn't enough guts in the batteries it would just slow down and then shut off. Just a thought.

John

Edited By John W E on 17/03/2019 18:24:00

I would initially have suspected a faulty cell or cells in the 12v pack which is/are dropping well below 1.1v when the current drain is high. First, however, I'd point the finger at that ESC – largely because those '320A' ones are known to be trouble. In a tug it's probably only supplying a few amps but a 540 motor with an airscrew is a different matter altogether. That 320A rating is almost certainly for the instantaneous surge current and the realistic continuous current rating will be much, much lower. Unfortunately there's no way of knowing what the true value is; my guess would be no more than 15A.
I'd try a different make of ESC with a known, reliable maximum continuous current rating and also use a wattmeter to monitor the current and voltage. There are numerous cheap ones on the Internet – this is the one I use **LINK**

Dave M

[Written before John's and Ray's postings hit the board. A brushless motor and a 3S LiPo pack would solve the problem, as Ray says]

Edited By Dave Milbourn on 17/03/2019 18:41:20

Do not be surprised that airscrews soak up power – some Merlin engines coughed out 1600 HP to drive their airscrew, a flower Cass Corvette had only a bit more to drive itself. Later Spitfies used a Griffon that coughed out nearly 2500 HP.

When you look at the wiring fitted to a "320A" ESC, you should figure that the "320" is either a decorative mark or total optimism. Many were sold as lower voltage types, the higher voltage variant looked much the same but had a cooling fan.

It is possble that the battery is not supplying the needed current at full power and the ESC is spotting the volt drop and cutting out, needing a power off reset to come back to life. Overheating might have exactly the same results.

When selecting an ESC, if a meter is not available, a box of assorted fuses helps. Find the top value that blows, take the next value up, look for an ESC that is known to handle more than that. Generous derating is a good, valid, engineering practice. Apart from that, what Dave just said above.

Ken

For General Info –

Many people believe that when they buy a new rechargeable battery it's already fully-charged. It ain't. There's some charge in it – the amount depending on how much was put in to start with and how long it's been on the shelf since then, quietly self-discharging. My advice is always to give a new pack a charge at one tenth of its C rating [which is 1/10 x 2.6A for a 2600maH pack = 260mA] for 14-16 hours, then use this charge rate for several subsequent charges before you attempt to fast-charge it. Also NEVER charge at more than the C rate. Despite what you might read, like Corporal Jones' fuzzy-wuzzies, they don't like it up 'em.

BTW just to illustrate what Malcolm said, 320A at 12v is getting on for 4 kW. You'd need wiring about as thick as your finger to take that amount of power!

Dave M

Edited By Dave Milbourn on 18/03/2019 14:56:21

Ken may have thick fingers, Malc, but I think the message got through that 12 or even 14AWG isn't quite the ticket for 320A. Frankly I wouldn't go near one of those 320A 'Blue Meanies' at any price and I'm surprised they haven't been banned under the Geneva Convention. Certainly they're not quite 'in step' with any acceptable advertising standard I can think of.

Ken
Take a look at the cable which earths the battery in your car to the body. That would just about stretch to 320A @ 12v, but not for very long!

Dave M

Ken

It's likely either a faulty cell in the 12v pack or a duff charger. One would expect both to work properly from new.
If it fails again I'd contact CompShop and request a comment from them and insist on replacements if necessary. Mucking about with trying to identify a faulty cell in a new pack of ten isn't reasonable if you've followed the charger's instructions correctly.

Dave M

Quite so – hence my comments about the charger and battery pack.

DM

As Dave says, Lead acid cells are very much yesterday's technology now. The actual capacity is only around 50% of the nominal capacity. For relatively sedate models NiMH are the way to go as they are simple to install and operate and you can usually use most of the nominal capacity so they are effectively much more efficient than lead acid plus the weight is lower in the hull which improves stability. For extra performance then LiPo is what you want with a bit of extra care in looking after them. As always, horses for courses.

Colin

Edited By Colin Bishop on 19/03/2019 19:33:12

Ken

I'm sure it's the case that lead-acid batteries are still used in models with conventional props and low current-consumption motors, but your original query wasn't about such an application. Similarly a speed controller which claims to have a current carrying capacity of 320A should at the very least be able to cope with the 2 – 3A drawn by such motors. That the type regularly fails at higher currents – and would have no possible chance of withstanding a current of 320A in any event – is also a matter of record. I've either handled or witnessed maybe ten that have done so when connected to 540/600 motors and run on 6 – 8 NiMH cells. I wouldn't purchase a unit with such dubious claims made for it and I wouldn't recommend anyone else to do so. Still, it's a free country – 'caveat emptor' not withstanding.

You might refer this correspondence to Component Shop to support any contention about the problem.

Dave Milbourn

Edited By Dave Milbourn on 20/03/2019 10:26:30