Hot Climate ESC/Motor

[pache]

G'day

There's a lot of discussion about motor/esc choice, but I'm having difficulty finding much about high ambient temperature conditions (Australia).

I'm talking paddock bashing at 35-40c ambient (about 95-105F) in the open sun. Surface would be paddock (grass, varying heights), gravel road, and the possibility of some sand or dirt. I'm after fun, so runtime is significant & I'd accept some top speed loss - I'm coming from a brushed crawler, this should be fast regardless...

My initial "safe default setup" was looking like:

- Hobbywing Max8 with 4274 sensorless 2200kv
- Ideally Backflip LP, but if they don't come back in stock it'd have to be something like Badlands or possibly the 6S Backflips (too heavy?)
- I have no position on pinion size, 17T seems to be the default recommendation. Also it would be simpler for me to get non-Tekno pinions, would the Arrma pinions work ok? (e.g. ARA310964 - Mod1 17T steel with 4mm set screw)
- I'm planning on using 4S (probably 50c 5000mA bashing series)
- Receiver'll be a FS-BS6 for my Flysky FS-GT5

1) Am I even likely to have a heat issue here with this setup anyway, or am I worrying about nothing?
2) Dropping pinion size down is an obvious heat reduction, but would going down to 15 or 16 be enough?
3) Hobbywing doesn't seem to do a sensorless 1900kv at present, but they do have sensored 4274's at 1900kv & 1600kv in the old generation. Worth it? Is sensored any better/worse in heat?
4) Swapping up to a 1/6th motor had occurred to me (e.g. Max6 and EzRun 4985), but that would require a chassis swap, yeah? (I'd like to keep it more default initially... this is my 2nd kit)

I keep mentioning Hobbywing solutions because product availability is an issue here without doing international mail order - Castle seems somewhat available & slightly higher price, while Tekin is expensive very limited availability. I'd rather do it right first time though, so if overpaying or importing is what it takes then I would shrug it off & do it.

 

[MAVERICK]

2200kv is not an option with hot temps and hard bashing

I think your best choice is to run a 1/6 scale set up

 

[PKMSM]

My ET48 2.0 has a Castle 1515 2200KV motor with a 15 tooth pinion, and I had set the ESC to cut off the motor if the temperature reached 160deg F. On a ~15deg C day, after 10-15 min of open throttle bashing in a parking lot the motor shut off on temperature.

On grass and at the ambient temperatures that you mentioned, I would definitely oversize the motor/ESC.

I am building an MT410 and will use a Castle 1520 size motor for this reason, but using a wide-body chassis. This is also my second kit.

 

[pache]

Hrm.. not the answers i'd have preferred, but not answers that come as a major shock

How about the sensored vs sensorless heat handling? There are sensored hobbywing 4268 1900kv motors available here at present, although it doesn't look like they've released a 1600kv & the sensorless 1600kv versions seem to be sold out. I'm guessing that a 300kv drop would not be enough regardless, especially in a shorter can(?)

I get the impression Castle setups seem to be a bit more waterproof but run a bit hotter than Hobbywing(?) but 15 minutes for the castle 1515 2200kv on what I'd call a slightly chilly day is not promising. Was that 6s or 4s?

A M2C widebody kit plus a hobbywing max6 / 4985sl would be spending roughly the cost of the MT410 all over again, and a Castle Mamba Monster X 8S plus 1520 or 1717 would be the cost of the tekno kit before even buying the widebody ... So if i were to try a 1/6th scale swap it would probably be the max6 & 4985sl. I'd also be more relaxed about the idea if the thread immediately next to this wasn't talking about production quality issues with the M2C widebody kit lol

 

[Nicochau]

Since you’re bashing, you can forget about sensored.

I would personally go for a 4082 or 4092 can, but not further and definitely not a 49xx motor. The smaller diameter will be more reactive on 4s. Keep the motor kv in the 2000 or below.

Turn ESC punch down to save power and reduce heat and go up in diff fluid weight in your center diff if you want to keep the wheelies going.

You could also pull it off with a 4074 motor and lower kv like 1700kv to 1800kv on 4s if you accept to sacrifice some top speed.

 

[macovial]

Hrm.. not the answers i'd have preferred, but not answers that come as a major shock

How about the sensored vs sensorless heat handling? There are sensored hobbywing 4268 1900kv motors available here at present, although it doesn't look like they've released a 1600kv & the sensorless 1600kv versions seem to be sold out. I'm guessing that a 300kv drop would not be enough regardless, especially in a shorter can(?)

I get the impression Castle setups seem to be a bit more waterproof but run a bit hotter than Hobbywing(?) but 15 minutes for the castle 1515 2200kv on what I'd call a slightly chilly day is not promising. Was that 6s or 4s?

A M2C widebody kit plus a hobbywing max6 / 4985sl would be spending roughly the cost of the MT410 all over again, and a Castle Mamba Monster X 8S plus 1520 or 1717 would be the cost of the tekno kit before even buying the widebody ... So if i were to try a 1/6th scale swap it would probably be the max6 & 4985sl. I'd also be more relaxed about the idea if the thread immediately next to this wasn't talking about production quality issues with the M2C widebody kit lol

Went with the Castle 1520-1650kv motor with 24T pinion with Mamba Monster 8S on 4S batteries. No regrets and I don't have a fan on it yet. There are several others here who were frustrated with their 1515s and had overheating issues. That's with the m2c gamechanger chassis and extra weight, and moving the ESC to top of the horizontal m2c brace, to keep the ESC away from the motor. With the 1520, there's virtually no overheating issues although it may be wise to add a fan.

From Australia: https://www.teknoforums.com/threads...ckflip-lp-tyres-mmx8s-1520-1650kv-combo.2350/

 

[pache]

Since you’re bashing, you can forget about sensored.

I would personally go for a 4082 or 4092 can, but not further and definitely not a 49xx motor. The smaller diameter will be more reactive on 4s. Keep the motor kv in the 2000 or below.

Turn ESC punch down to save power and reduce heat and go up in diff fluid weight in your center diff if you want to keep the wheelies going.

You could also pull it off with a 4074 motor and lower kv like 1700kv to 1800kv on 4s if you accept to sacrifice some top speed.

OK, good point about the diameter issues, I was losing track of that in the mix. Getting a sub 2000kv sensorless in oz seems to be a bit of a forlorn hope with the supply chain dramas - it'd be a matter of choosing to run without them hooked up. So it's bound to be a sensored-capable run without sensors.

Actually got my kit at the start of the week so I was able to make a few measurements of the stock mount tray. Seems to be about 125mm from the engine mounting plate's default position to the edge of the servo holder. Hobbywing ESCs seem to be 30 or 35mm wide, Tekin are 35.5mm, and Castle range from 47-54.1mm (and interestingly are shorter than they are tall so possibly you could try some sort of weird on-its-side placement if you were keen).

The beach footage macovial linked looked very neat, but I think we're seeing the extra length of the ET48 there - my measurements from unconstructed parts might be out a bit, but they're not 20mm out & the 1520 + Monster X 8S definitely won't fit without a chassis swap or ESC positioning creativity.

Although that's all a bit hypothetical, cos I can't find any of the sub 2000kV Castle motors available for sale out-of-combo in Australia currently, and the one or two stores still with ESC/motor combos are asking ~AU$200 more than equivalent Hobbywing & Tekin combos (i.e. about US$145 or 127euro). To quote the Pixies, "Gouge away".

I'm not seeing any 4080 type motors in oz (seems to be Hobbystar & Leopard? both would be imports here), but the Tekin Truggy versions of the T8 are 4077 in size and that's also the only decent can length motor I'm currently able to source in 2000kV and below options. The sub 2000kV hobbywings all seem to be 4268's (as are Tekin's buggy T8 versions).

So I currently have an order in for a Tekin RX8 Gen 3 and 2000kV truggy T8 combo. It may run hot for summer, but we're heading towards winter here at the moment and as Nicochau suggested I can always tune it down if it starts struggling in summer (or just buy a second lower kV variant).

I don't currently have a heatsink/fan ordered... eyeing off Yeah Racing's YA-02618K heat sink & twin fans or there's a VRP tekin specific motor fan mount that's out of stock - does anyone have any advice there?

Thanks for the help everyone, it's been very useful. I'll try to grab some photos & maybe try my hand at a build thread.

PS. After I worked all that through I went back & was kinda amused to realise the stock photos Tekno use on their MT410 product page include what looks like a Tekin RX8 & truggy length T8... so apparently I'm going ultra stock? Hoping to shake that up a bit with my choice of bodyshell tho