Kraton Hobbywing 4985 1650kv cooling

[Grimbles]

Good to know - Always thought it was a pain shipping things in from the US, but I'll probably end up doing this - do you find the fan speeds are high enough to give sufficient cooling?

It took a couple of weeks but is de minimis so HMRC don't muck it up. Honestly I found the PH fans too weak for bashing and broke them both on my first outing. Now replaced with aluminium bodied high rpm rocket fans also off aliexpress.

I'd also add I have it on a finned motor (a tp 4250) and just put a bunch of thermal pads on. I get v good cooling performance running 22t on my mojave exb.

 

[FatCatRC]

Good to know - Always thought it was a pain shipping things in from the US, but I'll probably end up doing this - do you find the fan speeds are high enough to give sufficient cooling?



That's actually something i didn't consider, I was thinking about using a load of thermal paste but I tried it before on the MERV and the mess it left was horrible - Still haven't been able to get rid of the excess stuff round the edges



I was actually asking speficically for how to fit the K8s heatsink onto the 4985 & whether there's enough clearance under the motor - can't see that specifically being mentioned in any of those?



From reading around before the build I actually thought 18T was pretty conservative as most are running 19T or 20T - I'm hoping to go up to get a bit more speed and bring the torque down so cooling is probably my only option now - I don't really find the 18T to be that fast



I think as above the fans are probably the best way to go - I've tried thermal paste before and just hated the mess it leaves

Thanks for all the replies guys - Looks like the Arrma heatsink is going on Ebay and I'll just order something off Ebay

I run 25t on my 17+ pound kraton, 2 40mm fans took care of the issue. I use the ntf heatsink from nick on facebook but aperently it's the heat sink for a x maxx I heard. It is a super tight fit.

 

[M240i_bandit]

It took a couple of weeks but is de minimis so HMRC don't muck it up. Honestly I found the PH fans too weak for bashing and broke them both on my first outing. Now replaced with aluminium bodied high rpm rocket fans also off aliexpress.

I'd also add I have it on a finned motor (a tp 4250) and just put a bunch of thermal pads on. I get v good cooling performance running 22t on my mojave exb.

This is something I was worried about - are the alu fans a straight bolt on to the PH? 40mm I assume?

But begs the question if I'm going to have to swap the fans out anyway I might as well just go for the Alza racing mounts and zip tie the alu fans on to the motor straight off the bat... Hmm...

 

[Harriot10]

Alza mounts work great, just takes a while to get them if you're in the US!

 

[slick2500]

Alza mounts work great, just takes a while to get them if you're in the US!

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Oh dang really? My last Alza order took 10 days he even made the part to order.

 

[M240i_bandit]

I run 25t on my 17+ pound kraton, 2 40mm fans took care of the issue. I use the ntf heatsink from nick on facebook but aperently it's the heat sink for a x maxx I heard. It is a super tight fit.

Jesus - on the 1650kv? She must fly....

Alza mounts work great, just takes a while to get them if you're in the US!

View attachment 128333

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That looks like a nice clean setup - I'm actually in the UK so these will probably get to me before the PH/Yeah racing stuff. Looks like 1 mount + fan is the limit?

 

[Harriot10]

Oh dang really? My last Alza order took 10 days he even made the part to order.

Took 40 days for my order!

Jesus - on the 1650kv? She must fly....



That looks like a nice clean setup - I'm actually in the UK so these will probably get to me before the PH/Yeah racing stuff. Looks like 1 mount + fan is the limit?

I think you could squeeze 2, definitely if you stagger them

 

[slick2500]

Jesus - on the 1650kv? She must fly....



That looks like a nice clean setup - I'm actually in the UK so these will probably get to me before the PH/Yeah racing stuff. Looks like 1 mount + fan is the limit?

You can buy this dual fan adapter for the motor fan mount and use 2 fans https://shop.alza-racing.com/en/universal-parts/186-motor-fan-base-dual-40mm-add-on.html

It attaches to this https://shop.alza-racing.com/en/universal-parts/175-motor-40mm-fan-mounting-base.html

Took 40 days for my order!

I think you could squeeze 2, definitely if you stagger them

The last time I bought a Russian body it took about 3.5 months.

 

[Harriot10]

You can buy this dual fan adapter for the motor fan mount and use 2 fans https://shop.alza-racing.com/en/universal-parts/186-motor-fan-base-dual-40mm-add-on.html

It attaches to this https://shop.alza-racing.com/en/universal-parts/175-motor-40mm-fan-mounting-base.html

The last time I bought a Russian body it took about 3.5 months.

That's awesome! How long has that one been on there? I haven't seen it!

 

[slick2500]

That's awesome! How long has that one been on there? I haven't seen it!

Idk I just saw it

 

[Grimbles]

This is something I was worried about - are the alu fans a straight bolt on to the PH? 40mm I assume?

But begs the question if I'm going to have to swap the fans out anyway I might as well just go for the Alza racing mounts and zip tie the alu fans on to the motor straight off the bat... Hmm...

Horses for courses! I have some alza kit on the way. Ordered a couple of weeks ago, slightly regretting not having bought the fan mounts in all honesty!

 

[M240i_bandit]

You can buy this dual fan adapter for the motor fan mount and use 2 fans https://shop.alza-racing.com/en/universal-parts/186-motor-fan-base-dual-40mm-add-on.html

It attaches to this https://shop.alza-racing.com/en/universal-parts/175-motor-40mm-fan-mounting-base.html

The last time I bought a Russian body it took about 3.5 months.

That's a great find!

Just so I don't accidentally end up ordering more desk ornaments again... These should be everything I need right?

https://shop.alza-racing.com/en/universal-parts/175-motor-40mm-fan-mounting-base.html

https://shop.alza-racing.com/en/fan-covers/170-dual-40mm-aluminium-fan-cover.html

https://shop.alza-racing.com/en/universal-parts/186-motor-fan-base-dual-40mm-add-on.html

+ 2 aluminium fans, probably looking at these:
https://www.centro-rc.com/centro-aluminium-cooling-fan-28000-40x40mm-JST

And a 2s lipo to run it all off with a lvc circuit, I'll probably end up having to replace the max6 fan at some point from what I've heard but I'll see how I go for now

Appreciate the help all!

 

[Harriot10]

That's a great find!

Just so I don't accidentally end up ordering more desk ornaments again... These should be everything I need right?

https://shop.alza-racing.com/en/universal-parts/175-motor-40mm-fan-mounting-base.html

https://shop.alza-racing.com/en/fan-covers/170-dual-40mm-aluminium-fan-cover.html

https://shop.alza-racing.com/en/universal-parts/186-motor-fan-base-dual-40mm-add-on.html

+ 2 aluminium fans, probably looking at these:
https://www.centro-rc.com/centro-aluminium-cooling-fan-28000-40x40mm-JST

And a 2s lipo to run it all off with a lvc circuit, I'll probably end up having to replace the max6 fan at some point from what I've heard but I'll see how I go for now

Appreciate the help all!

That’ll do the trick for your motor fan setup. Alza makes a 40mm fan mount for the Max6/BLX185 also. Might wanna get it now

 

[Woodley99]

There's so many of these treads about this lol but here's the powerhobby twin 30mm fans in the HW4985 1650kv motor. Its made to fit smaller motor yes, but it's very soft aluminum and easy to stretch to fit

 

[Evoandy]

While still waiting for my rocket fans to arrive i made my own alza fan mount...

 

[M240i_bandit]

While still waiting for my rocket fans to arrive i made my own alza fan mount...


View attachment 128643

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Pretty ingenuitive - I like it, my fans arrive tomorrow so I'll try this while I wait for the Alza stuff to arrive

On a separate note it looks like these fans draw around 0.5-0.6amps each - seems like a lot to pull through a single receiver port as I'll be hooking up 3 fans

Anyone got any ideas of the best place to store a second 2s lipo on the truck? I've found a switch with a 2s lipo low voltage cut off built in so I'll probably run it through that with a 3 way JST parallel cable

 

[Evoandy]

Can you provide the link to this swtich?
Alpine video on YouTube the other day with somebody attached the fan Lipo into the tower. Looked quite descent...

 

[jrm850]

Should be a few ways to mount 2s Lipos. On top of your other larger lipo packs or you can turn the 2s lipo while on top of other packs but face them sideways meaning toward the center body tower / support and the chassis brace bar. Just use ingenuity to strap them down with velcro straps and or zip ties. You could probably mount a small shorty hardcase pack on the tower mount, but idk how hard you bash yours and if you send it 40ft in air and flip it on the top of body.

 

[M240i_bandit]

Can you provide the link to this swtich?
Alpine video on YouTube the other day with somebody attached the fan Lipo into the tower. Looked quite descent...

It's a SkyRC 600054:
https://www.skyrc.com/SKYRC_Power_Switch
Not sure where you're based but all usual UK retailers seem to stock it, looks pretty neat for a tenner

Should be a few ways to mount 2s Lipos. On top of your other larger lipo packs or you can turn the 2s lipo while on top of other packs but face them sideways meaning toward the center body tower / support and the chassis brace bar. Just use ingenuity to strap them down with velcro straps and or zip ties. You could probably mount a small shorty hardcase pack on the tower mount, but idk how hard you bash yours and if you send it 40ft in air and flip it on the top of body.

Yeah that's something I'm a bit paranoid about - I don't bash hard but my biggest fear would be bursting it on a bad landing... I'll see if I can get one that'll fit in with the 6s or maybe strap it on top like you said

 

[Tony T]

Hi Guys,

I couldn't find anything concrete on a search but need a little help - I've got an EXB with the Max6 combo/1650kv on 18T which seems to be running a bit warmer than I'd like (can't keep my finger on the can for more than half a second)

I bought a K8s heatsink and fan but I'm not sure it it'll fit - has anyone managed to successfully fit it? It fits around the can, and would need stretching over the fins which seems achievable - but I'm more concerned about the lack of clearance underneath the motor. Once it's on the motor it doesn't look like it'll be easy to pull off so a bit hesitant to just give it a go

On a side note how hot is too hot for these things? I'm estimating the can somewhere around 70C give or take

Cheers
Daven

I use the same rig on my exb and I got a heatsink with two 30mm fans from "yeah racing ". It was supposed to fit a 42mm motor, but was really easy to gently bend to fit. You need to trim a small amount of the heatsink to clear the rollbar. It also fits under the motor and seems to support the motor really well. I posted on YouTube. Search "Arrma Kraton unboxing and parts chosen". Hope this helps.