Running a Mabuchi 540
Discussion
Hi folks - Ive had a sudden urge to bring an old project back to life.
As a student I scratchbuilt a beautiful Vosper Thornycroft 70' MTB from plans (MAP - Model and Allied Publication, remember them?). Power was a Mabuchi 540 with twin 7.2 NiCad battery packs, Futaba 2-ch r/c and a home-made speed controller which used 2 TO3 transistors. They got so hot I had to mount them on a massive heatsink on the deck!
The heatsink has got lost over the years and being on the deck it didnt do much for looks or stability. So Im looking for a modern speed controller, hopefully not needing two mahoosive red hot transistors. I expect the NiCads have expired too.
Im totally out of touch on modern r/c kit so suggestions for controller and batteries are welcome. Thanks!
As a student I scratchbuilt a beautiful Vosper Thornycroft 70' MTB from plans (MAP - Model and Allied Publication, remember them?). Power was a Mabuchi 540 with twin 7.2 NiCad battery packs, Futaba 2-ch r/c and a home-made speed controller which used 2 TO3 transistors. They got so hot I had to mount them on a massive heatsink on the deck!
The heatsink has got lost over the years and being on the deck it didnt do much for looks or stability. So Im looking for a modern speed controller, hopefully not needing two mahoosive red hot transistors. I expect the NiCads have expired too.
Im totally out of touch on modern r/c kit so suggestions for controller and batteries are welcome. Thanks!
Depends what you want really. You can by brushed motor speed controls from £6-16 from eBay. Might take a couple of weeks shipping if coming from China.
Or more expensive ones if you really want. 540 motors in a brushed sense haven’t really changed much. There are still “modified” motors of different turns and removable brushes.
Or you could look at a brushless motor setup. These will cost you a little more. But you can buy combo kits from around £25 to however much you want to spend. Brushless brings some advantages. But depends on you exact use for runtime and speed on if the benefits would be worthwhile.
NiMh is the replacement to NiCd and more tolerant to being part discharged. Much bigger capacities these days too. 6 cell 7.2v is still standard although you can easily get 7 cell 8.4v too. So long as your setup can handle it.
Or there are LiPo batteries. These are much more powerful. But a little more volatile and demand a little more care and a specialist charger. A 7.4v known as a 2S (uses two cells at 4.2v nominal voltage) will be more punchy than an 8.4v NiMh. You can get very large capacities up to around 6000mah if you have space for the pack.
LiPo can also be had in 3,4,5 and 6S for high voltage applications.
Or more expensive ones if you really want. 540 motors in a brushed sense haven’t really changed much. There are still “modified” motors of different turns and removable brushes.
Or you could look at a brushless motor setup. These will cost you a little more. But you can buy combo kits from around £25 to however much you want to spend. Brushless brings some advantages. But depends on you exact use for runtime and speed on if the benefits would be worthwhile.
NiMh is the replacement to NiCd and more tolerant to being part discharged. Much bigger capacities these days too. 6 cell 7.2v is still standard although you can easily get 7 cell 8.4v too. So long as your setup can handle it.
Or there are LiPo batteries. These are much more powerful. But a little more volatile and demand a little more care and a specialist charger. A 7.4v known as a 2S (uses two cells at 4.2v nominal voltage) will be more punchy than an 8.4v NiMh. You can get very large capacities up to around 6000mah if you have space for the pack.
LiPo can also be had in 3,4,5 and 6S for high voltage applications.
Thanks 300bhp!
Id like to keep the motor for old times sake, and its not been used much. So I need a 'brushed speed controller'? The old one used a square wave which wasted much energy as heat, will a modern one be better/cooler? Also, the 540 I recall draws a fantastic amount of current - are these up to it? https://howesmodels.co.uk/product-category/radio-c... I see some are water cooled, would I need that?
Id like to keep the motor for old times sake, and its not been used much. So I need a 'brushed speed controller'? The old one used a square wave which wasted much energy as heat, will a modern one be better/cooler? Also, the 540 I recall draws a fantastic amount of current - are these up to it? https://howesmodels.co.uk/product-category/radio-c... I see some are water cooled, would I need that?
If your motor is a silvercan Tamiya style motor, then they are 27 turn and don't usually pull huge current. Watercooling might be an idea, although I'm more familiar with cars and planes than boats. So probably not placed to answer.
You might want to have a look here:
https://hobbyking.com/en_us/power-systems/speed-co...
Quite a bit of choice and good prices. Note Hobbyking have a warehouse in China, the EU and the UK. If coming from China it'll take longer.
You might want to have a look here:
https://hobbyking.com/en_us/power-systems/speed-co...
Quite a bit of choice and good prices. Note Hobbyking have a warehouse in China, the EU and the UK. If coming from China it'll take longer.
Thanks - I've had both battery packs on charge for a few hours and they're up to 8+ volts (no load). Fired up the motor for the first time in 30+ years! They may not hold charge but it's a start.
One thing, the speed controller, batteries and motor are all in the same compartment, no ventilation. Is heat going to be an issue? Do modern speed controllers run cooler than my old TO3s which you could fry an egg on?
Also, why Li-Po not Li-ion?
One thing, the speed controller, batteries and motor are all in the same compartment, no ventilation. Is heat going to be an issue? Do modern speed controllers run cooler than my old TO3s which you could fry an egg on?
Also, why Li-Po not Li-ion?
make your way over to the hobby king website. choose the uk warehouse and before you know it you will have everything you need.
Personally, with the price of brushless motors, speed controller and lipo - i would upgrade - lighter, longer running times and more power seal the deal. if you want to go slower just reduce the throttle ?
Personally, with the price of brushless motors, speed controller and lipo - i would upgrade - lighter, longer running times and more power seal the deal. if you want to go slower just reduce the throttle ?
The_Jackal said:
Fit a water cooling jacket too. Otherwise it will cook itself.
To the speed controller? I hoped a modern one would be more efficient than my home-made one...On my next boat, which had the same insides, I set a small copper panel into the hull and inverted the TO3s onto it. They stayed stone cold. That might be easier than plumbing and pumps?
300bhp/ton said:
If you are using two 7.2v packs in parallel it will effectively double the capacity. Sharing the load across more cells will generally allow for higher amp draw.
That's what I thought. So am I still OK getting any of the speed controllers as mentioned above or do I need to look for a beefy one?go here and fill your boots - everything you need - lipo,ESC brushed and brushless
boat motors
https://hobbyking.com/en_us/power-systems/electric...
boat esc
https://hobbyking.com/en_us/power-systems/speed-co...
personally - i would go brushless - better efficiency, better ESCs and Lipo friendly
it's a bit like the not the nine o clock news - Hifi sketch running brushed these days....... it seems a bit pointless given the advantages that brushless and lipo offer and the brushless tech is so cheap now.
Just choose the UK warehouse and it arrives in 24 -48 hours
boat motors
https://hobbyking.com/en_us/power-systems/electric...
boat esc
https://hobbyking.com/en_us/power-systems/speed-co...
personally - i would go brushless - better efficiency, better ESCs and Lipo friendly
it's a bit like the not the nine o clock news - Hifi sketch running brushed these days....... it seems a bit pointless given the advantages that brushless and lipo offer and the brushless tech is so cheap now.
Just choose the UK warehouse and it arrives in 24 -48 hours
Edited by cati on Wednesday 27th February 08:52
cati said:
it's a bit like the not the nine o clock news - Hifi sketch running brushed these days
Ah yes, I shall need woofers and tweeters too!Great stuff, I think I have all the info now either here in links, thanks all.
At least budget isn't an issue now. When I did this the first time round £100 for r/c was about all I had!
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