Model Boat Mayhem
Technical, Techniques, Hints, and Tips => DC Motors (Brushed) and Speed Controllers => Topic started by: Ginger64 on March 01, 2016, 09:35:08 pm
-
Hi,just fitted a new pair of esc to my boat,at the same time replaced my two motors. These are Johnson 650 boat runs on 6volt 4amp battery. One of. Now the problem is this,when the boat is used slow speed no problems. When I increase speed to max the boat switches off!! And that leaves me the problem of retrieving it ha ha. Once it's back in hand if I switch it off and switch it on it's working fine again. I'm not sure if the 15amp marine esc,s are cutting out under load. Or could it be another problem.
-
15A is a bit low for 650s I think
-
I had the same problem with a Club 500 I used to run (although that was a single motor, single ESC). Changed to a Viper Marine 20amp ESC and that resolved the issue.
Hope this helps.
Regards,
Ray.
-
Could be the battery, at slow speed it can cope with the motors, as you throttle up it may not provide enough power to the BEC and reciever so causing the shut down as loss of signal
Mark
-
Pretty sure it's not the battery,the confusing thing is having two esc fitted. The ones I've used are mtronics marine 15amp. Can get boat to nearly full speed then it shuts off. Possible got a safty feature on esc to stop it overheating,or something like that. On dry land I can rev boat to max on forward and reverse No problems. Now when boat is in the water full speed shuts it down. When I turn it off and back on again it works fine. {:-{
-
That points to the power supply, when the motors are loaded up in the water they may be taking enough power to drop the reciever supply below its cutoff, causing the shut down, you need to put a watt meter in the boat this will tell you what is going on.
Just a thought, have you disconected one of the red leads to the reciever from the ESC's?? if not this could be the problem
Mark
-
6V 4AH battery indicates a SLA. Great for long gentle runs, but will not stand much abuse. Lead acid batteries will deliver a huge current (else your car would never start) but cannot do it for more than a few seconds without the voltage dropping, whatever their state of charge.
NiMH or LiPo can sustain a heavy continuous current drain without the early voltage drop.
-
Thanks for replays again people,boat has two esc. Both are plugged in receiver so no probs there. The esc,s have a two second setting window to set max throttle and max reverse throttle. Even when I try to set them they still remain in the same place if u understand. Personally I think the motors on max revs are tripping out a possible safty device on the esc,s which cuts the boat out.
-
I run the boat on two types of battery. Lead acid and ultra max lifepo4 lithium battery.
-
As Mark said have you removed a red wire from one of the ESC's Rx plug
-
Yes have cut the red wire from one esc. Just really copied what was already fitted in boat. But up graded the esc,s to new ones. Had lost reverse on one motor that's why I replaced the esc,s. That has fixed the reverse problem. But it now cuts out. Never has before.
-
Hi Ginger, still think its down to the battery, try disconnecting one motor, if it stops happening BINGO! possible that the new ESC's are more free flowing of the juice
-
Hi Ginger, still think its down to the battery, try disconnecting one motor, if it stops happening BINGO! possible that the new ESC's are more free flowing of the juice
.........and looking at the OP, the new motors might not be as identical to the originals as thought.
-
Could they be a couple of those dodgy current hungry johnsons
that were being touted on a certain auction site?
Ned
-
Could they be a couple of those dodgy current hungry johnsons
that were being touted on a certain auction site?
Ned
For those who didn't see the old posting about these motors on the main Mayhem site, here it is:
These are pictures of the rogue 550 fan-cooled motors which have caused several members some grief over the last year. They are available on E-Bay as well as at shows and from certain retailers. The legend on the can says simply “Johnson”; there is no further ID except the numbers around the flux rings (which mean nothing to me). These are three-pole motors with an internal plastic cooling fan which can be seen through the slots in the case just in front of the brushes. The backplate is a dark grey metal casting as opposed to the usual 540-style white plastic moulding or silver-coloured steel pressing. The case is substantially longer than a stock 540 – some 65mm from end to end, and the motors have two steel flux rings pressed around the forward half of the case.
We have found that the motors are not suitable for “normal” scale models if run at anything over 6 volts. For example, one member has two of these things fitted into a Graemsay ferry and has discovered that he has “low speed handling difficulties running from 12 volts” – probably the understatement of 2006. Another member reports that the stalling current is astronomical and I can personally vouch for the high current consumption, even at relatively low speed on 7.2 volts. They also get very hot very quickly and should be water-cooled for all installations.
In short I wouldn’t recommend anyone to buy one of these unless they are very familiar with all aspects of operating high-speed DC motors. Indeed, the only reason I have one to photograph is that it was given to me. Personally I wouldn’t install it in anything but a wheelie bin………
But what do I know!
The motors have since appeared in several different guises (600, 650 etc) but they are essentially the same i.e. designed to be run through a gearbox.
-
Do you think this may be one of those motors!
-
Batch no is the same :embarrassed:
We're you offered a 'Special Price'?
Ned
-
Can't think what I paid but not too cheap. Last 3 digits of bottom number is different.
-
Could be a serial number.
Yours has the alloy casting
at the rear instead of the white
plastic.
Is there a white plastic fan to be seen
through slots?
Ned
-
Can't see. Fitted in boat now. Gutted. >:-o
-
The old motors I used were exactly the same. In looks.
-
No need to be gutted, these motors are fine if treated just right :-) .. Firstly for direct drive you will need 20amp Vipers not 15s ( past experience with two single shaft 37" Perkasas. One had a 15 amp Viper, one had a 20 amp Viper, both had these Johnson motors on direct drive, 35mm 2 blade 'S' props and 7.2v 3600 mAh NiMhs. The 15 amp equipped model was just that bit slower until we swapped over speed controls. Both achieved run times of about 14 minutes, not bad for pre-brushless times. Both models got up on the plane..both models were the glass fibre variants so slightly lighter than the wooden ones.).
Second, as stated above, 6v is just that bit low for a supply voltage. Under full load the speed controls are tripping out as your available voltage is dropping below about the 5v mark. That or your Rx is dropping out and loosing bind temporarily ( had that last week with a little RNLI Lifeboat, those fifty quid things. I stuck two ex-coaxial heli motors in it for a set up on 4.8v..NOT the best idea. Ran like a mad thing and kept dropping out and re-binding after a few seconds, too many amps by a long way! Now happily equipped with a pair of MFA 280/1 motors, sweet as a nut..).
These motors have had a bad press, not least because of some of the less scrupulous people suggesting their suitability for 6v to 12v operation, my advice, don't exceed 7.2v on direct drive, after that slap them on some sort of reduction drive gearbox. I have run them up to 14.4v on Robbe 3.3:1 reduction drives with 42.5mm 2 blade props, pulling about 6.5 amps in the water. i am also using them on 5.5:1 reduction boxes in a 68" landing craft that I am slowly building, that is running on a pair of 6v 10amp gel batteries, one per motor.
lots of motors can cause problems. Only a few weeks ago, at a model show, I saw a scale 'grey funnel line' battleship with four Graupner 600 12v motors, a bit extreme for a five foot boat I thought. However the local expert had recommended them as he had used the same set up in his much faster boat and all was well.."anyway.." said he, "you can always just not use all your throttle.."
Good advice..better advice would be to put the right motors in, but I digress..to quote a great man...
Suit yourself %)
-
Thanks for reply unbuiltnautilus. But after just fitting new 15 amp esc,s think I may have to fix throttle levers so I can't max it out. Or maybe I could put a feed from another battery to my receiver so it stays powered. Would that work?
-
You could feed a separate 4.8v Rx pack into your receiver which would stop any brown outs caused by low voltage supplies to said receiver. You would have to remove the red wires from both of your Vipers instead of just one.
You could change over to 7.2v packs for main drive, which would give you a little more leeway on your voltage supplies.
If the problem is caused by too high a current drain from the motors, the only real option is smaller or shallower pitch props.
What type of model is it and what size props are you using at present?
-
Have un pluged one motor and it still trips out on the other motor alone. Props are 30mm three blade brass. Boat is 450 mm x 300 approx.
-
Ginger
What sort of model is it? 450 x 300 sounds a bit work-boat-ish. You'll find that any motor of this size (500, 540,545, 550, 600) has exactly the same mounting dimensions and shaft diameter, so replacing the motors with something a little less violent would be relatively cheap and simple.
Dave M
-
Just put a 12v 10amp battery on boat. And it's not cutting out at all. So think that's the problem. A few of you have said it may be this. So now have to try and find a battery the right size and power for the boat. Will keep you all up dated. Many thanks for all those who posted and stan who called me and enlightened me on many things. Great work people. :police:
-
So. Next problem. I need the smallest battery with the most power. And the lightest. Bet we all say that.!! Now what's your thought on power to reicever. Would I be better off with a separate power pack. Or keep as is. Which is off main boat battery. Would it be safer with a separate battery pack to reicever,and would it mean if main boat battery was low it could still make it back to dry land,be it a lot slower.
-
As before, don't run it on 12v! If you can fit a 6v 10amp gel ( or 12amp gel ), you should have enough capacity to avoid brown outs, but that kind of depends on your third dimension, i.e. depth? ( or failing that, is it a speedboat or tugboat? kind of important that bit :-) ).
I don't know, or more truthfully, have forgotten, if you will have the 'get you home' capability with Mtroniks or similar controllers, if you use a seperate rx pack. The size of this will depend on how many servos are working on the model. Anything above 1200mah should be good for at least three hours on one servo and two speed controls.
The other options for main batteries are 7.2v NiMhs, lighter than gel batteries, or LiPos. Even lighter, but you will need to fit some sort of low voltage protection for them on the model, plus you will need a dedicated charger to suit..
-
Boat has 1 servo,two esc,s. 3 led lights,that's it. Batterys I was using were 6v 4amp which as I now know are too small.
-
Would these do.
-
Another question,any one ever used lap top batterys. High amps and voltage. Just a thought,may be possible to alter one to fit a boat.
-
A variation on the theme would be advisable....It does say 'Superior Quality' on that Made In China battery, so assume the opposite :-)) .
Best advise would be 7.2v NiMhs of between 4000mAh and 5000mAh. These should stand up to some medium level abuse. The problem with bigger numbered cells is that its all promise but with no delivery. They may provide up to 6800mAh, but only at something like 600mAh for example. Much higher currents and they may well dump much earlier than the maths would indicate.
Try your local model shop, online via Component Shop or one of the big RC Car dealers, i.e Modelsport UK, for decent 7.2v batteries.
-
Another question,any one ever used lap top batterys. High amps and voltage. Just a thought,may be possible to alter one to fit a boat.
In that they are very ordinary cells inside a shaped case, yes they can be used with the case removed. BUT - not all are NiMH, many are lithium types and need the right charger. Since they are intended for use in a fixed environment and laptops do not present a particularly heavy load they don't tell you the C rating, so there is no telling whether any one particular battery would work. If the chosen one cannot supply the current wanted, you are back to square one.
In the medium and long term, it is probably more economical to go to a "proper" battery supplier as suggested above. If 6 volts is giving the wanted performance, they can supply 6 volt packs - you are not stuck with the higher voltage that you don't want anyway.
-
I get where ur coming from Malcolm. But my problem is battery size. Not having room for a big battery. Need 7.2 v and as high amps as I can get. Been having probs with the boat cutting out on 6v 4amps under load. Tried 12v 10amps and boat seems fine. Do you think if I put a seperate power feed to the rieciver it will help. Would it give me chance to get boat back if current on main battery falls low,
-
I have just tested a 20amp Viper Marine speed control with the set up using a seprate 4.8v Rx pack..just out of curiosity you know. The main problem was finding a dead or nearly dead battery for the main drive, found one that would take a charge in the end.
With an old Simprop 600 motor (similar to the Johnson motors) and a rapidly flattening 7.2v main battery, the 4.8v pack continued to operate the rudder, as the main battery dropped to 3.5v, when the motor stopped rotating.
So in answer to your question, yes, a separate Rx pack will provide a get you home function, for as long as you have reserve voltage in the main pack.. you could always use the rudders to paddle it home if all else fails.
I have been asked many many times if this or that is suitable for 'my model'? I find it handy to know what type of model it is...this is still a mystery, but we do know how big it is, which is a start :-))
Best quotes ever when asked what type of boat it is..
1)" Well you sold it to me!"
2) (personal favourite of all time, ever..) "Its a red one.."
More info always better than less info. Although in this case I think the colour scheme is not going to effect the final performance of the model %)
-
I've tried to post a pic for ya but it tells me file size is too big.
-
I know a picture tells a thousand words, but one or two should clear this up........Viking Longboat?
-
Its not two Springers glued together is it?
-
Boat
-
Twin props.
-
Had this boat years. Repaired it loads of times. Up graded it from fm to 2.4. Love the thing. Use it for fishing now and again. The boat has had all sorts of probes over the few years I've had it but most are now sorted. Have changed original direct drive motors to props and uni couplings sorted all the leak problems. Fitted new motors twice as the condensation rusted um. Now fitted new speed controls as the old ones gave up. So would still like to keep the thing running if possible. I know it's a bait boat,and prob will be frowned upon but hey,I'm trying. And do like to know how things work and repair my self when possible. And any help on the way is taken on board. Excuse the pun. %%
-
Dave Jones AKA Stavros is the bait boat guru
on this forum.
He might pop up with a word or three.
Probably tell you how to paint it too :D
Ned
-
Not to fussed about looks. Just want it reliable. How they managed to sell this boat in the first place is beyond me, it leaked through the prop shafts. Which were as said. Direct drive through an O ring seal in boat hull. When rotating the water leaked in. Which is why I fitted sleeved props and sealed them to boat hull. Motors were well under rated so fitted better ones. Bait drop was rubbish so I improved that. Just nice to try and improve it rather than chuck it!
-
That's not a Viking Longboat!!
So no rudders to wiggle you home either?
I have fixed a fair few bait boats over the last few years. The last one being a Sabre last week, pretty decent bit of kit for a change. Hull upper and lower bolted together onto a rubber gasket instead of gunged up with mastic or silicone. Typical fail point..cut price on/off switch, replaced that and all was good.
So I assume that it wont take a great load of batteries because of the hull shape. If it is intended for short trips out from the shore and back, typically three to five minutes at a time, 7.2v NiMhs should be fine. If you can stretch to it fit two at a time, one per speed control. A separate Rx pack will give you peace of mind, just fit a big one if you are going to be out for some hours.
It may also be worth investing in a 12v fast charger, plus a couple more packs, to boost your time at the waters edge up just that bit more.
Just don't skimp on the power plant of the model, its the difference between a pleasing day out at the pond and a frustrating half an hour retrieving the model from the reeds.
And never trust a battery that states it is SUPERIOR QUALUTY :}
-
As you can see mine has mastic to hold it together. Not nice to gain access lol. But hey I'm a plumber I can use a mastic gun. Would you recommend any 7.2 batterys. So many about. And when you say 12v charger do you mean for the car to the battery. Rx pack do I go for more amps or more voltage or both.
-
6v Rx pack would be good, anything over 2000mAh should be ample. Can you charge a 6v pack up? If not a similar bigger capacity 4.8v pack will suit also.
7.2v packs, as before, aim for between, lets say 3800mAh and 5000mAh. J Perkins sell 3800mah packs, Voltz do a nice mid priced 4600mAh pack and Component Shop do loads of different ones, all a good brand, Ripmax do a decent 5000mah pack also. Just stick to decent UK sources rather than out sourcing to the other side of the world..
12v charger, yes, a car type. Either croc clips on the battery or lighter adaptor types. Or a decent mains and 12v one, costs a bit more but pretty universal capabilities.
-
Thanks for info. Gutted I can't run it on lipo. So much lighter and cheaper. Should have researched better before getting the viper esc. Never mind will still see what's available.
-
6v Rx pack would be good, anything over 2000mAh should be ample. Can you charge a 6v pack up? If not a similar bigger capacity 4.8v pack will suit also.
7.2v packs, as before, aim for between, lets say 3800mAh and 5000mAh. J Perkins sell 3800mah packs, Voltz do a nice mid priced 4600mAh pack and Component Shop do loads of different ones, all a good brand, Ripmax do a decent 5000mah pack also. Just stick to decent UK sources rather than out sourcing to the other side of the world..
12v charger, yes, a car type. Either croc clips on the battery or lighter adaptor types. Or a decent mains and 12v one, costs a bit more but pretty universal capabilities.
Don't decry all far Eastern batteries. Bang Good do some great battries with names well known in Canada and the U.S.
-
re comments on far east Nimh batteries. If they are cheap there is a reason.
If they are marked as a high capacity but feel light in weight you have been conned.
I have an amp hour charging monitor and batteries I purchased marked 3800 mAh were in fact 1450 mAh, they were cheap I should have known.
I bought AA cells marked 2500 mAh KNOWING that they were 1000 mAh but on charge in a transmitter they over heated and warped the plastic and now I cannot use the Tx. I have had hot batteries before but never had plastic warp from the heat.
The higher the amp hour capacity the heavier Nimh cells should be.
I have some quality batteries in use that must be well over 20 years old now. In the long run buy from a known reputable supplier, it is cheaper in the end.
regards Roy
-
Thanks for info. Gutted I can't run it on lipo. So much lighter and cheaper. Should have researched better before getting the viper esc. Never mind will still see what's available.
Now who has told you that? You don't need a speed controller which will automatically slow down the motors when the battery pack nears its minimum value; Component Shop sell several low-voltage alarms for pennies. These have very bright LED indicators and loud buzzers to tell you when that critical level is close. All you need then is time to steer it back and change the battery. This one even has a built-in alarm that you can operate from the Tx if your bait boat gets lost in the reeds. http://www.componentshop.co.uk/3-in-1-battery-monitor-discovery-buzzer-signal-loss-alarm.html (http://www.componentshop.co.uk/3-in-1-battery-monitor-discovery-buzzer-signal-loss-alarm.html)
DM
-
I got some Chinese batteries that weigh a ton .Slightly higher amperage rating than advertised and have been working great for 2 yrs now I also have some british In Nimh and Nicad that were out of use for 8 yrs.They charged up great on a Hitec auto charger aND ARE DOING WELL on can motors. In fact the Chinese set upset the CoG on two planes. The others were OK as the batteries were on the Cog. I have seen a lot of Chinese ( I think they are ) batteries in use in America and Canada so they can't all be bad .Or can they? {-)
-
Forgot to mention the chinese batteries are now in boats and doing well
-
Most NiMH and LiPo batteries originate from that end of the world these days. Like anything, there are good-quality batteries and there are the others. Some Chinese manufacturers have proper quality control and describe their products accurately.......and then there are the others. Some would call them the majority.
If all you look at is the bottom line then you will encounter far more of those than the former. As long as you are prepared for that then you're free to buy as you will from wherever you choose. Looking after them properly also helps their longevity.
DM
-
How very true {:-{
-
Hi all, re batteries on the Internet. When choosing a battery or cells it is worth then 'googling' the make etc, as there are guys on the net that check if they are what they say they are.
regards Roy
-
How very true {:-{
John
You are a mere 38 miles from the best re-seller of batteries, chargers and all manner of other such stuff in the UK. All top-quality items and guaranteed. Nice people, too! http://www.componentshop.co.uk/ (http://www.componentshop.co.uk/)
Dave M
-
Thanks for that but I already deal with him. Very nice bloke by the sound of him on the phone. I have their catalogue too.Can't actually get to the shop at present but so far can't praise them enough Cheers John {-) :}