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[malcolmfrary]

Circlip kindly sent me a motor sheet from back when prices were in runes and perches.  I extracted the Graupner (Marx?) bit and kicked the image around a bit to make it fit the site requirements.

[rayna]

   Hi great reading from everyone and I have only just taken a look cause I am suddenly faced with a broken end housing on my 6v Decaperm 7121 direct drive and am looking to replace it probably with one (well two actually cause it is twin screw) of the Graupner range. Question is which one.
The boat in question is 33" RAF air sea rescue launch with electronize feeding two of the decaperms with what looks like graupner two blade 35 diam. plastic race boat type props.
Any help appreciated.
Raynor J

[malcolmfrary]

More likely, which two.  A replacement motor is unlikely to match the remaining one due to time moving on with the manufacturers and age and use catching up on the existing one.   Just pick a pair of the same size intended for the same voltage and wanting the same current.  Having a matching pair makes running straight so much easier, especially if they are both on the same ESC.

[georgo]

 
  great help...

BreezyB

The simplest question, but not very a simple answer.  Even the brief answer involves history, inflation and hijacking!

Originally they were Mabuchi designations, and I understand, but could be wrong, that they represented the armature stack length in mm.  The older ones (380, 540, 550) had that meaning.

At some point the 0 on the end came to mean 3 -pole (relatively high speed) and a 5 got tacked on the end to represent 5 pole (relatively high torque, lower speed), so 545 and 385 are 5-pole variants (very boat-friendly)

Have a look on the Mabuchi website - a good deal of history is still in there, I think.  designations like 120, 130, 180 still exist under the old meaning.

None of this, you will notice, tells you ANYTHING about the windings inside and hence the speed, current and voltage range.
It is worth bearing in mind that all the motors can be wound from 1.5 Volt windings (2 turns of coat-hanger wire) to 36 or 48 Volt winding - millions of turns of maidenhair wire.

After Mabuchi comes the hijackings and rampant inflation, and the first attempts to describe the windings

To be continued (if it of any interest)
andrew

[Bob K]

Motor Resizing

I need to downsize the motor shown in the photo below.  It seems a bit overpowered for a tug of less than half a meter, and depletes the twin 6V 4.5 AH SLA’s in only an hour and a half.  What “size” is it, and what motor should give at least 2.5 hours sailing with reasonable power?

 The motor has no identification, but is approx. 65 mm main body length and 37 dia. Driving a single 3 bladed prop of 45 dia.  The various descriptions in posts below for the 400/550/700 number sequence seem rather vague.

[inertia]

Bob
Go to this link http://www.modelboatmayhem.co.uk/ then to Electric Motors > Fast Motors and scroll down to Bad 540 motors. That looks very much like what you have - it certainly fits the symptoms. Extract it and file under wheelie bin, or save for ballast. If you paid more than a quid for it, seek out the person from whom you bought it and make him eat it.
I would suggest fitting one of these instead http://www.componentshop.co.uk/mabuchi-555-dc-motor-mounting-bracket.html . The screw fixings are identical; the shaft is the same diameter and the motor is comparable in length so it will be a very simple task. Connect your two 6v batteries in series to give 12v and off you go. I have one in my 30" Boothbay Lobster Boat and it's a pussycat with a 50mm 3-blade plastic prop on 12 cells.
Dave M

[Bob K]

Many thanks Dave.  Having acquired the boat from a fellow club member I am doing a rewire.  There were 6 separate battery packs for various functions.
First Mtroniks ESC I used for 3 years, hopefully an Action P80 will give me a single shaft equivalent to the trusty P94's in my other (twin shaft) ships.

[inertia]

hopefully an Action P80 will give me a single shaft equivalent to the trusty P94's in my other (twin shaft) ships.

That's the very one I use in the aforementioned lobster boat. If you select soft-start as per the instruction leaflet then it really does have an excellent low-speed performance. The 555 doesn't so much start up but more like groans, yawns, stretches and has a good look around first. A very good combination - but I am a touch biased.
Dave M

[malcolmfrary]

It might be worth doing a health check on the SLAs to make sure that they are both healthy, and, preferably, equally so.  One tired cell in the box can lead to much woe.

[Bob K]

malcolmfrary:  Good point.  I have just got two brand new SLA's for the tug so hopefully will balance reasonably for 12V load and charging. 
I intend tapping off one 6V battery for LED's but that is just mA.

Now ordered the motor Dave M recommended, plus a P80 ESC and other bits.
I have a preference for a charging socket plus c/o power switch. Beats fitting batteries and wiring up at the waters edge. Charge in situ.  At lake just switch on Tx, then boat, check operation, and lower into water. Simples.

[Bob K]

Thanks again for the helpful advice.  The new motor and P80 Controller arrived promptly from Component Shop.  As I was now to be using the twin 6V 4.5 Ah batteries in series for 12V, instead of parallel, another major rewire was required.  As advised the 555 motor was mechanically a straight swap, although I had to pop out to buy an allen key of an odd size.

Whenever I wire I check everything a dozen times, and checked the P19 BEC was OK for the higher voltage (= 6V to 15V i/p).  I used the largest wire size the P80 would take.



Turn on. Everything checks out. A quick bath test to make sure I have the motor going in the right direction in respect of the Tx stick.  Compared with before very quiet and responsive.  Unlike the Viper Marine style with its centre deadzone then 15% power, a touch of throttle just got the prop turning slowly.  Much more controllable as a rescue boat.

Off to the lake.  A totally different boat to last week.
 


Very responsive.  Good low RPM torque. Throttle progressive right off from centre.  The motor does the job nicely, and IMO the P80 is well worth the extra tenner over a Viper.

[inertia]

Jolly good! Nice when a plan comes together, innit? 
Dave M

[Z750Jay]

I am impressed how neat and ship shape it is in there. Before it's suicide my springer looked a right mess as I had not made the access large enough and not really thought things out. It was my first build and I learnt a lot from the mistakes I made

[Netleyned]

That is a very nice Springer
Is it home brew or a models by design
f/glass hull with your own superstructure ?

Ned

[Bob K]

Ned:  Can't claim any credit, I bought it from a club member and am just doing some rework.  It looked fun to sail and is a change from long thin warships.

Z750Jay:  I have only been into boating for three years but have learned so much from colleagues and this forum.  Apologies for the wiring, still to be tidied into 3 separated looms, DC; motor; and controls.  Access should always be as large as practical, you can never have enough room when something needs work on.

I sail twice a week (weather permitting) and seen many boats break down.  It usually comes down to electrics.  I use heavy gauge wire, all soldered reinforced joints, h/shrink sleeves over all tags and terminals.  Going ‘cheap’ invariably comes back to bite you.  Once fitted disturb connections as little as possible.  In my scheme that’s a changeover power/charging switch and charging sockets.  Make sure all batteries are fully charged and do a ‘pre flight’ systems check. So far very good reliability.

[inertia]

I sail twice a week (weather permitting) and seen many boats break down.  It usually comes down to electrics.  I use heavy gauge wire, all soldered reinforced joints, h/shrink sleeves over all tags and terminals.  Going ‘cheap’ invariably comes back to bite you.  Once fitted disturb connections as little as possible.  In my scheme that’s a changeover power/charging switch and charging sockets.  Make sure all batteries are fully charged and do a ‘pre flight’ systems check. So far very good reliability.

Everyone reading this should print out the statement above in large letters and display it in whatever place serves as his/her workshop. Irrespective of what brands you use this is excellent advice. My thanks to Bob K for reminding us.
Dave M

[Colin Bishop]

And if you have a paddler don't forget to feed the hamsters on the treadmills...

[Shipmate60]

Dave,
The battery manufacturers recommend that gell cell batteries are charged in a a well ventilated or forced ventilated environment.


Precautions

• The charging voltages given in this article assume an ambient temperature of 20° C (68° F). The charging voltages may have to be adjusted when ambient temperature is outside the range of 41° F to 95° F. For temperatures below 20° C, increase the voltage by 2mV/cell/° C for float charging and 6mV/cell/° C for cyclical charging. For temperatures above 20° C, reduce the voltage by the same factor.

   

• Resist the temptation to use an automotive battery charger on your gel cells. Many inexpensive automotive battery chargers are not properly voltage regulated or current limited.

   

• Continuous over-charging or under-charging are a gel cell battery's worst enemies.

   

• Do not store your gel cell batteries in an uncharged condition.

   

• Avoid exposing the battery to excessive heat. Service life is shortened at operating temperatures above 30° C.

   

• Never charge a gel cell in an air-tight container or near objects which produce sparks or flames.

   

• When using a solar panel to charge a gel cell battery, be sure to use a charge controller which properly regulates the charging voltage. Many solar panels are capable of producing as much as 18 volts -- more than enough to damage your battery.

Bob

[inertia]

From Bob's picture it looks like it would be very difficult to charge up the batteries using those sockets (so near the coaming) with the superstructure still fitted. For those who like to bury their batteries deep down inside the model the advice should be to leave the top off when charging.
DM

[Bob K]

Very true Dave.  I always remove the superstructure for indoors charging of SLA and NiMh.  Well ventilated and at room temperature as DieselDo says.  I appreciate that much heavier ships are easier to launch/lift with the batteries out, so I tend to avoid heavy boats as kneeling at the waters edge is beyond my ageing joints (LOL).

Incidentally, the only "tool" I bring lakeside is a bailing syringe.  If anything unanticipated goes wrong chances are it will need the dry dock facilities at home. Clean, dry, with all tools available.

PS:  Must look inside a paddle wheel boat, Hamsters, I always thought they had motors. 

[HUNTER]

Motor Resizing

I need to downsize the motor shown in the photo below.  It seems a bit overpowered for a tug of less than half a meter, and depletes the twin 6V 4.5 AH SLA’s in only an hour and a half.  What “size” is it, and what motor should give at least 2.5 hours sailing with reasonable power?

 The motor has no identification, but is approx. 65 mm main body length and 37 dia. Driving a single 3 bladed prop of 45 dia.  The various descriptions in posts below for the 400/550/700 number sequence seem rather vague.

The motor shown is a 550 which is very wrong both in output and there are a lot of rejects for sale.
I would recommend a 540 motor for your model.

[barriew]

Can anyone tell me what motor range the Deans Marine Kondor falls into? 3xx, 4xx, 5xx etc.


Thanks


Barrie