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>> Home > Tags > battery power

battery power
gas power
portland model power boat association
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Too Powerful Brushless ? by pmdevlin Fleet Admiral!   Posted: 2 days ago
I think you might need pointing in a direction, so I had a quick look on Hobbyking, and this motor is the sort of thing you can use, although this particular one would need you to swop the shaft around, this is just a guide, other s will no doubt add comment, its the right size, 5mm shaft, right kv and watts. https://hobbyking.com/en_us/turnigy-g15-brushless-outrunner-... brushless esc https://hobbyking.com/en_us/hobbyking-90a-boat-esc-4a-sbec.h... you don't need the high amp capability, but its reversing, programmable, water cooled, and has an sbec, so the main battery power this 5 mm shaft, move your motor to the centre section meaning weight distribution is more central, and you can now use a shorter shaft, and get a couple off plastic "x" props, I would say 40 to 45mm will be the one. This will give a good speed, and you can power on 3 cells or 4 cells lipo, get higher c rating (40c or more) and higher mah so you have fuel in the tank available https://hobbyking.com/en_us/turnigy-battery-3000mah-4s-40c-l... This is just a guide, a starting point, as I feel you are unsure where to start, others with more knowledge will come in regarding this, having experience with lipo, brushless, 3 foot ply boats, and esc's, depending on budget, this would be the sort of thing I would be getting.

Dumas 1203 Coast Guard Lifeboat (RNLI Waveney conversion) by Dave M Fleet Admiral!   Posted: 2 days ago
Hi I have the Billings version as does a fellow club modeller. Initially I used two 300 motors with a 12v 1.3amp battery placed in the rear cabin space. Good for about 4 mins then died. I now use two brushless 28xx size 30 amp ESC and an 11.1v Lipo 2.1 amp. My friend has a similar set up. Gives about 30 mins and exceptional speed. The lipo sits where the SLA was. I can understand your concerns about the lack of warning on your Mtronic but you can source battery alarms that will emit a loud noise when the cell voltage gets below the set voltage. Providing you are paying attention you will hear and bring the boat home. The running time will be similar on each occasion so you could also use a stop watch (on your phone). I have tried NiMhs but they lack the power and are nearly as heavy as the SLA.

Too Powerful Brushless ? by Dave M Fleet Admiral!   Posted: 9 days ago
Hi Doug Brushless motors may be similar to AC motors in construction but they are powered by pulsed sequential DC so there is no AC involved. I do agree Watt metres are the best way to make sure the motor, battery and ESC max values are never exceeded. I agree the spec sheets are very useful but are specific to the type of motor and original supplier, and many are for companies no longer trading. I do sometimes have difficulty in interpreting some of the info supplied but the nominal working voltage, max power are usually OK. The stall current is useful to decide on the wire and fuse size as well as choosing a suitable ESC. At the end of the day if the set up is getting too hot you are probably working over the specs and if water cooling doesn't help you need to adjust the prop and / or battery voltage.

Too Powerful Brushless ? by RNinMunich Fleet Admiral!   Posted: 10 days ago
"The max current is the Max Watts divided by the Battery Voltage." Hmmm! Dave, I=P/V works fine for DC and static resistances but it gets much more complex in a dynamic system like an AC motor, which is all a Brushless is. Don't want to get into rms and power factor and co here so I agree the wattmeter is the way to go to find out what's really happening. Normally (at least here, not so sure with China!!) the max power output is quoted at nominal voltage and max efficiency. If you (can!) trace the motors back to the original manufacturer they publish performance graphs showing efficiency, power vs current and volts. But who does that? Except nuts like me😉 According to the DC formula the ECO 600 would draw 131A at 11 Volts or 97A at nominal 14.8V. The real 'Black art' is then to work out what power you want/need for how much thrust, acceleration and top speed for a given boat and hull type🤔 Best way is to ask those who've 'Been there, done that'. That's why I appreciated very much Canabus' advice when I was looking for a brushless for my Sea Scout upgrade👍 Happy sailing all - Whatever pushes your boat! Doug

Too Powerful Brushless ? by Dave M Fleet Admiral!   Posted: 10 days ago
Hi Graham and Haig The max current is the Max Watts divided by the Battery Voltage. Most motors reach their max efficiency at much lower value, typically about 77%. You need to take care when interpreting the data especially when the description has been translated from a foreign language. The Eco range of motors were developed for model boats and in general were high tork, low revving and low current. They were also designed to work at lower voltages so that would explain the lower Wattage. I would only use the nominal voltage, Kv and max Watts figures. The amps appears to be the stall current but I am guessing. Also we don't know the voltage at which the stall current was measured. Providing you don't exceed the rated voltage and wattage your motor should be OK. I suspect running much above half the rated wattage may require some water cooling. There are many Wattmeters available that will measure the wattage, amps etc at reasonable prices and if you connect in line with your battery and ESC whilst holding the model in the water you will have a good indication of the max current / watts at full bore. This should be ideally about half the max rating (watts & amps) for both the motor and ESC. https://www.componentshop.co.uk/150a-watt-meter-and-power-an... Reducing the prop size will reduce the load.

Too Powerful Brushless ? by Traiderman Sub-Lieutenant   Posted: 15 days ago
hi all, i have a problem with my prop shaft, every time i start the Hobbyking Brushless 3660SL (3180 KV ) the prop shaft comes adrift from the boat hull. it's powered by a 14.7V Poly Lipo battery. is it too powerful for an Aeronault Queen 36"? or is the prop shaft vibrating because of out of balance propellor or the coupling? i have used Heavy Duty Araldite to glue the prop shaft on to the boat. it has come adrift 2 times now. Thanks for any help i may receive - Graham

Riva scratch built boat update by Alan999 Lieutenant   Posted: 17 days ago
I launched her yesterday and she went well. No ballast was needed and I put a 9.7 battery for powering. She is very fast and two weeks time will go on the boat clubs water in Torrevieja,

LiPo Battery Monitor by Dave M Fleet Admiral!   Posted: 17 days ago
Hi Andy There are many variations on the market but they all work basically the same way. Most modern Lipo ( and all Lithium based batteries) come with a small white plug with multiple contacts as well as the main power plug, usually connected to some heavy duty wires. The plug is connected to the battery negative at one end and then each pin is connected to the negative on the next battery etc. This allows the individual cell voltages to be measured. The monitors do this automatically when connected to the plug the correct way, if it doesn't light up it's probably the wrong way round. In my experience the monitor connector is not marked so you may need to try different combinations to find the correct way. You will not damage anything if you get it wrong. When correctly connected the monitor will display each cell voltage then the total voltage. This usually repeats after a few secs until you disconnect If you have a charger they have a selection of different size sockets for the number of pins and can only be inserted the correct way. You will need the manual that came with the charger to select the correct screen to display the values, but most can be found if you Google. Glad to hear you have a monitor, LiPos can be damaged if not kept balanced, or discharged below 3v ( some are higher, usually the high power versions) Hope his helps

Skiff by johnmont Petty Officer   Posted: 23 days ago
Try Hobbies,they sell various small battery powered outboards although you may have to modify the stern sheets to accomodate.

46" Firefloat What Motor/Battery by pmdevlin Fleet Admiral!   Posted: 27 days ago
Hi John, you might now be scratching your head, and wishing you have not asked the original question! This seems to be a common issue, as the boating community is light years behind the other disciplines, rc cars, planes helis and so on, its probably due to the facts general boating doesnt really need the later generation technology, the average boater age is probably higher than the other disciplines so budgeting might be an issue, and there is less younger blood in the clubs to explain the lipo/brushless etc. We see posts with a load of numbers, specs, warnings etc, its enough to put people off. Im a big fan of brushless/lipo/ 2.4 etc, been doing it for years, its cheaper and more efficient (once you have the basics) but for the average guy, who just wants to spend an easy afternoon at the local lake gently cruising around, brushed motors, nimhs batteries, even lead acid, will do the job👍 Your 4 foot ply boat, once painted, with fittings, will be heavy, I know, I own one. Those 600 motors are not big enough, they are better suited to the smaller 3 foot boat, then, pushing them with a 6v lead acid, just cant do it. The battery will be screaming HELP!! I started 15 years back exactly the same, 600 motor, 6v battery, massive 50mm prop, I knew no better and took advise from people who didnt know what they were talking about😡, remember those gold hi tech speed controllers!! I had one, it melted, literally melted on the first use😭 Get 700 size motors, they will need to be water cooled, as mentioned by jarvo, the nominal voltage or below isnt good enough, power them at the max voltage. Brushed means you can use one apropriate esc, look out for electronize (are they still in existance?) or mtroniks, preferably use nimhs batteries over lead acid with a high mah. If after all this you want to venture into lipos and brushless motors, go to a club, spot a boat that is similar in size to yours, if you like the performance talk to the owner and gain experience and knowledge that way, it will save money, lost time and a lot of disappointment, I have been there so feel your pain. I say I would never go back to brushed motors and none lipo batteries, but I always want silly speed, not runtime, after 15 minutes Ive had enough and am bored. Rambling over! My 4 foot boat is twin brushless and uses 4 lipo 5000mah cells per motor, it will do 25mph for 15 mins, then I go home😁 Message is, you can get a "reasonable" performance from brushed motors, with the correct batteries, right props, but weight is the enemy. Looks lie you are at Biddulph, get onto Dave M a moderator on here, and arrange to go over to see the crewe and district boys on one of their sailing days, take your boat with you, they will help👍

850 Brushless by canabus Admiral   Posted: 2 months ago
Hi Andy Slightly more power with a brushless motor is a no go!!! Brushless motors the same size are far more powerful !!! But, the about same RPM a Turnigy L5055-700kv(500 rpm more on a 4S(14.8 volts) Lipo battery would be a good replacement. Mind you at 1600 watts( about 2 and 1/4 HP) these will used in a large boat like a 46" Vosper Crash Tender or a 46" Sea Queen!!! My move into brushless motors I have found that they are 7 to 10 times more powerful and equal to, if not better than the old IC motors!!! My Sea Hornet, Sea Commander and Huntsman run brushless motors . My Crash Tender is getting the 5055 motor, so it will be interesting to see what it will go like!!

Happy hunter by jarvo Fleet Admiral!   Posted: 3 months ago
The motor units are Robbe EF76 with fitted gearboxes, rated at 6 - 8volts, superb units and very reliable, did you strip and clean the gearboxes as well???? were the photos taken before you cleaned the motors??? The battery space looks to have been fitted with 4 x 6v 4ah batteries, probably giving 6v drive power, might have been 12v. Is there an ESC fitted?? that would give us the final key, apart from the red and black wire in the 4th photo is there any other wiring??? Mark

46" Firefloat What Motor/Battery by jarvo Fleet Admiral!   Posted: 3 months ago
HI JJ. Your question about a safety bag, Damaged / overcharged lipo's can catch fire, think of the Boeing scandal that grounded the fleet last year. Charging in a safety bag is advised the bag is fire retardant material, which will contain any problem. Your remarks about the boat not coming onto the plane is down to the weight of the battery, my fireboat started with 7.2v NimH packs 1 for each motor, Graupner 700bb's, good cruise but not quick, but short run time, 10mins. I have re-wired to allow 3s lipo's, but not had chance to test it yet, but should go like stink. With a fast hull, weight is important, 4 x lipo packs, 1kg, half the weight and possibly 6 times the power delivery. In your first post you mention 600 motors on 6volts, they are probably rated at 8.4volts, same as my 700's hence the lack of performance, also the battery, at 12ah it should last about 30mins, was it fully charged??? and is it showing at least 6volts, ie not got a duff cell??? Canabus, in his post described an ideal set up with brushless motors, 1600 watts is just over 2 hp, 750 per horsepower so you can see the difference in performance with different motors and battery set up's

46" Firefloat What Motor/Battery by canabus Admiral   Posted: 3 months ago
Hi What type of props are you using(size and number of blades). I see your basic problem is under powered motors and a very heavy battery. I made the big switch over three years ago from brush to brushless motors and to Lipo batteries. With the help on the forum and club members it was a learning curve, but, I would not go back. A 5800mah Lipo battery is in the weight of 450 to 570 grams and would give you a good 1/2 hour run time. A good balance charger and safety bag are the main requirements, also maximum charging for the 5800mah battery is 5.8 Amps(same as the old Nicads). Also a low voltage battery alarm. Your 600 motors can draw up to12Amps !!! Replacement same size motors for your mounts would be 35mm brushless motors, but, you will require two ESCs with a Y connector to run on the same throttle channel. Replacement brushless motors are far more powerful e.g. a Hobbyking 3639-1100kv with a 60Amp ESC on a 4S 5800mah Lipo Battery is 800watts and with two in your boat is 1600 watts!!! Your old motor would in the 100 watt each mark !! I have the same size crash tender, but, with a single brushless motor. I have all the order numbers for the motors etc. and a setup the ESCs if your require. Canabus

46" Firefloat What Motor/Battery by moormedic Petty Officer   Posted: 3 months ago
Hello chaps. I'm very new to this but have just finished scratch building a 46" Vosper Firefloat in the old Aerokits fashion (ie all wood) to the point where I've primered it, fitted a radio and couple of motors (Graupner 600 chosen at random cos they looked adequate!) and a Lead Acid 6v 12Ahr battery. Tried it on the local canal today and two problems. 1: its underpowered...nearly gets on the plane with a fresh battery but not quite. 2: The battery only lasts about five minutes. I'm an old git and don't understand "Lipids" or the benefits of "Brushless Motors" etc and would appreciate any help or advice any of you experienced guys could offer me please on motor/battery choices to get the thing planing and running for more than five minutes. Many thanks in anticipation Cheers John