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>> Home > Tags > battery

battery
battery life
battery mount
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battery voltage
batteries
battery
Bulwarks and deck supports by AlanP Fleet Admiral!   Posted: 2 hours ago
The next stage was to smooth out the Bukwarks so that a deck support could be fitted around the hull, the washports and rope hawsers were cut out, if I was to do this again I would cut these out after filling the bulwarks. P38 was used to smooth out the Bulwarks, this really was a labour of love, lots of filling and sanding. For the deck support around the hull I used 3mm lime (Ikea blinds) two layers to give 6mm support glued with Araldite. The rest of the deck supports were then glued in place, I think it was at this stage that I added the two battery placements after having the hull in the bath to work out were they had to go.

Graupner Elke HF 408 by RNinMunich Fleet Admiral!   Posted: 1 day ago
Hi Allen, I heartily agree Chinese specs should be taken with a generous pinch of salt 😉 But even a quoted 'peak 320A' ESC should be able to handle 100-150A which is probably 10 to 12 times what you will need for the little Mabuchi. Your Wattmeter is almost identical to mine👍 Connect battery to the 'Source' wires and 'Load' to the ESC and away you go. Do the test with the prop / motor under load, i.e. in the domestic test tank! Don't forget the Souwester!! 😉 I'll be surprised if the full ahead test is more than 10A. Have fun, Doug 😎 Primroses and daffs are only out in the Garden centres and supermarkets here, be another 4 weeks or so before much happens outside. 🤔Although my Winter Jasmine is still bravely blooming bright yellow 😊

Graupner Elke HF 408 by AllenA Fleet Admiral!   Posted: 1 day ago
Thanks Doug. I am not sure I would rely on my Chinese friends' measurement of amps but I have used a few of the ESCs and they haven't blown up yet. How would I go about testing the amperage? I have my little unused Watt Meter. Do I, simply, connect it between the battery and the ESC and take the reading while running the motor? Sorry to hear about the snow, we are just moving into Spring. Primroses and Daffodils are out and days are lengthening. At last.

Hovercraft by Dave M Fleet Admiral!   Posted: 5 days ago
As requested I have obtained some pics from Brian Clewes's Hovercraft. The motors are 900 Kv with 80 amp Escs the lift fan is a 7 blade ducted fan, the thrust prop is a 12in x7in cut down to 10in. Battery is 14.8v 5000Ma.

Dumas 1203 Coast Guard Lifeboat (RNLI Waveney conversion) by Dave M Fleet Admiral!   Posted: 5 days ago
The 12v I used was small and didn't last long. I see from your next post that you have decided to go brushless and LiPo and you won't be disappointed. The battery warning devices are essential for LiPo type batteries and I am sorry if I lead you to believe they were required for SLAs.

Too Powerful Brushless ? by pmdevlin Fleet Admiral!   Posted: 6 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- style='background-color:yellow;'>battery-3000mah-4s-40c-lipo-pack-xt-60.html 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 Skydive130 Fleet Admiral!   Posted: 6 days ago
Cheers Dave, some good stuff there. Are there smaller 12v SLA than the giant house brick I have in my aerokits Solent? Don’t want to sink it with a huge brick lol. I may look at a brushless conversion at a later date, would be easy enough to swap out the brushed motors and replace. It’s just that I have all the brushed stuff available that was going to go in another model, may as well use that first. I have battery warning devices for my aircraft, but they are lipo only, will have to look for sla types?

Dumas 1203 Coast Guard Lifeboat (RNLI Waveney conversion) by Dave M Fleet Admiral!   Posted: 6 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.

Dumas 1203 Coast Guard Lifeboat (RNLI Waveney conversion) by figtree7nts Fleet Admiral!   Posted: 6 days ago
Back then Tom my friend was using a NiCad 7.2volt! But today who knows what battery you can use!

Too Powerful Brushless ? by Dave M Fleet Admiral!   Posted: 6 days ago
Graham That sounds much better and will move your boat at a very fast speed. I must reiterate my previous advice repeated by BOATSHED regarding the extra support for the prop shaft at each end and adjacent to the bearing. Unlike brushed motors, brushless accelerate to their KV rating at a very fast rate and if your installation is not solid (as concrete) you will experience all kinds of problems, all costly, and often terminal (personal experience confirms this). Finally do get a wattmeter and check the amps and wattage whist holding the boat in the water. If either are above the rating for the motor, ESC or battery you need to reduce the prop size. I can't emphasize this enough as the consequence can be an explosion on the water and total loss of the boat and all its equipment. Asw you have mentioned 10000 mA I assume you will be using two 5000Ma batteries in parallel. This is OK providing you use and electronic coupler between the batteries to disconnect a discharged battery to ensure no one battery discharges below the recommended value. These are not cheap and personally I would use one battery and change to a new battery when the first was depleted. I accept that if you are in a racing situation this may not be possible, but I suspect as a newbie you are using for pleasure purposes. I hope you will now be able to proceed to install the new motor and prop shaft and supports as suggested. Please keep us posted and I look forward to seeing your model on the water

Dumas 1203 Coast Guard Lifeboat (RNLI Waveney conversion) by Skydive130 Fleet Admiral!   Posted: 6 days ago
So here we go again! I have decided to give other projects a rest for a time in favour of this little gem. Pick up off eBay for less than £100 NIB posted, couldnt resist! Its the Dumas (kit no:1203) 44' Coast Guard Lifeboat. I dont know if this kit is still produced by Dumas and having looked at the Die cutting of the parts, certainly seems like an old kit? However, I love my building and the challenges, so I am sure it will turn out nice at the end. Finished length 33". I shall be converting this to a RNLI Waveney Class Lifeboat and will possibly go with 44-003 named "Khami" which was based in Great Yarmouth and Gorleston, which is local to me here in Suffolk. Sadly very little turns up on this boat via Google, but at some stage may pop out to the Great Yarmouth Lifeboat station and see if I can hunt anymore info on her. I shall not be using the recommended Dumas running gear for 2 reasons, 1st its a geared set-up (I am going with MFA540 brushed direct drive) and the cost of over £150! Photos show the box artwork, plans and the included wood. Last photo shows my electrics less propshafts and props that are on order. Note the Star Wars 3.75" figures that with poetic licence could be painted to represent crew. However, at this point the model is approx 1;16 scale and the figures would be 1:18 scale so maybe too small. There are 1:16 scale lifeboat figures available but pricey? My one issue at this point is going to battery choice? do I go with a small 6v lead acid or perhaps 2 Tamiya type 7.2v NIMH in series. anyone who has built anything like this may want to advise. LIPO not an option as the Mtroniks ESC do not support LIPO. Space inside the hull may also be an issue? Another issue is going to be fabricating some propshaft struts for the rear next to the props. There is quite a bit of prop shaft exposed outside the hull, so these would be integral to support and strength of the propshafts. Is there anything available off the shelf (they are included in the running gear set, but dont seem to be available on there own) of do I need to fabricate from brass tube and sheet/strip brass?

VolantexRC ATOMIC RTR racing boat by BOATSHED Admiral   Posted: 6 days ago
lovely little boat, and fast. can you up the lipo size battery on this.

Angela Mary by JRF1972 Chief Petty Officer   Posted: 7 days ago
Trawler enlarged to 1/48 from a free plan called Constant Star in a July 1966 Model boats 385 motor, 35mm 4 bladed brass prop, 6v battery, featuring sound unit and working lights on 3 circuits, Built from Scrap, about the Same Size as a billings Nordkap, but a lot Cheaper😊

Too Powerful Brushless ? by Dave M Fleet Admiral!   Posted: 13 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: 14 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