Model Boat Mayhem

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Author Topic: Model Boat Newbie  (Read 19048 times)

Mad_Mike

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Re: Model Boat Newbie
« Reply #50 on: September 20, 2012, 05:43:42 pm »

i cant answer the first question but that speed controller will work for any voltage between 4.8v and 8.4v. the high the voltage the faster the motor will run. You need to work out how much weight the hull will take and how much room you have spare to fit the battery. You can get small nimh battery packs, try a 7.2v and youl need a charger with an auto cut off. Ideally a lipo would be better because a lipo the size of a match box would run this boat, but you will need a low voltage alarm with that esc.

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Netleyned

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Re: Model Boat Newbie
« Reply #51 on: September 20, 2012, 05:45:33 pm »

You can take the rx out of its case and put it in a bit of heatshrink but the rx is small.50x24x10 mm in its case

Ned
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goBulawayo

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Re: Model Boat Newbie
« Reply #52 on: September 20, 2012, 05:48:10 pm »

Thanks Mad_Mike - Any suggestions as to a good low voltage alarm please - Excuse my ignorance but what is it for (yes I know to warn of low voltage) but why?

Also I need to wire up the motor with a suitable connector, are these universal or to I need to match it to the ESC (I assume I connect the motor to the ESC?)

Wayne
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goBulawayo

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Re: Model Boat Newbie
« Reply #53 on: September 20, 2012, 05:50:22 pm »

You can take the rx out of its case and put it in a bit of heatshrink but the rx is small.50x24x10 mm in its case
Ned

Thanks Ned that should fit OK in the schnellboot - I will check with GiantCod re getting two extra Rxs whrn I order the Tx

Wayne
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Mad_Mike

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Re: Model Boat Newbie
« Reply #54 on: September 20, 2012, 05:52:41 pm »

well the issue is i cant tell you what battery you need until i know how much room you have to fit the battery. If you give me that bit ill right you a in depth reply with everything you need to know :-))
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goBulawayo

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Re: Model Boat Newbie
« Reply #55 on: September 20, 2012, 05:58:30 pm »

Thanks Mad_Mike, I have an area of about 100-120mm long by 50mm wide by about 25mm high - Problem is the area is not square as the lower part is the bottom of the hull, so it tapers up a bit, the 100mm length also tapers in towards the bow to about 40mm wide - as to weight I have no idea at present as I don't know the weight of the ESC and Rx

Regards

Wayne
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Mad_Mike

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Re: Model Boat Newbie
« Reply #56 on: September 20, 2012, 06:05:46 pm »

from what your saying im guessin the depth is the very bottom right in the middle of the keel to the top of the hull right? I have a battery here that is 15mm deep, 30mm wide and 55mm long would it fit? Im guessing that the hull starts to point at the 20mm mark?
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goBulawayo

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Re: Model Boat Newbie
« Reply #57 on: September 20, 2012, 06:10:35 pm »

Hi Mad_Mike, that battery would fit easily, the hull tapers (in section) about 20mm down (and I did take off a few mm to get to the 25mm quoted) so plenty of space

Wayne
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Mad_Mike

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Re: Model Boat Newbie
« Reply #58 on: September 20, 2012, 06:12:06 pm »

bare with me then ill right up what you need to know but itl take a while  %%
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goBulawayo

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Re: Model Boat Newbie
« Reply #59 on: September 20, 2012, 06:16:19 pm »

bare with me then ill right up what you need to know but itl take a while  %%

No problem thank you for your time and assistance

Wayne
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dodgy geezer

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Re: Model Boat Newbie
« Reply #60 on: September 20, 2012, 06:58:05 pm »

Hi All, I am thinking of buying the Giantcod 2.4ghz 4-Channel Mode2 Transmitter - see http://www.giantshark.co.uk/giantcod-24ghz-4channel-mode2-transmitter-p-403779.html

Now I have three boats in the making and I was thinking to keep costs down I will buy this set and two separate receivers and bind them to the transmitter as and when I want to use a specific boat. Question is can I use any Rx or must I use a specific one? I see the Rx with the set is 6 CH, I wouldn't mind having a 3/4 CH one for my Schnellboot and my one yacht.  I see GiantCod sell a 2.4G 4Ch Frsky Rx, can I use this with the Tx above? ...


With most 2.4Ghz sets you have to use the matched Rx for the Tx. You only need one Rx - it's quite easy to move it between boats. Some people like to leave the Rx in the boat or plane, and buy a separate Rx for each model, but you don't have to.

Once an Rx is 'bound' to a Tx it doesn't need binding again - you will see what is meant when you start to play with your combo.

Giant Shark sells this Rx for your Tx - but since one comes with your combo you don't actually need to buy any more....  http://www.giantshark.co.uk/radiolink-receiver-r7eh-p-405468.html
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dodgy geezer

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Re: Model Boat Newbie
« Reply #61 on: September 20, 2012, 07:06:07 pm »

Thanks Mad_Mike - Any suggestions as to a good low voltage alarm please - Excuse my ignorance but what is it for (yes I know to warn of low voltage) but why?

The radio needs 5v. The motor probably needs more. So if you run the boat until it starts to go a bit slow that's an easy way to tell if your batteries are running down, and the radio will still work. This technique will work for a SLA (Sealed Lead Acid) or a NIMh. Ideally, these should not be run completely flat, but in my experience they can be run until the boat goes slow (pause for others to contradict me..  {:-{ )

IF YOU ARE USING Li-Po batteries, this advice is NOT correct. Li-Po batteries charge up to about 4V per cell, and mustn't be discharged below about 3v per cell. If they are fully discharged they are damaged. So that's what the low voltage alarm is for. I would suggest that you don't use LiPos until you get a bit of experience - they need special chargres and special handling...
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Mad_Mike

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Re: Model Boat Newbie
« Reply #62 on: September 20, 2012, 07:08:01 pm »

for a boat the size of yours the simplest way to get the current needed but still have a small a light battery is la ithium polymer battery. Lipo battery packs are made up of cells each with an average of 3.7v. We call each cell S (dunno why). 1s battery is a 1 cell battery, a 2s battery is a 2 cell, 3s 3 cell etc etc. For your boat you will need a 2s battery, itl have 2 cells connecting to each other making your pack a total of 7.4v.

Lipo batteries create much more current than theyre equivalent size counterparts so are ideal where a lot of power is needed but not too much room or weight to spare. Lipos however need to be respected and operated correctly otherwise they can fail on you and sometimes even catastrophically. They need to be charged with a balance charger, Its a must and not optional, it chargers the cells individually in the pack and once each cell has got to 4.2v the charger cuts off, beyond this the battery is damaged. On the other hand when the battery is being discharged in the boat the voltage must not drop below the 3v percell or itl damage the battery too.  This is where the low voltage alarm comes in, it sounds off when the batteries in your boat have reach 3v percell. When the sounder goes off you bring the boat in. simple  :-))

Right here is a lipo ill recommend for you:


the 2 pence peices and my lighter gives you an idea of the size. The item to the right is a lipo alarm this will work for batteries up to 4 cells. The item at 2 oclock is a lipo voltage checker and you will need this to keeo tabs on the individual cell voltages and total voltage. you buy this battery from here:

http://www.giantshark.co.uk/gens-2s1p-lipo-battery-p-406444.html

its connector will plug straight into your esc.

you will need a balance charger for it:

http://www.ebay.co.uk/itm/130761623057?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2648

this will charge both 2 and 3 cell batteries, you plug it in like this to your battery:



you will need an adapter to power the charger:

http://www.ebay.co.uk/itm/200812742842?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2648

i use this adapter, dont use the chinese ones, i had one and it turned into smoke.

voltage checker:

http://www.ebay.co.uk/itm/RC-Li-Po-Battery-Voltage-Indicator-Checker-Tester-2S-6S-/220755302516?pt=LH_DefaultDomain_3&hash=item33660a9874

low voltage alarm:

http://www.ebay.co.uk/itm/2-3s-7-4v-11v-RC-Lipo-Battery-Low-Voltage-Alarm-Buzzer-Indicator-Tester-Model-UK-/320935572815?pt=UK_ToysGames_RadioControlled_JN&hash=item4ab940354f

This is how you connet it up in your boat. The boat im showing it on has space for aa cells cos lipos are too fast it being a canal boat:



connected to voltage checker:


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Mad_Mike

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Re: Model Boat Newbie
« Reply #63 on: September 20, 2012, 07:15:14 pm »


IF YOU ARE USING Li-Po batteries, this advice is NOT correct. Li-Po batteries charge up to about 4V per cell, and mustn't be discharged below about 3v per cell. If they are fully discharged they are damaged. So that's what the low voltage alarm is for. I would suggest that you don't use LiPos until you get a bit of experience - they need special chargres and special handling...

was it me that got something wrong?
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dodgy geezer

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Re: Model Boat Newbie
« Reply #64 on: September 20, 2012, 07:57:45 pm »

The radio needs 5v. The motor probably needs more. So if you run the boat until it starts to go a bit slow that's an easy way to tell if your batteries are running down, and the radio will still work. This technique will work for a SLA (Sealed Lead Acid) or a NIMh. Ideally, these should not be run completely flat, but in my experience they can be run until the boat goes slow (pause for others to contradict me..  {:-{ )

IF YOU ARE USING Li-Po batteries, this advice is NOT correct. Li-Po batteries charge up to about 4V per cell, and mustn't be discharged below about 3v per cell. If they are fully discharged they are damaged. So that's what the low voltage alarm is for. I would suggest that you don't use LiPos until you get a bit of experience - they need special chargres and special handling...

was it me that got something wrong?


Whoops, sorry - I can see that what I have written can be misconstrued..   :embarrassed: :embarrassed:

I was advising that with batteries like NiMh or SLA you can run a boat until it goes slow. But that advice (of mine) does not apply to LiPos. You shouldn't run those until flat.

Your advice on using LiPos is, as usual, perfectly correct!!  I would have been a bit cautious about advising a newbie to use LiPos, but perhaps I'm being too cautious. With good advice, as you have provided, he should be fine....

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Mad_Mike

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Re: Model Boat Newbie
« Reply #65 on: September 20, 2012, 08:17:49 pm »

Il take that as a compliment and thankyou  :}
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dodgy geezer

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Re: Model Boat Newbie
« Reply #66 on: September 20, 2012, 08:41:25 pm »

Il take that as a compliment and thankyou  :}

Now that I did intend...    O0 O0
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goBulawayo

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Re: Model Boat Newbie
« Reply #67 on: September 20, 2012, 08:44:26 pm »

Thanks for the help Mad_Mike, I will have a look at getting the items needed - I take it the voltage checker is used before putting the battery into the boat to check it has the right charge?

Can I also confirm the charger will turn itself off automatically once the right charge is reached? I won't need to be checking it whilst it is charging

Regards, Wayne
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Mad_Mike

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Re: Model Boat Newbie
« Reply #68 on: September 20, 2012, 08:47:27 pm »

the white plug or balance lead as its called connects to all the batteries. you use the checker to make sure all the voltages of the cells are the same, to make sure its charged and to make sure you havent over discharged. For whatever reason you need to know the voltage really.

Yes the balance charger does switch off once the batteries are full. you plug it in turn it on and when its charging a green light comes on. When the batteries are full it turns off. thats it.  :-))
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goBulawayo

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Re: Model Boat Newbie
« Reply #69 on: October 05, 2012, 05:12:31 pm »

Got the motor connected to the shaft with thin plastic tubing from some or other electrical wire and it runs fine, motor not yet fixed into place but I cut a wooden cradle for it and connected it to a 1.5v dry cell battery and ran it across our fish pond a few times, the hull looks to be water tight after about 10 min floating and the boat goes quite well on just 1.5v. Not sure as yet whether the boat will be a bit heavy as i still have to fit the esc, servo, battery pack and receiver. Anyway will see how it goes. Having seen the boat move through the water has kinda perked up my enthusiasm again and I am hoping to work on deck and details this weekend

Wayne
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goBulawayo

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Re: Model Boat Newbie
« Reply #70 on: October 05, 2012, 06:15:50 pm »

Its not the greatest bit of video but it shows the S100 under it own power

Wayne

http://s297.photobucket.com/albums/mm223/gubulawayo/?action=view&current=S100hullmotortest121005.mp4
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Tug-Kenny RIP

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Re: Model Boat Newbie
« Reply #71 on: October 05, 2012, 07:58:23 pm »



Very nice.  She moves.   :-))

With Photobucket, have you considered opening up new Albums to keep all your pictures in separate sections to maintain their privacy.     %)

Regards

ken
 
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goBulawayo

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Re: Model Boat Newbie
« Reply #72 on: October 05, 2012, 08:10:16 pm »

Hi Ken, I am not too worried about privacy of these pics so not really looked into that sort of thing -

Wayne
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Tug-Kenny RIP

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Re: Model Boat Newbie
« Reply #73 on: October 05, 2012, 08:31:11 pm »



Hi Wayne,

I use Photobucket and find it easy to have separate albums for each subject. This is helpful when posting a series of build pictures as they are easy to find and that sort of thing.

I couldn't help noticing that you had over 1000 pictures under one heading grouped together. It must be a nightmare looking for a particular print.  %)

I wasn't particularly thinking of security but now you mention it, I'll bet every picture is tagged by Mr Google.   :}

Cheers

ken
 
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goBulawayo

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Re: Model Boat Newbie
« Reply #74 on: October 05, 2012, 08:59:45 pm »

Thanks Ken, yea there are a few too many pics altogether, must say after loading a pic to a forum I have not often needed to find it again - Maybe one day I will sort it out, then again most of the links would go haywire - Perhaps I should start from now on!

Wayne
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