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Author Topic: battery alternative  (Read 4084 times)

rem2007

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battery alternative
« on: November 13, 2007, 10:21:03 pm »

just bought some new rc gear at boatshow in warwick, good deal on futaba system from howes. problem is the battery pack puts my airfix 1/72 lifeboat  too low in water, and the system i'm installing by action electronics only requires 4.5v off the receiver, what can i use instead of the supplied battery pack , which is 6v or am I up a creek without a paddle?
robert :D
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RipSlider

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Re: battery alternative
« Reply #1 on: November 13, 2007, 10:35:07 pm »

There are a lot of options:

a 4 cell pack will generate 4.8v, and be lighter than a 6v pack. Ni-Cad is the more usual type, but there are plenty of Ni-Mh packs around in 4.8v, which are lighter than Ni-Cad.

if that's still too heavy, then Li-Po or Li-Ion are lighter still, but cost more for the charger.

Check out the Kong Li-po's and Sapherion Li-Ion selections, both have a 4.8v pack available and are very light indeed. Both of these are far safer than the original li-po packs that tended to go pop rather alarmingly if you messed up the charging, both use new designs and new technology, and you can't make them go bang.

As I said though, chargers are a little more expensive.

swapping the motors from normal "can" motors to Brushless out runners would also save significant weight for the same power, and these can come in incredibly small packages, some weigh less than 5 grams. However, the ESC sadly is more expensive for these.

If your fighting for weight, I would steer way from the marine modelling resources and have a look at the Indoor Flying and Park Flying sections of the areo modelling world. The entire product range in these spheres is totally centred on ultra-light weight kit.

Battery packs weighing 30 grams, esc's weighing 15 grams, motors weighing 5 grams etc etc.

Steve
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dougal99

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Re: battery alternative
« Reply #2 on: November 13, 2007, 10:38:29 pm »

Or you could just buy a ESC with a BEC and do away with the RX battety altogether.  :)

Sorry FLJ.
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rem2007

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Re: battery alternative
« Reply #3 on: November 13, 2007, 11:50:40 pm »

well I bought a system from dave at action which has a mixer, 2 separate escs for each very light weight motors and servo, all together very light and the mixer takes into consideration the rudders movement and adjusts the revs to the particular prop, ie turning port, the port prop slow and starboard speeds up, very good system, and dave is a decent bloke. do you have web sites for those other places you mentioned?
robert
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RipSlider

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Re: battery alternative
« Reply #4 on: November 14, 2007, 01:00:24 am »

Ni-Mh from ultra fast google search. Would speak to someone like barry at Westbourne models. I do like the otrnado batteries though

http://www.bizrate.co.uk/robotic_radiocontroltoys/oid550157331.html

Out runners for 4.8 volts:

Lots here: look for a "1s" motor

http://www.robotbirds.com/catalog/images/comptable_motor.html


Saphion batteries- you might need to get someone to make you a pack of 4 up.
http://www.valence-tech.com/saphion.asp
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FullLeatherJacket

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Re: battery alternative
« Reply #5 on: November 14, 2007, 07:54:30 am »

The complete system which Robert bought runs from the receiver battery, so doesn't need a BEC.  Just one pack will power both motors, the servo, the receiver, the lot. A charged 4.8v NiMH or NiCAD (4 cell) pack will be fine. See the details on my little Clyde Puffer on the main Mayhem website; it uses the same ESC etc. As a matter of fact, the demo system you saw at the show actually runs off a 6v regulated PSU, so you won't blow anything up if you stay at 6v or below.
My advice would be to put away the battery pack or battery box which came with the Futaba set; either will use AA cells which are too heavy for the Airfix lifeboat. Follow this link http://www.component-shop.co.uk/html/small_packs.html and look at the small 4-cell NiMH packs. Your whole system won't take much more than about 100mA, so there's no need to get paranoid about pack capacity either.
That should solve your problems, dude, and Iain @ Component Shop is a very decent bloke!
I'll hold you to that pint.............

FLJ  8)
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malcolmfrary

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Re: battery alternative
« Reply #6 on: November 14, 2007, 12:33:41 pm »

Have a close look at the AAA packs from Maplin.  With a little work with emery, flux and solder you get your custom pack at much reduced size and weight compared with AA cells.
I didnt mention capacity, as it seems to increase every time I shop there, but the last lot were 1000mAH.  I did have to ask about them, as the display didnt have room for them, so they were hidden in a drawer...
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rem2007

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Re: battery alternative
« Reply #7 on: November 14, 2007, 01:03:08 pm »

thank you guys for all your help, looks like the pack from component shop will do the trick.....I thought this was suppose to be relaxing
. never a dull moment
robert
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rem2007

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das tiny lifeboat from sirfix
« Reply #8 on: November 14, 2007, 01:12:03 pm »

this is waiting rc install
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DickyD

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Re: battery alternative
« Reply #9 on: November 14, 2007, 04:08:38 pm »

Have a close look at the AAA packs from Maplin.  With a little work with emery, flux and solder you get your custom pack at much reduced size and weight compared with AA cells.
I didnt mention capacity, as it seems to increase every time I shop there, but the last lot were 1000mAH.  I did have to ask about them, as the display didnt have room for them, so they were hidden in a drawer...

.component-shop.co.uk do AAA 1100mAh NiMH Batteries - Pack of 4 for £3.80 pack. Highest capacity currently available in this size.

http://www.component-shop.co.uk/html/aaa.html

 O0
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rem2007

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Re: battery alternative
« Reply #10 on: November 14, 2007, 07:00:47 pm »

good evening sir, just getting ready for evening rounds?
yeah, dave already set me straight on component shops gear and it looks thats the way i'll go
cheers anyway,
robert
what do you think of the build so far?
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rem2007

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Re: battery alternative
« Reply #11 on: November 14, 2007, 07:06:28 pm »

another quick newbie question, how do you recharge the shrink wrapped battery packs, remember i'm a newbie?
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DickyD

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Re: battery alternative
« Reply #12 on: November 14, 2007, 08:28:58 pm »

another quick newbie question, how do you recharge the shrink wrapped battery packs, remember i'm a newbie?


Battery packs  http://www.component-shop.co.uk/html/small_packs.html

battery chargers  http://www.component-shop.co.uk/html/radio_control1.html

Make sure the charger charges your voltage and the NiMH batteries and make sure your batteries have same connector as charger [normally Tamiya]

 O0
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malcolmfrary

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Re: battery alternative
« Reply #13 on: November 14, 2007, 09:29:40 pm »

Have a look under "Your Models" on the main Mayhem pages, and look for "LINDBERG TUNA CLIPPER" which is hiding behind my Gytha tug.
To save on weight, I just hard wired the battery pack to the switch with a servo lead to the RX and a lead via a small bridge rectifier and a resistor to a standard radio type power connector.  This means that I can use a battery eliminator set to 12 volts to charge at the overnight rate, and I dont have to remember what the polarity is.
With small models like this you not only need to minimise the weight, you want to be able to ensure that the trim is unaffected by shuffling connectors about.
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rem2007

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Re: battery alternative
« Reply #14 on: November 14, 2007, 11:12:37 pm »

hi richard,
well hope the evening rounds went ok, mine are all tucked up and so is the lifeboat. just put those little faffy pipe connections in the recesses along the exterior bulheads. lots of fun especially when I dropped one. Thanks for your help again, read up on the chargers and I think I've got that sorted.
oh, and malcolm....i think, thanks as well, but I'm trying to remain fairly straight forward on this one, as my learned friend the admiral will tell you, I am an OD with lots to learn and took on quite a challenge with this build, but cheers anyway.
Robert
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John - ModelPower

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Re: battery alternative
« Reply #15 on: November 15, 2007, 10:23:59 pm »

Hi all
      can i put my two pennyworth in into the proceedings we at modelpower can help have a look at our web site
       modelpower.co.uk
                                 Cheers  John@modelpower.co.uk
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Rechargable batteries for RC Models
http://store.modelpower.co.uk
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