battery recomendations

[adwb]

I am going to buy this kit[listed below] here in England to convert a Raptor 50.
Given that I do not want to do 3d or stunt flying , just hover and scale flying is it nessesary to use the battery indicated?
please can somebody explain or point me to the information that will explain the relationship between voltage and the power required and heat generated by lower voltage ect, ect.
many thanks
Alistair
Raptor 50 Electric Conversion Kit
This includes all the items you need to convert your Raptor 50 to Electric Power (excluding Battery)
Technical data
Motor diameter - 50mm
Motor Body length - 65mm
Motor Shaft dia - 6mm
Motor Weight - 410g
Regulator type 75A Opto Heli
Input voltage - 12-45 v
Max current limit - 90A / 10s
BEC - No
Regulator Modes - Gov / Std
Prog card - Optional

Recommended Power Battery - 10s LiPol 3000mAh - 4000mAh

Set contains: Brushless motor EM 50, speed controller 75A opto heli without BEC, main gear wheel, pinion, motor mount, all needed fasteners and manual. Optional is set of Li-Po Batteries.

[swatson144]

You'd probably want to google "raptor emoli" and you should find lots of hits. For just putzing around or on a budget the emolies seem to be the bomb. I have no experience but have been kinda eyeing that option. Folks are looking at the a123 cells from BD/dewalt.

Steve

[G-MRM]

Hi, I fly the T-Rex 600 and as you may know covered it on my web site. I find the Align LiPos good value but these are 6S2P 4200mah at £110 or 4600ma at £125 I think. You may get away with two of these making 8 cells. I do find the performance good with the 600 and it is a true 50 size !!

I can give you more info if you want. I was going to wait until this month (Oct) when the real e-Raptor is being sold and I was going to try to use the Rex 600 batts to save me buying yet more cells, I have a Swift too you see !

And.... my battery will fly the 600 for a tad under 10 mins under forward flight conditions, it takes 3800ma to recharge, so 22.8 amps average running current in 10 mins approx. My batts are 16C that is I can take out a max current of 16 X 4200 = 67.2 amps so I am under using that battery, a VERY GOOD THING... (unless you want a battery life of just a few cycles !! )

Heat wise these are good, just warm after a flight however the FlightPower ones in the Swift are much warmer but thats to do with the construction of he battery, they give more power when they are hotter, I am not so keen on this !!

Hope this may help, keep us posted with what you do and find with this project !

Martin

[adwb]

Steve that is interesting as I work for a store that sells BD/Dewalt tools and batteries. So what size am I looking for? Soory to be dense but i dont understand these batteries.
Adwb


You'd probably want to google "raptor emoli" and you should find lots of hits. For just putzing around or on a budget the emolies seem to be the bomb. I have no experience but have been kinda eyeing that option. Folks are looking at the a123 cells from BD/dewalt.

Steve

[adwb]

[quote=" the Align LiPos good value but these are 6S2P 4200mah at £110 or 4600ma at £125 I think. You may get away with two of these making 8 cells. I do find the performance good with the 600 and it is a true 50 size !!

I can give you more info if you want.

Martin, so is it the voltage that is important? is this what controls the max head speed? if that is the case why can one not just serial connect up a bunch of cheaper 11.5 volt 3s2p batteries?
I also assume that the battery capacity [ma] is what determines the lenght of flight time? if that is correct then to parrallel the pack would give the flight time?
is that correct??

[swatson144]

A123 cells are in the dewalt 36V tools. Newest latest and greatest and of course most expensive.

The de facto discussion over on ezone has reached 17 pages. http://www.rcgroups.com/forums/showthread.php?t=566256&highlight=a123 .

I still haven't caught up on it as that could lead to a swift, or something. :-)

Plugging in series is common practice. Plugging in parallel (on a temporary bases) is considered dangerous. If both packs being connected in parallel aren't at the same voltage the low one can be charged by the full current capacity of the other. It's far better to get them to the same voltage 1 time and connect them permanently. Too much room for error.

So yes you could solder up 2 2100 3s packs in parallel and 3 sets of the same in series to have 9S and charge with 3s chargers but the cost and size wouldn't be a benefit. You'd be better of with 2 5s2p packs.

I haven't seen Thahntran around but he flies his swift with emoli.

I skipped over the last part of the OPs Qs.

Yes the voltage * motor KV * ratio of gearing will determine the HS. You can run HV or LV helis it all boils down to a compromise with what you want. P=I*E P power measured in watts is the measurement we look at in an E heli. If you determine you need 1000W to be happy with heli X you could get there with 10V @ 100A or you could get there with 100V @ 10A or anywhere in between. There is a sweet spot for every one to determine what to run cost/performance/weight compromise.

For the same gear ratio you need a lower KV motor to run higher voltages. You can get a pretty good idea of the HS by KV * V * pinion teeth / maingear teeth x .8 = HS the .8 is a number I have found to be realistic for losses etc. So it is best to consider using a medium pinion and not the smallest or largest so you can adjust up or down cheaply.

In setting up a mature make of heli it is probably best to read some other folks setup and crunch the numbers and see how well it fits with what you want. IE you may have a couple astro 109s you are using so 10s wouldn't be a problem, or you may have 4s chargers and want 2 4s to run in series to avoid buying 400$ worth of batteries and 200$ worth of chargers. What fits and balances etc.

The mAH rating determines flight time, really it states how many amp hours the pack stores which affects flight time.

You are on the right track to study look at you options and get it all right 1st time. It's better to need a larger pinion than finding your packs won't fit though :wink: .

Steve

[adwb]

[quote="swatson144"]A123 cells are in the dewalt 36V tools. Newest latest and greatest and of course most expensive.

Steve, thanks please can you explain what means emoli? I know and understand nicad,lithiumion,lipo,etc. are accronims for.

also i assume that you have therefore to remove the battery from plastic case that fits a drill. do you still use the devalt charger ?
adwb

[swatson144]

emoli is a different lithium chemistry.

for charging
It seems most are using lipoadapter from slk, some are setting their chargers at a lower cell count. IE 7x4.2=29.4 8x3.6=28.8 so they are charging 8s A123 at 7s lipo settings etc.

Post #100 in the link above is a spread sheat comparing lipo/emoli/A123 on a eR50.

I'm going to get caught up on the thread. If I wind up with a Joker it's your fault :D .

Steve

[adwb]

Steve, so lets see if I get this correctly
1 for a given motor type/model the voltage supplied governs the max amount of torque [ hp] the motor out puts.
2 as a result of the votage selected you then gear the pinion to get the correct head speed forom this torque available
3 the voltage you get by parraleling up battery packs [which if cells are different voltages will ballance out each other.]
4 the length of time the motor will run at the desired power output is determined by the aMh capacity of the battery cell/s which you connect in series to increase this capacity.

if all the above is correct how do you determine the voltage given ;
that you know the head speed required [raptor 50 no stunt work ] ;
and the motor this info from the maker ?
No. of cells: 20-30
RPM/V: 305
Max. efficiency: 88 %
Max. efficiency current: 18 - 40 A (>84 %)
Current capacity: 55 A/60 s
adwb

[swatson144]

1 close but not quite right wattage is the equivalent of HP P=IxE Watts=ampsXVolts. 1000W is 1.34 HP. While the voltage x KV (listed as RPM/V in your motor) determines the total RPM your motor will put to the drive train (minus losses). It is a function of determining power also.

2 You would choose a pinion for the expected RPM your power plant is putting in the transmission. I think one of the MG choices for an R50 is 86 tooth. HS=V * KV * pT / sT * .8. So with the figures we have on hand to get 1600 rpm HS you'd need a 26t pinion at 6s (22.8)or around a 14t at 11S 41.8v. Though the motor listed is rated for 25V so...

3 yes they will balance perhaps violently and expensively depending on the mismatch. I=E/R so a .25V difference on a tp lipo @ .01 ohm internal resistance would balance out at 25A. or about 5x the acceptable charging rate Puff Instant excitement. That's why I say it's better to match the voltages 1 time and parallel them with solder and not connectors.

4. Yes


This stuff would be a good bit less ambiguous if the motor manufactures would drop the old NiX cell numbers and use volts, and forget about current ratings and list watts. It's like trying to figure out how a car will perform by fuel consumption. IE In your motor @ 16V and 40A the thing would be 640 w and the heli might hover. @25v and 40A it's 1000w (1.34 hp) and the thing wouldn't be a power house IMO. Yet they are recommending 10S lipo which would get you closer to 1500W and would likely work fine for sport flying though it exceeds the voltage recommendation.

I am certainly no Eraptor expert but I've enjoyed the chance to crunch numbers and I hope there aren't too many mistakes in there.

The Eraptor is being released soon so perhaps holding off a couple weeks your conversion can be done effectively and cheaply from that price list.

Steve

[adwb]

Steve thank you for your help.
I was going to wait for the E raptor [and I assume their conversion kit] to come available but I fear the next month availability is not going to happen. From what I have been told, in England anyway, it might only be in the New Year
Any way I think I will just hold off for a while and see what happens.
regards
Alistair

[adwb]

Martin, do I understand you correctly? are you using one only of the 6S2P 4200mAh 22volt battery to fly the trex 600? [/size][/size]
quote" I find the Align LiPos good value but these are 6S2P 4200mah at £110 or 4600ma at £125 I think. You may get away with two of these making 8 cells. I do find the performance good with the 600 and it is a true 50 size !!"

I am given to understand that the "E " Raptor will now only be available next year jan/feb or do you have different info? Will there be a conversion kit do you think?

I can give you more info if you want. I was going to wait until this month (Oct) when the real e-Raptor is being sold and I was going to try to use the Rex 600 batts to save me buying yet more cells, I have a Swift too you see !

Unless the power requirements of the MS Composit kit are very different to your 600's motor then that battery should give similar performance to what you have found in the 600. http://www.mscomposit.com/motorsaccessories/electric_92/brushless/power-50.html

And.... my battery will fly the 600 for a tad under 10 mins under forward flight conditions, it takes 3800ma to recharge, so 22.8 amps average running current in 10 mins approx. My batts are 16C that is I can take out a max current of 16 X 4200 = 67.2 amps

I was going to wait for a Raptor make Raptor kit but that seems to be along way off and if I price motor and esc combinations for other German 50 size helis the MS Composit kit is a good price?
what think you?
B.T.W. congratulations on the 600 build web site, it is brilliant and sets a standard for others to weep over!!
I had it in mind to do similar re the Rappy conversion, but think not now!!
adwb

[thanhTran]

A123 cells are in the dewalt 36V tools. Newest latest and greatest and of course most expensive.
...
I haven't seen Thahntran around but he flies his swift with emoli.

I skipped over the last part of the OPs Qs.
...


I'm now using A123 cells for my Swift as well. So far I like it more than the emolies. In the cold weather, the A123 cells seem to hold voltage better. A123 cells are lighter than the emolies and take the same about 2300mah back when charged.

A123 cells are much cheaper than LIPO cells. They are really tough (crash resistant), and can be charged in just 15 minutes if you have a capable charger. The only bad part is that they are heavier than lipo...

Thanh

[adwb]

Thanh,
please can you tell me how you tell what type of battery is in a devalt 36 volt battery pack. the reason I ask is that here in england I get told by devalt they are nicad which i doubt but you never know.
I dont want to buy one to find that they do not contain the A123 type battery.
adwb

I'm now using A123 cells for my Swift as well. So far I like it more than the emolies. In the cold weather, the A123 cells seem to hold voltage better. A123 cells are lighter than the emolies and take the same about 2300mah back when charged.

A123 cells are much cheaper than LIPO cells. They are really tough (crash resistant), and can be charged in just 15 minutes if you have a capable charger. The only bad part is that they are heavier than lipo...

Thanh[/quote]

[thanhTran]

the Dewalt 36 volts pack comes with the A123 cells. It's a new type of Li-Ion cells: http://www.a123systems.com/html/products/cells.html It has 10 cells in that pack. Each cell is 3.6 volts, so you need this: http://www.slkelectronics.com/lipodapter/index.htm to charge them with a standard NiCd charger. I currently charge them with my regulated DC supply (just need to set it at 3.6 volts * # of cells, in my case 4S * 3.6 = 14.4 volts, I serialize 2 4S packs to make an 8S pack for my Swift).


The pack I bought looked like this:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ih=020&item=300029191757&rd=1&sspagename=STRK%3AMEWA%3APIC&rd=1#ebayphotohosting

http://i13.ebayimg.com/01/i/08/49/24/2e_1.JPG

Thanh

[adwb]

Thanh,
thank you very much, this now gives me the part number so I can ask for this and see what happens.
many thanks
Alistair
:D