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Dual Rx battery/Switch Set-up?

Old 12-05-2014, 11:35 AM
  #101  
Boomerang1
 
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Originally Posted by pedroaleman65
These are not evolta or eneloop. If the diagram shows an AA or Mignon size, it must be an old type. The new AAA or micro size could give you 3-4 amps. If my AA were that weak, all my machines come down.
The curves may be of the older type of Eneloop cells.

When the cells were introduced of course I did some research into them and this is what I found, it's still posted on the net.

Next step was to measure what current the types of servos I use when under heavy load or stalled. The most powerful I use
drag less than one amp stalled so I'm comfortable using the Eneloop batteries for my applications. If the next lot I buy (the
originals are still working perfectly) have better discharge characteristics, well, even better!

Lots of guys that were having issues with the early Spektrum stuff was using the supplied 4.8V battery.
Yep, lots of guys had lots of other problems with Spektrum too, the antenna carry-on & changing DSM types as well.
I'm not an 'early adopter' when it comes to new technology, I tend to hang back for a couple of years & wait for the
people who are to work through the problems & crash THEIR models. Me? I just changed to Futaba 2.4 which has never
had issues on 4 cell packs.

John.
Old 12-05-2014, 01:35 PM
  #102  
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Originally Posted by Boomerang1
The curves may be of the older type of Eneloop cells.

When the cells were introduced of course I did some research into them and this is what I found, it's still posted on the net.

Next step was to measure what current the types of servos I use when under heavy load or stalled. The most powerful I use
drag less than one amp stalled so I'm comfortable using the Eneloop batteries for my applications. If the next lot I buy (the
originals are still working perfectly) have better discharge characteristics, well, even better!



Yep, lots of guys had lots of other problems with Spektrum too, the antenna carry-on & changing DSM types as well.
I'm not an 'early adopter' when it comes to new technology, I tend to hang back for a couple of years & wait for the
people who are to work through the problems & crash THEIR models. Me? I just changed to Futaba 2.4 which has never
had issues on 4 cell packs.

John.
You are right John with not being an early adopter.

The later generation of the eneloops could be identified by the crown-symbol. And indeed they had better discharge rates. Maybe their inner restistance had been lowered and therefore they delivered higher Ampere-rates.

I remember some test with the eneloops in the freezer. The earlier nimhs had the problem, to lose some power on cold days. But the eneloops still work powerful on winter days.

When the digital servos flooded the market, some people said, they consume more energy from your battery. Later I read, that this could not be proven, to be that simple.
While they move to the position where you want them to, this could really be the truth. But once they reached the position their consumption was less than the analog types.

As most of us heard, the digitals develop much more holding-power. The analogs fight much harder to keep the position. This fact shows, why there is no big difference in the energy-consumption.

Some 4 cell packs I saw, had to fight with problems of the planes, such as rudders not working lightly or blocked, cause the travelling was not programmed exactly.

Some manufactured packs were produced as time bombs. The Calmato trainer of my friend Marc came down in the automatic failsafe mode. The new futaba radios carry this safety issue out of the box.
The throttle is closed to idle-speed, to show you a weak battery power.

Marc had a 4 cell eneloop 2000 on board. The cables were bent over a sharp edge of a cell connector. And also pressed against it by the shrink tube. The connector had cut the isolation of the two cables and caused a short circuit.The two inner cells of the four cells standing in line, had opened their security valve. This can also happen, if someone has no idea of soldering packs and heats the cells up too much or too long.

This season I soldered a new 8 cell panasonic evolta for Roberts futaba transmitter. The original battery had started heating and losing capacity after less than 3 years.

The original pack had welded connectors. If the welding is done firmly, I will not moan about this way. But I found two cells where the plus-poles were not hit exactly. There were little holes shot beside them from the welding tool.

Robert is really happy now with his new soldered 8 cell evolta and the "stay charged-feature".(=ready to use)




Few weeks ago I replaced a 6 cell 1800mA from a new futaba 8 channel transmitter. I think it also had less than 3 years and started heating. The charger, though working in the nimh mode, could not note the delta peak anymore and kept charging on and on.

I did not take the transmitter at home and soldered a pretty 6 cell eneloop. I went to my friends house and had to realize, that this transmitter had cells in between the mignon and micro size. There was no way to get the eneloops into the housing, so I changed the 6 cells to another 4 cell RX battery, my friend also needed.

I soldered then two sanyo lithium ion mangan in line. Those have 2050 mAh, don`t need to be balanced, can be completely empty without damaging, can give 18amps current and are totally safe in their round, red steel mantle.

These examples show everyone, why I no longer rely on other people`s work...... And why other people start relying on mine.
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Last edited by pedroaleman65; 12-06-2014 at 02:12 AM.
Old 12-05-2014, 02:16 PM
  #103  
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I would think that unless you really need to reduce weight, there wouldn't be much reason to use a 4 cell pack As mentioned before, servo speed and power increase with the extra cell. The biggest problem with this type of cell chemistry, is the length of time it takes to charge them...usually overnight. With LiPo, and A123 type of cells, charge time is about a half hour. That is nice when you make a last minute decision to go flying.
On my larger gas planes, I like to use dual A123 cells, a Wolverine dual battery switch, and the Servo City "Servo Board". This setup isn't the cheapest way to go, but it is a good solid combination that gives me confidence in my power system. I like overkill. I use EC3 connectors for the battery to switch connection, and all other connections to the Wolverine switch and the Servo Board are soldered 16 or 18 gauge wire.

https://www.servocity.com/html/servo...l#.VIIsvWea-kg
Old 12-05-2014, 02:57 PM
  #104  
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The way I see it, if you are going to spend money on new stuff, you may as well get the best thing going. To me that is an A123 pack. Sure, we can reminisce about what was, and why this is that and so on and so forth. I have Eneloop packs as well, but I am still replacing them with A123's as time and money warrant. Where I have really seen NiMh perform badly, is on ignitions. The Eneloops are OK for this, but I have been using a lot of small Lipos I have had floating around the shop for this purpose.

Abu, if you are new to gassers, then this is another battery area that you need to think about. It sucks to have problems here as well. As many times, if the power drops off of your Ignition battery, the Ignition goes into a 4 cycle mode, firing every other stroke. I guess to preserve what is left. This can be mis diagnosed as a mixture issue. It is very important to watch your ignition voltage, and keep it fresh. Of course, an A123 would be good here as well. But a NiCd would be better than a NiMh in my opinion, because of the internal resistance.
Old 12-05-2014, 05:06 PM
  #105  
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I don't have any gassers at the moment don't have an expectation of getting one for quite a while. But they do seem to be good choices for the usual 1/4 scale WWI fighters. I bought the 6.0V 2000mAh NiMh 5-cell packs a couple of years ago, but have not used them. If and when I get new batteries I'll probably go with the A123 packs (or whatever has supersede that a the battery of choice by that time).

The on-board glow system I got to use with the 770 (Microsens) actually requires its own 3.7V lipo battery (5000mAh). The only suitable battery I could find is the Turnigy 5000 hardcase which seems like a ridiculous thing to put in a flying model.

Actually, I'm not thinking about flying (or at least testing) the 770 without the on-board system and even the exhaust ring, all of which probably add a full kilo to the weight.
Old 12-05-2014, 05:16 PM
  #106  
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Originally Posted by abufletcher
I don't have any gassers at the moment don't have an expectation of getting one for quite a while. But they do seem to be good choices for the usual 1/4 scale WWI fighters. I bought the 6.0V 2000mAh NiMh 5-cell packs a couple of years ago, but have not used them. If and when I get new batteries I'll probably go with the A123 packs (or whatever has supersede that a the battery of choice by that time).

The on-board glow system I got to use with the 770 (Microsens) actually requires its own 3.7V lipo battery (5000mAh). The only suitable battery I could find is the Turnigy 5000 hardcase which seems like a ridiculous thing to put in a flying model.

Actually, I'm not thinking about flying (or at least testing) the 770 without the on-board system and even the exhaust ring, all of which probably add a full kilo to the weight.
You know Abu, you can wire a lipo to be multi cell to kick up your Mah. You would want say a 1s5p battery of 1000 mah capacity per cell. This is 5x1000 to get 5000. That battery would be no problem to track down. Maybe check with Cheapbatterypacks.com They do custom packs. If not, no biggie to buy the cells and solder it up yourself. That amount of Mah, should give you plenty of engine run time.
Old 12-06-2014, 12:43 AM
  #107  
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I found this 1S lipo but, honestly, I don't have a clue to how I would attach it to my system.
Old 12-06-2014, 01:10 AM
  #108  
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Not 100% sure but you have to attach leads to the cell tabs & I think they are aluminium.

Have you noticed these?

http://www.hobbyking.com/hobbyking/s...APPROVED_.html

In the reviews a guy mentions his using one for a 7 cylinder radial with success.

One thing has me puzzled, it has no balance leads & it's actually a 2 cell pack but they are wired in parallel to increase capacity, not voltage.

Perhaps it has some internal circuitry to balance the cells as they charge? - John.
Old 12-06-2014, 02:04 AM
  #109  
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John, I have one of those (as well as the slightly different one I linked to earlier). It works fine with the glow-system. But it just seems crazy to put a brick like that in a flying model.
Old 12-06-2014, 02:33 AM
  #110  
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Originally Posted by abufletcher
John, I have one of those (as well as the slightly different one I linked to earlier). It works fine with the glow-system. But it just seems crazy to put a brick like that in a flying model.

My "BRICK".......

As a suggestion to you Abu....... This is a 2p sanyo lithium ion mangan 4100mah. It powers the ignition of my Zenoah 20cc.

One cell therefore has 2050 mAh, nominal 3,8 Volts. No balancing needed, safe, you can charge them in the lipo mode, You can pull them totally empty without damaging. 18 Amps current, here not needed. Easy to solder.

43grams, 18mm diameter, 65mm length

A 2s powers my electric sailplane, and two more are used to power lipo-ignitions.
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Old 12-06-2014, 06:47 AM
  #111  
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When I google it I only come up with the German version of Amazon (was eigentlich kein Problem ist). But Sanyo must sell these in Japan. The reason I originally bought the Turnigy "brick" was that not of the RC shops in Japan sold a 3.7V battery and, in fact, none of the guys in my club had ever heard of one.
Old 12-06-2014, 07:44 AM
  #112  
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Lipo cells are 3.7v, it is just a matter of how many are soldered together. Either in series to boost volt, or parallel to increase Mah.
Old 12-06-2014, 12:07 PM
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Originally Posted by abufletcher
When I google it I only come up with the German version of Amazon (was eigentlich kein Problem ist). But Sanyo must sell these in Japan. The reason I originally bought the Turnigy "brick" was that not of the RC shops in Japan sold a 3.7V battery and, in fact, none of the guys in my club had ever heard of one.
In some sheets the nominal voltage is 3,6 or 3,7 and really it is about 3,8V. This is not a lithium polymer!!!

I bought mine from the german distributor HG-Elektronik. (can be googled) The owner Helmut Gunzert is an expert in batteries or accus, coming to all german expositions with his products. He has no internet-shop, where his products can be ordered. I called him or sent a fax. I guess, his cells have to be shipped from overseas.

I talked to him personally, when I bought my first two cells for my electric sailplane 4 years ago. He told me, that this cells had been developed for and used in electronic tools, originally.

I would not have made a transmitter battery for my 17 years old club-mate in my french club, if this cells were rubbish. Because this young man is gonna mix up the french F3A-scene. Finished the national competition on the 5th place. Among the adults, not talking about the rooky-class!

These cells are not seen so often in our hobby. But they will be my choice as a high-voltage setup for future projects with HV-Servos. In my mind I see a three meter version of my "Raudilio grande".......4 cells...2s+2s soldered parallel to 4100 mAh...

......what I forgot....you can order any configuration, no need for you to do the job.

Last edited by pedroaleman65; 12-06-2014 at 12:16 PM.
Old 12-06-2014, 01:03 PM
  #114  
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Abu, take a deep breath & think carefully about the 'brick' versus the single cell you mentioned.

Look carefully at the weights on the Hobbyking site, there are two, shipping weight & actual weight of
the item.

The brick weighs just 34 grams more than the single cell. To that you have to take away the weight of
whatever means you use to connect it to leads plus the leads themselves which ARE included in the
weight of the 'brick'. In practice the difference will be two tenths of bugger all.

Remember too we are talking about a 3 metre aeroplane with a seven cylinder radial. A kilogram will
make very little difference to it's performance, 34 grams - nil, zip, nothing, nada, not a sausage, not a bean.

You may even find that 'brick' battery very handy when you stuff it in the tail somewhere to balance that big
lump of aluminium you intend to fit up front!

Did you fly free flight in an earlier life? Weight obsession is a characteristic of free flight flyers, believe it or
not lots of radio models fly better with a little extra weight on board.

You probably have the ideal battery already, good choice! - John.

Last edited by Boomerang1; 12-06-2014 at 01:08 PM.
Old 12-06-2014, 09:45 PM
  #115  
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Last edited by Steve Percifield; 12-06-2014 at 09:47 PM.
Old 12-06-2014, 09:46 PM
  #116  
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Originally Posted by abufletcher
When I google it I only come up with the German version of Amazon (was eigentlich kein Problem ist). But Sanyo must sell these in Japan. The reason I originally bought the Turnigy "brick" was that not of the RC shops in Japan sold a 3.7V battery and, in fact, none of the guys in my club had ever heard of one.
http://www.hobbyking.com/hobbyking/s...SortOrder=desc
Old 12-06-2014, 10:06 PM
  #117  
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Abu like you I can be electronically challenged.i ventured into gas airplanes.i have a wild a by hair edge 540. I purchased a DLE 30 and was told what servos to use.the rudder was probably over kill .then I was oh you don't need dual batteries for a 30 cc plane.so I bought a salsa be eliminator and that was a good investmeni didnt do anything for a year.then I questioned why not use a redundant battery installation.i did upgrade earlier to an 8 check futaba fg.fabulos radio.i have enough ports.so I bought 2 life batteries from wrong way rc here in florida.the additional weight in my opinion is nominal.many of the big gassers are over powered and trust me nothing wrong with that.i did buy a miracle dual switch.i learned years earlier that inadequate switches can kill your plane as easy as a bad battery.the wiring of the switch is heavy gage twisted wire.if you use a rx with less ports of course you can piggy back.y harness the spare battery into your throttle port.no biggie.u will get a better peace of mind.is it fool proof .hardly but nearly 80 percent of failures come bad batteries and switches and connections.if a critical servo locks up you can pretty much figure you will crash. And the second battery doesn't need to be the same capacity as your primary are battery.but a smaller battery same chemistry will get you down safely.
Hope that helps.

l

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