Battery combinations and connectors

[Droider]

Since I set out on this roller coaster I have spent a fair amount of wedge and my total investment is now far past what I ever thought I would have spent.. But now after many lessons learned an lots of wasted money I feel I have the perfect MultiRotor in my DroidWorx ADX3 standard lift. One thing concerns me and that the batteries.

I am using combinations of packs from 2 cell, 3 cell and 4cell. I have all these combinations because I have bought what i thought was the best deal per amp but now I am not sure my striving to save a few quid here and there was worth it. I had a fright today when a pair of 7.4v 2cell 5000amp power packs failed to power up my ADX. On close inspection of the wiring adaptor had a sloppy deans connector.

So The questions

Is it better to use a single battery, say 5000amp 4 cell rather than two 5000amp 2cell?

Or should we use 2 4cell 2500amp just in case the single 5000amp fails?

Also which are the BEST connectors?

 

[Redhotpearl]

I use two 2 cell lipos in series with a Y-Adapter. I use anywhere from two 2650mah lipos in seriers to two 5000mah lipos in series. All are 2 cell, all run in series with a Y-adapter, and all are deans! I've flown with deans for over a year now and everything has been fine. I've heard the warinings about deans but I don't see any issues. I just leave the Y-adapter plugged into the hexa and plug the lipos in the other ends one at a time.

 

[Bartman]

same here. two Lipos at a time in the Okto with a Y adapter and all Deans plugs. The Deans are difficult at first but they loosen up ever so slightly and you gradually develop jedi powers to get the plug in smoothly on the first try. I've also tried lubing up the deans plugs with a very light electronics spray lube. so far so good.
on the X650 i've got one battery but will likely switch to two in parallel as I learn more about what it can lift. so far there's been more crashing than lifting (been better lately )
there's no redundancy though if you're powering the multi-rotor with two batteries in series. to get any back up you've got to have two in parallel. likely failure mode moves to the deans at the head of the y connector but just give it a good check once in a while along with everything else.
in London on the 27th, you?
Bart

 

[Droider]

My concern is using 2 cell in series. If one battery fails it is end of subject and crash. If its 2 3cell or 4 cell in parallel at least you have a fighting chance of getting down.

Is general preference is to have two batteries rather than one?


General thought then is that deans are OK..?

 

[Droider]

in London on the 27th, you?

Not sure. I think I am in North London but need to check with PA...... (her in doors )

U on the way somewhere or on the way home... one night in London seems short.

 

[RTRyder]

My concern is using 2 cell in series. If one battery fails it is end of subject and crash. If its 2 3cell or 4 cell in parallel at least you have a fighting chance of getting down.

Is general preference is to have two batteries rather than one?

General thought then is that deans are OK..?

I always run 2 for balance reasons, one in front of the Pro Mini and one behind with the mount as close to centered under the frame plate as possible. The less work the F/C has to do to keep the MK leveled, the more time it has to make other things work right is the way I look at it

That said, running a pair of 2S in series is a couple solder joints closer to a potential crash than a single 4S pack. I had an "almost" late last summer when doing a preflight and found one of the wires in the series connector was down to about 1/3 of the total number of strands still intact, couple more flights and it would have been time for brick mode, but that's why we do pre-flight checks, right?

On the Hoverfly I run a pair of 3S in parallel, again partly for balance, partly because I can, and I like having 15 to 20 minute plus flight capability with up to 10,000 mAh of power in the biggest packs I can fit under it.

As for connectors, never liked Deans, don't use them, instead I use these... http://traxxas.com/products/parts/accessories/highcurrentconnector ...I have them on all of my batteries and absolutely love them, never had any problems since I've been using them and they're available at just about every hobby shop that sells RC cars here in the US.

Ken

 

[Droider]

Thats my feeling with the 2 cell packs.. if you have a minimum of 3cell if you loose one you at least have a fighting chance of getting her down.. Just ordered 2 5000amp Overlanders.. just need to decied on what connectors.. was thinking of bullets bit Ill check your sugestio out.. Thanks// OBTW I had a BSA A10 for a very short period.. Not been on a Mbike since I went through that Hawthorn hedge!!! Nice to know you like the Nortons.. now thats a great sound!

 

[Crash]

I now use XT60 connectors.

I never liked combining packs to make a 4s. It's 3 connectors that can fail rather than one and the extra connection adds some unnecessary resistance. Also, I thought that the cells in a quality pack were matched in some way, shape, or form. (I don't know how much that matters though.)

 

[Ellipz]

XT60 are indeed very good connectors and even 10mm2 cables are relatively easy to solder and they resist high temperatures.

 

[FlyEYE]

I'll give another vote for the XT60.

 

[Bartman]

feel free to send me all your old Deans connectors folks!

 

[Cabe]

+1 for XT60

They are (if that makes any difference) about a third of the price of deans.

I only with they were "push in pins" so that the shroud would come up over the soldered connections and protect them more.

 

[Droider]

Had a feel of both today and I have to say the Traxxis ones RtRyder uses definitely feel the business and were also highly recommended by my local RC shop. Not Knocking the XT60 that also has a good feel but the Traxxix has it for me.. I also ordered some Overlander 5000amp 4 cells.. get away from them there adaptors for the combo battery set up...

Bart if I manage to get down to West London on the 27th I give you my Deans.. you may need to get an excess baggage ticket!

 

[matwelli]

i use deans

talk connectors and you always get debate

For the record, I push 96 amps thru mine, no worries in 30 flights , basically using a y adaptor, the two deans that go to the batteries handle 40 odd amps each, the one dean between the ESC and Y harness never gets pulled apart, and it happily handles 90+ amps bursts (average amps are probably 40 continuous) - its in a Ritewing, not a MR

My view on bateries , i use whatever I have at hand have some 2S 4000's that i series up, also have some 4S 2650's that I parallel .

at least with dual batts (or even tripples/quads) if a pack gets tired (they usually fail sitting on the shelf, not in the air) and needs replacing, its only half the cost of replacing a full pack, same with a crash, at least you may only bannana one half of your battery source

 

[Cabe]

OK those Traxas connectors look pretty sweet, especially the fact they shroud the solder side.

 

[Droider]

I guess you can panic to much that one part of your system is not quite up to the standard of the next and its a rolling perpetual never ending circle.. ! Ill stop at the connectors now

 

[Bartman]

Dave,
If you have Deans connectors and don't feel great about the security of the wires, file a small notch on each edge of the soldering tabs and give the tab/wire a few wraps of copper wire before soldering. It'll actually help make soldering your power wires to the tabs a lot easier as well. Now that I think about it, I think I'll give it a try next time I'm fixing up new batteries for flight.
Does this mean I don't have to bring an extra suitcase?
Bart

 

[Droider]

Went full Traxxes connector so I thought.. what I got was Traxxes compatible connectors.. Grrrrrr.

 

[PaNt]

What about EC5 conntectors guys??

I want to put them on an Okto HL...!
My lipos has the 5.5mm bullets and the EC5 are 5mm ...! Is there a need for more that 150Amps??

Thank you

 

[david.scarbrow]

I now use the EC5s on all my battery connections. The interference fit is quite strong so they have to be tugged quite forcefully to seperate them...however if soldered correctly the conductor insulation goes slightly into the coonector shroud. They (apparently) will also carry 90A with ease.