A123 set up in 50cc Extra

[billpilotca]

Guys - I have been reading the A123 threads with keen interest and now have several 2300 packs myself. I have a couple of basic questions that I would appreciate your feedback on.

Plane - Lanier Extra 330, DA50. Hitec 5645's on ailerons, elevators, and rudder.

Last year I flew IMAC with twin 1500 NiCd packs thru two MPI heavy duty switches to two receiver receptacles, ie each battery thru an MPI switch to separate receiver inputs.

I would like to swap out the NiCd's and substitute A123's. Is there any problem with me hooking the A123 packs up to the MPI switches by changing the standard connectors on the MPI to appropriate Dean's connectors (male ends) and leaving the MPI switches connected to the separate receiver inputs ?

I have a related question re the use of a Power Expander Pro in a 35 % plane. I realize that I can hook the A123's to the PE Pro directly to the Deans connectors, but then they are not swtiched. Can I connect the A123's to the MPI switches (as above) and then hook the MPI's to the Deans connectors on the PE Pro ?

Last part of the question then would be can I charge the A123s thru the built in charge ports on the MPIs ??

Thanks in advance.

Bill

[Sin City Jets]

Bill,

You can switch out the batteries with nor problems. You don't even need to switch the connectors of you don't want to. We can build the packs with JR connectors on them.

On the Power Expander Pro, you can use the available failsafe switch. To me, this is the best way to go.

And for your last question, it depends on if you plan on balance charging. I am not familiar with the MPI switch, but some people on here figured out a way to balance charge through the built in charge jack. If you do not want to balance charge, then YES you can definitely charge through the switch's charging jacks.

[billpilotca]

Chad - thanks for your advice. Re the balance charging issue I have read a lot of posts and I am not convinced that balancing is necessary from everything I read here and on other forums. Seems the cells rarely get out of balance and then discharging and recharging seems to bring them back close to balanced. The early threads seemed to be preoccupied with balancing, much the same as LiPo's, which I do balance by the way. A123's seem sturdier and more resistant to out of balance situations. Maybe I am wrong but that is my impression. Balancing maybe impacts longevity. I stand to be corrected if I am wrong.

MPI switches are just heavy duty switches - probably with 21-22 guage wiring. Dare say they can only handle 3-4 AMP's so I would not be charging at 8-10 AMP's.

Bill

[GooseF22]

MPI switches have a signal feed that is common. So if you use the signal wire to bring the 3.3 volt intermediate to the switch, disconnect the signal wire from the receiver input wire. just tape it back after sliding out the pin. this lets you balance at the port.

Both the MPI switch, and the regulated miracle switches work that way.

Caution. If you use the MPI switch with the voltage lights. DO nOT trust them with A123's. the green light will be on most of the time. iF you let the yellow light come on, you are moments from disaster.

they are quite capable of 5 amps to the receiver. fully tested in my shop. I have charged at 6 amps but they get warm. a good chaargiing amperage is 4 amps for them.

I rarely balance my 2S packs. instead I charge them to 7.5 volts. I balance every 10 or so, and they have never been very far off. I use a A123 blinky because I dont have a cellpro bal chgr. I use the 6 amp orbit two wire, and I have several packs. I am also using a test charger that does 7.5 volt cutoff. they bleed down to low sevens quickly but they are full. they drop into the high 6's in a min or so, so I just turn everything on when checking the plane for preflight.

not a single issue so far.

[billpilotca]

	Quote: Originally Posted by GooseF22
	MPI switches have a signal feed that is common.

I was actually thinking I would only connect the compatible Deans connector to the red and black wires and leave the white one unconnected at the battery connection end - am I OK doing this ?

	Quote: Originally Posted by GooseF22
	Caution. If you use the MPI switch with the voltage lights. DO nOT trust them with A123's.

Thanks !! I have one of these so I won't rely on it or maybe I will just swap it out for a plain switch wihout the indicator lights and use the lighted one on a plane with NiCd / NiMH batteries

	Quote: Originally Posted by GooseF22
	they are quite capable of 5 amps to the receiver...a good chaargiing amperage is 4 amps for them.

Thats great info - much appreciated

Bill

[Wild Thang]

I'd use just one pack. Most of the time it's a bad switch not a bad battery (from what I hear). Just make sure you use a voltmeter just to be on the safeside. Tower has a nice one for $10. It's the one that mounts in the airplane. I perfer to mount them in the canopy. I would not reccomend a powerbox in a 50cc. The Smart-Fly power box sport is more reasonable. But it's not a must. Just my oppinion.

[GooseF22]

	Quote: Originally Posted by billpilotca
	I was actually thinking I would only connect the compatible Deans connector to the red and black wires and leave the white one unconnected at the battery connection end - am I OK doing this ? Thanks !! I have one of these so I won't rely on it or maybe I will just swap it out for a plain switch wihout the indicator lights and use the lighted one on a plane with NiCd / NiMH batteries Thats great info - much appreciated Bill

I personally like the MPI switches with the lights because it tells me when its turned on. So with 123's I just use it for an "on" indication.

Alot of folks put the signal wire of the three wire on the middle voltage of a 2S pack. it allows balancing and checking with any balancer. If you want to you can add a balancing tap instead. My larger aircraft I use a two wire deans ultra and a three wire charging tap.

all that being said with A123's there are basically what I consider options for a straightforward system.

1 A123 Battery with two switches, resulting in two outputs to the Receiver. good for 10 amps.
1 A123 Batt with a wolverine with three outputs and two Deans inputs. 15 amps. very good setup.
1 A123 with one switch with two outputs. 5 amps with a three wire input, 10 amps with a Deans. downside: no switch redundancy.
2 A123's with a switch each or wolverine. Full redundancy with added 5.5 oz, good for 10 amps as well or 15 with three output option.
2 A123's wiith deans or 1 A123 with Dual Deans with cermark switchs with dual outputs, resulting in 4 input lines. 20 amp system nominal.
My planes all use some variation of these above .90 size. My .90 and below just use one 123 and one or two standard or MPI switches.
My .40 and below just use whatever I have on hand.

I have tested the wolverine to over 40 amps with no issues...it had dual deans outputs for a Power Expander. worked extremely well, it also had a smoke pump and an output for seiko. Big power.

So. now back to the 50cc. If weight is a factor, one battery with two switches or wolverine. If weight is not a factor, and 6 extra ounces dont bother you...then two A123's and two switches, just for the insurance and extended fly time. I would recommend a 1500 Fat A Nickel ignition or a 1100 A123 VPX

Thats my 2c worth....

2

[texasporty]

Anyone using a Wolverine switch and two VPX packs for this size aircraft. I have hard time using just one pack and know two 2300 packs are overkill for this size aircraft. Are the VPX inferior to A123 packs?

Mark

[Sin City Jets]

Mark,

The VPX are A123 cells, they are just the 1100 mah version. Run 1 2300 with 2 battery leads. We can make them that way if you like. Better way to go if you are only looking for 2300 total Mah.

[billpilotca]

	Quote: Originally Posted by GooseF22
	So. now back to the 50cc. If weight is a factor, one battery with two switches or wolverine. If weight is not a factor, and 6 extra ounces dont bother you...then two A123's and two switches, just for the insurance and extended fly time. I would recommend a 1500 Fat A Nickel ignition or a 1100 A123 VPX Thats my 2c worth....

I really appreciate the time you took to write all the options out. I think I will go 2 A123's and 2 switches. I might look at a VPX pack for the ignition also. I have been using a 1400 A cell NiCd or 1500 4/5A Elite NiMH which also work fine.

Thanks Goose !!

Bill

[Mitsu1]

Ok, can someone chime in on what switch/charge port setup will allow you to run a single A123 2300mah pack, and allow you to charge at up to 10 amps thru the charge port? I'm thinking about picking up the new CellPro 10s charger, and would like to recharge a 2300 from near empty to full in 10 -15 minutes without having to open the canopy to get to the battery.

[texasporty]

	Quote:
	The VPX are A123 cells, they are just the 1100 mah version. Run 1 2300 with 2 battery leads. We can make them that way if you like. Better way to go if you are only looking for 2300 total Mah.

I don't understand why one 2300 pack would be any better than 2 1100mah packs if both are quality cells. Useing two VPX packs fed thourgh a Wolverine switch would seem pretty safe to me.

Disadvatages are a loss of 100MAH and the weight penalty for using two packs.

Advantages are batterys can be purchased locally, easily converted to RC Packs, redundency of two batterys.

I don't think the cost differance is enough to justify either setup. By the time you buy two VPX packs and convert to 2300MAH the price is about the same.

Am I missing something?

Mark

[Scott Gerber]

Mitsu1

On my single tanicpack A123 2300 mah pack I have installed my own three wire pigtail or charging/balancing node replacing the original. This pig tail runs to the side of the fuse next to a single HD JR switch. I am using a DB-9 female connector to charge/balance through, taking 3 pins tied together for each of the three wires to make the most of paralleling the connections since they are there anyway. I have on order the 3 foot extension cable from FMA that has the proper connector for my CellPro 4 and will have the mating DB-9 male connector on the other end so I will be able to charge at the field without taking the battery out or remove the canopy and not have to worry about the current limitation of a standard servo style connector to charge through. Same thing for the ignition with a VPX pack.


Scott

[Sin City Jets]

Scott,

Why not just use the JR connector and use a standard servo extension to make your balancing lead as long as you need it. Then just use one of my JR to CellPro connectors (or make your own) to switch it over to the cell pro connector. It will save you a $20 propietary extension cable.

Mark,

To each their own. As an end-user, I would like the lower weight, 100Mah more, easier in-plane sorage, and overall less money and work.

[Scott Gerber]

Sin,

Peace of mind more than anything. I know a few guys have done some testing on the standard servo connectors and extensions to verify they can pass higher current than rated, however I feel much more at ease using a little heaver duty connector to charge through. I realize it's over kill, a tiny bit heavier and will cost a bit more and I can live with that. I've used the standard charging connectors for years like everyone else charging at overnight rates and periodically cycling at an amp or so without problems and I think that's exactly what they where designed for. When we upgrade our equipment to pass 4 or 5 times the current it intrudes upon the max rating too much as far as I'm concerned. Call it redundancy by moving to a slightly larger connector, a connector that sees several connect/disconnect cycles by the way, causing a breakdown over time on the delicate and minimum surface area of the standard connectors. Guys will never think twice installing redundant switches, batteries and receivers for that "just in case" warm fuzzy feeling... I'm just throwing in a bit more fuzz....


Scott