P47flyer

My Feedback: (6)

Does anyone know a non-dsc type switch that breaks ground as well as the positive lead from the receiver? This would solve the common ground problem for charging dual packs without having to unplug one pack from the receiver.

Dave

MR G

I think that Smart-fly makes some switches that are DPDT (double pole double throw) switches that cut the circuit continuity on both the positive and negative leads. These would solve the problem.

MR G

nonstoprc

My Feedback: (90)

Would the reliability suffer when such a switch?

Josey Wales

My Feedback: (61)

Unless they came out with something new their switches are just regular JR DSC switches

Campgems

The Standard Futaba switch is a DPDT swithch but with both poles in parallel. There is no need to break the ground circuit (black wire) for charging or operation. A SPDT swithch (which is how the Futaba switch is wired but with parallel contacts) will seperate the batteries for charging. You just need two switches, one for each battery, with their own charging plugs.


Don

Zeeb

My Feedback: (41)

Well perhaps I might inquire as to the OP's original question and your response?

The issue with our currently available switches has to do with simultaneously charging two flight packs connected to the rx which is a common buss and if the ground circuit is not disconnected then you have an issue with the chargers.

Most will not accomodate a common ground with another pack and using two chargers is a real problem. Now I don't see a problem with charging the batteries one at a time without disconnecting them from the rx with the currently available switches, but barring the use of a single charger with dual (at least) outputs which is capable of dealing with the common ground, I don't see how what you say would work?????

tail strike

My Feedback: (1)

I reall don't know why youall have so much trouble charging your batteries.
My set up is
1 battery for ignition one switch
2 batteries for reciever one JR DSC switch for each battery ( battery - switch -reciever )
I plug my peak electronecs quad carger into each charge receptical and charge no problems.
I do not unhook any batteries to charge.
I can cycle each battery through the JR DSC charg jack or like I said charge the batteries.
I have never hade any problems doing it this way.

Campgems

I hadn't considered a ground loop issue, but I can see that it could present a problem to some chargers. I suspose that a quick check would be to do an ohm check between the charger's black output line to the ground pin on a 110v charger or the neg lead on a 12v one. If the output ground is common to the input ground, then it should work. If it's floating it could be a crap shoot as to wheather it would work or not.

There is really nothing special with the switchs used in the harness other than the cap over the lugs. Given that, one could easilly sub the switch and wire up your own harness and switch the ground as well as the positive line. I'll take a look at DIgikey and see what they might have in 4PDT switches.

Don

Campgems

Larry, do you charge both batteries at the same time?? That would be where the problem would show up.

Don

tail strike

My Feedback: (1)

I have no problems, I charge boath reciever batteries at the same time through each batterys JR DSC heavh duty switch

P47flyer

My Feedback: (6)

Don,
Thanks for the input. I hadn't thought about checking continuity on the input/output neg. leads. Digikey has the dt4p switches but I was hoping that with all the dual flight packs being used someone might have prepackaged a unit. Tail Strike-Some chargers WILL false peak with a common ground. I'm not fortunate enough to own a $400 Sirius Quad Charger[]. Thanks for the input.

Thanks all

Dave

Josey Wales

My Feedback: (61)

Fromeco has the Cube charger and it can charge packs connected by a common ground.

nonstoprc

My Feedback: (90)

I myself have been using a Sirius charger made by Peak Electronics (http://www.siriuselectronics.com/ind...roducts_id=344) to charge two packs at same time. No problem whatsever. Each pack is connected to the only receiver via a MPI switch with charging jacket.

My unit has two output connectors: one for receiver and one for the radio. But magically, the radio output can be used to charge the receiver pack directly. A simple adaptor is sufficient to bridge the connector to a receiver pack.

airbusdrvr

I presently have started a build where I may consider using two five-cell receiver batteries(more for weight to bring CG aft than needed capacity). To say I'm a bit confused after reading the various inputs above would be an understatement. I had planned to use two JR Gold switches and two charge jacks. One switch plugged into the receiver batt port and one switich plugged into the other batt port(JR 921 9-channel receiver). I had planned to use two separate chargers to individually and similtaneously charge the batteries. If this is not a good idea and I have to use the extra battery for CG purposes, I could Y connect the batts to the switch and charge as a five-cell 4000mah battery I guess. Is there any electrical problem with either of these setups? To summarize, setup one would be two batts, two switches, two charge jacks and two individual chargers. Setup choice two would be two batts y-connected and charged as a 5-cell 4000mah batt.

tail strike

My Feedback: (1)

This is what ine of my setups looks like, enjoy.

tail strike

My Feedback: (1)

This is the setup I have in my Yak 9
There are two batteries there one on top of the other.
This is the plane with the two JR DSC switches with the charg jacks.

Flying Geezer

My Feedback: (14)

When you charge two battery packs with common ground you can get by with it for a while, assuming they are very equal is condition, (charge and discharge rate). However, if you are using a charger with low side current sensing, (most are), when the packs begin to differ in condition. One pack can have an open circuit or other problems and you won't know it. This has resulted in cooked packs, during charge), or flying on essentially one battery pack.

Chargers with high side current sensing do not present this problem. Cycle your packs regularly to check capacity if you are charging in parallel with a charger you are not sure about. Not having a problem thus far does not mean you won't.

Campgems

Would one of you guys with the JR switches check to see if the ground, black wire, is switched? That could explain why there is no trouble with two packs charging.

I tore apart a couple old switches tonight and although I couldn't find any specs on the switches, they looked like about 500ma capacity. That could be the reason that they are paralled, that would up that rating to 1 amp.

There is another way to go here. Two switches with a common throw. Kind of like the 220 circuit breakers in your house pannel. You could use two standard switches with a ganged slide. Runt the positive side through one and the ground through the other. That would be the low tech solution. It would require a bit of wire splicing, but it would be an easy A better one would to have a charging circuit in the plane supplied by a single bulk sorce. The good thing is that the planes this problem comes up in isn't going to be bothered by a couple ounces of extra weight.

Don