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Spektrum S120 charger help

#1
Hi,
Newbie here. Got a Spektrum USB smart charger and a couple of batteries for my birthday in January after wife gave me a plane.

I charged them then to see that they would take a charge and play with the controls.

But now that we have flying weather and someone to coach me they won’t charge! The smart charger just shows a solid red led, which manual says is an error. This is for both batteries. Different usb converters of different amperage were tried.

Halp!

Thanks,
Jab
 

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Bricks

Well-known member
#2
Do you have a way to check the batteries voltage as many of these chargers will show an error if the voltage is below a certain point.
 

Hondo76251

Well-known member
#4
looks like it might be a 3s? either way, you can test each cell, starting from the ground side (opposite the orange wire) you test the first and 2nd wire; it should read above 3.5v ideally. To test the 2nd cell, you go (-) on the 2nd wire and (+) on the 3rd. To test the 3rd cell you'd use the 3rd wire as (-) and the orange 4th wire as (+) If you use the main lead it to test voltage it will give you the total charge of the battery. A 3s discharged to its lowest safe setting will be about 10, 10.5 volts. I've rescued quite a few batteries that have fallen below 3v per cell and worse, but it's definitely not a recommended practice. if its damaged (below 3v per cell) I'd toss it and get a new one.
 
#5
Thanks for the clear directions. Will do ASAP. But, how does it discharge to below an unrecoverable level when left alone for a couple of months?! Is that really the state of battery tech in this hobby when cell phone manufacturers figured this out years so?
 

Bricks

Well-known member
#6
What state was the battery in when left. If left in the discharge state it could of dropped enough voltage for your charger to not recognize it. The battery may be just fine but below what the charger will charge. Once you check voltages we will know more of where the batteries are at and what can be done to help. Many times all it takes is to hook another battery to it for a few minutes to get the battery up to a voltage your charger can see to start a charge, I have done this a few times, without any problems.
 
#7
Appreciate the help folks. Following Hondo's directions it would appear each cell is exactly the same, 3.9v. The cell's output is ABOVE the label's 11.1V -- yet when I tried to use the battery my controls moved sluggishly (rudder & elevators) or not at all (ailerons). That and the red error light when charging made me think I had a problem with the batteries.

Testing method
Starting from the right hand side, counting from right to left with 4 being the orange wire:

Testing results
Battery 1:
1&2: 3.9v
2&3: 3.9v
3&4: 3.9v
1&4: 11.9

Battery 2:
1&2: 3.9v
2&3: 3.9v
3&4: 3.9v
1&4: 11.8
 
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#9
The batteries are good, something else is the matter...
I think taking a multi-meter to the battery AND the charger rebooted the "smartness" of one of them. It's now showing that its charging! The picture in the OP appears to show the balance plug backwards -- I don't know how that's possible given the lugs on the bottom of the plug mating up with recesses in the charging port. Maybe I was excited and forced in the plug causing the smartness to shut down the charge?

But, that means I have a different problem, because when I tried the battery my ailerons weren't responding at all and the rudder and elevator just seem sluggish to me -- but then again I have no real experience to back that assessment. Unless the smartness in the battery had it discharging slowly? I'll check throws after it indicates a full charge.

Gonna fly with the secretary of our club, who has the same airplane, next non-rainy weekend day. Hope to get sorted out then.
 
#10
Yes, oh yes, another newbie mistake --- aileron issue was a reversed cable in the Y connector- my human factors training makes me wonder how anyone these days can make plugs that can be connected backwards?! Also, because this is a trainer with SAFE, can't be in the newbie mode because the ailerons don't even get a signal then.
 

Bricks

Well-known member
#11
Yes, oh yes, another newbie mistake --- aileron issue was a reversed cable in the Y connector- my human factors training makes me wonder how anyone these days can make plugs that can be connected backwards?! Also, because this is a trainer with SAFE, can't be in the newbie mode because the ailerons don't even get a signal then.

Because sometimes it is nice to have to think for yourself instead of having someone else do it for you.
 
#12
With differernt colored wires on both male and female plugs; and nothing in the manual telling you which way is which (i.e. orange matches to white) -- it's not an exercise in thinking but simple trail-n-error. They now have a grey marker line so I can tell which way goes which.
 

Bricks

Well-known member
#13
At least they did standardize the positive pin is always in the middle old Futaba stuff the postive was the bottom pin and if you plugged it in wrong the magic smoke came thru, now it just does not work..
 

Hondo76251

Well-known member
#14
I've let the magic smoke out if a lot of things. When you start scratch building you learn that many of the connectors and electronics have different wiring patterns. I'm pretty religious about checking my orientation now, but I still get it wrong once in a while! 😣

Just thought I'd throw this in there:

https://m.banggood.com/Wholesale-1S...MIuNL_o-CN6QIVlxatBh093AIZEAQYISABEgJBo_D_BwE

I used to use a multimeter all the time at first but then I found these ^^

Quick and easy to check all the cells, plus if you leave it attached to the battery (providing your model has enough room) it has a loud alarm if your cells drop too low.
 
#19
Hey, I also have a spektrum charger.
IMG-7991.jpg

Can anyone tell me about the meaning of these icons here? The manual is super short and doesn't explain this. I guess you can find these on other chargers, too. But this is my first and only in this hobby.
IMG-7992.jpg