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20m QCX+ internal battery pack connection point


W5EGA@...
 

Hello all,

I am planning to take out my 20m QCX+ for its maiden voyage this weekend for a POTA operation. I don't want to let out all the magic smoke out following a successful build, alignment, and testing process so I am asking my question here first before assuming and hoping for the best! 

I want to use 4 or maybe even 6 18650 batteries with a DC-DC step-down converter (for 15V constant power) mounted to a board directly above the QCX+ main board. Is the best place to provide power to the QCX+ from the internal battery pack at the 3 PIN header directly south of the DC In Jack and just west of L3? OR is it better to use JP27 +12V and ground?

My future plans include using the battery pack in conjunction with a BMS and Charge Controller to allow for the batteries to be charged without having to remove them from the unit. Could the 3.5mm DC In jack be used to charge the battery pack in this manner? Or would a separate charging port be a better option?

Thank you in advance for your advice and thoughts!

73, John W5EGA


Colin Weaving
 

My first /P operation would be a very cautious one to protect my successfully built new rig. The opportunity for something to go wrong ( in my case) multiplies when I am putting up portable antennas in unfamiliar circumstances. Shudder the thought of magic smoke to spoil your day.

So , I would not even think about running my QCX+ at 15V which is close to the absolute max that the rig can be safely operated at. Much more conservative to use 12V or even 10V until the /P set up has been shaken down and is as “bullet proof” as possible.

I like to keep things as simple as possible. I use a battery pack of 3 18650 batteries which start out at about 12.4V and run down to 11.1V. I have never had a fully charged pack ever run down during a days operation, but admittedly I do not operate hour after hour. But just in case, I have another battery pack on hand, just in case. Incidentally this pack has a switched 10.2 and 7.5V output.

I find the simplest way of recharging the batteries is to remove the batteries, and use a 4 station recharger. Yes, if you have bought the case , it could be built in, but for me that would be a secondary consideration..

There will many views on this, but primarily, I would protect my lovely little rig.

73 Colin M3WCK




On 23 Sep 2020, at 17:16, W5EGA@... wrote:

Hello all,

I am planning to take out my 20m QCX+ for its maiden voyage this weekend for a POTA operation. I don't want to let out all the magic smoke out following a successful build, alignment, and testing process so I am asking my question here first before assuming and hoping for the best! 

I want to use 4 or maybe even 6 18650 batteries with a DC-DC step-down converter (for 15V constant power) mounted to a board directly above the QCX+ main board. Is the best place to provide power to the QCX+ from the internal battery pack at the 3 PIN header directly south of the DC In Jack and just west of L3? OR is it better to use JP27 +12V and ground?

My future plans include using the battery pack in conjunction with a BMS and Charge Controller to allow for the batteries to be charged without having to remove them from the unit. Could the 3.5mm DC In jack be used to charge the battery pack in this manner? Or would a separate charging port be a better option?

Thank you in advance for your advice and thoughts!

73, John W5EGA


@CurtisM
 

John

I am thinking go simple, and avoid feeding it with a higher voltage using a step down dc dc. Any high voltage spike could damage circuitry. A straight 12 to 13.x volt battery is preferred. Anything more sophisticated needs rigorous testing.

Work out your battery solution,  then see if internal mounting and charging makes sense. It won't save much weight to mount the battery inside, and outside it could feed a different rig as desired. 

73 curt


W5EGA@...
 

Thank you both for the advice... I will keep it simple and stay at 12 - 13 Volts. 

So, now where do I make the connection on the board? JP27 or the 12V In just south of the 3.5mm barrel connection?


Ronald Taylor
 

If you use the 12v in just south of the DC connector, your battery will connect via the polarity protection diode, so that's probably the best place to hook it. Just don't connect an external DC supply to the barrel connector while the battery is connected.... at least until you get the BMS installed later.. Big bunch of smoke otherwise. Hi Hi .... Ron


On Wed, Sep 23, 2020 at 4:26 PM <W5EGA@...> wrote:
Thank you both for the advice... I will keep it simple and stay at 12 - 13 Volts. 

So, now where do I make the connection on the board? JP27 or the 12V In just south of the 3.5mm barrel connection?


superDIYer
 

I've been thinking on this. As fascinating as a QCX-mini is, I'm thinking that needing an external battery makes packing the thing harder than I want. That volume inside the case of a QCX+ seems tailor made for a battery like the Bioenno BLF-1203AB. The question is how tricky to get in tying it into the unit. I've attached a schematic of sorts that leaves I've been mulling over.

With the proposed switch in one position, external power is supplied to the guts of the QCX+ and the battery is completely out of the circuit.
With the switch in the other position, the battery output is available to the normal QCX+ power switch and the external power is tied to the charging port on the Bioenno battery. This allows you to charge or operate... wouldnt expect to try to do both at once!

The question is whether the protection diode stays in the circuit for this or gets pulled. Maybe the charging voltage supply gets pulled off before the diode to avoid any interference with the charger that might occur with it left in.

Thoughts? Barking up the wrong tree?

Thanks
Jason


Richard
 

The barrel connector and powerpoles are wired to the same point internally.  You could simplify your design by just connecting both charger and QCX to the power poles.  It will work the same and adhere to the KISS principle.


Pierre Guillot
 

Interested by que QCX+ I could choose it with the enclosure, the TCXO and the Dev kit. The Dev kit because it could support batteries, their charger and an antenna tuning unit like this one https://www.qrpkits.com/sota.html
Unfortunately due to Covid 19 nothing enters anymore my island in the South Pacific, the Covid did not enter but also no goods. I shall have to wait before ordering my QCX+. FK8IH


Pierre Guillot
 

Added to my former post this mini SWR indicator, which protects the finals during the tuning : 
 https://www.qrpkits.com/miniswr.html


superDIYer
 

On Thu, Oct 15, 2020 at 10:24 PM, Richard wrote:
The barrel connector and powerpoles are wired to the same point internally.
Ahh... that gem was buried on the FAQ page and not in the datasheet. THANKS for pointing that out. Yes, it means the complicated 4pDt switch can be downgraded to something simple and tiny! I also can say why I was bothering to switch the low side of that contraption. I think I will still keep it as a SpDt (on-none-on) switch, pulling charging power from the un-protected side of the diode near JP15, while putting the output from the battery in AFTER that diode.

Jason


markus@...
 

Dear OM's

I have just finished my second TRX, now a QCX+ 20m after a QCX (previous style) for 30m.
In order to supply power inside the enclosure I had designed a PCB for this purpose.

See attached pics.

vy73
Markus


The Crunchbird
 

Markus, that is great work. I may copy what you have done, Dave. N2SN ex G4FEB


markus@...
 

Dave,

KiCAD project files are available.
As well as a zip-File for JLCPCB Manufacture.

Enjoy.

vy73
Markus
DL8MBY


Shane Justice
 

Markus,

You might want to replace those rubber bands with zip ties. The first time the radio gets a good shock, to batteries will overcome the rubber bands and be rattling around loose in the case.

Nice packaging, otherwise!

Regards
Shane


On Oct 17, 2020 at 09:35, markus <markus@...> wrote:

Dear OM's

I have just finished my second TRX, now a QCX+ 20m after a QCX (previous style) for 30m.
In order to supply power inside the enclosure I had designed a PCB for this purpose.

See attached pics.

vy73
Markus


John
 

Looks really sharp!

Agree about the zip ties!

73
 JOhn K5MO


On Sat, Oct 17, 2020 at 6:18 PM Shane Justice <justshane@...> wrote:
Markus,

You might want to replace those rubber bands with zip ties. The first time the radio gets a good shock, to batteries will overcome the rubber bands and be rattling around loose in the case.

Nice packaging, otherwise!

Regards
Shane


On Oct 17, 2020 at 09:35, markus <markus@...> wrote:

Dear OM's

I have just finished my second TRX, now a QCX+ 20m after a QCX (previous style) for 30m.
In order to supply power inside the enclosure I had designed a PCB for this purpose.

See attached pics.

vy73
Markus


markus@...
 

Dear OM Shane and OM John,

I will of course use a heat shrink tube for the battery pack to secure the battery against shock.
But as the PCB arrived yesterday h have not ordered this part yet.
I have smaller diameters of such heat shrink tubes but unfortunately not one that's fits the PCB.
I need a 260mm circumference tube. If you have a corresponding link would be fine.
An other solution would be to use a zip tie of corresponding length, but I prefer the HST.

Thanks for your objection experience and expertise

vy73
Markus

PS.: My second Version of the PCB will be extended in length so that it use the full
enclosure length of 143.5mm. In this case you do not need to fix the battery PCB to
the main trx PCB and it is still fixed inside the enclosure by the front and rear covers.


Jim Painter
 

Markus, I don’t think you mentioned what batteries you are using.

Thanks...Jim...kq3s


On Oct 18, 2020, at 4:26 AM, markus@... wrote:

Dear OM Shane and OM John,

I will of course use a heat shrink tube for the battery pack to secure the battery against shock.
But as the PCB arrived yesterday h have not ordered this part yet.
I have smaller diameters of such heat shrink tubes but unfortunately not one that's fits the PCB.
I need a 260mm circumference tube. If you have a corresponding link would be fine.
An other solution would be to use a zip tie of corresponding length, but I prefer the HST.

Thanks for your objection experience and expertise

vy73
Markus

PS.: My second Version of the PCB will be extended in length so that it use the full
enclosure length of 143.5mm. In this case you do not need to fix the battery PCB to
the main trx PCB and it is still fixed inside the enclosure by the front and rear covers.

<QCX_BH-V2.jpg>


markus@...
 

@Mike,

what concerns the security of the PCB Battery circuit,
you are right in principle, but...
I have used a poly-fuse in the circuit (1.3A/30V) against
over current due to damaged QCX+ parts like the PA fets
as mentioned by you.
I have a pin header on the PCB with the separate voltage of
every single cell. This is for extensions that use a balancer
for loading the battery.
If you disload a LI cell you could damage the cell but
not cause a burning event as long as the current is limited
to less then 1C what is ensured by the poly fuse.
But you are right that while loading you have to watch
the cell voltage. But on the other side HAM's have to know
this circumstance while loading LI packs and have take
precaution not to overload a cell ;-)

vy73

Markus

DL8MBY




I add the mail from Mike with his objections concerning my PCB.

Nice one, Markus... but... where is the charge control, cell balance, voltage limiter? charge control to prevent burning the entire unit cell balance for optium cell life voltage limiter to prevent over volt of the QCX, as it appears you could put 4.2v x 4 = 16.8v across the pa fets.. iiwy, I would also use tagged batteries rather than holders and retaining straps.. there are chips to do all three safety checks in one, very small, package and the tagged cells will reduce size, weight and cost. but nice presentation so far. QCX+IBP v2 coming soon ?. ( qsx internal batt pack kit v2 ) Nice one, Markus... but... where is the charge control, cell balance, voltage limiter? charge control to prevent burning the entire unit cell balance for optium cell life voltage limiter to prevent over volt of the QCX, as it appears you could put 4.2v x 4 = 16.8v across the pa fets.. iiwy, I would also use tagged batteries rather than holders and retaining straps.. there are chips to do all three safety checks in one, very small, package and the tagged cells will reduce size, weight and cost. but nice presentation so far. QCX+IBP v2 coming soon ?. ( qsx internal batt pack kit v2 )


markus@...
 

@Jim Painter,

Jim I'm using LI cells from a old disk controller with buffer battery of a server rack.
The cells are labeled SE US18650GR (T 8A124RF28S).
According to Google search a 2.2Ah
"Lithium ion rechargeable batteries with lithium cobalt oxide cathodes and graphite anodes"
See links listed below.

https://www.energy4people.ru/upload/instr_file1549.pdf
https://cdn.sparkfun.com/datasheets/Prototyping/Lithium%20Ion%20Battery%20MSDS.pdf

vy73
Markus

PS.: Take into consideration that these LI cells are old and not state of the art now but I get them free of charge.


Jim Painter
 

Thanks Markus, free is alway good.

Jim...


On Oct 18, 2020, at 6:47 AM, markus@... wrote:

@Jim Painter,

Jim I'm using LI cells from a old disk controller with buffer battery of a server rack.
The cells are labeled SE US18650GR (T 8A124RF28S).
According to Google search a 2.2Ah
"Lithium ion rechargeable batteries with lithium cobalt oxide cathodes and graphite anodes"
See links listed below.

https://www.energy4people.ru/upload/instr_file1549.pdf
https://cdn.sparkfun.com/datasheets/Prototyping/Lithium%20Ion%20Battery%20MSDS.pdf

vy73
Markus

PS.: Take into consideration that these LI cells are old and not state of the art now but I get them free of charge.