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Lion or LiPo4 for 12v power

Posted: Tue Sep 26, 2023 1:03 am
by AC4ZY
New to QRP. Organizing a GO kit. Lion is cheaper but it appears that lion phosphate has a slower voltage drop-off. All advice appreciated.

Re: Lion or LiPo4 for 12v power

Posted: Tue Sep 26, 2023 2:34 am
by kc0myw
I don't have any direct experience with using Lithium Ion for radio stuff, but do have a LiFePO4 that use on a regular basis and really like.

For me, a few of the big factors were:
- More appropriate voltage for radio use
- Safety during charging
- Discharge curves
- Lifespan

I know a lot of people use various Li-ion batteries with positive results and they can be quite a bit cheaper for similar capacity as compared to LiFePO4 but if you consider the lifespan and rated discharge cycles for each chemistry, the LiFePO4 is often cheaper over the life of the battery.

The safety issue can be a big thing with regards to lithium batteries. The LiFePO4 chemistry is inherently safer than other Li-ion chemistries and is not the fire hazard that some of the others can be.

Probably the largest reason that I chose LiFePO4 over other options is because of the voltage. I don't remember all the specifics at the moment, but I recall from my research that a 4S LiFePO4 hits the sweet spot for radio operations. A 3S Li-ion is a bit on the low side and a 4S Li-ion is a bit too high as I recall. Of course this depends on the voltage requirements for your specific radio, and I have since acquired a "9V" LiFePO4 for one of my QRP rigs. At the time when I first decided on LiFePO4, the specs on all the radios I had was something like 13.8VDC ± 15% (11.73 - 15.87) and the discharge curve of the LiFePO4 matched up with that voltage range better than any of the Li-ion batteries that I was finding.

Re: Lion or LiPo4 for 12v power

Posted: Tue Sep 26, 2023 5:18 am
by AC4ZY
Your reply is most helpful. I am planning for the arrival of a Qrp-labs QMX by putting a field kit together.
72 Gene

Re: Lion or LiPo4 for 12v power

Posted: Wed Sep 27, 2023 9:33 am
by SkipRD
Gene -- what a coincidence. I just got the FedEx notice for my QMX yesterday! (Deliver is expected next week.)

I'm not sure what power supply I'll use, but I will be careful. The operating manual states, "The supply voltage range for QMX is 6.0 to 12.0V. Maximum power output depends on the supply voltage." And the QMX assembly manual states: "Operation at more than 12V will reduce the protection safety margin available in the event of very long key-downs, hot environment, antenna mismatch, cable faults etc. I don’t recommend more than 12V."

I think the little TalentCell battery pack (LiIon) is 12V, but I'll check to be sure. It would be very convenient if it works. I'll post here after I charge it up and check.

73 Skip K4EAK

On edit: I charged up the TalentCell 3000 mAh Battery Park ( ... 01M7Z9Z1N/). (It's the same one Thomas K4SWL uses.) The zero-load voltage is 12.35V, so I'm sure it'll be fine for the QMX. Whew!

Re: Lion or LiPo4 for 12v power

Posted: Wed Sep 27, 2023 5:01 pm
by AC4ZY
Now I'm jealous. My QMX is number 460 or so on the list. I've been going back and forth between their lion and lifepo4 batteries. Please give us your review of the QMX. Some of us are living vicariously!

Re: Lion or LiPo4 for 12v power

Posted: Sat Oct 07, 2023 9:42 am
by SkipRD
So, I got my QMX and I've started playing with it. So far, though, it's a challenge.

I've gotten it working with CW and actually did an activation with it yesterday. But I still have more work to do to get it the way I like. For example, I need to figure out how to narrow the filter width--right now strong adjacent signals are giving me trouble. And there must be a setting somewhere for AGC. A couple times during the activation, a VERY strong signal came in and the volume was so loud it burst my eardrums and I had blood running down my neck! (Not really, but you know what I mean.) I haven't given up on it, but I haven't gotten the performance anywhere near what I'm used to with my KX2.

And I still haven't gotten it to work with WSJT-X. All I get now on the waterfall is bright red vertical bars and zippo decoding. I'm sure I have the audio settings set incorrectly somewhere (probably in my laptop), or maybe it's RFI coming from somewhere that's overloading the front end, or something. I don't do much digital, so I'm not sure I really care, but at least as a challenge I'd like to get it set up so it's working as it should. Again, I haven't given up on it, but so far it's harder than I thought it would be.

Incidentally, in response to the question that started this thread, yes, the TalentCell battery (Li-ion) is good. It's right at 12V and I used the TalentCell for a full activation (about 45 minutes) and it was still showing 5 lights when I was done. So it looks like the QMX has very minimal power draw and the TalentCell is more than enough for several activations without recharging.

Further updates to follow...
73 Skip K4EAK

Re: Lion or LiPo4 for 12v power

Posted: Sat Oct 07, 2023 10:16 am
I've been using the QMX for a month or so and I can tell you it's very much a work in progress. As others have noticed there are many advertised features that don't yet work. The lack of CW side tone adjustment, general volume control issues, and lack of AGC makes the QMX a serious danger to your hearing. These are all known issues and supposedly will be fixed with future firmware updates. IMHO...If you're a CW operator don't waste your time with the QMX in its current configuration. If you're a FT8 operator, then things work mostly as advertised. I'm a BIG fan of QRP Labs/Hans and I'm sure this time next year the QMX will be a valuable multi-mode portable rig. Be patient and feel fortunate if you haven't yet received your QMX.

Also, be aware that the QMX manual says to limit the input voltage to 12V. I think, this means you shouldn't use a LiFePO4 battery that can have a charged voltage of ~13.5V, The Talentcell lithium ion battery should be fine as it only charges to ~12.3V. There's much Internet discussion about this issue so please don't take my opinion as the final word. FWIW...I've used both a LiFePO4 and a lithium ion battery with my QMX and both have worked fine...maybe I've been fortunate.

Re: Lion or LiPo4 for 12v power

Posted: Sat Oct 07, 2023 9:09 pm
by N8TGQ
I still haven't made the jump to lithium batteries. My nimh cells don't weigh that much more and I can easily adjust the voltage by adding or subtracting cells. No new charger needed and I can buy alkalines anywhere in a pinch. My current set of batteries just turned 5 years old and still going strong.

Likewise on new radios. I always wait at least a year after sales start before buying new offerings. Wait for the feeding frenzy to die down and all the bugs to be discovered and worked out. Seems like there's a lot of new QRP rigs coming out that aren't quite ready for prime time.

But Im still having a lot of fun with my radios!

73 Rick N8TGQ

Re: Lion or LiPo4 for 12v power

Posted: Fri Nov 10, 2023 4:48 am
by K4FBI
I use three 18650 Li Ion cells in series to power both my FT817nd and MTR-4V2.3. No problems so far with a fully charged pack delivering 12.6 VDC and dropping from there. 73, Mike K4FBI