LifePo4 issue

Sounds dead then

Fill the aperture at the top with a generous amount of glue, blu tac, mud, whatever takes your fancy. It makes them much less annoying.

These are the ones I use. Interestingly they regularly give 3 reds when you plug them in first, then alarm even when its a freshly charged battery. Unplug them then plug them back in and they’re fine. The bigger ones never do that

I have just ordered one of the Zippy Compact 4200mAh 4S2P LiFePo4 packs from Hobby King.

They have been out of stock for months, so thanks to whoever mentioned they are back in stock.


So where do the electrons you don’t want go if they don’t heat the LM 338 up?

16.4 in 13.8 out = 2.6V lost. 5A load = 2.6 x 5 = 13W. 13 Watts of heat is going somewhere.

OK, better put the heat is dissapated over the heatsink. Compared to the extremely hot diode solution, this is way better!.


Wire ended diodes ( 1N4001 etc) use the wire to dissipate the heat, you are meant to stand them vertical (skyscraper style) so there is a longer length of wire available. Likewise some very small transistor like the (probably long obsolete) ZTX651 which could have 2A of Ic in a tiny package because the PCB pad/track had to be a minimum size to dissipate the heat. A bridge rectifier on a heatsink with a pair of switches and two diodes in series would be my way.

As for boost and buck converters, I have been lucky. I bought a bag of 3 from the Middle Kingdom for use with the 13cms transverters (get the 11.1LiPo upto 13.8). Mine is silent, can’t hear any noise on HF when it sits under the HF antennas on an activation. I gave on to Jack GM4COX and he said his screaches away across the bands.

You might want to test the integrity of the balance charger connections. I had a LiPo that the charger told me had failed on one cell, but it was an intermittent fault in the balance line.

If you delete the Global and Netherlands warehouse on the webpage it should show that the UK warehouse has them in stock, so no problems with shipping. The Netherlands warehouse will ship to the UK anyway. Buy 2 and it should be free post and packing.

Now do I buy 2 ready for the next Trans-Atlantic S2S Event in early November?

Edit - I didn’t see the little orange note confirming that it would be the EU warehouse that has them in stock.

Thanks Ed for the detailed circuit info.

All these sort of challenges were why I was looking at the LifePo4 because I like to keep it simple where possible - enough challenges getting out a good signal without adding more challenges.

Lots of things in short supply at the moment so took the plunge and ordered the 4S2P, problem is that they had no chargers in stock - had forgotten how frustrating the website is, you select in stock EU it offers a range of stuff then the turnigy one that is reasonably priced is only in the global warehouse and it’s out of stock!

Have to go order a charger somewhere now, probably Far East and take the wait.

Hi Paul,

LiFePo4 batteries used to be expensive but once you add in the extra components to get the voltage down safely to 13.8v with a 4S 5Ah LIPO, a 4Ah LifePo for $45 as John DK9JC has found, doesn’t sound that much more! I remember when they were €65-80 !

When the LIPO batteries that I currently have finally give up, I think I’ll most likely switch to LifePo4 at least for the rig (the portable amplifier needs to run straight off the 16.4v from the 4S LIPO).

73 Ed.

Looks like the batteries are now out of stock in EU, mine shipped yesterday so waiting to receive but the charger is coming from Far East to longer wait.

I went for " ISDT Q6 Nano BattGo 200W 8A" because its small, light, 8A is more than enough and it was in stock. I also ordered the BattGo BG-8S smart checker, as that looks like it could be a good monitor in the field, also has USB output to charge phone etc - and there was a sale on so buying both I got discount so it was a lot cheaper (man maths) to buy now together.

Also got a balanced lead extension, already have some XT60 “in stock” to make up charger leads, as well as Anderson’s for the battery - just need to wait a few weeks for it to turn up now.

Will go build a linked dipole in the mean time, found my spare rolls of sotabeams wires yesterday and the plastic link pieces I bought at least a year ago for that project.

Ditto. Looks like the supply is still very limited.

Will you still be doing SOTA then Ed? My 4AH LiPOs are still doing okay at 11+ years. I never had that sort of lifespan with a SLAB. Hopefully with care my LiFePO4s will last as long.

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While taking a look at your purchases Paul, I came across the following in the “bargain bin” - which might interest others:

It’s a buck/boost convertor for 4A 12.6v output but the case is worth the €1.86 on it’s own.

There’s a Gotchya though! This is ONLY available from the Global warehouse (China) and the shipping fees to Europe are steep! I ordered three and with the shipping it came in around €21 - so not bad in any case.

73 Ed.

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Not sure if you talk about the 5A LiFePo4 cells that I ordered on eBay. I tested them for 5,3 - 5,45 Ah with 1A discharge. Seems that I can soon solder the pack together. 48 Euro shipped or so.

I was referring to your text " I ordered a new 4S2P 4,2Ah last night. Could not resist. 45 bucks is not so bad, even if it works only a year or two." in LifePo4 issue - #15 by M0PWZ

73 Ed.

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Here’s something on Amazon - a 6Ah (6000mAH) LIFPO4 12.8v battery for €60 with free shipping inside Germany.
The important point is that it’s not just cells, it has a battery management system (BMS) built into the battery.

73 Ed.


I guess there are 4 32650 or 32700 in it. I paid €42,40 EUR for 4 32650 from a German Ebay seller. I tested them for 5500mAh each. I do not like BMS as you never know what you get. I prefer balance wires and a balace charge which a quality charger.


Security at departures in Manchester Airport are looking forward to your visit!

73 Phil


18650s in a USB power pack is how to get the batteries on a plane. Security people see so many power packs they don’t even blink.

Are there still planes flying out of Manchester?

I suppose if there are, every passenger will have 4 security officers “looking after” him/her !

73 Ed.

DIY battery looks smart, but getting the cells is the challenge.

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