LiFePo4 Choices

There does seem to be a dearth of the RC style batteries yet no shortage of round cell types.

As long as you can get your hands on 26650 style LiFePos and holders then 817/818/KX2 are sorted. Of course KX2 owners can buy the genuine Elecraft LiIon pack and either the inboard charger or outboard charger depending on depth of your wallet.

I just counted the “dogging” cells, all LiPo, 13x 13400 550mAh, 10x 13350 500mAh 6x 13300 360mAh plus 4x odd ball sizes awaiting use and I’ve made up a 3S2P 1100mAh pack and a 3S1P 1500mAh pack. That seems like enough QCX style radio batteries.

18650 LiIon cells are available for free in used laptop batteries though the move to modern “thin enough to use as a razor” laptops means they are now a thing of the past. I’ve 12x 1800mAh. They fit into USB power packs and are simple to get through airport security and power an 817 for two average FMF holiday activations. Probably will do for three using the KX2 and very long time for my QCXs.

And I have 3x 4000mAh LiFePo packs still. I’d buy some 26650s LiFePos to play with but TBH I think I have enough Lithium cells to jump start a battleship right now.

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Very nice as a backup supply for the shack or a campervan but I reckon i would soon tire of carrying it. Looks very nice though, the sort of equipment item you start trying to find a use for in order to justify purchase.

I’m was set on staying with LiFePo4 due to the perceived greater safety, but mifht end up going with 3 LiPo 18650s and printing the interal enclosure for the ft818.

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Well like many people, I used to use a 7Ah SLAB. The Tracer 16Ah pack is slightly greater volume, but only 2/3 of the weight, so it’s a bit of a win to me. I occasionally do 48+ hour expeditions so these are great for that. It really isn’t that heavy. I carted around all the GM summits on my recent trip. I still haven’t recharged it since before I set off to GM either!

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  1. Order a 12V 4Ahr LiFePo from Eremit in Germany. Eremit only ships to German addresses. But there are 2 international dealers listed on the website. You can check if they will ship internationally, probably not.

I ordered from the good people at Funk-Elektronik who attempted to ship me an Eremit pack earlier this year. They accepted and shipped my order, only for DPD to turn it around at the air freight terminal and send it back to them. They issued a full refund with apologies.

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Tracer batteries are excellent, but I went for the 4 x 4.2AH approach so I could split them and generally I only use one or two. The full 16.8AH pack complete with metering and enclosure weighs 2.8kg. At 2.215kg the Tracer is lighter… but I win hands down on the cost. :wink:

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Hi Alex,
Yes not only do we have the more complex customs issues and higher shipping costs since BREXIT, most courier services wont carry litium batteries anymore in fear of them exploding or something.
73 Ed.

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Bummer. At least you got a refund. DPD will ship Lithium batteries as long as the package does not need to travel by air or through a major tunnel.

I can’t remember who HobbyKing used to ship my LiFePo from Holland, it could have been UPS. I looked, UPS will ship Lithium batteries by air when packed and labelled according to IATA regulations.

It’s not really a VAT or Brexit issue here and LiFePos get lumped with LiIon cells even though they are much safer. But simply couriers avoiding dangerous goods. It looks more and more like UK hams will need to arrange a self help system involving bulk purchase, delivery to an address in Northern Europe and then someone from the UK driving over, collecting them and an arrangement to redistribute when back in Blighty. Current import limits are £390 for goods (not alcohol/tobacco) which is about 10x 4A Eremit packs. Those who want LiFePo cells need to coordinate themselves.

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collect from Eyemouth, at 4am, flash .-… … …-. .

In fact, LiFePO4 batteries are hard to find even in continental Europe, especially RC style ones, which I prefer.

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I’m using 26650 LiFePo4 batteries.
Four in series with a balancer.
I have two different packs one with 2300mAh and another with 3500 mAh.
There are also types with 5000 mAh.
Weight 93 g x cell.
Also charging works well with like max. 2-5C

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Well, I made the 3D printed battery pack for the ft818, from thingiverse. Works well except for the fact that yiu have to supply external power to the radio in order to start the BMS board…or I guess you can short the positive of the top battery to the positive line.

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Yes, you need a start button. Don’t forget to have some R in series with tact switches - inrush current kills them.
Battery Circuits

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Well done! Saw the same modification on a youtube video from Q26 channel.
But he is powering the radio via the backside input… Same as I do.
Bought for 2€ a case (uploaded pic) and made a cable for my FT817.
image
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The advantage of 3x 18650 is the weight.
I also got a powerbank where 3x 18650 cells fit. So when I’m traveling I can take my batteries with me.
And the best I can charge them with USB-C

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I have glued a two pin header to the back of the pcb which I can short with the nib of a ball point pen. There isn’t quite enough room for a tact switch.

At some point I may swap for a micro slide switch but the header pins seem to work fine

This is perhaps a better solution. I quite like the internal battery option but since you have to remove the batteries to charge them, its and extra hassle just to save having an external power supply.

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Yes your’e right…
But after all this tesing and trying out (btw I like it haha), I came to the conclusion that the 3000 mAh battery from Windcamp for 90€ would be a good solution…

I have the Windcamp battery too, but its old and has only like 300mAh left…

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You must be able to get a battery protection board which includes a balance charger and USB C socket with PD/QC circuitry?
I had a look on Aliexpress and couldn’t find a combined one but it sounds like something that should be available.

I was looking for exactly the same thing, with the extra constrant of being suitable for LiFePo4 - but can’t find anything

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As the LiFePo voltages are different to the LiIon voltages you need a BMS configured for one or the other. Also you need a 4S BMS for LiFePo vs 3S for LiIon.

All the LiPo LiIon BMS I have found provide over voltage / under voltage protection and over current protect. The output terminals provide the voltage and can be used for charging but you need a charger to provide the CI/CV characteristic and charge complete detection. Yes you can use the BMS to go to over voltage protection but that’s a naff way of doing it. They do not have the charge algorithm features in the BMS.

I use these for 3S LiIon BMS. You don’t need a start button/voltage but the cells are not left connected. From eBay for pennies. They are bigger than my “dogging” recovered battery cases so the BMS is external to the cell holders. Works for me, YMMV.

The 4S BMS in my Eremit LiFePo pack handles balancing and charging as well the normal protections.

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Made a new version with a tiny sliding switch to allow jump starting the BMS by connecting B+ to the the positive terminal of the power out.

Also added a plastic flap to prevent shorting against the ft818 case.

Really very pleased with this as a solution…I’m using unprotected 18650 LiPo cells, so it is the opposite of my original intent of improving safety by finding a LiFePo4 external pack. Although I like to think that not much harm can be done if you take care to store correctly.

It has even prompted me to try some QRP from home.



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