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Finding a battery in the UK ***#!

Having researched which battery to get for SOTA, using a Xiegu G90 I settled on the popular ZIPPY 4200 mAh LiFePO4 model… unfortunately the delivery date turned out to be March 2021! So what is plan B? Any suggestions?

…and don’t get me started on finding a 6-7 meter compact antenna pole in stock!

Thanks
Martin

Turnigy nano-tech 2000mAh 2S1P 20~40C LiFePo4 Transmitter Pack
SKU: 9210000040

Buy 2 of these from Hobbyking’s UK warehouse. Not ideal but still very useable. £11.49 ea plus p&p.

Combine 4 of those in a pack:

Add a 4S LiFePO BMS pcb or a 4S balancer connector as preferred.

Joe

Unfortuantely I had the same issue during the summer when I planned to buy a battery to compliment my FT-818. Supply and demand has seriously been skewed since the up take of hobbies during lockdown and the reduction in manufacturing!

I settled on a GNB 6200mAh battery from HobbyRC.co.uk (https://www.hobbyrc.co.uk/gnb-6200mah-2s-90c-hardcase-lipo-battery)

I couldn’t be happier with my purchase, the battery easily lasts most of the day, has an indestructible hardcase (not many batteries have hard cases), small dimensions, cheap and the delivery was lightning quick. I can’t help but feel that HobbyKing batteries are rather a rip-off after my experience!

As for rods, I’ve also had a good experience with Decathlon Lakeside series travel rods (https://www.decathlon.co.uk/p/lakeside-1-travel-400-telescopic-still-fishing-rod-4m/_/R-p-102580). I purchased the 6m version but managed to snap off the top meter by hauling a rather heavy dipole centre in the air. They pack down to less than the length of my arm! I can snuggly fit inside my small capacity backpack. Availability fluctuates but they often are not out of stock for more than a few days.

Beware unless you shell out on thick walled telescopic poles then you will most likely get the full 6m/7m extension unless you have a particularly lightweight antenna.

Do you have a source for a 4 cell holder so you can assemble a pack? I have a pair of 3x18650 cell holders I use already. 18650 holders are quite common.

I have just found these? https://www.ebay.co.uk/itm/100PCS-18650-Lithium-Battery-Holder-Space-Pack-Combination-Cell-Fixture-Bracket/154041845888?hash=item23dd9c0880:g:c0QAAOSwvi9fMmKF

That’s only a 2S (7v) battery, however - for an FT817/8 you need the 3S version ( GNB 6500mAh 3S 110C Hardcase LiPo Battery | HobbyRC UK ). For Martin’s G90, he’ll need the 4S version and some method to reduce the voltage (- LMxxx voltage regulator circuit - that’s what I do - I have two Hardcase 5000mAh LIPOs, One I use directly to give 16v to my amplifier when I use it and the other supplies 13.5V through my voltage regulator circuit) or he could go with a 3S and some electronics to increase the voltage but beware of Buck converters that cause RFI (it’s hard to know which do and which don’t create noise across the HF bands).

73 Ed.

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Maybe find someone to 3D print some holders

They perfectly fit in a plastic pipe M40 from the hardwarestore (in DL or OE).
So I plan on adding them in a straight 4 cell tower.

I have 8 of those at home and are just thinking how to setup that pack. With 3D Printed endcaps (or maybe they have them at the hardware store) this would even be waterproof.

Joe

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That’s only a 2S (7v) battery, however - for an FT817/8 you need the 3S version

You are very correct Ed, my mistake! I wasn’t particularly vigilent when I was copying the link. You are correct I purchased the 3s version and there is also an identical 4s version available from HobbyRC. I’ve now updated my original post with the 3s battery I purchased.

4s version: https://www.hobbyrc.co.uk/gnb-6500mah-4s-100c-hardcase-lipo-battery

If you have a charger with balancer connector (the small 5 pin plug) then you don’t need a BMS (battery management pcb).
For the holders I can find them on ebay - but not shipping from UK.
Maybe you can find a plastic box to put them in? Either from the electronic store or from the household supply (the ones with a silicon seal for the lid).

I know it is some improvising at that point :laughing:

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Watch out 4s LIPO is potentially to high voltage for the radio. You would need to add diode to reduce voltage. 3S should be fine.

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Being new to this, what is the difference between LiFePO and LiPO is it just management issues?

Main difference is full / empty voltage.
And the risk of fire/explosion.

LiFePO4 = safer but lower end volate (4 in series are perfect for every radio)
LiPO (or also Li-ION) = fire hazard if over/under charged, 4S too much for the radio, 3S okay for 817 but some radios struggle as volate drops below 12 V relatively quickly

Quote:

The voltage of a single LiPo cell depends on its chemistry and varies from about 4.2 V (fully charged) to about 2.7–3.0 V (fully discharged), where the nominal voltage is 3.6 or 3.7 volts (about the middle value of highest and lowest value). For cells based on lithium-metal-oxides (such as LiCoO2); this compares to 1.8–2.0 V (discharged) to 3.6–3.8 V (charged) for those based on lithium-iron-phosphate (LiFePO4)
from https://en.wikipedia.org/wiki/Lithium-ion_battery#Charge_and_discharge

3.65 V is the typical charge voltage maximum for LiFePO4 resulting in 14.4 volt. Perfect.

4.2 V times 4 is too much for almost every radio.

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Forgot to reply on this one.

While the fibreglass poles are out of stock SOTABeams still have the 6m carbon fibre masts in stock:
Carbon-6 ultra-compact 6 m (19.6 ft) mast (sotabeams.co.uk)

Personally, if you intend using a vertical antenna, I would not buy this but if it needs to hold up an Inverted-v dipole of some sort - it should be fine. (they say the loss on a vertical antenna is minimal but my preference for a vertical would be a fibreglass rather than carbon fibre pole - personal choice).
You may need to have the dipole feed point sit a couple of sections down (so at 5m AGL) to have it strong enough - that will depend upon the weight of your antenna.

73 Ed.

Thanks Ed I have ordered the Bandspringer Midi , end fed antenna, 10m-60m. I want to keep my options open and keep it small. Thats why I wanted the tactical mini.

73s

Thanks for that! the radio voltage: 13.8VDC + 15%

Poles…

I have both the SOTABeams 10m pole and the Decathalon 6m pole. On longer treks I take the Decthalon pole because it is about 1/2 the weight. It stands up to high winds very well just because it is so light. The SOTABeams pole is a monster and clearly gets your antenna much higher in the air, but it adds to pack weight significantly.

Both have their moments. The SOTABeams pole being particularly resilient to much abuse.

The LifePo4 battery supply to the UK has always been sporadic, unfortunately that has turned into non-existent at the moment.

For my FT-817 I bought the LifePo4 3 cell 2100mAH battery which is a perfect match. It is also a good match for the Mountain Topper, if a bit on the large side! Unfortunately that is out-of stock too at the moment.

Mark.

The SOTAbeams 7m pole is considerably lighter than the 10m. The 10m is used just for the 30m quarterwave groundplane, as the length is needed, and for foreign holidays (remember them?) as it’s packed length fits into a suitcase - which the 7m does not.

For all other HF band aerials (dipoles and QWGPs), and VHF/UHF I use the 7m for convenience.

I am in the process of building a pack with these.
Headway LifePO4 40152S 3.2V 15Ah [EA11] - £19.49 : Eclipsebikes, electric bike kits,EV chargers

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