My older Flightmax LiPo 4S charges to over 16 volts when full, so I use the voltage dropping diodes in series with power lead. My KX3 has an over voltage safety feature and lucky for me it wont turn on if over 15 volts. That LiPo is my back up battery I take on SOTA the Flightmax LiFe 4S has been my SOTA battery for 10 years. 3S Lipo would be my choice next time but I cant kill these older batteries and there probably should be better tech around by the time I need a new battery.
Regards
Ian vk5cz …
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Hi Mark,
from what I saw in the description - you achieve 10W at 13,8V.
BP-307 comes also with 7,2V, as such it should generate only max 5W.
Any battery with 13,8V or similar should produce the desired effect.
73s
Ingo
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Hi Ingo,
Just wanted to know what the 5w longevity is with the bigger battery if I decide to go without an external battery. I’m trying to see what the IC-705 equivalent is to the FT-817 with internal battery, although I suspect even with the standard battery the IC-705 would last longer than the FT-817 with internal battery on an typical activation when using 5w.
I might put this to the test later…
Cheers, Mark.
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Hi Mark,
there where some special editions of the 705 that came already with the bp307 and with the rucksack.
Will check and let you know how long the batteries are lasting…
73
Ingo
the new standart USB c PD (power delivery) can deliver 5 to 20volts with 5A (max 100watts !)
So an external battery for smartphone or tablet with usb c PD can feed an IC-705 via a usb-c - jack cable connected on the DC power jack of the IC-705 and it works !
73, de Bruno, F6HHK
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The problem that I have found with the USB power packs that can generate higher voltage is that they use a square-wave invertor to provide the higher voltage and this can be RF noisy. So while the idea seems great, you need to make sure you don’t wipe out the receiver with the noise from the battery pack. There are some that are correctly RF suppressed but many who aren’t. Don’t forget also, that a lithium 5Ah battery at 3v isn’t 5 Ah at 13.8v, it’s nearer to 1 Ah.
73 Ed.
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So realworld experience on Sunday was a 2 hour 40 minute activation of Red Screes G/LD-017 in freezing conditions. I took a 3S LifePo4 with me but forgot the IC-705 to powerpoles cable so the entire activation was conducted using the standard battery at 5w. I was down to one bar on the battery meter at the end, so still some life left.
Very impressed with this and will consider doing more activations using this setup for higher summits.
Regards, Mark.
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