Re: Maximum safe input voltage to ubitx?

Paul Schumacher

They are salvaged from new computer battery packs.

Paul K0ZYV

From: Vince Vielhaber <vev@...>
Sent: Monday, February 19, 2018 11:54 AM
Subject: Re: [BITX20] Maximum safe input voltage to ubitx?

What kind of 18650 batteries are you using?  E-Cig batteries are
designed for an intermittant high current drain while keeping their
voltage up.


On 02/19/2018 06:49 AM, Mvs Sarma wrote:
> during Tx time the battery drops . Yes, You said you wont diacharge
> below 3.3V. I observe here that the 18650 cells show 3V while on 1 or 2
> amps of discharge. That is what mde me feel the regulator trouble.
> However , perhaps using a LDO regulator at 12V you could overcome this
> issue.
>  Thanks for the reply, John.
> regards
> sarma
> vu3zmv
> Regards
> MVS Sarma
> On Mon, Feb 19, 2018 at 4:52 PM, John <passionfruit88@...
> <mailto:passionfruit88@...>> wrote:
>    Hello Sarma,
>    Regarding the voltage drop, I do not discharge my lithium batteries
>    below 3.3V per cell.
>    So a 4S battery pack would need to stop being used at 13.2V. With a
>    regulators' drop around 1.5V (we only pull 0.4-0.5A from the main
>    board on Tx, and the finals go strait to the battery), the final
>    voltage to the main board is around 11.7V. Quite a decent supply
>    voltage.
>    Regards,
>    John (VK2ETA)


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