16.3V OK for HL2 supply?

[zl2...@gmail.com]

I would like to run my HL2 from a Lithium battery pack which supplies 16.33 Volts when fully charged.  

Am I likely to cause any damage exceeding the 11-16V specified, by 0.33V ??

[Mats Sundin]

I have a couple of S4 LiPo's and I use 2 diodes in series that brings it down to abt 15V

//Mats SM0FPR

[Tim Thorson]

That voltage does seem a little high (LifePO4?)  I recently discovered that the monitor from Walmart branded ONN, would not take lithium voltage (14V) To the credit of the design, it simply would not boot up (vs releasing the magic smoke). Only until I put in three diodes in-line on a specially made power cable for it did it work. However, I became very concerned about the amount of heat coming out of those diodes. Afraid the insulation could have melted ...(Any thoughts experiments and ideas upon that)

Tim KD6HOF

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[Tim Thorson]

If you're using 18650 cells 4.2x3= 12.6v max  (3.7x3=11.1v Nominal) I read: generally 9V to 15V DC ok, though it’s designed to work optimally around 12V to 13.8V.

Personally I would definitely make sure it's in the proper range for fear of strange anomalies popping up, causing me to chase my tail  (when all along it was an unreliable power source)

Tim KD6HOF

[Mats Sundin]

I never been checking the current draw of the HL2. I have been running my KX3 full power thru this circuit.
https://www.arrl.org/files/file/QST/This%20Month%20in%20QST/April2015/SALAS%20QS4.pdf

Remember.. diffrent chemestry gives diffrent voltage... 
4S LiPo are not the same as LiFe4Po

//Mats

[Noel Woodfield]

Little tip ... if you need a 1.4v (two diode) drop, a really convenient method is to use a bridge block. Ignore the AC terminals, feed batt pos to the - terminal and connect your load to the + terminal.

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[zl2...@gmail.com]

Thanks to all the repliers.

Noel's tip  to use a bridge block has the advantage that it would dissipate the diodes heat more easily, especially if used with a heat sink.  
I will combine that with Mats suggestion of using the voltage controlled relay. 

[Clifford Heath]

Personally I would just reduce PA bias a tad and just use 16.3V

Probably nothing else will care, and probably the PA doesn't either. 

Clifford Heath 

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[Steve Haynal]

Hi Group,

The 16V limit is due to the LP2985 regulator. This is the power regulator for the premp's op amp. See the schematic and take a look at the LP2985 datasheet.

www.hermeslite.com

The final PA is not connected directly to the input supply. U8 provides a regulated voltage to the PA. Changes to the input supply voltage do not affect the PA.

73,

Steve

kf7o