[Elecraft] [KX3] Hi Curr Warning

[Gary Hawkins]

Hi Mark,

Thanks, this seems to be the best explanation as to why the Hi Cur 
warning is happening.

I'm now trying to decide whether to go for LifePo or LiPo.  I like fact 
LiPo have higher voltage per cell thus creating a nominal working 
voltage around 14.8V but I will likely go for LifePo (nominal working 
voltage 13.2V) since they seem a lot safer during charging process.

Gary
KK6GXD


On 12/13/2013 10:01 AM, Mark Petiford wrote:
> Gary,
>
> I didn't find the table, but I did find two relevant posts:
>
> This was the problem reported by one poster:
>
> >>During xmit at modest power 8 - 9 watts, I occasionally see a msg 
> flash on the display that shows "hi curr". It seems that when that 
> happens, the xmit power gets reset to 5.0 watts. I have the battery 
> charger option installed and NiMH batteries in the unit, but have been 
> running from an external 12v gel cell.
>
> Sounds quite similar to your experience. There was a response from 
> Myron, WV0H, who has done considerable testing on his KX3:
>
> >>8-9V will allow you 3W on any band.
> >>9-11V will allow you 5W on any band.
> >>11-13V will allow you 10W on 160-15m, 8W on 12-6m, and HI CURR if 
> you exceed 2.5A.
> >>13-15V will allow you 12W on 160-15m and HI CURR if you exceed 3.0A, 
> or if on 12-6m HI CURR
> if you exceed 2.5A.
> >>If the HI CURR warning shows up, expect to see the power setting 
> throttled back.
>
> I have tested some of these data points and my results are very 
> similar to Myron's. In addition, I took a look at some SLA datasheets, 
> and would be very surprised if the voltage at the KX3 during transmit 
> stays above 11v for long. The discharge curve (NOT the same thing as 
> the resting curve, or the charge curve) for SLA's is pretty steep. 
> Combine that with the relatively high internal resistance of the 
> cells, cable/connector drop, and the KX3's reverse polarity 
> protection, and the voltage at the KX3's Power Amplifier tends to get 
> knocked down a lot. I ran successfully ran SLA's for a while after 
> receiving my KX3, but only at 5w and below.
>
> I suspect your decision to move to Lifepo/Lipo cells is the right 
> answer if you want to stay in the 8-10 watt range. There are lots of 
> folks using them successfully for that reason.
>
> Mark
> KE6BB
>
> From: Gary Hawkinsgary at hawkins-zhu.com>
> Sent: ‎Fri, ‎Dec‎ ‎13‎, ‎2013 at ‎9‎:‎04‎ ‎AM
> To: Mark Petiford rv6amark at yahoo.com>; elecraft at mailman.qth.net 
> elecraft at mailman.qth.net>
> Subject: Re: [Elecraft] [KX3] Hi Curr Warning
>
> Hi Mark,
>
> I have revision C2 of the manual and, if I remember correctly, 
> theimportant power voltage setting is >11V for full power. Thatbeing 
> said, if 13.8V is what is required this may explain what'sgoing on. 
> The SLA nominal voltage is marginal. I'm going topurchase some 
> Lifepo/Lipo batteries to both reduce weight in packand provide a 
> slightly higher nominal voltage.
>
> I'm not a member of the Yahoo KX3 user group - perhaps I shouldjoin. 
> If you do find the table you referenced I'd love to see it.
>
> Best regards,
>
> Gary
>