Is 12.6V battery power OK?

NX6D Dave

My Flex 6300 wants 13.8VDC power, which I am supplying with a well regarded switching power supply.  But I'm interested in creating a lower noise system, so I'm thinking of going to pure DC power supplied by one or more 12.6VDC lead acid batteries that I would recharge when not in use.  When in use, I would not run a charger as chargers frequently are noisy.

I have not been able to find anything in the Community along these lines.  I can't tell if 12.6VDC, or perhaps a bit less, would be OK.  Does it have to be 13.8?

Jon_KF2E

David,

Check out this article...

https://community.flexradio.com/flexradio/topics/is-12-6v-battery-power-ok

In it Tim suggests that 11.5 volts is okay with reduced output.

73,

Jon...kf2e

Alan - KA4B

Jon, it appears that your link leads back to this same page.

Jon_KF2E

Oops, sorry, it should have been this link.

https://community.flexradio.com/flexradio/topics/flex_6700_shuts_down_and_gives_power_supply_error_m...

Jon...kf2e

NX6D Dave

OK, Tim's answer from a year ago clarifies the situation completely.  I think I may run experiments with a well charged RV/Marine battery to learn just what noise, if any, this power supply makes.  Perhaps it is quiet (probably not), perhaps it's acceptable and perhaps I'll be looking for big linear supply.

Thanks for finding the answer.

73

Dave

KK6FCH

Stan VA7NF

I run my flex on a marine battery all the time - Charge as needed.  Works well unless I forget to charge it, then get that low power message and have to restart.

Bob G W1GLV

I found solar to be the best. I use a 60 watt panel hooked to a regulator and a wet battery. From there I hook to an inverter that produces AC for the power supplies. Works great no ripple or other types of noise.

Alan - KA4B

Stan, what kind of power are you getting out using the 12.6 V deep cycle battery?

Stan VA7NF

Full power

Alan - KA4B

Interesting!  In the thread mentioned above Tim said that to get the full 100 watts you need to have 13.8 volts.  I find that with my ICOM 746 when I use the battery system that supplies power to my house, my power drops off significantly.  If the 6300 gives full power on batteries that would be very nice.  I am in a remote area, with a noisy inverter and when I turn it off and operate on batteries it gets VERY quiet! 

Steve-N5AC

There are two factors at play here: 1) The PA transistors put out more power with a higher voltage, 2) We calibrate the radio with an input voltage of 13.8VDC.  

At lower voltages, the transistors can not always make the required output power on all frequencies.  Since shacks are nominally 13.8VDC and we require a certain level of voltage in order to get the rated output power on all bands, we calibrate at 13.8VDC.  So there are calibration factors that adjust the power to get 100W at 13.8VDC.  Necessarily, as you lower the voltage, you're going to see a lower power output.  But 50W (a rather extreme degradation in power that would be expected from a very low voltage) is still only a half an S-Unit or 3dB.  So the recommendation is to run at 13.8V. but you're welcome to run it lower and it's really not going to make that much difference in how well you're heard on the other end as a general rule.

While we're on the topic, I recommend measuring the input to the radio at full power output.  If you have a significant drop from your power cable because it's long, etc, you can bump up your supply to achieve 13.8V in transmit (higher voltage to compensate for the drop during a higher current load).  If this supplies 14.5 or 15V during receive, no problem.  The radio runs fine up to about 16VDC.

Steve K9ZW

What about use of a booster like the "N8XJK Boost Regulators"  ( http://stores.tgelectronics.org/ ) ??

I've one in a HF go-kit I put together, but have less than 4 hours using it so far.

73

Steve

K9ZW

BLOG:  http://k9zw.wordpress.com/

KY6LA_Howard

Take a look at my paper on How to Build a Quiet Statio https://community.flexradio.com/flexradio/topics/how-to-build-a-quiet-station I give specific example of how I rin my 6700 via DC supply. I have been on battery power for years I use my 6700 to drive a SPECIAL Expert 2K-FA amp so I never need ore than 40W for full " power from'the amp m

K6OZY

I have one of these for my Flex 6700 and it solved my issue when using my Flex in the field.  Every time I would TX while on my AGM, the radio would power off due to an under volt.   This has solved my problem.   I haven't tried it on my 6300 yet, as I'm curious if the result would be the same or if the 6700 is taking more power.

http://stores.tgelectronics.org/the-n8xjk-super-booster/

NX6D Dave

KY6LA -- it was your paper that got me started on this.  The N8XJK booster looks interesting to me for the simple reason that it appears to have been designed by a ham.  I'm thinking it may produce very quiet power.

Thanks to everyone for all the information and suggestions.

NX6D Dave

Can't beat being a Flexer.  This is the sort of detail I wanted to know.  Thanks!!

K6OZY

I have the Booster model that has the RF Detector but have not used that function yet, using it as an always-on.   This is obviously very inefficient.   In efforts of switching to the always-on-battery wiring method,  I'd like to get the RF Detect function working.  I have two questions:

1)  Can I attach this to the booster's UHF input:  http://www.ebay.com/itm/250706793454 and then simply put the output of my flex inline through it without it impacting SWR?

2)  The default low-volt cutoff for the booster is 10V.  I would think this is too low and would likely damage my very expensive 100aH AGM battery if it was allowed to discharge that low during a power outage.   Should I increase it to the 11V setting?

Thanks!

Phil - N6ERP

Good info. Same situation here. Off grid, all solar power..