[Elecraft] Portable Power for digital and Phone operation

[Mark Goldberg]

On Fri, Sep 1, 2017 at 10:37 AM, Michael Chowning <mike.chowning at mgccc.org>
wrote:

> Being there is no better place to get advice than this reflector, I am
> seeking your recommendation.  I have an Elecraft K3, P3, KAT500 & KPA500.
>
> I want to operate somewhat portable with the K3, P3, monitor and laptop,
> buddipole on SSB and digital modes on Field day, and demonstrations on
> outings to community events (like festivals, etc).  My options, I’m
> considering are:
>
> 1) Honda 2000i gasoline generator
> 2) Yamaha EF2000iSV2 (with propane option)
> +++++++++++++++++++++++++++++++++++
>

I don't use generators for field day as we are in the woods and don't want
any noise. The inverter generators are quiet though. I have been threatened
that my RV generator will suffer from "Lead Poisoning" if it is run in the
woods. It is very loud.



> 1) Deep Cell 12v 100amp battery (brand, model, control charger?)
> 2) Lipo battery (brand, model, control charger?)
> 2) appropriate solar power panels and controller charge for either of the
> above battery (brand, model, adapters?)
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> ++++++++++++++++++++++++
>

I use a solar system with deep cycle lead acid batteries, recently
installed in my RV, but it was standalone. A description with specific
models may be found on:

https://sites.google.com/site/marksrvmods/

The RV has a large inverter for 115V. I previously used a large inverter
standalone. Both are Xantrex, a good brand. They make some RF hash, but
they are tamable with Ferrite cores. Some inverters are very noisy.

200W of solar panels and two 75 Amp Hour batteries will run a 100W ham
station for field day late into the night. I have 4 batteries and 400W of
solar panels to run the RV too. I am really keen on the flexible solar
panels I use. They are very light and efficient. They have gotten lots of
attention whenever I set them out. They may not be the best for a permanent
installation, but for quick setup and teardown they are ideal.

Note that MPPT solar charge controllers are the most efficient but usually
make lots of RF hash. I use a Morningstar PWM controller that has a bang
bang option, that will either be on or off, no RF hash from switching. It
does reduce the actual output of the 400W panels to 300W though.

Lipo batteries do not produce the right voltage for radios. 4 Cells is too
much, 3 cells is too little. LiFePO4 batteries do and they are safer. A 4
cell pack runs from about 14.4 V down to 12 V at 90% discharge, which is
ideal for remote operation. They still take special charging, sometimes
built in to the batteries, but they are very expensive.

I have a 20 Amp Hour from batteryspace,com that I use for long QRP, and I
have a separate special charger. They also have ones with built in charging
/ balancing circuits, but they cost more.

I have two small 4s1p LiFePO4 packs from buddyrc.com for remote QRP, but
they don't seem to sell them any more.

bioennopower.com has lots of options with built in charging circuits that
make it a little easier and they get good reviews. I could not afford to
have the big boys be LiFePO4 though and have not bought from them. A few
hundred Amp Hours of LiFePO4 will be in the thousands of dollars.

For all these batteries, it is a good idea to monitor them and stop using
them when they get down to about 12V. LifePO4 especially can be permanently
damaged if discharged too low.

Good luck in whatever you choose. As you can see, there are many options
with no "best" option for all circumstances.

73,

Mark
W7MLG