Larry,
Thank you for the good info on lead acid batteries. I'm not sure what
Specific Gravity numbers to look for? Also is there any proper way to
know what cycle time to use for a charger system?
As for battery power to a rig. Is it possible to put two batteries in
series and run the 24 VDC into a voltage regulator circuit like that
found in a common power supply. This way we could have 13.8 VDC regulated
as well as longer battery charge.
A while back I noticed in QST there was a write up with plans to use the
ham rigs power supply to also charge a back up battery. After what you
wrote here that doesn't sound like such a good idea.
73 Jeff aa8ve
On Sun, 26 Dec 1999 09:30:43 -0500 "Larry Kayser" <kayser@king.igs.net>
writes:
>
> Greetings:
>
> The thread about using Lead Acid Batteries has me concerned for
> those who
> might choose to go this route for powering a Hercules II amplifier
> or a
> radio.
>
> Please read the following, save yourself some money, save your
> equipment,
> save the environment.
>
> First NEVER EVER connect a regulated power supply as a battery
> charger to a
> battery without putting a SERIES connected diode with the output of
> the
> regulated supply. You will only have the accident once and it will
> be
> expensive, but if the regulated supply gets disconnected from the AC
> Mains
> while the battery is connected to the supply the reverse current
> from the
> battery back into the regulator circuit will blow up your regulator
> in the
> Power Supply instantly. Put a large diode, or one arm of a diode
> bridge, in
> series with the regulated supply output and connect to the battery.
> Increase the regulated supply voltage output, there is usually an
> adjustment
> somewhere to raise the voltage about .6 volts to overcome the effect
> of the
> I^2R losses of the diode. Parts for these newer regulated supplies
> are hard
> to get, be careful, failure to protect the regulated supply can be
> very
> expensive instantly.
>
> Second do the following to lower the maximum specific gravity of
> your lead
> acid battery. You want to lower the maximum specific gravity of the
> battery
> to drop the maximum capacity of the battery about 5 to 10%. This
> simple act
> will stop or greatly reduce the battery becoming calcified, that is
> the nice
> white hard stuff that forms on the battery plates and will kill your
> battery
> for you. To do this when the battery is a full charge, use a
> battery
> hydrometer and take out, of a more or less standard sized
> battery,100 to 150
> Milliliters, 1/2 cup if your not into Milliliters, of acid from each
> cell.
> reduce this acid to neutral by adding soda to it so it becomes ph
> neutral.
> Get rid of the stuff that is left. Replace the amount of liquid
> removed
> with distilled water. Use the battery some and then recharge it.
> This
> simple reduction of the amount of acid will extend your battery life
> by two
> or three times or more. The specific gravity at full charge will be
> about
> .01 less than before. Calcification caused by the marketing
> department of
> battery manufacturers demand for "high" performance kills almost
> every
> battery made. Defeat these designed to fail conditions by removing
> a tiny
> bit of the acid and greatly, by many times, extend the life of your
> battery.
>
> Make absolutely sure that your battery charger has a way to cut off
> when the
> battery is fully charged. Put a timer on the charger. If your
> using one of
> these modern taper chargers that the manufacturer tells you can be
> left
> connected to the battery for ever - be prepared to pay in $$ many
> times over
> for this possible luxury. I usually open then use and rip them out,
> they
> are designed by the same guys who want to put the extra strong acid
> in your
> battery. Use a timer, cheap at twice the price, to manage your
> battery
> charging cycle. If the battery charger people were into your
> interests at
> heart then they would have put a very accurate terminal voltage
> adjust knob
> on the charger so you could set the float voltage level to the
> specific
> needs of a given battery. If the knob is not there, and it very
> rarely is,
> then the marketing department is after you again.
>
> Buy yourself a battery hydrometer. Manage the battery charge state
> by
> managing the specific gravity of the battery. Get a 2 liter soft
> drink
> bottle, plastic, cut the top off, and put a few inches of water in
> it and
> keep your hydrometer washed out after using it. Dispose of the
> waste
> material every year or so. Put the result in a bottle, neutralize
> with
> soda, and then get rid of it.
>
> The ACID used in a battery is the lowest form of H2SO4 that can be
> shipped
> from the manufacturer of the ACID. It has every contaminent known
> to man in
> it. This will never change. The issue here is that the ACID can be
> so
> badly contaminated that it will eventually kill the battery anyways.
> Contaminants are so many an varied that they are very hard to spot.
> If you
> get a brand new battery that has no acid in it, consider making
> friends with
> a high school chemistry teacher who can tell you were to get clean
> H2SO4 and
> he/she should also supervise you in diluting the laboratory grade
> H2SO4 down
> to the level the battery will need. This simple act will put your
> battery
> on the road for double to quadruple life.
>
> The only difference between a deep discharge battery and a regular
> automobile battery is the amount of lead in the plates of the
> battery. The
> deep discharge battery will have a greater plate size and thickness.
> IF YOU
> HAVE DROPPED THE ACID LEVEL IN THE BATTERY AND YOU RARELY DISCHARGE
> THE LEAD
> ACID BATTERY MORE THAN 20% OF CHARGE THEN YOU CAN LIVE WITH ANY CAR
> BATTERY
> MADE WITHOUT ANY PROBLEMS. The operative word here is how far you
> discharge
> the battery. If your into Contesting or long operating hours at a
> session
> then the battery needs to be of the heavy duty type. If your into
> grabbing
> a new country with the Amp ON then idle or off, then you have no
> need of a
> deep cycle battery. Please remember that the starting motor of a
> car really
> gives the car battery a nasty reminder when the multi hundred amp
> load hits
> the battery. The survival trick is to make sure the battery is
> recharged
> quickly which is what the alternator does in a car immediately after
> the
> starting motor does its job of starting the engine.
>
> If you are going to use a lead acid battery to start a car when the
> battery
> has been left for some time at very cold conditions try this. Try
> to start
> the car for about 30 seconds to one minute. Then get out of the car
> and
> take a walk for 5 to 7 minutes. The battery will be in a state of
> large
> chemical change after the heavy load put on by the starter motor.
> By
> waiting a real clock measured 5 to 7 minutes, maybe up to 10
> minutes, the
> chemical reaction inside the battery of recovering from the attempt
> to start
> the car will warm up the battery and get it ready to really work!
> After
> waiting the real amount of time, and I am serious about the waiting
> period,
> get in and try again, the car should start. I have used this trick
> at minus
> 40 (C or F they are the same at this point!) and it really works but
> you
> have to wait the 5 to 10 minutes.
>
> Make sure your battery charger will really take your battery up to
> the
> needed terminal voltage to achieve a full charge. Failure to
> achieve a full
> charge is the greatest killer of batteries known to man. I know
> people who
> use a wall wart power supply to charge a car size battery. This is
> 99%
> wrong. If your battery charger wont put out 3 to 5 amps at the
> terminal
> voltage point then get one that will. Remember the goal to make the
> battery
> last a long time is to charge it, measure the charge level with a
> hydrometer, and then turn off the charger. If your battery is left
> consistently with as little as 2% to 5% less charge than that needed
> you are
> inviting the calcification of the plates and the eventual ruination
> of the
> battery.
>
> If you have an expensive battery that has bad calcification on the
> plates
> the battery can be recovered sometimes. Here is the trick. Find a
> high
> voltage water purification filter, I found several in a junk yard a
> while
> back. Inside these things is a relay type vibrating assembly that
> pumps air
> and a low pressure. Make up a manifold from the little air pump and
> a
> separate tiny plastic tube that is wiggled down into the bottom of
> each cell
> in the battery. I have used a 555 timer and stuff to turn the tiny
> vibrating pump on and off at a rate of once a minute for about 4
> seconds.
> the air bubbles rising through the battery electrolyte will
> eventually,
> sometimes, not if the acid is contaminated by some of the real bad
> chemicals
> I mentioned above, break down the calcification. I have two 140 lb
> each 12
> V batteries from a large diesel plant that I treated this way for
> two
> years - they now will willingly deliver full performance in current
> to start
> my diesel tractor after it has been sitting out doors during the
> winter.
> The batteries have a replacement cost of over $270 US$ each, not bad
> for $5
> worth of electricity and two years of watching the magic happen.
>
> There is a common thought that keep the charge rate of a battery
> down and
> there will be no smell. Yes this is right, there will also not be a
> full
> charge on the battery either.
>
> There is a price to pay for using a battery to replace a power
> supply that
> would deliver the power needed to operate the radio or amplifier.
> THERE IS
> NO FREE LUNCH. If you want to use a battery that is well and good,
> then you
> must also put in the effort and care needed to look after the
> battery or the
> economics you thought you were dealing with will not be working the
> way you
> want them to work. Remember please THERE IS NO FREE LUNCH. I have
> talked
> with amateurs who use batteries to replace large power supplies,
> until I
> point out the economics of that decision and how to change the
> economics to
> the amateurs advantage they thought they could just buy a battery
> and a
> charger and that was it, sorry it doesn't work that way. Carefully
> work out
> the amount of power consumed by the radio or amplifier, evaluate the
> work
> associated with a battery and make an informed decision. You can
> PAY NOW OR
> PAY LATER BUT YOU ARE GOING TO PAY!!! Beware of articles touting
> the value
> and benefit of using a battery to replace an AC driven power supply.
> In the
> latest issue of a popular back to the land magazine there is an
> article of
> this type that pushes the value of a Battery based system. The
> writer
> forgot to balance the applicable economic equation by pointing out
> the work
> needed to look after the battery system. When you have an
> unbalanced
> economic equation it is like the opportunity that is to good to be
> true, you
> are about to get it put to you hard, real hard.
>
> In closing, failure to vent a battery properly can cause enormous
> damage to
> the equipment in the same room. I have a Swan 240 here that was
> kept in a
> shack with a battery left on charge for months at a time. The radio
> is
> largely dissolved. The surface is eaten off all the metal, copper
> wires
> will fall off the terminals if they are touched, tube socket pins
> will break
> off if they are touched, some of the glass tubes have all their pins
> eaten
> almost or completely through. This occurred over a period of less
> than
> three years and the acid out of two deep cycle batteries being
> boiled out of
> them. It isn't pretty, it was terribly expensive for the chap who
> owned the
> radio. Remember please - THERE IS NO FREE LUNCH.
>
> Larry
> VA3LK
>
>
>
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