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Chargers in Parllel

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Posted by Norman Dowds on January 6, 2005, 12:42 am
Has anyone had experienced using two chargers in parallel ? I have been
considering doing so and am looking for experienced guidance on how to
protect against reverse polarity and backfeed if indeed that can be easliy
done . One possilbity seems to be to rely on a charger feature of revese
polarity protection .

Would like to hear from practical experience .

Posted by Eric Sears on January 5, 2005, 4:16 pm
As other have said, it depends to some extent on -
a) WHAT you are charging  (lead acid battery??)
b) WHAT KIND of charger you are using.

From practical experience, I have often put two battery chargers
(simple transformer type) on a car or deep cycle battery to increase
the charging current - but I watch the voltage and the gassing of the
In general the diodes or bridge rectifiers in the chargers will
prevent current from feeding back into them - though this may not
apply in some situations where you are using more complicated

I am presuming you are talking about grid-power chargers.
Clarifying your question, or explaining the situation,may help .



Posted by Norman Dowds on January 6, 2005, 5:32 am
 Thanks for the reply . In my off grid application , I am using an inverter
whose performance of interest is much more on charging than providing
inverted ac power . As such I have been giving thought to using a charger in
parallel versus upgrading the inverter . I would like to sustain a C/5 or 6
charging rate and believe that to do so will require boosting the charge
rate . I understand the trade offs of doing so as they are related to
battery life etc .

I hope this shed some light .


Posted by Gymy Bob on January 6, 2005, 2:07 am
 It depends on the type of battery you are using and the nature of each
charger. If it is a low impedance charger then oscillations (hunting) can
occur between them.

Many chargers are not filters and depend on the battery charge to provide a
charge dfeedback to the control circuits.. Seeing the other charger's peak
waveform charging spike may upset the others sensing circuit. Gain and
anti-hunting controls may help. Turn them on with caution and possibly
provide some impedance in the wiring between them. Common connection at the
bank and not the chargers.

I doubt diodes will work becuase of the negative charge current not going to
the sensing circuit between waveform peaks. Depends if the charger has good
filtering on the sensing and/or power output.

Posted by m II on January 6, 2005, 2:32 am
 Gymy Bob wrote:


A few GymyBobisms..the saga continues:

At 11.6 volts a 12v battery is about 50-70% charged still.

Polish solar panels are what americans called "flashlights"

Propane will disapate and freeze when it evaporates.

Gasoline is not nearly as volatile as hydrogen.

Many people have browsers that economize the download

Let's say youre solar cell was trying to put out
14.3 volts DC and you stuck a 10 ohm meter in series with a charged 13.8
volt DC battery.

This is power grid induction through capacitive proximity

A thought I have is rain water from a roof on a three story home through a

Breakers are good for one time usage of one fault and then they need to be
replaced for any warrantied usage.

If the breaker interupts a fault, it should be replaced.No warranty will
honoured after that.

I don't have a link at this time

There are no hydrogen molecules in water and the oxygen in water isn't
flammable either.

NiCads and NiMh batterries are designed to take a current charge forever.

Did they have electricity back in 1994?

I have been around so long with this stuff I believe I invented the diode in
1941 but I am not familiar with the solar panel usage requirements of them.
(no P & N substrate explanations please. I wrote the GE manual...LOL)

NOTE: do not pass ground wires through metal holes or cable clamps with two
screws on a metal surface.

There is **NOT*** enough energy in a lightning bolt to power your house for
more than an hour...if that. Do the math.
The figures escape me but let's say it puts out a roughly MWatt of power for
100 nanoseconds?
100 x 10-9 x 1 x 106  / 3600 (sec/hr) = 0.0027 wH
oooops.... Wouldn't light your home for a 1/2 second.
OK..OK.. multiply the figures time 100 or 1000. Now it would light a 100W
bulb for 1 second.

The IEEE-232 standards were never followed or known by many.

Fossil fuels are still renewable and being cxreated as we speak.

Children are venerially created.

If you want to discuss this then fine, otherwise go fuck yourself like your
mother did.

Can you let go of my dick before it explodes on ya, goofball?

Petroleum is not related to Natural gas.

I would rather work at my $00/hour job than at chopping wood for hours to
save $/hour

I have no license, I wire and inspect other's wiring for a job and work for
a medium size electrical utility.

The majority prefers top posting.

Get your tear ducts flushed by a knowledgeable optometrist.

Not many materials have the huge exponential resistance/heat curve aluminum
does. Overload doesn't make it glow like copper...it flashes and explodes.

A bathroom fan motor would never push hot air down ten feet or cold up ten

Bathroom fans have a hard time pushing 55 cfm through a 3-4" pipe 20
horizontal feet. They are made to vent smells and humid air horizontally

Why not spend the money on a contract with the grid company and get an
exclusive line to your house and never have brownouts.

Usenet rules dictate top posting for readability

Many cell modems are set up to filter bottom posts out.

Cell modems do not cut off anything.

What security flaws. (refering to Outlook Express)

Bottom posting was the was in the 70s and 80s before threading browsers were
available cheap (like OE)

What is a PMW?

10 pounds per gallon Imperial. That gallon is totally unique to the
US....ooops..I think all gallons are unique to the US now.

The copper isn't worth more than 5 cents per pound. It is classed a mixed
copper and nobody wants it.

Hey moron! The copper is considered "mixed" copper and is worth about $.02
per pound, if he seperates it all.

Just don't ever lose weight. Toxins are stored in your fat cells.

Did you know, **NO***, I repeat ***NO*** death has ever been related to

Insulated square copper wires from a dry transformer are not 99% copper and
take a lot of work to remove the insulation.

I have tonnes of insulated copper wire if you want it. I think you could
almost have for the picking it up. How many bins can you take per year

Can't this tranformer be used by somebody to generate a second 120V from a
single phase 120V inverter? It sounds pretty beefy.

BTW: once you knock the wedge out of the coil form the laminations will be
easier to get out. This keeps them from buzzing until the varnish and other
impregnations go into it.

All you guys have a bad Christmas or Jewish and didn't see Santa or something?

Run each signal twisted with a ground for noise. RD twisted with gnd as a
pair, TD twisted around ground as a pair etc... This means signal/logic
ground not power ground or case ground, if they are different. Do not
connect the other ends of the ground conductors.

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