electrical question - 2 generators/alternators
 

Here is the pertimnant part of my original question. If I had 2 wind
generators (for example) and wanted to use them to both charge the batteries
while sailing, would I have to "split" the house bank so that I was actually
using both generators at the same time. The answer I receieved (I think)
points to "yes, you would split the house batteries during charging, with
each generator charging a separate bank."
"Rick Cortese" wrote in message
et...
Jeff wrote:
Rick Cortese wrote:

Jeff wrote:

There is no problem that I know of. My boat (and several hundred

sister ships) has twin engine that feed a house bank with no diodes,
etc. In addition, many have solar panels and/or wind generators that
are always connected. Further, they use a combiner to also charge two
starting batteries, and it all magically works.



Alternators 'cept the solar panel which probably has blocking diodes
which have diodes built in. The OP may have misspoke but he included
generator.

I'm just old enough to remember old style generators that we used to
hook up to 12V batterys to see them run. I seem to recall my family had
a pit bike type minibike made out of a 12V lead acid automotive battery
hooked to a generator/drive motor for riding around the farm *but* I am
really foggy on that one. My memory of things in the 50's is really bad.


Is your point that without blocking one generator would try to run the
other as a motor? Interesting point, although it doesn't apply to
alternators.

Right. More info then you probably want or need, but the old systems only
used relays to isolate the generator when a set point was reached. The
phase+DC was picked off permanent magnet generator by brushes on the
armature.

I admit it probably doesn't apply but I have seen a lot of equipment that
is cheaply designed so it can hit a price point. Things from arc welders
to battery chargers that limit current by the amount of iron in the
transformer rather then real current limiting circuitry. I wouldn't trust
anything until it has been checked to see if blocks current.

electrical question - 2 generators/alternators
 

Mark Newcomb wrote:
Here is the pertimnant part of my original question. If I had 2 wind
generators (for example) and wanted to use them to both charge the batteries
while sailing, would I have to "split" the house bank so that I was actually
using both generators at the same time. The answer I receieved (I think)
points to "yes, you would split the house batteries during charging, with
each generator charging a separate bank."
"Rick Cortese" wrote in message
et...


I don't think that is necessarily so. You should be asking this
question of the wind generator people, since they would understand how
their particular devices work. As I've said, I have all of my
charging sources feeding the house bank, and the only noticeable
affect is that regulators (there are three in the system) would
sometimes shut off and defer to the strongest source. This, however
has never been a problem worth solving, its only a curiosity, since I
really don't care about 2 Amps of solar power when a 100 Amp
alternator is running. With two identical wind generators, there
could be an issue if each had a regulator that would be affected by
the other. This issue might not exist, or it could be solved with a
dual source regulator (there are some on the market). Splitting the
house bank into two sidesteps the issue, but then you have two banks
at differing charge states, which is less than optimum. Since the
wind and solar systems are "set it and forget it," designing the
system so that you have to monitor charge and flip switches is not
desirable.

electrical question - 2 generators/alternators
 

Mark Newcomb wrote:
Here is the pertimnant part of my original question. If I had 2 wind
generators (for example) and wanted to use them to both charge the batteries
while sailing, would I have to "split" the house bank so that I was actually
using both generators at the same time. The answer I receieved (I think)
points to "yes, you would split the house batteries during charging, with
each generator charging a separate bank."
"Rick Cortese" wrote in message
et...

I'm pretty sure you don't have to split them.

I can't recall the right term, something like excited field alternator.
Anyway the wind generators are actually alternators with a magnet in
them to get away from the problem of completely discharged batteries.

All the circuitry to prevent reverse flow is integral in their design.
That is unless you happened to pick up a couple some farmer made out of
old automotive generators.grin

If you are using any wind generator that is currently marketed for the pleasure boat industry and that wind generator has not been modified this will be the result of connecting multiple generators in parallel:

As long as the voltage of the bank of batteries being charged is below the free wheeling voltage* of the generators the generators will charge the batteries in proportion to their output. i.e., #1 gen = 20A #2 gen = 10A then #1 will supply 66% of the total charging current while #2 supplies 33%.

If the voltage of the batteries being charged ever reaches the free wheeling voltage of one of the generators then that generator will not contribute to the charging until the battery voltage falls below the free wheeling voltage again.

free wheeling voltage* is the voltage of the generator measured with it disconnected from the batteries.