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From: (no name) (no email)
Date: Mon Aug 30 1999 - 22:13:13 EDT
About those batteries...
My suggestion is to combine all your deep cycle house batteries into one bank
for simplicity.
Reduce voltage differences in the bank by making sure all the wires are the
same wire size, all the short jumpers connecting the six volt batteries into
twelve volt batteries are the same length, all the longer wires connecting
the pairs of six volt batteries into the parallel bank are the same length.
The idea being that the voltage drops across all the wires in all the battery
pairs will be the same if all the wires are the same.
The battery wires should have ring terminals soldered on to them. You can
use copper tubing to make your own terminals. Cut short lengths of tubing
and clean the insides with a wire brush. I got my brush from a refrigeration
supply house - they come in different sizes for different size tubing - and
are specifically to clean the insides of copper tubing prior to soldering.
Tin (coat with solder) the inside of the pieces of tubing. Set up a propane
torch burning on your workbench. Hold the tubing in a vise-grip with one
hand whilst applying solder to the inner surface of the hot tubing with the
other. This way you can tilt the tubing so as to completely coat the inside
with solder. You can use acid core solder here if you wish, but be sure to
wash all the acid off with the wire brush and water after tinning the tubing.
Squash one end flat in a vise and drill to fit your battery terminal
fasteners. Use brand new wire. I recommend the Ancor battery wire sold by
West Marine because the wire is already tinned making it easy to make a good
solder joint. Use rosin core solder to solder the wire into the terminal.
Acid core solder has more aggressive flux so it removes oxidation better but
the acid wicks up into the strands of wire and eventually will eat up the
wire. Clamp the terminal by the flat part in a vise, insert the wire and
somehow keep it held in position straight into the terminal, heat the
terminal with the torch, and when hot enough to melt the solder add solder
until you fill the tubing almost to the brim. You can cool the connection
rapidly with a paint brush dipped in water. (Some say this "crystallizes"
the solder, but I learned to do this from a very experienced radiator man
many years ago when radiators were made of copper and were actually repaired.)
Clean your battery terminals well. I use a knife to scrape, followed by a
small wire brush. Apply Vaseline/baking soda mixture (described below in
"hints") liberally to all connections when making them up.
If you wish to go even further to insure equal voltages, you can
"CrossConnect" the bank, that is - connect together all the points of equal
voltage with jumpers. Imagine a drawing of a battery bank of three pair of 6
volt batteries connected series/parallell to form a 12 volt house battery
with the positive end of the bank at the top of the page and the negative end
of the bank at the bottom of the page and the 6 volt batteries in two
horizontal rows with all positive terminals up and all negative terminals
down. In addition to all the normal connection wires, make up 12 more
jumpers. Use them to connect all the positive terminals of all the upper row
of batteries together, then all the negative terminals of those batteries.
Then all the positive terminals of the lower row of batteries together and
finally all the negative terminals of the lower row of batteries. This way
you can insure that equal voltage points are as equal as you can get them.
It is a good idea to have a crossover switch (a big red battery "off-on"
switch) to connect the starting and house batteries together if you wish.
For example, I can start my genset (but not my main engine) with my house
batteries, then see about charging the 8D with the genset running.
Conversely, I can operate the house circuits, including the Trace inverter,
from the 8D.
On Bandersnatch we have two pair of golf cart batteries for the house bank,
and one 8D starting battery for engine starting of the 8KW genset and the
Detroit 6V-53 main engine.
Whenever the genset is running, a 35 amp alternator on the genset charges the
8D and the Trace inverter charges the house batteries from the genset main
output.
Whenever the main engine is running, I turn on the crossover switch between
the 8D and the house batteries, charging them both with the main engine
alternator (about 50 amps) controlled by a Heart 3-stage regulator. This is
not a good situation because the 8D needs very little charging while the
house batteries usually need a lot. Also, I often forget to switch the
crossover switch off when shutting down the main engine so the 8D gets
discharged along with the house battery from house loads which is not good
for the 8D as well as having the potential of leaving me with all batteries
flat.
What I will do (when I find that elusive round tuit) is to install a
"1-2-Both" switch to feed the main engine alternator output to "8D-House
Battery-Both," expecting to leave it on house battery most of the time and
let genset operation take care of topping up the 8D since I use the genset
almost daily.
For automatic operation I might go with the West charge combiner relay to
connect the 8D after the house battery gets up to a certain voltage because
it is the house battery that is usually the most depleted. When the house
battery is mostly charged, the main engine alternator will top up the engine
starting battery too.
The best solution might be to mount another, generic, internally regulated
alternator on the main engine just to charge the engine starting battery
while the big, expensive, alternator/regulator takes care of the house
battery. This situation would have the most independence and (except for the
mechanical aspects) simplicity. This is the way it is when I am using just
my genset and it works very well.
Some hints for flooded batteries:
The hydrometer is the last word in state-of-charge.
Melt a jar of Vaseline in some hot water and stir in some baking soda to make
a good battery terminal protectant.
Check batteries every month for specific gravity, water, tightness of
terminal fasteners, cleanliness, and security of tie-downs. I discovered a
dead cell in a 8D during a monthly hydrometer check and was able to exchange
it for a new one while it was still under the 100% part of the warranty
(Sam's Club) and I could still start my main engine.
Very carefully pour some baking soda/water solution over the battery tops,
wires, and terminals to neutralize the acid that collects there (your
batteries are in acid-proof tubs, aren't they?). Avoid at all costs getting
any inside - use plain distilled water if you have any qualms about
contaminating the electrolyte.
Do an equalize charge at least once a month - every two weeks is better.
Keep a record book on all the above.
Any Questions?
Norm
S/V Bandersnatch
Moored 79th St Marina, NYC
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