Santiano:
Sounds like you are on the right track now :-)
There are, conceptually, only three circuits in your
boat: 1) the 120V circuits which we will ignore for now. 2) the "housekeeping" circuits operating on 12V and demanding only low "draws", i.e. they are "low ampage" circuits, and 3) the
Engine Starting circuit which is also a 12V circuit but carrying HIGH ampage (draw). High ampage circuits have FAT wires, low ampage circuits have skinny wires. Both kinds of circuits get their
current from the battery/batteries.
There are different kinds of batteries, distinguished sometimes by their internal construction and sometime by their chemistry. Most likely what you have is "flooded" batteries with a liquid electrolyte. Such batteries require
maintenance and therefore they have "caps" that
permit you entry to each cell. What I do to know the SOC ("state of charge") of my two 27 series flooded (fake marine) "deep cycle" batteries is remove the caps, suck a little of the electrolyte from each cell into a hydrometer (a five-dollar gizmo that measures specific gravity), read it, put the electrolyte back in the cell from which it was taken and
record the hydrometer reading in my log. We can come back to what the readings "should" be and what it means if they are not what they should be. You can get all sorts of fancy little meters to tell you SOC and other things about you electrics, and they are nice to have,but I think it's a wise sailor who can get along without them.
I imagine that you have about a 30HP
engine. It matters not whether its the old Atomic 4 gas pot or whether it's a
diesel. The AMOUNT of current required to start it is so little that you DON'T need a separate "starter battery". I don't have one, and I "even out" the "wear" on the batteries by setting the selector to Batt #1 on odd numbered dates and to Batt #2 on even numbered dates. So think about this: My little Beta 20HP engine requires 15 seconds of preheat. Let's call it 1/4 minute drawing 75 amps. 1/4 minute is 1/4 x 1/60 of an hour = 1/240 hour. 75 amps for 1/240 hour = 0.3125 amp hours. After that the starter
motor will require 200 amps also for 15 seconds. Same kinda calculation: 200/240 = .83333 amp hours for a total of 0.3125 + .83333 = 1.1458 amp hours, so let's be generous and call it 2 amp hours to start.
Now, the
alternator on the Beta is rated at 40A but in actuality it wouldn't like to be asked turn out 40A continuously. When the engine starts it will turn out something like 15A and do that continuously. But I only need to replace 2 amp hours after starting, so at 15A it will take 60 minutes x 2/15 = 8 minutes to replace everything I took out of the batts to start. In practice, that means that just getting out of my slip replaces all juice used to start the engine. Your numbers will be slightly different, and you should determine what they are and do the calculations just because being able to do that confers protection against eager salesmen :-)
The charger you just bought will be made so it can tell the SOC of your battery bank. It's probably got two output terminals so you can wire each terminal to a separate battery. It will also have a special third terminal from which you take wire to the NEGATIVE terminal on one battery. This is how the charger gets to know whether the batteries are
charging "too fast" which could happen because the charger is able to "push out" juice faster than is good for the batteries. The charger also senses the SOC of the batteries, and knowing that it will adjust itself to charge at one of three rates: 1) Bulk, 2) Absorption and 3) Float. On my charger they are called "Equalize", 'Bulk" and "Maintenance", That doesn't matter because both the charger and I know what the charger is doing. What happens chemically and electrically at each of these rates of charge is really, really fascinating, but there is no need for you know it at this point. Your new charger is gonna see you right. Provided you connect it correctly :-)
So if your entire
wiring system is neat and clean so there are no short circuits or loose terminals anywhere, you troubles should be over. Remember that your
bilge pump is wired for safety's sake so it will switch on automatically when required even when there is no-one in the
boat. That can drain a battery fairly fast if you are taking in
water, say through the stuffing box. But with your new charger more juice will be supplied to the batts than a
bilge pump will drain out of them so you'll be okay in that respect.
Before you spend money on extra charging capacity I recommend that you spend it on REDUCING DRAW. The more modest your energy
budget, the quicker you can get back to "full charge" after a night on "the hook" Wherever you can, substitute
LED lights for incandescents. Learn to live without a
refrigerator, learn to live without a
water maker. Your expenditures of both money, effort and emotions will be reduced drastically if you go that way about it :-)!
All the best
TrentePieds
Re: Troubleshooting Drained batteries and Dead Charger.
Linear Mode
Recent Discussions