pcg":7534ub15 said:
thataway":7534ub15 said:
... but I limit it to 30 amps for any battery charging...
Bob, can you explain the process by which you do this please?
And...
thataway":7534ub15 said:
I believe you have a Suzuki 70 hp. That will put out 27 amps max. The engine and boat systems, will take at least 10 amps--leaving 17 amps to charge the batteries, at max RPM/output for that alternator. Running an alternator at full power can cause overheating, and damage. I believe this is a flywheel "alternator"
Can you elaborate please? Do you mean that, in this case, if you attach a load that wants to draw more than 17A for a sustained time, you can overheat the alternator? If this is the case, what happens when the alternator is trying to charge a low battery that results in a demand for more than 17A? What limits the current other than the ability of the alternator to supply it?
Thank you!
The Sterling Battery to battery charger has verious perimeters which can be set, The amount of charging is one of those. In my case, the 150 Honda Alternaator can put out 44 amps, max (by specs, I have not measured), I have a Battery to battery charger which basically acts like a voltage and current regulator. I have the ability to set the profile for one of a number of battery types, or set my own specific profile (the Bulk, Absorption, and float stages, with voltage, current and time limits)
The over heating of an alternator is probably more of a theoretical issue, in this specific case. The point being that there is really very little "spare current' available. We don't know exactly how much his motor and systems use power--the 10 amps is a fairly good guess. If he is running a depth sounder, radar, chart plotter, fan to defrost, his current requirements may be more than 10 amps. I don't know what electronics his motor processor requires.
I I have seen a number of cruisers who try and get the max out of the 30 or 40 amp small case alternators which come with the diesels, burn up the alternators when they run the alternator at full tilt for long periods of time. They may or may not have a sophisticated regulation (often after market) system. The outboards we use, don't really have a sophisticated regulator. We occasionally se the smaller outboards burn up parts of the charging system because of "over use". Running as the OP suggested; an inverter, with heavy loads with group 24 battery is a great set up to damage the charging system.
i do not get what people do not like about gas stoves and heaters. We run a diesel heater and a alcohol stove. simple easy and can be refueled. The heater will run for 4 days and the stove can cook twice a day for a week? or more. Just seems that the whole electric shuffle is more trouble then its worth and you are taking a change or draining your battery and leaving your self stuck. ( yes we have done that ). Another good reason for a kicker with a alt. and a pull l start.
My argument against explosive gas stoves, is that often the external tank storage area is not properly drained overboard. Few of the C Dorys have a proper shut off valve at the tank and shut those off after each and every use. The I have personally seen 3 propane boat explosions and fires. I have either treated or known of friends who have had serious injuries after being burned by a LP gas explosion involving boat stoves.
I have used LP stoves safely on cruising boats, which had a number safety factors, and sailed over 100,000 miles with these systems over a number of years. But there were several "sniffers"; one under the stove, one in the lowest part of the bilge. The LP tank was in a locker on deck, sealed from the cabin, and properly vented overboard. Same with storage of back up LP tanks.
I have used diesel heaters for many years. They are just not necessary in Florida.
If I lived or at this point in my life was boating in the PNW, I would have diesel heat. We spent 4 seasons (April thru Oct) on the Inland Passage and AK with a 46' boat and 45,000 BTU hydronic diesel fired heater. Worked great!
As for alcohol stoves--the older ones were dangerous--I have seen several fires related to spreading raw alcohol. The pot burner types are fine, reasonably safe. But the Admiral does not like cooking on them for several reasons: regulation, odor, and inconvenience. I have had several pressure Kerosine stoves, they require alcohol pre heat, a real pain. I have had 4 Wallas stoves and they have worked well for me. The current boat only had a small cartridge LP gas stove, which sat on top of the counter. Because of our risk adversity to propane, we gave that away. We do have a single burner propane stove, with two cartridges in PVC pipe which are vented overboard as a back up to the electrical induction burner (and had that same backup for the Wallas). The propane would be only used in the cockpit with adequate ventilation.
The Li batteries are an experiment for us--certainly not for everyone. I believe I have the background and knowledge to put togather a safe and efficient arrangement. We have been using this for 2 years now, and it is cool (good when you boat in a hot area). We can easily sustain both a chest freezer (65 quart size) and a chest refrigerator (45 quart size) so we can carry food for a month. So far normal outboard running has kept the batteries charged. We have a back up of a 2200 Honda generator. Before I designed my system, I consulted with both boaters and RV folks who had been using the LI batteries beginnging about 2005. The price has come down, and the safety remarkably improved since then.
I should point out, that my boat has a group 24 starting battery, two group 27 "house batteries". These take care of normal demands. The 200 amp hours of LI Fe PO4 batteries are only for the freezer, refer, inverter (microwave and induction burner).
I agree with the back up kicker. In our case we either use a 3.5 hp separate fuel supply, pull start, or the electric Torqeedo outboard. As our back ups. I have used the low hp kickers for over 60 years, and the type of boating we do, it works very well. If I was going offshore, I would have a 8 to 9 hp "big foot" outboard, with separate battery and fuel system.
