battery charging

Fishpants

Active member
Joined
Jun 27, 2015
Messages
28
Fluid Motion Model
C-30 S
Vessel Name
Doug
Hello all,

As I'm planning a 3-week trip and am hoping to spend as much time as possible on the hook vs at marinas, I was wondering if someone could tell me how long it would take on average to charge up the house batteries by running the boat? (not at anchor, but in transit) Would I need a few hours at a fairly high RPM, or would an hour or two at a leisurely pace do the trick?
 
there are three phases to charging. bulk, absorption and float. what you need for full charging of the batteries is time at the absorption phase. This is what really gives you the long lasting charge. You will read on here and other places on the internet about surface charging. this is what can happen with short periods of bulk charging as in a short run with the engine; the batteries appear charged but in truth are not. You want a good period of time (multiple hours) with the engine on to get power into the batteries.

Engine speed should make no difference to the outputted current from the alternator. Better to go slow enjoy the scenery, save fuel and charge the batteries over a good period of time than blast to the next destination and turn off the engine after 30 mins.

The other factor that can increase the amount of power getting to your batteries is the solar panel: but make sure you have it completely in sun and watch the output current on the solar controller to get a sense if its charging.

for the best idea whats going on install a shunt and amp hour meter and watch your usage. Turn off items you dont need and keep the fridge door closed and turned down to reduce the power usage. if you havent already done so change all bulbs to LED: including the anchor light. (Marinebeam is your friend for our boats). turn off your chartplotter when not in use. avoid using the inverter.
 
To summarize, two or three hours traveling after a night on the hook works well. When I am traveling and staying on the hook I like to get to my destination later in the day so that the charge is full before nightfall.
 
So would running a small portable generator for a couple of hours accomplish the same thing? (Thinking about picking up a 2000w Honda) I’d like to be able to stay 2-3 nights in one spot without worrying about battery power. FYI we’re pretty good about minimizing usage.
 
With the solar panel, we have stayed out for two days without running the engine during the summer when we have long hours of daylight. We just don't use anything except the anchor light at night. The only problem is that you won't have hot water without running the engine.
 
Fishpants":w0xdnpi0 said:
So would running a small portable generator for a couple of hours accomplish the same thing? (Thinking about picking up a 2000w Honda) I’d like to be able to stay 2-3 nights in one spot without worrying about battery power. FYI we’re pretty good about minimizing usage.

The Honda will do the trick because you will plug in and then do your normal shore power setup. However, I had a Honda 2000 on my boat for three years and used it three times just to exercise it. If you plan on staying a day or two in one spot then you should be fine without charging up. I also joined my thruster to the house so that gives me more capacity. I have a switch between the house and thruster so I can always isolate them from each other if I choose to do that.
 
On a recent trip I went two days with no OB running and had plenty for lights, stereo and refridg
At the end the Hester would fire because of low voltage, but quite happy with the 2 day time
 
Ernie":ubjv5isj said:
On a recent trip I went two days with no OB running and had plenty for lights, stereo and refridg
At the end the Hester would fire because of low voltage, but quite happy with the 2 day time
Do you have a solar panel to help keep the batteries charged?
 
I recently inherited a Honda 1000 portable generator and would like to use it to charge my batteries on the occasions that we are in one spot for a few days and the solar panel can't keep up, but I see a lot of strong warnings (online) about using a portable gas powered generator on a boat... namely due risk of CO poisoning & fire and something about how they are grounded.

Is there a consensus in Tugnut Land about whether it is safe to use a portable generator onboard our boats (perhaps on the swim platform)?

And for those of you who are comfortable using a portable generator,
1) do you plug directly in to your shorepower connection?
2) do you use any sort of surge protector to help protect the boat's electronics?
 
We have a Honda 2000 and it works great especially when staying on the hook multiple days. My wife loves the microwave and inverter to make a pot of coffee and heat things up. Here is the big BUT though. As quiet as they are I do not really like listening to it or sometimes getting a whiff of the fumes. So we typically fire it up for the 15 minute brew then turn it off. Solar panel keeps things charged somewhat at least above 11.5 volts for everything else. After breakfast we fire it up and jump on the paddle boards for an hour or two which tops things off and makes hot water. Mind you I never leave it running if we have any boats around as that is not cool. Sometimes we might just fire up the main engine but it has to run at least 45-50 minutes to make hot water and I do not like to let it idle that long. If we went without the microwave and minimized the coffee maker we probably would not even need the Honda.

The other situation is with A/C. In our part of the country we do not need it that often. However when we do it runs it fine and I do not notice the noise since everything is closed up. We do have multiple monoxide detectors to be safe and I usually swing on the anchor to keep it down wind. Underway I fire it up and leave it running in the cockpit as there is enough air moving at that point and you cannot hear it anyway. We have only done this once to try it out as I suspect we we do it quite often when we go east of here. Overall convenient to have and small price to pay to have your boating companion.
 
If you have the propane stove/oven can't you use that to boil water for a French Press and heat things up in the oven ?
 
Yes. Some things are not worth pushing. If this is the price to keep her happily boating then it is a small price to pay.
 
S@LTD":q08ujysh said:
Yes. Some things are not worth pushing. If this is the price to keep her happily boating then it is a small price to pay.
Absolutely... can't argue with that. 🙂
 
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