How Long Should it Take to Charge House Batteries?

[maytrix]

Agree with most of the above - if the batteries were not replaced during the phaseout, then you very likely need new batteries. Checked everything else related to them just to be sure and add solar if you can as that just makes good sense.

Our boat is in Moorings and only been in service a couple of years and last time we were on it, the batteries already seemed to not be any where near where they should have been. Charterers just don't care often or know any better and let the batteries go well below what they should.

[skipmac]

Originally Posted by Vasco

Just a note to those recommending AGM batteries for cruising. AGM's have to be fully charged often. This is seldom achieved on most cruising boats as the last 15% of charging takes a long time. Most cruisers end up using the band from 50% to 85% and the batteries seldom get fully charged. In this type of charging regimen flooded batteries are preferred. AGM's will last about two years if not fully charged often.

This detail is frequently overlooked. Considering the high cost of AGMs I just don't think they are the best choice for most cruisers. If you have a killer, onboard charging system that can keep AGMs topped off then they may be a good option. Otherwise I stick with standard FLA deep cycle, 6V batteries.

[rw58ph]

Gee, all money you are going to spend on battery stuff, why not buy a small portable gen set? When/if we start anchoring I plan on buying a portable diesel gen set 3 to 5 KW rather than run the 10 KW gen set. Saves fuel and should be quieter.

I agree good old flood batteries are the best bang for the buck and easiest to charge/abuse.

[Cheechako]

You need to investigate what you have. With a decent alternator you should be charging maybe 2 hours a day max.
* determine your alternator. If you are running a stock 45 amp one then that's a problem. You need a 100 amp alternator and good regulator. This will put out maybe 85 amps for 15 mins or so and then taper off.
* You dont need a huge battery bank... you have no way to recharge all those extra amps if you use them!
* with a 100amp alternator and your type of electrical usage (we tried to be careful about monitoring where we were by reading voltage a few times a day though) we charged about 1.5 hours per day.
* Nothing wrong with wet cell batteries at all. They seem to last a minimum of 5 years. After a long charge cycle...feel the side of each battery with your hand, often one will fail (shorted inside) and be soaking up all the charging amps. It will be very warm/hot to the touch compared with the others.
Get to know your electrical system intimately and amend your usage or your system. Refrigeration is the big user by far. We just kept food minimally frozen and bought more often.
How low are you idling? Your alternator wont put out max amps at low idle, 1200-1400 might be better. You need a way to see what the alternator is putting out! At least a voltmeter. Preferably an ammeter also.

[sailorboy1]

Originally Posted by filhere

need to run the engine for 10plus hours per day to keep charge in the 4 house batteries. that's too much based on your usage

Is 4 house batteries adequate for our modest energy consumption - I say modest because we rarely use all the other electrical appliances on board. probably enough

Are our expectations unrealistic? yes and no

Is it the fridge that uses so much energy? yes

Does idling the engine for that long cause damage to the engine? yes and no, you need to run it hard (high rpms) every few hours

Should we instal more batteries? wouldn't change anything, if anything it will mean you run the engine longer because you start charging at a higher charge which is a lower acceptance rate for the batteries

Any advice or suggestions appreciated. how are you determining state of charge??

Thanks, Phil

How are you determining your state of charge and how are you determining when the batteries are fully charged?

If you are running the engine 10 hours a day, what are you using to decide the batteries are charged enough to turn it off?

My feeling is that you are trying to get to 100% charged each day, on engine alone. This isn't practical because the battery acceptance amps are dropping so low as the battery charge increases. Then you are hardly putting anything into the batteries.

If your only charging source is your engine you need to rethink your battery management and accept that you are going to maintain the state of state at 50-80% charge in order to use the least amount of engine run time.

You really need to get solar, around 300 watts for your use at anchor.

[Cheechako]

Alot of charter boats used to have engine drive refrigeration; less likely to end up with dead batteries. If you had that, you would be running only 1.5 hours per day. During that time the batt's would charge up for your other elect usage and the cold plates would be frozen by the end.

[smac999]

idling the engine? yikes... they don't do much if anything at idle...

step one. buy a battery monitor and install it properly. then you will see what your batts are doing. and what your charging is doing.

[Kenomac]

Battery problems can be very frustrating. Been through it several times.

But you're engine will not like what you're doing to it. Diesels... especially turbo diesels need to be run hard, having them sit and idle plugs them up with carbon and will cause a failure of a turbo.

[sailorboy1]

Originally Posted by smac999

idling the engine? yikes... they don't do much if anything at idle...

that is a good point, you probably need to run the engine a little faster to than idle to get any charging, I normally increase my rpms till the aps stop increasing

[filhere]

Thanks for the wealth of information and suggestions. What a great forum!



Well, we got lucky with the awesome guy two over in the marina who had a load tester which showed two of the batteries are dead. The batteries are AGM Optima Yellow Tops AH 55 YT S 4.2 and the plan is to replace the deceased ones at our next stop in Hvar.


If that brings joy, then next steps are to look at reducing consumption and adding solar. Will also look at the 3 stage generator and consider some threads on the forums about resuscitating dead AGM batteries.


Thanks so much for all the following ideas in the threads above:
(a) Put a meter on the batteries to test them (DONE)
(b) Don’t run the diesel for extended periods(OK)
(c) Don’t just install more batteries(OK)
(d) Change over to LED lighting (WILL DO)

(e) Use more efficient appliances, such as the fridge (WILL LOOK INTO THIS)

(f) Check the regulator (ANY SUGGESTIONS HOW?)

(g) Check the alternator(ANY SUGGESTIONS HOW?)

(h) Consider modifying the alternator to run a 3 stage generator (WILL CONSIDER)

(i) Consider solar or wind power (ARE CONSIDERING)

(j) Have the charging system checked (WILL DO AS PART OF A COMPLETE REVIEW)

(k) Measure the power draw on the boat (ANY SUGGESTIONS HOW?)

(l) Make sure AGMs are fully charged (OK)

(m) 6 volt Lead acid batteries are fine (WILL CONSIDER)

(n) Separate house battery from starter battery (ALREADY SEPARATED)

[skipmac]

Originally Posted by filhere

(a) Put a meter on the batteries to test them (DONE)

By meter you mean a battery monitor like the Victron BMV-600?

(b) Don’t run the diesel for extended periods(OK)



(c) Don’t just install more batteries(OK)



(d) Change over to LED lighting (WILL DO)

Depending on what kind of lights you have currently this could save a lot.

(e) Use more efficient appliances, such as the fridge (WILL LOOK INTO THIS)

The biggest saving in power use with the fridge is making sure you have adequate insulation. A modern, efficient compressor helps as well.

(f) Check the regulator (ANY SUGGESTIONS HOW?)

Look at the wires coming off the alternator. Does the largest, red wire go directly to the battery or your electric panel or does it go to a small external box? If it goes directly to your battery or some other connection in the 12V panel then you have an internally regulated alternator and 99% it is not a smart IE multi stage, high output charge. Depending on the alternator you may be able to convert to an external regulator like the Balmar.

(g) Check the alternator(ANY SUGGESTIONS HOW?)

Well to check for basic function get a good, digital volt meter and test the voltage at the battery. With batteries at a low charge state compare the voltage with the engine off and running. Run the engine up to moderate rpm to make sure the alternator is putting out full voltage. You should see the voltage at the battery over 14V. If not you have a bad connection or low output on the alternator.

(h) Consider modifying the alternator to run a 3 stage generator (WILL CONSIDER)

I think you mean 3 stage regulator. Like the Balmar mentioned above.

(i) Consider solar or wind power (ARE CONSIDERING)

(j) Have the charging system checked (WILL DO AS PART OF A COMPLETE REVIEW)

(k) Measure the power draw on the boat (ANY SUGGESTIONS HOW?)

The battery monitor will do this. Installed correctly it will show all the power that goes in or out of the batteries. So when you are charging it will show voltage at the battery and how many amps going in. When not charging it will show how many amps are going out. You can switch things on and off, one at a time to see how much power each item is drawing. One of your first upgrades should be installation of a battery monitor.

(l) Make sure AGMs are fully charged (OK)

Very important for the life of an AGM.

(m) 6 volt Lead acid batteries are fine (WILL CONSIDER)

A lot cheaper and much more forgiving of abuse and poor charging than AGMs

(n) Separate house battery from starter battery (ALREADY SEPARATED)

Glad to hear you have at least found the battery problem. Good luck on the upgrades.

[Cheechako]

Originally Posted by filhere

Thanks for the wealth of information and suggestions. What a great forum!



Well, we got lucky with the awesome guy two over in the marina who had a load tester which showed two of the batteries are dead. The batteries are AGM Optima Yellow Tops AH 55 YT S 4.2 and the plan is to replace the deceased ones at our next stop in Hvar.


If that brings joy, then next steps are to look at reducing consumption and adding solar. Will also look at the 3 stage generator and consider some threads on the forums about resuscitating dead AGM batteries.


Thanks so much for all the following ideas in the threads above:
(a) Put a meter on the batteries to test them (DONE)
(b) Don’t run the diesel for extended periods(OK)
(c) Don’t just install more batteries(OK)
(d) Change over to LED lighting (WILL DO)

(e) Use more efficient appliances, such as the fridge (WILL LOOK INTO THIS)

(f) Check the regulator (ANY SUGGESTIONS HOW?)

(g) Check the alternator(ANY SUGGESTIONS HOW?)

(h) Consider modifying the alternator to run a 3 stage generator (WILL CONSIDER)

(i) Consider solar or wind power (ARE CONSIDERING)

(j) Have the charging system checked (WILL DO AS PART OF A COMPLETE REVIEW)

(k) Measure the power draw on the boat (ANY SUGGESTIONS HOW?)

(l) Make sure AGMs are fully charged (OK)

(m) 6 volt Lead acid batteries are fine (WILL CONSIDER)

(n) Separate house battery from starter battery (ALREADY SEPARATED)

Did you ever check to see if one battery is shorted pulling the bank down? (feel for heat after charging) You dont need to do a whole bunch of stuff to solve a recharging issue... not that I'm saying it wouldnt be nice....

[nigel1]

If two of the batteries in the bank are dead, it may well be worth replacing all four, I'm no expert on batteries but from what I listen to and read, the common opinion is not to mix batteries of different type or age.

[carstenb]

Originally Posted by nigel1

If two of the batteries in the bank are dead, it may well be worth replacing all four, I'm no expert on batteries but from what I listen to and read, the common opinion is not to mix batteries of different type or age.

you can't mix batteries of type or age (don't ask me how I know this). If you change batteries you have to change them all at one (assuming they are interconnected)

[captainjay]

You have already received some good advice. Use a load tester to check the batteries they are likely shot. Also don't charge at idle, you may not be exciting the alternator at that RPM, put it in neutral and bring it up to 1500 rpms. Four times a day 45 minutes at a time should be more than adequate to charge the system you have. The 12 volt fridge on that boat depending on the brand will pull between 4 and 5 amps per hour while running. Also as a previous poster noted the halogen bulbs are big load items. Get led replacement bulbs for them. Bang for buck on that type of boat would be group 31 deep cycle lead acid batteries, forgiving and relatively inexpensive. I wouldn't go to the expensive of a larger alternator and better regulator unless you were going to increase the battery capacity.
Jay