House Batteries

[SkipH]

We spent five days on the hook this past Labor Day, it was great. However two of those days at the end of the day the house batteries were down to 8V. We have the original configuration of two batteries per engine and one for the gen. The port side engine battery is also the house battery source.

What I'm wondering is, not running the gen set during the day means that the fridge, stereo, water pumps, head pumps and so on all run off the house batteries without being maintained at full voltage, so the battery bank is depleted. However running the gen set isn't desirable either if for no other reason than noise.

Has anyone installed dedicated house batteries with larger capacity? If so I'd like to hear about it.

1999 Sundancer DA 400
Twin 7.4 MPI

 

[Sundancer]

You have 5 batteries on board and only one of those is a house battery? Am I missing something?

 

[Jackie J V]

I have four dedicated 8D batteries running to an inverter to run the house systems. In my boat, the fridges only run off 120V (no DC) and therefore I needed the inverter system for the style of boating that I do (lot's of anchoring out in quiet anchorages where I also don't want the excessive noise).

I also have 2 x 8D's per engine, 2 x 8D's for the thrusters and one smaller battery for the gen set. I think the 12 and 24V house systems also run off the port engine battery bank (but I could be wrong on that one).

Unfortunately, even with that set-up, I have to be pretty focused on power management. After two days on the hook, the inverter bank is mostly run down (kids incessantly playing PS/3, fridges and other power draws). I changed most house lights out to LED's, which has helped and I did an electronics update to replace the salon TV with an LED and some other stuff, which reduced power draw by about 75%.

When it comes time to replace the inverter bank batteries, I'll be getting rid of the 8D's though, and swapping in some big 6V batteries (like those used in lift trucks, golf carts, solar storage, etc.) for the improved amp hours. I had these in my previous boat and they're the way to go.

Paul

 

[Graham Lorimer]

Just read your post........

I went through the same as you when I purchased my 400DA nearly three years ago.

I did lots of research and I think I came up with the best set of options.

We have this afternoon returned to the Marina after 14 days around the island of Ibiza in the Med, and have not wanted for cool drinks TV and DVD players, and everything else needed to make a holiday complete.

I go back to the UK tomorrow, and will over the next few days post a complete list of what we fitted, how it works and the Limitations that we encounter (trust me every system will have limitations).

I found getting useable information on this was very difficult, and I am sure my proven findings will be of benefit.

Graham.

 

[Glen S]

SkipH,
Got the same boat (1997) and battery configeration. We came from sailing to this boat and were quite surprised by the set up of starting battery for port also being the house battery bank. I believe the other bank of 2 batteries is for critical systems like bilge pumps etc.

For sailors it is very common to start the engine for an hour or so a day to charge batteries while on the hook. The engine alternators seem to charge way better than running the generator to run the battery charger. Sailors also very often have aftermarket alternators that can really charge a bank of batteries.
Running the engine also adds some hot water for dishes etc. May be an alternative to adding lots of extra battery capacity.

 

[SkipH]

Thank you everyone, and Graham, I'm interested in hearing what you have done.

Thanks again all!

 

[Graham Lorimer]

I bought my boat in Stuart, Florida in late 2007, and collected it in January 2008. I spent 7 days travelling down the ICC to Fort Lauderdale for shipping to Europe, and was immediately struck by the inadequacies of the house battery system.

Every morning, one engine (starboard from memory) would not start without using the emergency start switch, due to the fridge and lights having dropped the charge from the battery, and if I woke early and wanted to use the coffee maker, I had to start the Genset, not good in a quiet anchorage. It should be noted that the engine batteries are still in use 3 years later, so their condition was not an issue.

I had intended to convert the boat to 220 volts for Europe, but early investigation showed that to be unnecessary, expensive and messy, so opted for a pair of 3.6KV 220 – 100 volt transformers in the transom locker, they are lighter than the pair of 100 volt cables that the boat came with. There is a transformer fitted to each Line, One and Two, for shorepower.

When I got the boat back to the UK, I fitted a Victron 100 volt 3000W Invertor Charger, mounted where the original battery charger is fitted to the engine room forward bulkhead, a Victron battery monitor, (an invaluable piece of kit) mounted in the panel next to the main DB Board and easily visible all the time, and a 120 amp alternator on the starboard engine.

There is also a remote power control panel for the Victron; it is mounted in a locker by the main DB Board.

The Victron also supplies a Float Voltage charge for the Engine batteries and Genset battery, switched through a simple voltage sensing relay, when on shorepower.


However the main addition to the system was a set of 6 two volt wet lead acid cells inside a custom battery box that is mounted between the two engines just aft of the mid bilge pump / aircon pump. The batteries are linked together to give 12 volts, and the total capacity is 630 amp hours at the 20 amp rate. The box that they sit in measures approximately 15 inches x 15 inches and is 18 inches high. The box has a lid on it, and makes an excellent step down into the engine room.

I then altered the configuration of the Line One and Line Two outputs on the main DB Board. Line One, which is only supplied by Shorepower or the Genset, supplies AirCon Forward, Aircon Aft and Aircon Pump, Line Two, which is powered by the domestic battery / Invertor, supplies Refrigerator, Cook Top Hob, Microwave / Convection Oven, Galley Systems, Port Systems and Starboard Systems.

The 12 Volt supply switches have remained unchanged.

Both 100 volt lines also have a supply to a Rotary switch I fitted that supplies the Water Heater, and by setting the rotary switch to Line One or Line Two, the water heater can be run from either, I will explain why later.

In use on anchor, we run the Genset when using the aircon (seldom used on anchor), water heater and oven or cook top, however while these items are being used, the Victron very cleverly utilises all spare amperage to recharge the domestic battery. We find that 3 hours running during 24 hours, (if there is no main engine running during that period) , pretty much breaks even for power requirements and we do that when making toast and coffee in the morning, and whilst preparing dinner in the evening. Coffee and toast can be made from the domestic battery and Invertor if needed, as can a hair dryer be used, televisions run and the fridge is always on. During these times, when the Genset is running, the water heater is on also, we always seem to have plenty of hot water.

When on shorepower, the Victron Power Control panel has a rotary adjustment that enables the system to be set to draw from 4 – 32 amps, dependant on what is available from the shorepower, a feature we found very useful when travelling through France, many of the Marinas had very low power supplies, and everything that is on Line Two can be used, and the Victron smoothes out the current draw, always using anything spare to recharge the domestic battery between load fluctuations, without tripping out the supply.

The reason for the selection switch to run the water heater off either Line, is that if arriving at the boat after several days or weeks away, and initially needing full aircon or heating, as well as water heating, lighting etc, we switch the water heater to Line Two, and the Domestic Battery, through the Invertor, smoothes out the power requirements, otherwise with all air con or heating on, and the water heater, there is not enough power to supply all that is initially needed through Line One.

Whilst at anchor, if we retire for the night at about 90% battery capacity left, it will usually be down to 75 – 80% in the morning. This means the day can continue, and we run the Genset to bring it back up if we are not motoring anywhere that day, otherwise 3 hours main engine running will have the Domestic battery over 95% full again.

The Victron puts up to 80 Amp Hours into the battery initially, either from the Genset or Shorepower, the Starboard engine alternator puts out 75 Amp Hours.

I hope this convoluted explanation of the system is of some assistance, we find it very user friendly, and pretty much serves all our needs. Feel free to post any questions.


Graham.

 

[Pietro]

I have 6 of these to run the fridge and the ice maker through an inverter I can use for the occasional coffee also... they last easily for one day on the water..

 

[SkipH]

Thank you again everyone, I will now look at how these soultions can be used for our boating style. This is really great information from experienced boaters!

 

[boughtabouy]

This will help you understand batteries a little more. Pay special attention to the "State of Charge" chart about 3/4 of the way down.

http://www.windsun.com/Batteries/Battery_FAQ.htm#Battery Voltages

I don't think you should be letting them go below 12 Volts (50%) before recharging (hard on the batteries), according to what I've heard.

Kevin

 

[Graham Lorimer]

We try very hard not to let the batteries go below 65% before charging, in all the time we have had the system, according to the monitor it has only gone into the 50s% three times.

The voltage depends quite a lot on the current draw when you take the reading, above 65% and it will still give over 12 volts even with a heavy (100amp) draw.

Graham

 

[Chung]

The 40 DB has two banks of G-27 batteries plus one for the genset. The two banks are set up to be port and starboard systems respectively and also start the port and starboard engines repsectively.

As an old sailor, I do not like this set up. I would prefer dedicated engine start batteries.

We also stay on the hook quite often.

Here is what happens; the fridge runs quite a bit pulling about 7 amps or more. Of course, then there is everything else, but lets just talk about the fridge. It is not very efficient. Let us say that is it running at a 30% duty cycle - not unusual. In 24 hours it will take about ( .3 x 7 x 24 ) 50 amp hours. Now, the 110V battery charger (off the genset or shore) is a PD 2040. They say it will generate 40 amps, but that is over 3 battery channels. So really you are only getting about 13 amps. To refill the 50 amp hours you have to run the genset almost 4 hours! I tend to run it in the morning for breakfast and in the evening for Dinner. But I have to leave it on for 2 hours or so each time.

There really should be a heftier charger and/or a much better fridge. I will probably replace the charger next year.

Like one of the other guys, I converted almost all halogens to LEDs from the - a great help.

I have the feeling that the Sea Rays are designed for those of you who go from marina to marina. Certainly a different cruising lifstyle than ours.

 

[Jacob]

We have (6) L16 6 volt batteries for the inverter and these perform very well. You might want to investigate these before your next purchase.