My House Battery Bak

Bill1565 · Feb 11, 2013

BWagner said:
Hi,

We're cruising, currently on a mooring at Boot Key Harbor in Marathon, FL. My question has to do with my battery bank. We have a 2003 Hunter 426DS that we purchased last April and brought south this past fall. In preparation for this trip I had the old 4D batteries removed and 10 six volt Trojan golf cart batteries installed for a total bank capacity of 1200 amp hours. Our biggest draws are our 12 volt frig and separate freezer. Other than that nothing special - some interior lighting, an occasional fan or a DVD movie.

Until recently, we have been maintaining this bank exclusivly with a 6.5 Kw Fischer Panda Generator which we would have to run twice a day. Recently we installed a 325 watt solar panel and charge controller and now have to run the generator once per day. Which brings me to my question - is it normal, with a battery bank that big that I should have to run a generator so often? In the morning our battery voltage is 12.2 to 12.3 and we run the genset. I had these batteries installed hoping that the capacity would allow us to go a couple days between charges but that isn't the case. Does this sound right or is something wrong?

Any thoughts would be appreciated.

Brian

Something is very wrong. I only have
Half your bank and I go days w/o recharging whe I start with fully charged batteries. Trojan dealer at marathon is excellent,but I don't think batteries are your problem.

Ray Bowles · Feb 11, 2013

You need help from Maine Sail and he will probably see your post and reply. It sounds like you don't have anywhere near enough charging power as needed for a bank that size. You can also go to his site by going to the "Featured Contributors" and then to "Musings with Maine Sail". There you can read up on postings with exactly your problem.
Ray

Rick486 · Feb 12, 2013

BWagner said:
Hi,

We're cruising, currently on a mooring at Boot Key Harbor in Marathon, FL. My question has to do with my battery bank. We have a 2003 Hunter 426DS that we purchased last April and brought south this past fall. In preparation for this trip I had the old 4D batteries removed and 10 six volt Trojan golf cart batteries installed for a total bank capacity of 1200 amp hours. Our biggest draws are our 12 volt frig and separate freezer. Other than that nothing special - some interior lighting, an occasional fan or a DVD movie.

Until recently, we have been maintaining this bank exclusivly with a 6.5 Kw Fischer Panda Generator which we would have to run twice a day. Recently we installed a 325 watt solar panel and charge controller and now have to run the generator once per day. Which brings me to my question - is it normal, with a battery bank that big that I should have to run a generator so often? In the morning our battery voltage is 12.2 to 12.3 and we run the genset. I had these batteries installed hoping that the capacity would allow us to go a couple days between charges but that isn't the case. Does this sound right or is something wrong?

Any thoughts would be appreciated.

Brian

Something to check is how are you measuring battery voltage? I have a 44DS, which is essentially the same boat, same fridge and freezer I think. I checked my batt voltages with a digital VM last year and found that the panel analog voltmeter was reading low by about 0.3 to 0.4 volts. I then adjusted it to read correctly. Recommend measuring voltages at the batts using a good digital VM first.

Chef2sail · Feb 12, 2013

Something amiss. What's you daily electrical diet (usage)? We have set up of 6-6volts=660 amp hours or 330 usable.
Refrigeration, lights,pumps,instruments use an average of 78 amps/day. Most of it is the reefer. We can go three days with no charging.

I will bet your full charge is not set at 12.8. How many amps per day does your solor give you.?

You have a much larger than normal bank so it shouldn't draw down to 12.2 on one day. Your settings must be off . Do you have a Victron or similar battery meter?

Maine Sail · Feb 12, 2013

BWagner said:
Hi,

We're cruising, currently on a mooring at Boot Key Harbor in Marathon, FL. My question has to do with my battery bank. We have a 2003 Hunter 426DS that we purchased last April and brought south this past fall. In preparation for this trip I had the old 4D batteries removed and 10 six volt Trojan golf cart batteries installed for a total bank capacity of 1200 amp hours. Our biggest draws are our 12 volt frig and separate freezer. Other than that nothing special - some interior lighting, an occasional fan or a DVD movie.

Until recently, we have been maintaining this bank exclusivly with a 6.5 Kw Fischer Panda Generator which we would have to run twice a day. Recently we installed a 325 watt solar panel and charge controller and now have to run the generator once per day. Which brings me to my question - is it normal, with a battery bank that big that I should have to run a generator so often? In the morning our battery voltage is 12.2 to 12.3 and we run the genset. I had these batteries installed hoping that the capacity would allow us to go a couple days between charges but that isn't the case. Does this sound right or is something wrong?

Any thoughts would be appreciated.

Brian

Brain,

We really need a lot more information to help.

#1 How are you charging via the genset? Through an on-board AC battery charger or an alternator on the genset?

#2 If it's a battery charger or inverter charger how many amps/what brand & model? Alternator what is its rating in terms of current?

#3 What voltage settings are you using for charging? What is the highest voltage you see during charging?

#4 Have you measured the voltage at the battery terminals? Under charging and when discharged?

#5 Do you have a battery monitor? (you really should consider one)

#6 What is your average daily Ah consumption? (pretty hard to tell without a battery monitor)

#7 How is the bank wired? Where do the neg and positive connections join the bank?

#8 How long do you run the gen set to charge?

#9 What is the duty cycle of your fridge and freezer 50%, 60%, 70%...? Together they could be burning more than 160-200Ah's / day.. This is why a battery monitor is critical...

#10 When charging are you also using "loads" or do you turn everything off and let the banks charge?

It seems to me like you are running a daily charge deficit. This means you lack the charging capacity or capacity/time at capacity to keep up with your use. Again, this is why a battery monitor is such a great tool because it will show you exactly what you've used and put back if calibrated properly. The size of the bank is only as good as your charging system, time spent charging and what you are actually putting back into it on a daily basis. Also you have charge efficiency to consider so for every 100Ah's removed you need about 115Ah's replaced.

While you have an 1125Ah bank you really only have about 400Ah's of usable capacity or 35% of the bank as usable capacity.. You don't want to go below 50% state of charge, for longevity, and while off cruising it is nearly impossible to get back much above 85% SOC without running the motor for hours, and hours and hours... 85% - 50% = 35% Usable...

If you are not ever even getting back to 80% - 85% SOC and using close to 200Ah's per day then your voltage may not be as far off as you suspect, if you are running a daily deficit.......

Bill Roosa · Feb 12, 2013

Your battery bank does not address how much energy you use. Your boat is a system of energy production, consumption and storage. Three components that all work together to provide energy when you need/want it. If you produce it as you consume it then you don't even need storage. Course you would need a solar panel that can drive a starter! Enter storage requriments. With your size bank and a normal reefer load, anchor lights.....etc you should be using around 100ish AH per day or taking a full bank from 1200 to 1100 AH
I'm thinking that if you are needing to charge twice a day either your consumption is off or you have a leak in storage somewhere. Are you using an inverter?
There is a spread sheet in the downloads section that may help you figure out what is going on.
email me (i made the spreadsheet) if you need help.

onecoolair · Feb 12, 2013

BWagner said:
Hi,

Here is a response to some of your questions - others I will have to work on.

1. We are charging with an onboard Xantrex 2500 watt charger/inverter.
2. The alternator is the standard 80 amp that came with the engine.
3. Voltage settings for charging are "wet less than 80 degrees" Voltage during charge runs about 14.0 to 14.5 amps.
4. When the solar was put in a week ago we also had the Xantrex Link Pro installed and this is where I am getting the voltage readings from.
5. Still working on the Ah daily consumption. The Link Pro is not accurately measuring consumed amps. The readings are way too low - 4 amps in 24 hours. The tech that installed it is due out to track that problem down.
6. See above.
7.There is a neg bus bar that joins everything together and all of this now runs through the shunt installed with the Link.
8. The generator requires about 90 minutes to get to float.
9. I have no idea on this.
10. No, we continue the loads while charging.

Thanks, I appreciate your taking the time to respond.

Brian

Hmmmm??.....
8. The generator requires about 90 minutes to get to float.
You mean your ships battery charger takes about 90 minutes before it goes to float mode on house bank batteries.
Wither it is getting it's required 120 volts to operate from generator or while plug into shore-power. The Results are same.
Is this battery charger a three or two bank charger. It it charging each bank separately meaning does it only give only what each bank needs regard less of what the other bank needs.
Next it's not one of thowes inverter/battery chargers were the charger gets 120 volts from the inverter is it??
Is the inverter always running and pulling down a load on battery bank even though it is not needed or in use ?
Is this charger hooked up wrong so it makes a difference were your main battery selector switch is set too? And you always have to worry and remember to make sure the selector switch is set to proper position so as to be able to charge your all your house banks as well as starter battery at the same time....

Rick486 · Feb 13, 2013

My 44DS is set up identically to your boat except I have 3 4D gel batts in my house bank. Cruising in New England I run the freezer and fridge and miscellaneous lights, and an occasional movie (with the Bose system and TV they use lots of power). The fridge and freezer run about 1/3 to 1/2 the time and each draws 4-5 amps on 12 V. The upshot is the house bank is usually around 12.4-12.5 (correctly calibrated analog VM reading) in the morning. I run the Panda about 1 hr 15 minutes morning and evening, as much to have hot water as anything, and almost never see float. This has been my routine now for 5 years and the batts seem to like it. I'm not convinced you actually have a problem. I'd check your VM reading at the batts as I've said above, and I would also run the "dollar bill" check on your freezer and fridge.

Benny17441 · Feb 15, 2013

I would start by testing the 10 batteries individually as a weak one may be drawing power from the others.