Battery Bank Flexibility

[Hkalan]

Hello,

I require some real world input... to many sales people are causing conflicting input.

I am planning to have a large 24v house bank that a solar array will charge that has a high AH value, and the vessel has a standard 24v bank at 200Ah that I want to keep and use for the bilge pumps etc.

The weight of the new batteries require having the entire bank separated into 2 different location on the vessel. I thought that because of this, I could be creative and have some flexibility here with the new large bank. I will mainly use the 2 connected in parallel but it would be great if I could isolate one side for maintenance reasons, but I still need an isolator due to the standard bank is only 200Ah, but the new large bank will be over 1,000Ah.

Attached is the DC diagram I am planning and the 8Kw/24v Victron Quattro will be the AC charger and inverter for the new large bank in conjunction with the 80A Apollo solar charge controller the solar panels are connected to.

The sales people are telling me that the 1/2/Both/off switches (rated at 600 to 900 Amps) are stupid and should be only an on/off switch. I do not see any harm for having flexibility to take one side offline if I would want by just turning a switch, and still have the inverter getting some power from the bank rather then NONE at all, as they will be in parallel so I do not see any harm... is there something I am missing that they are not telling me.

Also, they say that I have the isolator in the wrong place... Perhaps I am not seeing something there as well.

I will be using the Victron Battery monitor (Blue Power Panel) to watch all the banks as well... that seems to be the only thing they have not called stupid.

Thanks for your input !

Alan

[btrayfors]

Yes, it appears to me that the isolator is incorrectly placed.

Isolators are generally used to divide the charging current amongst several battery banks, while preventing them from back-feeding and draining when there is no charge current. These were popular in the past, but these days there are generally better ways to accomplish this task, e.g., using combiners, voltage followers, etc.

In any case, that is not what you are apparently trying to do here.

It seems to me that you have six battery banks:

1. a 120AH generator bank;
2. a 200AH @ 24V engine starting bank for the starboard engine;
3. a 200AH @ 24V engine starting bank for the port engine;
4. a 200AH @ 24V auxiliary bank for bilge & sump pumps, and misc. other;
5. a 897AH @ 24V house bank; and
6. a second 897AH @ 24V house bank.

The two house banks will generally be run in parallel, except for maintenance.

These are charged by three Victron 24V battery chargers powered from shore or generator, and by solar panels controlled by the Apollo 80A capacity regulator.

220VAC power is provided off grid by an 8KW inverter, drawing off the house batteries.

My first thought is that you're going to be a very busy boy there in Hong Kong just keeping after this very complex system! Won't leave you much time to enjoy the delights of Nathan Road or Wanchai :-)

Based on a quick reading of your diagram, I'd say the first thing to do is to lose the isolator...you don't need it.

Hook up one of the Victron chargers so it's primary purpose is to charge the house batteries. Then, use a Balmar DuoCharge or Xantrex EchoCharge to maintain the auxiliary 200AH battery bank. No switches necessary...it's automatic.

Also, be sure the inverter is fed directly from the house batteries, with appropriate wire and fuse sizes.

The comment given you re: ON-OFF switches vs. 1-2-Both-Off switches is generally correct. These are much easier to understand, and avoid the possibility of someone turning the multi switches to the wrong position. If you understand the system thoroughly and are very careful, you can get by with the 1-2-Both-Off switches, but no doubt the simple ON-OFF switches IMHO are to be preferred.

You have a very complex system here, my friend, and my advice would be to seek out the services of a qualified marine electrician to look over your wiring diagram and, perhaps, to visit your boat and have a look around. It would be well worth whatever that would cost.

With a total of 1,900AH @ 24 volts in the house bank alone, you've got plenty of power aboard to get into real trouble; seek out expert advice before you do, and don't give up until you're satisfied that you've got good advice.

Bill

[Hkalan]

Hello,

Thanks so much. I can tell you have spent time in Hong Kong... You know the Hot Spots... SMILE

You are correct about the 6 banks. Just my girlfriend and I on the vessel. She would not be touching any system switches, so I feel safe with the 1/2/Both/Off switch staying where I set it.

The large house bank (Trojan IND-17 batteries) will mainly be charged by the 9 - 300w solar panels on the Flybridge Hardtop as well as 2 500w wind turbines. Do you think that having the Quattro be the charger for that if needed best used because of the setting adjustability for charging if ever needed ??

I need to do my homework about the isolator !!!

This is a complex system, but should allow us to live off the grid as this will be our full time home so after October.

Thanks so much !!!

Alan

[btrayfors]

Alan...

Originally Posted by Hkalan

Hello,

Thanks so much. I can tell you have spent time in Hong Kong... You know the Hot Spots... SMILE

Yep. Wasted youth! Been there 25-30 times, beginning in 1956. Haven't been back since the Brits left, though. Gotta be some changes, I'd guess.

You are correct about the 6 banks. Just my girlfriend and I on the vessel. She would not be touching any system switches, so I feel safe with the 1/2/Both/Off switch staying where I set it.

OK.

The large house bank (Trojan IND-17 batteries) will mainly be charged by the 9 - 300w solar panels on the Flybridge Hardtop as well as 2 500w wind turbines. Do you think that having the Quattro be the charger for that if needed best used because of the setting adjustability for charging if ever needed ??

Yes, it's a good idea to have a battery charger connected for charging the house bank. You could have a long dark spell and, of course, wind generators are mechanical devices which can and do fail. I'd feel much more comfortable with one of those Victrons available for charging the house bank(s) if needed.

I need to do my homework about the isolator !!!

Yep. But, you really don't need it. Much better to use one of the devices I mentioned.
This is a complex system, but should allow us to live off the grid as this will be our full time home so after October.

I'd still keep my eyes open for a good marine electrician. There are no doubt some in HK.

Thanks so much !!!

My pleasure.

Alan

Bill

[Hkalan]

Good Morning,

I have made an appointment to meet with an electrical engineer today.

The Victron Quattro is a charger as well as an inverter (see the attached image), so even when a typhoon crosses Hong Kong darkening the sky for a few too many days, the Quattro has the AC feed from the Generator or Shore Power to charge the battery bank up if the sun and wind can't.

Quattro / 3kVA - 5kVA - 8kVA - 10kVA - Victron Energy

I have the Victron "Blue Power Panel" battery monitoring as well, so if we are at anchor and the generator is off and using the solar and wind only for charging, and the bank falls to a low level. The Victron monitoring system will automatically start up the generator and all the battery chargers (including the Quattro) will keep all the batteries happy and healthy.

Since Hong Kong has been handed back to Mainland China, the skyline has many more buildings crowding the skyline. The Hong Kong dollar is still pegged to the US dollar, so the exchange rate from the Hong Kong dollar to the China RMB is what has been drastically effected with the economic storm !

I will let you know what I learn today, and hopefully have a new diagram put together that if flexible and correct... SMILE

Alan

[Hkalan]

Hello,

I had a nice meeting with a Marine Electrical Engineer today... He has over 28 years as the electrical designer for large cargo shipping vessels. A really nice person to talk with !

He said I was on the right path... only needed to fix the isolator. The Isolator is good because the 200ah and 897ah banks should be isolated this way, as the different AH values of the banks would create issues that may effect the life of the different size AH banks if not isolated... and the price of all these batteries makes me want to make every small protections that will assist me to get every minute of life from them !!!! SMILE

The 1/2/Both/Off switches are a nice feature when it would come time for maintenance, and as long as I am the only one monitoring the gear, all will be fine... he also noted that the 600 amp to 900 amp switches I will be using do have the ability to lock with a pad-lock if needed.

The one thing he did suggest is to install 2 of the 5Kw Quattro, OR 2 of the 8Kw Quattro in parallel, and I would be able to run 1 or 2 of the air conditioners with the inverter power during the peak sun hours with the size bank I have without any major issues.

Here is the diagram after the meeting with him...

Thanks,

Alan

[Hkalan]

Hello,

I have been looking at the diagram, and I found a way to eliminate the isolator and still give even more flexibility !!!!

Replacing the one 1/2/Both/Off switch and having the two On/Of switches with the emergency Parallel just like on the engine batteries would be perfect !!!

Have a look at the diagram I just made and tell me your thoughts !!!

Alan

[Pete7]

Yikes, the battery sales rep is going to be doing back flips when he sees that lot being orderd. Can't it be rationalised a bit. Do both engines need 200AH @ 24v or could 100 AH @ 24v be used to start them and a cross over incase one failed to start. Can't the genny share a engine start battery to start again reducing the number of batteries to buy and maintain.

What are you running that needs 1800 amps of house bank, small ice cream parlour perhaps?

HK has all changed now, but used to be up at Sek Kong before the MTR was extended past the mountain.

Pete

[Hkalan]

Hello,

There is a lot of batteries. The boat has 2 Yanmar 900hp engines, and the boat builder said it needs that size batteries... I won't argue with that SMILE.

The generator is a Kohler 20Kw and uses a 12v 120Ah for starting. The same battery is also used for the VHF radio and a few other 12v devices, but everything is mainly 24V on the vessel.

The vessel is a full time residence for me that I hope to have the ability to live off the grid with the solar house bank. I even have a Spectra 200T water maker that makes all the water we need. I learned with my last 150T water maker that they are most happy when working all the time. The UV filter and 2 additional filters make me a happy camper. Unlike living in the city or outlying villages to the New Territory of Hong Kong, I had always boiled the water before drinking when I had an apartment (Hong Kong gets most of its water from mainland China), I drink straight from the tap on the vessel... all my Hong Kong and mainland China friends that visit me are shocked that I can drink from the tap. After a few cocktails, I tell them that the Ice was made from the same water... then they accept the quality of the water and drink from the tap as well... LOL

When I was planning the Solar Panel system, I was lucky to find an importer for Trojan Batteries and was able to buy the Trojan IND-17 batteries for $620 US Dollars each (shipping and tax included), and they come with a 3 year warranty from the importer.

The only batteries that are in the engine room (under the floor boards) are the 4 for the engines, and the 12v for the Generator. The Trojan IND-17 batteries are in the stern with proper ventilation and climate control. The Inverter and chargers are in the stern as well with proper ventilation and climate control. We had the hull made at the shipyard to extend under the swim platform to float the weight of the 3,800 pounds of weight we have in the stern of the vessel (see the drawing).

Thanks,

Alan

[DotDun]

Prediction: 8-10 years from now when you are buying the 3rd set of batteries, you'll wish for a more simple design.

Just a guess.....

[Hkalan]

Hello,

I would like a more simple design, but the solar panel bank requires the high AH value to give me the ability to live off the grid.

Your suggestions !

Alan