Best Configuration for twin diesel battery system

[ChrisN67]

Hello all,

I have a project boat I have been working on for 2 years and I have come to the point where I have to install batteries.
I have twin Yanmar 6LY2's and a genset.

I was thinking of using one redtop optima 50 Ah with 1000CCA at 0C for staring each engine with a Blue Seas Battery Cluster with Voltage Sensitive Relay (VSR)
Then qty(2) 75 Ah blue optima for house batteries (4 batteries total)

The boat is a 36 Intrepid Walkaround. I have a genset I will install in the future but for now the only source of charging is the 60 Amp Yanmar Alternator.

Electrical load is mostly a stereo and Raymarine chartplotter/radar autopilot.

The VSR cluster has a parallel for both starting batteries, but I will also add an electric solenoid to parallel starting and house batteries.

Any ideas or suggestions?

[michael pierzga]

Gee...whats a Blue Seas Battery Cluster with Voltage Sensitive Relay (VSR)
? what is it for ...start batteries ? or to tie the whole system into one ? Normally you keep start batteries separate..completely.. separate charging alternator on each engine ,with a simple crossover switch to allow you to suck service power to start engines in case of failure. And whats a gen set for ? Charging the house bank ? Normally an additional , single ,dedicated engine driven high output alternator and naturally a battery charger for dock use does the trick .
For generating limited AC , an extra pair of extra house batteries and a combo battery charger dc ac verter does a fine job on a small boat .

And keep an eye on those Optima high output batteries. They seem to put out so much power during a start, that the terminal on the battery is overwhelmed. Twice Ive had Optima battery terminals fail after one or two years. By fail I mean the terminal stud physically becoming detatched from the actually battery. Perhaps its a design or manufacturing flaw ?
For shoreside start bank charging Ive had good luck with dedicated...in your case two, simple, cheap, trickle charging battery maintainers.
Perhaps skech out your propsed installation and post. Seems to me to be complicated.

[ChrisN67]

Thanks for the response. The blue seas cluster basically allows each alternator to charge the respective starting battery. When the battery reaches 95% charge it then connects the alternator to the house batteries. The idea is to charge starting batteries first.

Originally Posted by ChrisN67

Thanks for the response. The blue seas cluster basically allows each alternator to charge the respective starting battery. When the battery reaches 95% charge it then connects the alternator to the house batteries. The idea is to charge starting batteries first.

Read this


http://www.amplepower.com/tech_docs/index.html

To get a grip on the topic.

The mentioned failure on Optima batteries are new to me. By so far no other member here mentioned a similar case.

Regards
Richard

[michael pierzga]

Ya Ok...your trying to use your present alternator system to best capacity. Makes sense. certainly cheaper. Guess it works !! Perhaps for daytrip type of boat its the inteligent way to go about it. I see various Smart charging . load sensing systems around. I believe Balmar sells one. You might swing by their website also Victron and Mastervolt to check out their thoughts and system layouts. . . I prefer dedicated sytems for robustness. Not really an issue for day tips and generaly having fun. A good detail on boats with sensitive electronics and a big load placed on alternator charged service and house battery bank combos is to protect your delicate electronics from overvoltage, voltage surges with dc to dc converters...ei...10 to 20 volts dc in and perfect 12v dc out. Not expensive

The Blue Seas relay works well but you will never quite have the house battery at full capacity and you need to have a manual switch in case it fails (or for jumping main if starting battery were to fail.). I have a spare onboard but have not experienced failure. I thought that Blue Seas was discontinuing this item is the main reason I bought a spare!

The combiner I think we are talking about is in the upper right of the pic. The switch that would bypass in the event of failure is below it.


Of course a main battery switch and breaker near the starting battery (I think, Ideally, this switch would be outside the engine space but I wanted it where nobody could dink with it (I carry passengers) and minimizing cable runs


How they tie together on my boat. It's in the process here.


Hope this helps. I am not an electrician so this may not be the best way but was farly intuitive for me. It has worked well for 3,000+ hours.

[Stumble]

Chris,

I haven't revisited these in years, but as I remember them the relays do draw down some voltage from the starting battery to monitor the system voltage. This for a day sailor is fine, but for a long range cruising boat minimizing any current draw from the starting batteries is a necessity so that there is no question that they will start when called upon. My decision at the time (admitedly this was about 5 years ago) was they just weren't justified.

My system is built around four banks of batteries. Each of the starting banks holds two (these engines are 550hp cummings diesels so one would work for you i think) starting types of batteries. There is also a built in jumper cable system that runs through typical battery switches that allows me to do one of two things. 1) Simply jump the non-starting engine, or 2) remove a bad bank from the system and run both engines off of one bank (This is in case I have a battery melt down or something catastophic not really a big wory).

The third bank is really nothing more than a starting battery for the generator. Though I can tap into one of the engine starting batteries if I need too.

Finally my fourth bank is a collection of 6 2V true deep cycle batteries in parrallel that operate the house loads.

I then have three battery chargers. One that charges each of the starting batteries. The second charges the house loads and the generator. The reason for this is to fully seperate the engine starting batteries from even the possibility of a draining current from anywhere pulling down the engine starting batteries. Since I can deal with anything (almost) at sea, but a boat full of dead batterys means I am screwed (can't even call the coast guard cause the batteries are dead ).

I am a little nuts about these systems, but I can promise you I have done everything I can to ensure that I will always have the electrical power necessary to get an engine cranking.

Stumble, I am obviously no electrician. Does what you are saying mean that my setup as I posted above is drawing down the starting battery if I don't turn its switch to "off"?

[Bglad]

If you put a red top on one engine and three blue tops on the other with the vsr between you will increase the size of the house bank so you can draw off it longer. The red top cranking battery will come up to full charge quickly allowing both alternators to work on the house bank. The three blue tops offer a combined 2700CCA.

[ChrisN67]

Sounds like a great idea. This is the system I will use. I will forward pics when available.

Thank you

[Stumble]

Mark,

As I understand the units it does. At the time I looked at it I remember seeing something like 1amp draw for the monitoring of the primary battery bank. But remember I am working off of a memory of a system I researched years ago, I could certainly be remembering wrong.

You could put a voltometer between the leads while the system is on and see if there is any/how much current draw .

[CDK]

Originally Posted by Stumble

At the time I looked at it I remember seeing something like 1amp draw for the monitoring of the primary battery bank.

Stumble, I find that hard to believe.

I've designed a few of these systems, both for marine and photovoltaic applications and never needed more than a few milliamps to monitor battery condition. Especially if solar panels are involved, every expensive Ah needs to treated as precious.

When charging current is available, you can use some to operate a power relay and during starting, a device to switch batteries parallel can draw a few amps. But it takes a very stupid designer to let the system draw 1 amp when the battery charge needs to be conserved.
I've used bipolar relays that can be toggled with a short pulse, so once in the desired state, the power demand is zero.

But stupid designs do exist. In my RV there is a fancy controller for the start- and house battery with alternator and solar input. The circuit itself draws about 5 mA, but the LED display(!) needs 60 mA.
That adds up to 1.5 Ah each day, so after a month under a roof the battery is depleted to the point where the under-voltage protection cuts in.

[Bglad]

Specs for Blue Sea Systems 120 amp relay:

Continuous Rating 120 Amps
Intermittent Rating 210 Amps
Inrush Rating 280 Amps
Closed Current Draw 175mA@12 Volts
115mA@24 Volts
Open Current Draw 15mA
Maximum Cable Size 1/0 AWG
Terminal Stud Size 3/8"-16 (accepts M10 ring terminal)
Maximum Torque 140 in-lbs
Relay Contact Position: Combine (30 sec.) 13.6 Volts@12 Volt
27.2 Volts@24 Volt
Relay Contact Position: Combine (2 min.) 13.0 Volts@12 Volt
26.0 Volts@ 24 Volt
Relay Contact Position: Open Low (10 sec.) 12.35 Volts@12 Volt
24.7 Volts@ 24 Volt
Relay Contact Position: Open Low (30 sec.) 12.75 Volts@ 12 Volt
25.5 Volts@ 24 Volt
Relay Contact Position - Open High 16.0 Volts@12 Volt