Help understanding my batteries

7tiger7 · 03-06-2011, 01:05 AM

Hi,
on the new Marine Trader 43 I bought - I am trying to understand how the PO set up his battery banks (I'd ask him, but he passed away).
From what I see, he has 3 battery banks, as follows:
6 x GC-2
2 x GC-2
2 x 4D

(many of their cases have cracked from freezing).

From what I surmise:
6 x GC-2 - house bank?
2 x GC-2 - generator cranking?
2 x 4D - cranking for the 2 Volvos?

Also, she has a Heart Interface Freedom Mairne 25 inverter / charger with a "Link 2000" controller.

SO - any thoughts on which batteries would logically be cranking, which would be house?
And - advice on replacing the cracked batteries?

Thanks
Phillip

FF · 03-06-2011, 05:01 AM

The guess you made would be mine also.

With the Link 2000 on the house you should be able to get 4-6 years out of std golf carts.

Frequently Sams Club or similar is cheapest.

Look at the build date ID and get the same for all 4 , chose the ones with the highest voltage if there are many to choose from.

IF you anchor out a lot , and your noisemaker is fitted with a 200+A alternator and 3-4 stage v regulator , more expensive (higher initial absorbtion rate) batts might equal less genset time.

**Larry M** · 03-06-2011, 06:37 AM

Get a hold of Nigel calders book:****Boatowner's Mechanical and Electrical Manual: How to Maintain, Repair, and Improve Your Boat's Essential Systems.* He gets into lots of detail about batteries & battery boxes, cabling, troubling shooting and the proper wiring.* It's great reference to have on board.

Not knowing what experience you have, you may want to just remove everything and start fresh.* By the time you get done you will understand your electrical system and it should be problem free for years.

As far as the*cracked batteries, I would replace them for*they can't be repaired.

Good luck.

Larry/Lena
Hobo KK42
Baha de Sol, El Slavador**

-- Edited by Larry M on Sunday 6th of March 2011 07:38:05 AM

marinetrader · 03-06-2011, 07:07 AM

I would think the 4Ds were starting batteries but disconnect one and see if you can start the diesels.

I recommend AGM batteries; maintenance free.

koliver · 03-06-2011, 08:15 AM

Some time spent in the ER, in awkward positions, following the wires will tell you what those batts are powering.
Cracked ones must go, so now is the time to redesign your whole system into something sensible. You don't need a separate start batt for each engine. You have TAMD40s? With glow plugs? If so, I would keep a single 4D for all starts, then a single bank of Golf batts for house loads. Size your house bank according to your fridge demands. If you have a DC only fridge, 4 Golfs will be adequate. If you run an AC/DC, you will need 8.

Delfin · 03-06-2011, 08:30 AM

Tiger, I'm with Keith and Larry.* Calder's book is a great reference, and starting over may be best.* You don't need three banks and the Link will only measure two in any case.* What size starter bank can be found in the engine manual or from a dealer.* What size house bank you need is partly preference, but if you total up the amp hours at anchor you will probably use and double it, you have the absolute minimum size for the house bank.* I designed my system for 2-3 days at anchor with a 60% depth of discharge by way of reference.* The Link will provide the answer to your average consumption.

Another advantage of starting over is you will have an opportunity to clean up any weirdness introduced by the PO.* Things happen over time, and when you have fuel filters mounted over the batteries you wonder how much thought was put into whatever "owner enhancements" were implemented to a critical system that can also be pretty dangerous if not done right.

JohnP · 03-06-2011, 08:58 AM

Tiger,* I tend to agree it is a good time to set things up the way you what.

One thing you may want to include are covered battery boxes.

Exposed terminals can be trouble if you drop a tool on them or such.

Lots of choices on line -* mine look like this.

JohnP

sunchaser · 03-06-2011, 09:22 AM

For twins, I may be the odd duck here, but if space allows it, I much prefer that each main engine has its own start battery with a parallel switch connecting the two. Also, I prefer the genset to have its own dedicated battery with no other loads attached.*

Don't discount that the PO may have done*something right. Other than looking *messy, the wiring may be quite acceptable. As previously suggested, trace each cable line from the starter (s)*backwards. If in doubt, get a marine eelctrician to spend an hour with a VO meter. You may want to add battery boxes since you are taking out the batteries anyway.

If located in the ventilated ER, I recommend lead acid. With the right inverter & charger (it seems like you do, but the electrician can tell you) setup you can get 7+ years out of the house set. I am currently *buying* 8 new house bank Trojan 105s for $116 each and 3 engine start 8Ds for $165 - much less than AGMs.*

boatdriver47 · 03-06-2011, 03:18 PM

Tiger, Check your private message. Bill

Moonstruck · 03-06-2011, 06:21 PM

It looks to me that you have a serious situation that needs to be corrected.* There is enough DC ampherage there to do some serious harm.* If you do not want to tackle it as a DIY, it would be good to have a good marine electrician for 2 or 3 days to straighten it all out.* AGM batteries have been suggested.* I have them, but they are not necessary.* You could easily put a couple of grand in new AGMs.* They wire the same as other batteries except maybe terminals.Proper battery boxes with covers are imperative.

Some of the wiring on Moonstruck I have done with the help of a qualified electrician.* Household electricians do not understand boat wiring and grounding systems.* Get a marine electrician.

Good luck.* It looks like you can have a very nice boat there.

Here are some shots of*Moonstruck's set up.* I admit that I am annal when it comes to electrics, but I can sleep in Peace knowing it is there.

Delfin · 03-06-2011, 07:31 PM

Outstanding, Don.

DCBD · 03-06-2011, 11:32 PM

While we're on the topic, my boat has 4 x 8D AGMs that serve as both main/gen starting and house batts. Not the ideal set up I guess, but it sure simplified the wiring. As long as I monitor my power consumption while anchored (which I do very closely) I think it's probably a good way to go. For back-up starting I can switch the thruster battery to start the main or generator. Also, I can start my generator with a hand crank, although I've never tested that. The boat went through a fairly extensive refit about 8 years back and this was done at that time. Is anyone else rigged like this?

JohnP · 03-07-2011, 06:15 AM

Quote:

Moonstruck wrote:

Here are some shots of*Moonstruck's set up.* I admit that I am annal when it comes to electrics, but I can sleep in Peace knowing it is there.

******** Don,* No fair-- I looked and looked, and looked again and can't find anything I did not like.

Nice!** JohnP

**Baker** · 03-07-2011, 09:49 AM

If you want to keep it very simple, do what DCBD did above. I would only add one modification....have a seperate genset battery. That way if you do run down the house/start bank, you can crank the genset and charge the house/start bank. The chances that both banks go dead at the same time are VERY small. And if your genset start bank goes dead, carry jumper cables to jump from the house. This is how my last boat was wired and I had absolutely no issue with it. Obviously we could get into all kinds of arcane scenarios where this set up may not be the best. But if you are cruising coastally, then it should be adequate.

Moonstruck · 03-07-2011, 11:47 PM

Thanks, Delfin and John.* There is one improvement that would be nice.* I would like the battery disconnects outside the engine room.* The large 450 gal. fuel tank is behind the engine room.* To put the disconnects outside it would mean*moving the switches a long way.

There are three things that I*feel are the most important.* They are fusing, disconnects, and grounding.* A dead short on a circuit with no fuse or circuit breaker can cause you to lose your boat.* As you can see in the pictures, every fuse, circuit breaker, and disconnect switch is readily accessible.* The inline fuses coming off the batteries are a little harder to get to, but if they do their job they can save your a_s.

I am a real estate developer and licensed general contractor in several states.* I do not use any of our electricians for marine work.* No Romex and no household or land type wiring.* Boats are complicated animals.* Too many ways for stray currents to work.