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Discussion Starter #1
Good Day

I have 2 batteries that on my Guest switch are configured individually-Meaning the first battery I can draw from if I use position 1, they other battery is battery '2' on position 2.

I obviously can draw from both using the "all" setting of the guest switch. Both are Deep Cycle batteries, bought together when I got the boat, 2 years ago.

For whatever reason, the previous owners, were fine with this configuration. I am now on my second year of using the boat and have realized that when I go out for a weekend, I am dipping below the 50% use of a deep cycle of a battery before I go to the other bank and or run the engine to charge everything up.

I need more battery run time before getting towards 50% of a Deep Cycle and there by needing a charge.

I am on a 32 foot Sailboat with no AC/refridge. I just have GPS, Sailing instruments, colour chart plotter, and a LCD TV (for my daughter which is probably the biggest draw other than my wife liking to read a book while out...


My question is:
How do I go from 2 batteries (1 on each bank) to 2 batteries on each bank. I would buy 2 new batteries and put one bank with the newest the other bank with the 2 year old batteries.

Assumptions:
I wish to keep the configuration the same (meaning just stay with Deep Cycle versus AGM) and while I understand the logic behind starter battery versus House batteries, I am electing -maybe foolishly- of staying with 4 Deep Cycle wet cells and forgoing the "starter battery". I know (well I think) I understand the risks associated with this, but I do have a portable 12V jumper device that I keep on hand in case I have the case of the stupids and draw everything down and cant start the engine.

If I am completely wacko for going down this path, please let me know, but from the polling at the marina I am at it seems a 60/40 slit on Starter battery versus House runs all. But when asked why, they all say "dunno, just because that is how I was taught".

Ian
 

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With your explanation, I would consider putting all four batteries on one bank then in needed add an echo charger for the start battery. On my boat the PO had one 4 battery bank and no start battery and it worked fine. I added an echo charger and added a start battery just in case. I pulled my battery switch and got a blue sea one it has a switch on/off for house and on/off for start. It also has an emergency combiner key switch. You cant really mess it up. really like not having to deal with 1-2-both-off.
 

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Have similar set to bad santa's with separate starter bank and house bank with probably the same type blue sea switch that allows me to use one or the other or combine them if necessary. Only possible difference is that my house batteries are deep-cycle 6-volts wired in pairs in series to give me 600 AH of house power. Put this together when I completely rewired my boat last year and has worked very well. Running my 12-volt reefer and multiple fans. No tv though
 

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Have similar setup to bad santa's with separate starter bank and house bank with probably the same type blue sea switch that allows me to use one or the other or combine them if necessary. Only possible difference is that my house batteries are deep-cycle 6-volts wired in pairs in series to give me 600 AH of house power. Put this together when I completely rewired my boat last year and has worked very well. Running my 12-volt reefer and multiple fans. No tv though
 

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Discussion Starter #5
Cont'd Batteries going 2 to 4

Does anyone have a diagram on how to wire it?
 

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First, I would suggest getting and reading Nigel Calder's "Boat Owners Mechanical and Electrical Handbook."

Second, what you absolutely do NOT want to do is to buy two new batteries and connect them into one bank with your old batteries. Mixing old and new batteries is a bad idea, and will significantly shorten the life of the new batteries.

You could buy two more batteries and wire them as a second bank, but then you are always going to be in a situation of having two newer batteries and two older batteries. I would be inclined to pitch the old batteries and buy four new ones, all wired together into one big bank.

Also, have you considered solar panels? They can be a very worthwhile investment regardless of any other consideration, and that might give you enough extra wattage to manage with the batteries you have until it is time to replace them anyway.

Good luck!
 

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Your situation is a bit complicated because -- as was mentioned above -- you don't really want to mix new batteries with 2-year old batteries.

On the other hand, it would be a good idea to build up your house battery capacity and, while you're at it, reconfigure the batteries to meet current preferred schema.

Here's what you might think of doing.

1. Buy two new deep-cycle batteries (golf-carts if you can fit them), to be wired as a single large house battery bank. If you do use golf-carts, you'll then have 225AH house capacity which should be enough for your needs, so long as you don't have refrigeration.

2. Remove one of the existing batteries and keep it as a spare.

3. Use the other battery for starting, until it (and, maybe, the spare) dies. Then, replace it with a real start battery.

4. Change your wiring as follows (this is easiest, not necessarily best):

  • Attach the new house battery bank to position #1 on the switch.
  • Attach one of the old batteries to position #2 on the switch.
  • Leave the switch in the #1 position all the time, unless you need the house batteries for starting and the start battery is dead.
  • Be sure the alternator and the battery charger (and any other onboard charging devices) are all wired to the house battery bank, not the starter battery.
  • Wire in a new EchoCharge device between the house batteries and the (now) start battery. This device will keep the start battery topped up, by drawing a bit from the house batteries whenever it senses a charge on them.
With this setup, you won't be mixing old and new batteries, you'll have a large(r) house battery bank consisting of all new batteries, you'll have a separate start battery, and you won't have to switch anything. The charging will take place automatically.

All you have to do is be sure the batteries have enough distilled water in them, and keep an overall eye on things.

Bill
 

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You really

You really need two banks.

1) House Bank: This will consist of two, three or four batteries purchased at the same time and wired in parallel if 12v or series/parallel if using 6v batteries and can be wired to position #1 on the batt switch.

2) Emergency/Start/Reserve Bank: This will consist of one battery with ample marine cranking amps to start your motor. This will get wired to position #2, or second position for the second or back up bank.

You do not need or want to be switching back and forth between house and emergency banks with the battery switch as this can leave room for human error. Any sufficiently sized deep cycle house bank Wwill and should re-start your motor at 50% depletion with zero issues. I have even once re-started at roughly 15% capacity. I have been starting on the house banks on my boats for well over 20+ years and I've never understood why anyone would need or want to switch back and forth on a small aux engine. Sure if you have a huge Caterpillar diesel then a dedicated start bank might be necessary but they generally are not on small sailboat aux engines.

When we get to our boat we simply flip to bank 1 (house) and when we leave we switch it off. It's that simple..

As others have said you'll want a battery combining relay or "ACR" or an Echo charger to keep the emergency bank topped off. I personally prefer the Echo Charger.

One more upgrade you'll want to do while in there is to run your alternator output wire directly to the house bank. By doing this you will no longer run the risk of frying the alternators diodes by passing through the off position on the battery switch or having a guest flip the battery switch off, at the end of a sail, with the motor still running, thinking they are doing you a favor.

So in summary

House & emergency banks, you coud re-use one of your old batteries as the emergency bank battery, ACR or Echo charger and direct wire the alt to the house bank. This is about as fool proof a system as you can get on a small budget. Oh and you NEVER want to "combine" banks 1&2 in a situation where one bank is dead!!!

It sounds like you have room for four total batteries? So I'd suggest three 12V deep cycle group 29 or 31 batteries, wired in parallel as one big bank, and one single deep cycle or starting grade battery with sufficient MCA's for your engine as the emergency bank.
 

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Very interesting thread!

What type of echo charger are you using? Reading through the description of the Xantrex Echo Carge, it sounds like it charges from the alternator, not from the house battery bank. Reading through the thread above, it sounds like the latter is the desired approach, especially if you want to combine the setup with solar or wind/water charging.

What is the blue sea switch you are using? Looking at their website it seems like the multi circuit ones are rather big (means won't fit in the cockpit locker, where the electrical switches and engine panel are).

Finally, are you guys using battery monitors?

Best regards,

Daniel
 

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To my knowledge there is only one Echocharger. It has three wires, input from house +, output to start +, and a ground wire. Because it's wired to the house battery bank it detects when a charging source is present from any source - matter of fact all it knows is a charging source is present and can't distinguish between them.
Brian
 

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Hmm. I think I got confused with some of the details, thanks.

Do you have a regulator for the main bank?

Daniel,

The regulator is connected to the alternator and controls its output to the house bank if wired as suggested by Maine Sail in Reply #8.

Stu
 

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What type of echo charger are you using? Reading through the description of the Xantrex Echo Carge, it sounds like it charges from the alternator, not from the house battery bank. Reading through the thread above, it sounds like the latter is the desired approach, especially if you want to combine the setup with solar or wind/water charging.
Daniel, the echo charger, like any other voltage sensitive relay, is connected between the two banks (house and reserve). It ONLY closes (allows power to pass) when there is a charging source present, usually slightly above 13 volts.

ANY charging source (alternator, shorepower, solar, wind) which has a charging voltage above that 13V will make it work. When the charging is done, and the voltage drops below that 13V, the relay opens, isolating the two banks.

Charging is not done from a house bank, but that's where you connect the echo charger or any other relay.
 

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Thanks for all the explanations and answers even for the dumb questions ;-). This and two books: Boatowner's Illustrated Electrical Handbook by Wing and Boatowner's Mechanical and Electrical Manual and by Calder (the latter is the better one IMHO) got me so far that I *think* I understand it now ;-). Now I am going to try and sketch up the existing wiring...

Cheers.
 
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