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Barking Dog
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Discussion Starter · #1 ·
I currently have 2 decent sized house banks that are also used to start up the engine.

Each house bank consists of 4 6v Trojan T105s (total of 8).

I really don't like the design because when one bank drops down to about 50%, I hesitate to use much of the 2nd bank because if I drain that too low, I won't be able to start the engine.

I recently bought an Xantrex Echo-Charge and my plan is to pull off 2 of the Trojans to make a starting bank and then use the remaining 6 for my house bank.

As far as I know, these Trojan T105s are deep cycle and I am wondering whether or not I should be using "Starting Batteries" for my starting battery. It may actually be easier for me to buy and install a new 12v starting battery.

If I can and should get a new starting battery, can I get a AGM or do I have to stick with wet?
 

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what engine are you starting?

I have a perkins 4.154 62hp engine. I use a standard group 31 starting battery with 1000 CCA.
I would combine all the 6v batteries into one large bank and add a starting battery.
all chargers that I know of want to only charge one kind of battery, so don't mix in AGM with your wet cells

Buy calder's boat owners mechanical and electrical manual. Detailed explainations on what, how and why for all this stuff. Or one of Don Casey's electrical books
 

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Sailing Junkie
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Craig,
I'm with XORT on this, pair down your starting bank with a single battery and increase your house bank to 6- 6 volt T105's. You may want to wait until your current batteries are finished because re-arranging them now will shorten there lives a bit. Some here will tell you that one big bank works fine, but I would only do this IF you have a pull start generator ready to go.
The banks you have right now is mighty big (and heavy) for a 38 foot boat......unless of course you have the hot tub option with the 1000w stereo!!!:)
Happy Sails
Tom
 

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Barking Dog
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Discussion Starter · #4 ·
I have Calder's book, but with the Echo-charge, you don't actually connect your typical charger to the starting battery. The echo-charge connects the house to the starting battery and will sense a charge on the house (from your charger, alternator, solar, etc.) and then float some of that charge over to your starting battery to top it off.


The instruction manual on the echo-charge says this:

"Only similar batteries should be connected together in one bank. Do not
connect old and new batteries together or wet and gel cell batteries
together."

I think that this is referring to a bank and not the entire system. If so, I can use an AGM dual purpose for the starting battery. Anyone?

My engine is the Yanmar 4JHE (about 45hp). The manual doesn't spec out CCA or MCA, but does say that you want between 100 and 150 AH. I think for starting, I need to be concerned about Cranking Amps. There is a Group 24 dual purpose AGM at WM with 735 MCA. Anyone know if i can use this as a starting battery for this engine? (This is assuming that I can use an AGM with the echo-charge).
 

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I have two house banks, one of which is 6 T105s. There's also a separate, single 12V starting battery (also Trojan). I've have had no problems despite the "mixing" of battery types -- the batteries are six years old and seem to be holding up well.
 

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...I think that this is referring to a bank and not the entire system. If so, I can use an AGM dual purpose for the starting battery. Anyone?
Well, we were discussing this the other day and Camaraderie reminded me that the optimum charging voltage for wet cells is actually a slight bit higher than for AGMs. But that was with a "smart" battery charger.

Are you talking about charging from a battery charger, or simply off an alternator, or both? Does the alternator have a "smart" regulator that is adjustable for battery types, or is it a simple stock alternator with a pre-set internal regulator? Do you know what voltage that regulator is set for?

Answers to those questions would be helpful. But my gut is that an AGM starting battery should be okay if it's getting the juice from an echo-charger. But there are some sealed lead-acid starting batteries that might work just as well.
 

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I'd combine all the T-105's into a single house bank, and connect ALL onboard charging sources to charge that bank.

Then, add a Group 31 starting battery -- flooded or AGM -- and an EchoCharge device to maintain that starting battery.

Unlike deep-cycle batteries, starting batteries are designed with thin plates to deliver a lot of amps quickly, for a relatively short time. This will make your engine very happy. And the EchoCharge will make the starting battery very happy.

Bill
 

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Barking Dog
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Discussion Starter · #9 ·
I am charging the house bank off of Charger, Alternator and Wind Generator. I know that the Charger and Alternator have 3 stage charging. The wind generator has a regulator, but I think that it just a simple one.

The charger and alternator have been tuned for the specifically for the Trojan lead acid batteries that I have. The only source of charge on the echo-charger will be a spill over from the house bank.
 

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I'd be inclined to combine all the Trojan wet cells into the house bank and buy a 27 wetcell for starting, connected thru the Echocharger. Two reasons for this choice. If you use an AGM, as was stated before the optimum charging voltage is lower than that of thr Trojan wet cells, so the echocharger will possibly cook the start battery. The wet cell will give you the most bang for the buck, but have a shorter life expectancy than a properly charged AGM. Therefore you will not feel so bad about scrapping it at the time the trojans need replacement, and you want to go with all batteries of the same type and age. The major disadvantages to wet cells are: you can spill acid if the boat is knocked down, and you have to check regularly to see that there is water in all cells. Since you have this problem with the trojans anyway, why worry?
 

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Optima brand spiral cell AGM's are able to handle the higher voltages typically associated with 'wet cell' batteries. I use nothing but them for both house and starter but if you are looking to mix that's a good choice if you are worried about over voltage on the starter. IIRC it can handle up to 14.8v without burnoff/damage. I charge at 14.3v and have had no problems at all in three years of use.
 

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Barking Dog
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Discussion Starter · #13 ·
I am in the middle of installing my echo-charger and starting battery and I have a couple of questions.

1) The alternator has a + that I will connect to the main switch and then to the house batteries, but it also (according to the wiring diagram) has some wires (labeled R & L) that connect into the Starter Switch and I think a Charging light. What do I do with these and are they of any concern?

2) The easiest conversion for me is to keep my two house banks and then add the starting battery. Can I connect the echo-charger house battery connection to the positives of each house bank. I like the two house bank setup because I can continue to use my link 2000 to monitor each bank and charge them independently with the battery charger, alternator and wind generator if necessary.

An additional change from my initial post is that I have decided to replace all 8 6v Trojan T-105s with 2 AGM Group 4D (1 per bank) and will be using a Group 24 AGM Starting Battery. I have a Yanmar 4JHE engine.
 

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Bender of Nails
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Since the thread's revived anyway...

Just curious here fellas, but why not keep the deep cycles split into two banks for redundancy and use a separate start battery without wiring it to the onboard charger at all ?
Either a two- or a three-channel isolator in the alternator's output will take care of separating the start and house batteries, and I would expect that motoring out of the marina will be more than enough to replenish the start battery. For the start battery to self-discharge would take quite a while.
It would be easy enough to wire a parallel relay between the house banks' battery switch and the starter just in case the start battery is flat (did I mention I like redundancy? ;^)
 

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Telstar 28
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KindOfBlue

You'd be much better off using all eight T105's for a house bank and setting up a small starting battery. Then connect all the charging sources to the big house bank and use an echo charger to charge the starting bank. The eight-bank house setup will actually give you more run time than it did when it was two four-battery house banks, since the Peukert factor goes down.
 
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