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Old 09-05-2014, 14:58   #31
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Re: Automatic charge relays - good or bad

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Originally Posted by D.D. View Post
I just installed a Xantrex Echo and did not re-wire the alternator. There was no indication of this with the instructions nor any indication that this was remotely necessary. Please explain the need for alternator re-wiring and I will proceed.

Thank you........
This is because their manual SUCKS.. All charge sources need to feed the house bank so the Echo can then feed the start/aux battery. It will not work in reverse so if you leave the alternator on the "C" post of the battery switch and flip to the other bank there is no charging in reverse. It is intended to take from the house bank and give to the start/aux bank.
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Old 09-05-2014, 15:11   #32
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Re: Automatic charge relays - good or bad

Seems like a simple way to go, and I like simple.
I'd just keep another spare emergency start battery somewhere not connected to anything. Maybe make it a lithium battery or capacitor bank that holds a charge a long time.

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I don't believe in a separate starter battery.
Back when people had small house banks and no way to keep track of the State-Of-Charge of their house bank keeping a separate starting battery made good sense.

Now we generally have big house banks and good SOC instruments and don't need to keep a separate start battery.
The large house banks can supply all of the current needed to start the engine. House banks are generally sized in the hundreds of Amp-Hours. It takes less than 1 AH to start my diesel.
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Old 09-05-2014, 16:22   #33
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Re: Automatic charge relays - good or bad

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Originally Posted by Cowboy Sailer View Post
I don't believe in a separate starter battery.
Back when people had small house banks and no way to keep track of the State-Of-Charge of their house bank keeping a separate starting battery made good sense.

Now we generally have big house banks and good SOC instruments and don't need to keep a separate start battery.
The large house banks can supply all of the current needed to start the engine. House banks are generally sized in the hundreds of Amp-Hours. It takes less than 1 AH to start my diesel.
You would believe in it if you owned a catamaran with two diesels that would require 30-40' one-way runs of 4/0 cable to use the house bank as the starting bank. And you wanted to start both of them at once.

If your house batteries are right next to your engine, then using them for starting is OK. On the other hand, giving the engine its own normally isolated inexpensive small Walmart battery does give you more options for when things go wrong.

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Old 09-05-2014, 16:27   #34
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Re: Automatic charge relays - good or bad

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It matters if you have a smart regulator and the bulk phase is set to a high voltage. If you big house bank is discharged and the bulk max voltage is set to something like 14.8 or higher then your fully charged starter battery will be overcharging during the time the house bank has charged enough that the voltage is higher than a normal dumb charger voltage of around 14.4 until the trip point out of bulk at 14.8 is reached.

Out of the box, at least the couple I have looked at the bulk and acceptance voltage is set the same at about 14.4, which is where many dumb regulators are set so it wouldn't make any difference anyway.
We use combiners to combine our 675Ahr house bank with a small starting battery on each engine. We have our absorption set point at 14.8V, and it spends a couple of hours there each day before going to float, so our small starting batteries experience this voltage and time along with our house bank.

The last set of starting batteries lasted 14yrs, by which time we were on our third house bank.

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Old 09-05-2014, 16:49   #35
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Re: Automatic Charge Relays - Good or Bad

Mainsail has a real knack for explaining thanks to him.
My solar panels are on the house side. My not so big 70 amp alternator is on the engine side. I think the engine bat is never really taxed. Once running a few minutes at most the combiner kicks on and the batteries are combined. The house and start batts are kept topped up by the solar. When cruising with the kids the solar won't quite keep up and then I need a boost every few days with the motor. Should I move the alternator wire over to the house side. If the batteries are combined does that really matter?


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Old 09-05-2014, 17:42   #36
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Re: Automatic Charge Relays - Good or Bad

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Mainsail has a real knack for explaining thanks to him.
My solar panels are on the house side. My not so big 70 amp alternator is on the engine side. I think the engine bat is never really taxed. Once running a few minutes at most the combiner kicks on and the batteries are combined. The house and start batts are kept topped up by the solar. When cruising with the kids the solar won't quite keep up and then I need a boost every few days with the motor. Should I move the alternator wire over to the house side. If the batteries are combined does that really matter?


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In your specific case, it doesn't really matter where your alternator output goes. When your alternator kicks in, within a couple of minutes or less, the charge relay will open and everything will look like a single bank to your alternator. Your house batteries will be charged just fine.

If your house batteries are near your start, and you don't have to spend a lot of money for larger or longer wire and fittings, then I would make the change to put your alternator (and sense wire) to the house bank. If you have to spend more than $5 to do that, I would forget it.

In fact, Andina recommends wiring combiners and alternators just the way yours is set up. I have never fully understood the reasoning she uses, although she has patiently tried several times to explain it to me.

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Old 09-05-2014, 18:06   #37
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Automatic Charge Relays - Good or Bad

Thanks that is what I have found. It's so stupid simple I almost can't remember how I set it up 7 years ago. If my alternator was bigger then I would want it to go to the house side? The nice part of this if the engine runs the alternator is connected. You can't start the engine without turning the bat switch. If the house was off and the engine started then the alternator is not connected to a battery if the charge source is on the house side.


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Old 09-05-2014, 18:19   #38
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Re: Automatic Charge Relays - Good or Bad

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If the house was off and the engine started then the alternator is not connected to a battery if the charge source is on the house side.
Doesn't it ALL come down to "How is it wired?"

If you run your AO through a battery switch instead of simply to the house bank, then if the switch is off then you fry the diodes. While the AO should have both a fuse and a separate switch to allow working on the engine without having to pull the fuse (which also works just fine), there should be no issue.

As long as the AO has a battery, live, direct connected, at the other end, the alternator will be OK.

What's so hard?

Maybe we have not been good at explaining this for the past 15 years.
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Old 09-05-2014, 18:28   #39
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Re: Automatic Charge Relays - Good or Bad

Right so I fuse both with Atn at closest point. Also I like the 3 switch house off engine off combine off option. Nothing is hot except the fused bilge pumps and the fused sole panels. Yes it matters how it's wired. I don't like the idea that the alternator is left hot even if it is fused. No reason just like that I turn everything off when the switch says off.


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Old 09-05-2014, 19:16   #40
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Re: Automatic Charge Relays - Good or Bad

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Right so I fuse both with Atn at closest point. Also I like the 3 switch house off engine off combine off option. Nothing is hot except the fused bilge pumps and the fused sole panels. Yes it matters how it's wired. I don't like the idea that the alternator is left hot even if it is fused. No reason just like that I turn everything off when the switch says off.
I understand, but it really doesn't matter. That's why I said: and a separate switch to allow working on the engine without having to pull the fuse (which also works just fine),

Oh, shoot, not another switch!

But I've been running with a "hot" alternator with my 1-2-B switch OFF for the past 15 years and things are just fine.
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Old 09-05-2014, 19:34   #41
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Re: Automatic Charge Relays - Good or Bad

I am old school on that. It's easy and no way is my alternator a part of a hot circuit unless I choose. Funny how we have stuff that works okay but others think it can't be. I keep listening to see if I can do better, learn or have just been stupid lucky. I am a C student with karma. This beats the hell out of salvaged battery's from the scrap pile.
Yes that was the make up years past. I would look for heavy Trojan batts in the marina bin. Pull a bunch and load test them. Use the good ones until I found something better. 12 years and I did not buy a battery. I trashed them but I could find another set easily. Now it's not so easy to raid the marina battery dump.




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Old 09-05-2014, 19:57   #42
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Re: Automatic charge relays - good or bad

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This is because their manual SUCKS.. All charge sources need to feed the house bank so the Echo can then feed the start/aux battery. It will not work in reverse so if you leave the alternator on the "C" post of the battery switch and flip to the other bank there is no charging in reverse. It is intended to take from the house bank and give to the start/aux bank.
Here are the details:

Xantrex Echo Charger Rant - SailNet Community
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Old 09-05-2014, 20:32   #43
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Re: Automatic charge relays - good or bad

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We use combiners to combine our 675Ahr house bank with a small starting battery on each engine. We have our absorption set point at 14.8V, and it spends a couple of hours there each day before going to float, so our small starting batteries experience this voltage and time along with our house bank.

The last set of starting batteries lasted 14yrs, by which time we were on our third house bank.

Mark
Yep.....
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Old 09-05-2014, 20:41   #44
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Re: Automatic Charge Relays - Good or Bad

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Mainsail has a real knack for explaining thanks to him.
My solar panels are on the house side. My not so big 70 amp alternator is on the engine side. I think the engine bat is never really taxed. Once running a few minutes at most the combiner kicks on and the batteries are combined. The house and start batts are kept topped up by the solar. When cruising with the kids the solar won't quite keep up and then I need a boost every few days with the motor. Should I move the alternator wire over to the house side. If the batteries are combined does that really matter?


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If it is working, it is working.

The problem is in relay cycling. The start batt voltage comes up nearly instantaneously because of SOC. The relay CLOSES/MAKES and combines with the depleted house bank. The alt can not maintain the combine voltage set point of the combiner so the relay drops out/opens. Repeat, repeat, repeat. If this is not happening you are fine. I still prefer not to run the entire alt output through the contacts in the relay. Voltage sensing for alternator I also prefer to wire that to house too.

It is much easier for the alt to bring the house bank to combine voltage and then have it combine with the start battery, than to have the start battery combine with house and have relay cycling. If the banks are close to the same size, no big deal most combiners are dual sensing these days and relay cycling would only be a problem with small current sources like solar or wind...
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Old 09-05-2014, 20:41   #45
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Re: Automatic charge relays - good or bad

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Yep..... I don't know, people must think I just make this stuff up or something... The myth will come back next week though, don't worry....
I'm thinin' about some

MYTHBUSTERS

T shirts...
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