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Discussion Starter · #1 ·
i'm installing a blue sea ACR and a bluesea 8686 battery panel. attached is the wiring diagram from the 8686. it shows the 1 positive coming off each battery to the ACR, then a second positive lead from the battery to the 8686 battery selector. can i run a positive from each battery to the ACR, then go from the ACR to the 8686? the wires from the battery to the current battery switch on the panel are a little short when trying to open & work on the panel. i was hoping install the ACR under the elec. panel. i would take the existing pos. leads connect them to ACR then get some shorter pieces and run them from the ACR to the 8686. i attached the 8686 sketch and what i'm thinking of doing.
 

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Electrically, it is the same thing...they just need to be connected in parallel.
 

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Discussion Starter · #3 ·
thanks sd,
i thought it was the same thing but i just wanted a second opinion. it wouldn't be the first time i wired something wrong.

i have a second question. i'm also installing a new panel w/a digital voltmeter. the wiring diagram shows the neg. going to the neg. bus and 2 pos. wires going form the meter to each battery. could i just run the pos. to the house connetion on the ACR and another pos. to the engine connection on the ACR and get the voltage rating that way rather than run all the way to the battery terminals?
 

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i'm installing a blue sea ACR and a bluesea 8686 battery panel. attached is the wiring diagram from the 8686. it shows the 1 positive coming off each battery to the ACR, then a second positive lead from the battery to the 8686 battery selector. can i run a positive from each battery to the ACR, then go from the ACR to the 8686? the wires from the battery to the current battery switch on the panel are a little short when trying to open & work on the panel. i was hoping install the ACR under the elec. panel. i would take the existing pos. leads connect them to ACR then get some shorter pieces and run them from the ACR to the 8686. i attached the 8686 sketch and what i'm thinking of doing.
A couple of changes you might consider would be to wire your alternator directly to the house bank and add an ANL type battery fuses within a few inches of the both batteries.

By wiring your alternator directly to the house bank you will never run the risk of frying the alternator diodes, and leaving you without charging, by switching through the off position because a load is always connected.

On another note you may want to consider a Echo Charger type of device between banks. Rather than combine the banks, which can be problematic, an Echo type charger uses output from the alternator to turn it's self into a up to 15A charger which is perfect for replenishing a starting battery.

The Echo Charger detects when the house battery bank is being charged and directs a portion of the charge current to auxiliary or starting batteries but does not electrically combine both banks. I currently have a combiner but I am switching over to an Echo this winter as I've never been 100% comfortable with the combiners....
 

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One other point about what Maine Sail wrote. All the charging sources—solar panels, alternator, AC-based charger— should be connected to the house bank, and the echo charger will charge the starting bank whenever it detects a charging level current on the house side, not just the alternator.

The main two differences between an echo charger and a battery combiner are:

First, under certain circumstances, you can draw down a fully charged starting battery with the battery combiner, since it will try to equalize charge levels between the house and starting battery banks—an echo charger doesn't allow this since it is basically a one-way device.

Second, you can overcharge and possibly damage a starting battery if the house bank is every very badly depleted, since it will reach full charge long before the house bank does and require the voltage to be stepped down, but a battery combiner treats it as part of the house bank, and won't step down the voltage until the house bank reaches the same level of charge. An echo charger is usually a three-stage smart charger, and won't do this, since it keeps the house and starting banks essentially separate.

While I am currently using an ACR unit, I will probably be upgrading to an echo charger type unit later this year as well for these two reasons.
 

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Second, you can overcharge and possibly damage a starting battery if the house bank is every very badly depleted, since it will reach full charge long before the house bank does and require the voltage to be stepped down, but a battery combiner treats it as part of the house bank, and won't step down the voltage until the house bank reaches the same level of charge. An echo charger is usually a three-stage smart charger, and won't do this, since it keeps the house and starting banks essentially separate.
this really is not much of a concern because of the equalization that occurs when the two banks are combined.

Picture two five gallon buckets with a hose and a valve connecting the two. With the valve closed (relay broken or open) the bucket on the left can be drained (like your house bank) but the bucket on the right is still full (starting bank).

When you open the valve between the buckets (relay makes) the water from the full bucket (starting battery) flows into the empty bucket (house bank) until both buckets are equally depleted and at an even level (state of charge). Water always finds level and so do electrically connected lead acid type batteries.

This equalization of the batteries takes more time than it would for water to equalize and become one but with the large battery cables it does happen fairly fast. By closing the relay the full starting battery will be drained off to charge the depleted house bank until both are at an overall equal level of discharge.

Because of this you are not actually overcharging the start battery, except for the few seconds right when the alt fires up, and begins trying to force amps into it before it has dumped its charge off to the house bank. After a few minutes all is pretty much equal..

Hope that made sense..
 

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Good point. :)

Maine Sail-

Just checked my notes on that one...the electrician had installed diodes to prevent the starting bank from equalizing with the house bank..that's why the start battery got fried—in solving one problem, they created another. In a standard installation, it shouldn't be an issue.
 

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Yeah, but why in heaven's name would you want to draw down a fully charged starting battery (12.7 volts) to the level of a badly depleted house battery bank (12.2 volts or less)?

Doesn't make sense to me to combine batteries. The Xantrex EchoCharge (15A maximum one-way smart device) or the Balmar DuoCharge (30A maximum one-way smarter/programmable device) make a lot more sense. IMHO.

Been running the EchoCharge on my boat for several years. Flawless. Have installed both types on client boats. They work like a charm.

Bill
 

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Discussion Starter · #10 ·
maine sail,

so if i'm reading this right, i should get rid of the ACR & get an echo charger. any particular model. xantrex? by the way, thanks for the info. glad i haven't gone too far yet.
the new battery selector that came with the 8686, goes, off, on, combine. so i don't have to worry about frying the diodes. that's one reason i went with this selector. i could just envision my kids twisting the dial the wrong way.

if i get rid of the ACR and add an echo charger i'm not sure how it charges. would it charge when the battery selector is in the on position and the engine running or would it only charge when the battery selector is in combine and the engine running?
 

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maine sail,

so if i'm reading this right, i should get rid of the ACR & get an echo charger. any particular model. xantrex? by the way, thanks for the info. glad i haven't gone too far yet.
If you have the choice...yes, get the echocharger instead.
the new battery selector that came with the 8686, goes, off, on, combine. so i don't have to worry about frying the diodes. that's one reason i went with this selector. i could just envision my kids twisting the dial the wrong way.

if i get rid of the ACR and add an echo charger i'm not sure how it charges. would it charge when the battery selector is in the on position and the engine running or would it only charge when the battery selector is in combine and the engine running?
Basically, the echo charger will sense whenever there is a charging level voltage on the house bank side and then use that as a source for it to charge the starting bank. The switch should be in the run position, not the combine position. Putting it in the combine position defeats the whole idea behind having an echo charger.
 

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maine sail,

so if i'm reading this right, i should get rid of the ACR & get an echo charger. any particular model. xantrex? by the way, thanks for the info. glad i haven't gone too far yet.
the new battery selector that came with the 8686, goes, off, on, combine. so i don't have to worry about frying the diodes. that's one reason i went with this selector. i could just envision my kids twisting the dial the wrong way.

if i get rid of the ACR and add an echo charger i'm not sure how it charges. would it charge when the battery selector is in the on position and the engine running or would it only charge when the battery selector is in combine and the engine running?
If it has an OFF position you have kids you can still fry your diodes!! Switching between 1/2/ALL will not fry the diodes it's switching to OFF with the engine running that will. I am a firm believer that the alt should not be able to be easily disconnected from a load via a battery switch.

The Echo Charge is the model and it's made by Xantrex. I linked to it in one of the above posts.. Good luck!!
 

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wchevron,

IMHO, you don't need the 8686 panel. It was designed for a two-engine system, and really complicates the install you're after, while not really adding anything valuable.

A good, robust 12V DC system for a smallish cruising boat (I assume you do have the C30 in your Profile) would consist of:

1. One house battery bank, comprised of however many house batteries you have, wired together into one large 12V bank;

2. All onboard charging sources -- alternator, battery charger, wind generator, solar panels, gas or diesel generator, etc. -- all wired directly to that house battery bank, through an appropriate CPD (circuit protection device -- fuse or breaker);

3. Assuming there's a separate starting battery, it should be maintained with an EchoCharge or DuoCharge device. For your boat, the Xantrex EchoCharge would be more than enough, and it's less costly than the Balmar DuoCharge. This device sits between the house battery bank and the starting battery, and bleeds off some charging current whenever it senses a charge on the house batteries from any source;

4. Appropriately sized cables from the batteries to the engine, alternator, distribution panel(s), etc., with appropriate CPDs; and

5. A reliable means of measuring voltage (at a minimum) or a more sophisticated battery monitoring system (like the Link series) if you wanna get fancy.

Re: battery switches, my preference would be for a simple ON-OFF switch for the engine starting battery and an ON-OFF switch for the house batteries. But, because many folks are worried about how to easily combine the batteries, you could also use a 1-2-OFF-BOTH switch, which would only combine the house and starting batteries when in the BOTH position.

If you're really worried about your kids playing with the switches, I'd find some way to put the fear of god in them to leave them alone (I had 6 kids...all grown now...who grew up sailing; NEVER had a problem with them getting near the battery switches).

Bill
 

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Discussion Starter · #14 ·
alright,
let me see if i have this straight.

1.i already have the 8686 so i'll keep it. it's only designed for 1 engine.
2.i'm going to wire the alternator directly to the house battery.
3. i'll install an echo charger between the house & starting battery
4. if the engine is running & the batt. selector gets turned to off, i don't fry the diodes because the alt. is not connected to the batt. switch only right to the house batt.
5. when i set the batt. selector to run or on, with the engine running, the alt charges the house batt. and the echo charger senses the charge & charges the starting battery.

here is where i'm getting confused. if i wire it per maine sails directions with the alt. to the house batt. and i use the echo charger. if the starting battery gets drained and the house is still charged and i can't start the engine. if i put the batt. selector to combine, will both batteries combine and charges equal out. if this doesn't happen, how come & how would i start the engine. would i take the wires off the engine battery & put them on the house battery to get the engine running? if this is what to do, i'm assuming the echo charger would charge the engine battery while the house is running the engine.
 

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Yep, one engine. Sorry, some of the sites have this advertised as designed for twin engine installations.

I dug out the detailed pdf instructions and specs from the blueseasystems site.

OK, the 8686 is just a couple of ganged battery switches, and a distribution panel with CPDs (breakers)...all in one. You only have to turn one switch to turn on both the house batteries and the starting battery.

Now, for the EchoCharge. It is wired directly between the house batteries and the start battery. It does not go thru any switch. It's completely automatic in operation. It just sits there and whenever it senses more than about 12.8 volts on the house batteries -- meaning there's a charge on them -- it will bleed off a bit for the start battery. It will not overcharge the start battery, nor will it allow the start battery to be depleted by the house batteries.

So, the changes needed from the diagram shown at the bottom left of the installation papers for the 8686 are two:

1. Wire the EchoCharge in place of the 7610ACR shown -- according to directions which come with the EchoCharge; and

2. Run a healthy-sized wire from the alternator output to the house batteries, though an appropriately-sized CPD (rated about 20-25% higher than the maximum alternator output).

Possible problem re: #2 -- the alternator may at present be wired to the starting battery via the starter solenoid (as is assumed in the Blue Sea wiring diagram). That's why they show an ACR (relay) which would pass a lot more juice to the house batteries.

Soooooo..... If you don't feel comfortable changing the alternator setup, it might make the most sense for you to forget all of the above and just go with an ACR as shown. Sometimes a less-than-optimum setup is better...for practical reasons.

I'll shut up now. Sorry if I've confused the issue.

Bill
 

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Discussion Starter · #16 ·
bill
thanks for the reply. i'll have to check to see how the alternator is currently wired and then make a decision. appreciate the help.
 

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alright,
let me see if i have this straight.

1.i already have the 8686 so i'll keep it. it's only designed for 1 engine.
2.i'm going to wire the alternator directly to the house battery.
3. i'll install an echo charger between the house & starting battery
4. if the engine is running & the batt. selector gets turned to off, i don't fry the diodes because the alt. is not connected to the batt. switch only right to the house batt.
5. when i set the batt. selector to run or on, with the engine running, the alt charges the house batt. and the echo charger senses the charge & charges the starting battery.
All good...

here is where i'm getting confused. if i wire it per maine sails directions with the alt. to the house batt. and i use the echo charger. if the starting battery gets drained and the house is still charged and i can't start the engine. if i put the batt. selector to combine, will both batteries combine and charges equal out. if this doesn't happen, how come & how would i start the engine. would i take the wires off the engine battery & put them on the house battery to get the engine running? if this is what to do, i'm assuming the echo charger would charge the engine battery while the house is running the engine.
If you put the battery selector in combine, yes, the batteries will try to equalize, but unless the starting battery bank is shorted, it usually isn't much of a problem, since the house bank is usually far greater in size on most boats. If you have a large house bank that has a decent charge on it trying to equalize to a small start bank that is nearly dead, your overall voltage levels don't drop anywhere near as far as if you have a small well-charged starting bank equalizing to a large dead house bank.

For instance, look at the house bank and the starting bank as two buckets. The house bank is a 55-gallon drum, and the starting bank is a five-gallon paint pail, and you have them connected by a hose...and at the same level.

The first situation is like having a half full 55-gallon drum and pouring some of it into the empty five gallon bucket... how much is possibly going to leave the 55-gallon drum for the five gallon drum?? The second situation is like having a full five gallon-drum and having it pour into the 55 gallon drum...

Which do you think is going to take more water—the 55 gallon drum or the five-gallon bucket.

BTW, this is not a perfect analogy...but you get the idea.
 
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