Blue sea ACR

[wchevron]

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.

[sailingdog]

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

[wchevron]

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?

[floatsome]

As I recall, the Blue Sea ACR instructions specify only one cable per bolt on the ACR?

[Maine Sail]

Originally Posted by wchevron

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....

[sailingdog]

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.

[Maine Sail]

Originally Posted by sailingdog

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..

[sailingdog]

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.

[btrayfors]

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

[wchevron]

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?