Electrical System Breakers- Why Two?

[pelagic2530]

In a lot of the recent posts regarding power distribution, I've noticed that most late-model Parkers have two breakers that feed the house power. This is in addition to any windlass, aux charging, or specific accessory breakers that have been added. It appears that in most cases the breakers are the same amperage, and the cables are routed similarly.

Has anyone taken the time to trace out those power leads and determine exactly how the house power is divided between the two breakers, and what the separation accomplishes? I'm wondering if it was simply to avoid running a single large cable forward, or if they power separate systems (fuse panel vs. switch panel, for instance). I'd be interested to know if there is a reason that Parker elected to go this route vice a larger cable and a single larger breaker.

Thanks in advance for anyone who's checked this out.

 

[Antidote]

The way my 2019 2520XLD was set up from the factory was. A start battery for each engine. The #2 battery (starboard engine) was the house and ran everything except the windlass. #1 battery (port engine) supplied a second bus and the windless. One circuit breaker for the #2 battery bus. One breaker for the Port battery bus. One breaker from the port battery to the windless.

 

[pelagic2530]

The way my 2019 2520XLD was set up from the factory was. A start battery for each engine. The #2 battery (starboard engine) was the house and ran everything except the windlass. #1 battery (port engine) supplied a second bus and the landless. One circuit breaker for the #2 battery bus. One breaker for the Port battery bus. One breaker from the port battery to the windless.

Thanks Antidote. I'm a bit confused about the nature of your setup. Did you have breakers coming directly off the batteries? When you say the port battery supplied a "second bus", what was on that second bus? Where did the battery switch(es) fit into this?

In most of the ones I've seen, it looks like there's the normal 1-2-Both-Off switch, with the positive lead out for the outboard, and then two breakers, both coming off the output of the switch (more if there's a windlass involved).

 

[Antidote]

The set up for both Starboard and Port was engine - 1, 2, both, off switch - battery - 1, 2, both, off switch - circuit breaker - bus. The windless comes off the Port (#1) battery - 1, 2, both, off switch - circuit breaker - windless.

 

[warthog5]

Yea.....Doesn't make all that much sense to me either.

In mine...And I wired it.

BEP Cluster.....CB close to BEP coming out of House switch Supplying Power to all House circuits.

Then from BEP Start a CB that supplied power to windless....The idea of that is engine is still running while retrieving anchor.

Then another ON/OFF master from House Batt [GpD4] thru a CB to supply power to stereo amp.

It's hard for me to buy the idea that they want 2- smaller cables to supply power on the late model boats.

 

[pelagic2530]

Yea.....Doesn't make all that much sense to me either.

In mine...And I wired it.

BEP Cluster.....CB close to BEP coming out of House switch Supplying Power to all House circuits.

Then from BEP Start a CB that supplied power to windless....The idea of that is engine is still running while retrieving anchor.

Then another ON/OFF master from House Batt [GpD4] thru a CB to supply power to stereo amp.

It's hard for me to buy the idea that they want 2- smaller cables to supply power on the late model boats.

Wart,

That's the same thought that I had. Hence why I asked the question.

I'm setting the 2530 up pretty much the exact way you described. Just trying to make sure I'm not missing something that the good engineers at Parker have discovered and fixed with this particular solution.

 

[sydngoose]

Yea.....Doesn't make all that much sense to me either.

In mine...And I wired it.

BEP Cluster.....CB close to BEP coming out of House switch Supplying Power to all House circuits.

Then from BEP Start a CB that supplied power to windless....The idea of that is engine is still running while retrieving anchor.

Then another ON/OFF master from House Batt [GpD4] thru a CB to supply power to stereo amp.

It's hard for me to buy the idea that they want 2- smaller cables to supply power on the late model boats.

What boat are you running now? I think you sold the 2530 right?

 

[warthog5]

I don't even own a boat now. I still work on others all the time to afford this.
Building a Hot Rod. It's all apart now.....'18 Mustang Coyote Power[460HP] 10 speed auto trans, On air Ride, Custom chassis

 

[chas650r]

my 2012 2520xld is wired as noted here w/ 2 # 6 or 8 cables from 2- 40 amp breakers at the stern . I spent the time to trace everything and made a complete schematic. both circuits are fed from the common (output) of the main 1/2/both switch. from there they go to 2 separate buss bars behind the dash . loads are then divided up between the two. my guess is the buss bars are not rated at 80 amps so they are split wired at 40 amps each . my boat came with few options so lots of room and current available for additional items and i can divide them appropriately. being an electrician by trade i kinda like this system as there is room to expand and if 1 of the 2 feeds has an issue i don't lose all power to the house / electronics ect.

hope this clarifies things a bit.

as an added note;
I plan to add a ez anchor drum winch and will take power off both buss bars for a combined 80 amp charge circuit through a breaker and a disconnect to a dedicated group 27 mounted in the existed anchor locker to power the winch. i will make a new anchor locker hatch with no rode slot and semi perm seal it closed . finally NO more water in all the bilges from the idiotic anchor locker design

 

[pelagic2530]

my 2012 2520xld is wired as noted here w/ 2 # 6 or 8 cables from 2- 40 amp breakers at the stern . I spent the time to trace everything and made a complete schematic. both circuits are fed from the common (output) of the main 1/2/both switch. from there they go to 2 separate buss bars behind the dash . loads are then divided up between the two. my guess is the buss bars are not rated at 80 amps so they are split wired at 40 amps each . my boat came with few options so lots of room and current available for additional items and i can divide them appropriately. being an electrician by trade i kinda like this system as there is room to expand and if 1 of the 2 feeds has an issue i don't lose all power to the house / electronics ect.

hope this clarifies things a bit.

as an added note;
I plan to add a ez anchor drum winch and will take power off both buss bars for a combined 80 amp charge circuit through a breaker and a disconnect to a dedicated group 27 mounted in the existed anchor locker to power the winch. i will make a new anchor locker hatch with no rode slot and semi perm seal it closed . finally NO more water in all the bilges from the idiotic anchor locker design

Chas, thanks for the breakdown. I suspected it might be something like this.

For the record, it seems like most system components (at least the ones that I'm using) are baseline rated at 100A. I'm sure there are many exceptions and it's definitely worth checking. But I can see the wisdom of splitting the electrical system in this manner, provided it's done sensibly and labelled properly. Which, from what I can determine from looking at numerous Parker electrical systems here and elsewhere, I kind of doubt.

As far as your anchor winch plan goes... I'm a bit confused as to what exactly you're trying to accomplish with the dual power feeds going forward AND an additional battery in the locker. The general wisdom suggests keeping your anchor windlass circuit (and other heavy amperage draw circuits) away from your electronics power source to avoid heavy instantaneous power draws and the accompanying voltage drop. Also most people will simply run a new circuit from the cranking battery to the bow via heavy cables to power the anchor windlass, with the thought being that when you're operating the windlass you're most likely running the motor, so the windlass circuit is seeing around 14VDC and isn't creating a heavy draw on the cranking battery. How do you intend to recharge the bow mounted battery without drawing down the power from the other batteries in the system, if they're tied together via the existing electrical system?

Just some food for thought, if you've already worked all this out I'm sure people would be interested in hearing your logic.

 

[chas650r]

2530, I went back and looked at the buss bars again and they are small but stout w/ big input posts , so I suspect they would be closer to 100 amp than I remembered. also the feeds are at least #6 so parker did do a pretty good job keeping voltage drop to a minimum on a 40 amp circuit. more than I can say for some other boats I have owned. after I bought my boat I spent a few cramped hours and redressed all the wiring behind the helm and in the process labeled all the fuses and outputs from the bus bars. parker could have done a bit better in that department imo.

after reading how much people go through with their batteries , multiple switch banks, charging relays ect , ect and I get it ( been there before) , I sure like the the simplicity that goes with the yamaha dual alternator output on my current boat. I have 2 batteries and 1 switch that only gets moved once in a while for a load test . thats it , no relays, no switch banks, nada. I run everything off battery 1 which is hooked up to the 80? amp yamaha output and battery 2 is always in back up being trickle charged by the 15 amp yamaha output.

as far as the drum winch and forward battery goes it seems it will kill a few birds. imo my boat needs all the weight I can add to the bow as I am not a big fan of the balance w/ the outboard on the bracket. so the battery in the bows helps w/ that as well as being a 400-500 amp supply 2 feet from the 85 amp peak winch. not much voltage drop there. maybe I am wrong but I dont see how using the 8o amp feed from the stern (40x2) to augment and keep charged the bow mounted battery could ever brown out modern electronics. the motor would always be running when using the winch . If I were to not have the battery in the bow , it's a whole different (bad) story.
the battery in the bow will also be able to be used as an additional house if needed while still having stern battery 2 in start backup at all times. I will install a breaker and a on/ off battery switch between the helm and the bow battery so I can chose to isolate the winch battery if desired.

I use a similar system in my other boat ( yes I am afflicted) and really like the power source close to the draw because as you know 12v system losses are a killer.

 

[pelagic2530]

2530, I went back and looked at the buss bars again and they are small but stout w/ big input posts , so I suspect they would be closer to 100 amp than I remembered. also the feeds are at least #6 so parker did do a pretty good job keeping voltage drop to a minimum on a 40 amp circuit. more than I can say for some other boats I have owned. after I bought my boat I spent a few cramped hours and redressed all the wiring behind the helm and in the process labeled all the fuses and outputs from the bus bars. parker could have done a bit better in that department imo.

after reading how much people go through with their batteries , multiple switch banks, charging relays ect , ect and I get it ( been there before) , I sure like the the simplicity that goes with the yamaha dual alternator output on my current boat. I have 2 batteries and 1 switch that only gets moved once in a while for a load test . thats it , no relays, no switch banks, nada. I run everything off battery 1 which is hooked up to the 80? amp yamaha output and battery 2 is always in back up being trickle charged by the 15 amp yamaha output.

as far as the drum winch and forward battery goes it seems it will kill a few birds. imo my boat needs all the weight I can add to the bow as I am not a big fan of the balance w/ the outboard on the bracket. so the battery in the bows helps w/ that as well as being a 400-500 amp supply 2 feet from the 85 amp peak winch. not much voltage drop there. maybe I am wrong but I dont see how using the 8o amp feed from the stern (40x2) to augment and keep charged the bow mounted battery could ever brown out modern electronics. the motor would always be running when using the winch . If I were to not have the battery in the bow , it's a whole different (bad) story.
the battery in the bow will also be able to be used as an additional house if needed while still having stern battery 2 in start backup at all times. I will install a breaker and a on/ off battery switch between the helm and the bow battery so I can chose to isolate the winch battery if desired.

I use a similar system in my other boat ( yes I am afflicted) and really like the power source close to the draw because as you know 12v system losses are a killer.

Definitely understand the desire to reorganize and relabel everything behind the console. That's one area where Parker falls quite short, although they're certainly better about it than other MFRs.

I'm having trouble visualizing the forward battery system your describing. It sounds like you'll have it hooked up to the two house power leads running forward from the stern, and that's what's providing charging current? It seems like without some sort of isolator in the system, you run the risk of discharging one battery into another which could definitely cause problems. I would think the better option would be to run a positive charge cable through a VSR up to the battery in the bow, which would keep it charged. You could then run a power cable back to the helm bus if you wanted the ability to use the bow battery as a backup house power source, provided that you have a way to isolate the power source coming from the stern (an on/off switch or a CB rated for switching that you can open).

I'd just think that I would want two batteries in separate banks to be isolated from each other if they were capable of providing power to the same location.

 

[chas650r]

ok, couple of questions;

where would the charge circuit come from? if it comes from the common on the main switch then would it not be the same to put the vsr between the house power leads and the forward battery? I only say this because I believe those existing cables a capable of the current needed for battery charging and running the other forward items . imo the 2#6 at a rating of 55 amps each and fused at 40 each should not break a sweat at even 60 amps.

in what situation do you see 1 battery discharging into another? do you mean in use or a failure mode? I see the additional battery as just a 2 battery bank in parallel essentially . as I said before I did plan a breaker and a on /off switch for the forward battery between the battery and the house power busses . although manual this seems similar to what you suggested w/ the vsr, correct?

really appreciate your thoughts and comments.

 

[pelagic2530]

ok, couple of questions;

where would the charge circuit come from? if it comes from the common on the main switch then would it not be the same to put the vsr between the house power leads and the forward battery? I only say this because I believe those existing cables a capable of the current needed for battery charging and running the other forward items . imo the 2#6 at a rating of 55 amps each and fused at 40 each should not break a sweat at even 60 amps.

in what situation do you see 1 battery discharging into another? do you mean in use or a failure mode? I see the additional battery as just a 2 battery bank in parallel essentially . as I said before I did plan a breaker and a on /off switch for the forward battery between the battery and the house power busses . although manual this seems similar to what you suggested w/ the vsr, correct?

really appreciate your thoughts and comments.

Adding the ACR off of the lines going forward might work... the issue I see is that most of those relays work on sensed voltage. I.e., when the voltage at the ACR/VSR is above 13.6VDC, the relay closes, providing charge current to the auxiliary battery (the forward battery, in your case). Depending on where in your system you locate the ACR, due to voltage drop in the cables coming forward you might not see the voltage needed to close the relay.

If I were going to install the system with a forward battery, I'd locate the ACR at the stern, coming directly off the cranking battery through a fuse/circuit breaker as per the MFR. That way, with the engine running, it'll see the voltage to close the relay. Run the positive charge cable up to the bow to charge the auxiliary battery. Run the negative cable from the bow back to the negative bus. Make the connections for the windlass to the positive/negative terminals of the aux battery, with the appropriate circuit protection as per the windlass MFR. If you wanted to add a cross connection to provide power to the house buses in an emergency, I would run another line, through an appropriately sized CB and an on/off switch, from the forward battery back to the dash and tie it into the appropriate bus bars there.

As far as running the two batteries in a parallel configuration... I don't feel comfortable commenting on why I think that's a bad idea, other than on the surface it FEELS like a bad idea. Something about attempting to parallel two batteries on either ends of the boat through existing distribution cabling just does not seem right. Furthermore, I'd imagine the size cabling you'd need to make that arrangement work with minimal voltage loss between the batteries would likely exceed what you've got now, and the size of the new cables would make running ones solely for that purpose impractical. If I get the chance I'll do some more research, run some calculations, and see if I can get you a more specific answer. But I'd want to triple check before planning on doing that to make sure I'm not going to mess anything up.

Again, to reiterate, if it were me doing this install, I'd try to eliminate having the forward battery at all and just run heavier cables to the bow to run the winch motor. But if you're set on the forward battery idea, these are just some ideas. Furthermore, make sure you secure the HELL out of that battery; it's going to see some pretty drastic dynamic loads up there.

 

[chas650r]

good thoughts here and agreed , the mounting on the battery in the bow will be stout to say the least. I realize i will be doing some battery durability testing but I have no issues w/ utilizing my warranties. some of our discussion brought me back to another plan I considered earlier , to use a 12v to 12v charger for the winch battery. this would have a few benefits , by sizing the charger I can limit the charge current even if the bow battery were to get discharged more than expected , say 20 amps , the charger auto connects and disconnects like a vsr , I can use different battery chemistry as it is selectable (agm most likely for durability) , voltage drop to the charger is immaterial as it's input is 7-17 volts.
if I did this and put the charger near the bow battery , run it off the house power as discussed before I could avoid 50' of 2/0 cable?? I figure even at 50amps for 5minutes pulling the hook , with a the 3step charger at 20 amps it should take only 20 minutes to regain most of the discharge.
thoughts?

 

[pelagic2530]

good thoughts here and agreed , the mounting on the battery in the bow will be stout to say the least. I realize i will be doing some battery durability testing but I have no issues w/ utilizing my warranties. some of our discussion brought me back to another plan I considered earlier , to use a 12v to 12v charger for the winch battery. this would have a few benefits , by sizing the charger I can limit the charge current even if the bow battery were to get discharged more than expected , say 20 amps , the charger auto connects and disconnects like a vsr , I can use different battery chemistry as it is selectable (agm most likely for durability) , voltage drop to the charger is immaterial as it's input is 7-17 volts.
if I did this and put the charger near the bow battery , run it off the house power as discussed before I could avoid 50' of 2/0 cable?? I figure even at 50amps for 5minutes pulling the hook , with a the 3step charger at 20 amps it should take only 20 minutes to regain most of the discharge.
thoughts?

As I see it, the major complication in your proposed installation is wanting to use the bow battery as a parallel power source for the house loads. If all it's doing is powering the windlass, then things get a LOT simpler.

I don't have any first hand experience with B2B chargers, but from what I've read about them it sounds like they would work fine in this case and allow you to pull power from your existing house distribution system, provided the power draw of the charger doesn't exceed the capacity of the cables or the level of circuit protection currently in place. You'll still need to connect the bow battery to the boat's negative bus, so you'd need a length of cable for that.

 

[chas650r]

This is the charger I was looking at ;
12V DC to DC On-Board Battery Charger ( 20 amp version )

as far as the negative goes there are 2 #6 cables going forward to 2 more neg buss bars next to the positive ones . maybe I am missing something here but i don't see the need to go to the stern, again limiting the current to ~ 20 amps it should be the same load on the neg as the positive.

still not sure about using this method and back feeding to the house , I need to check w/ the charger people because as shown I would have the input and output negatives common . I believe the charger isolates both neg and pos. not shown are the circuit breakers ect.