Wiring House Bank - Your Input?

[bobfnbw]

At last I am almost ready to start the rewire.
This question relates to battery bank and fusing.

8 220AH 6v house batteries in series and parallel.
2/0 wire to windless.
2/0 wire to D/C panel.
4/0 wire to Victon 3000w inverter.

starting batt is seperate.
inverter is <5 ft away, Windless about 20', d/c panel 12'.
Should I wire the battery bank to a bus bar on the battery box, then fuse each cable to the relative loads, or can I put in one fuse prior to the bus?
Right now, nothing is fused, so something is better than nothing.....

Which fuse type would be best, class T, ANL or mega. Or should I use the Terminal fuse from blue sea and just go with that ?

Appreciate your input.
Bob

[clearsea]

Originally Posted by bobfnbw

Which fuse type would be best, class T, ANL or mega. Or should I use the Terminal fuse from blue sea and just go with that ?

Not all fuses are ignition protected.

[bobfnbw]

batteries are below sole in main salon with a rule fan and venting to engine room.
No spark wihere fuses are..

Also, does one have to have a battery switch?
My current switch broke, and I never use it. Why have a battery switch ?

[CharlieJ]

Bob-
First of all; assuming 100 amp for 20' to the windlass using 2/0 will yield a 2.7% voltage drop which is acceptable. Assuming 50 amp for 12' to the DC panel using 2/0 yields a 0.81% voltage drop; very acceptable. The 4/0 to your I/C is fine.

There are two schools of thought regarding series/parallel battery banks. One view (mine!) is to use whips from the batteries to respective B+ and B- bus bars and then feed your loads from the B+ bus bars via appropriate circuit protection devices (CPDs). The second view is to connect the B+ and B- of each set to its neighbor until all are interconnected. From opposite ends of the bank, pull off the B+ and the B- to separate bus bars and then feed your loads via appropriate CPDs.

Regardless of how you do it, it is a high quality installation that ends up with a B+ and a B- bus bar to service the loads. Your I/C requires a Class T fuse. This is a very fast acting CPD and it protects the largest continuous electrical load on your boat. You should also install an isolation switch in the I/C B+ (Blue Sea 6006 is fine for less than 3.0 kW).

Your other loads can be protected by appropriately sized ANL fuses, Blue Sea Series 187 circuit breakers, or the new Marine Rated Battery Fuses (MRBF). All three devices have sufficient ampere interrupt capacity (AIC) to be the first fuse between the battery B+ bus bar and the load. And they are all ignition protected too.

The battery switch is required by ABYC E-11 and surveyors will ding you if you don't have it. The Blue Sea 6006 is the candidate again, put one between the battery bank and the bus bar and you are in compliance. Note that if you use View 1 above, this will require four switches (about $25 each), whereas if you use View 2 above, you will only need one switch.

[Pblais]

I think Charlie did a great job with his post. As you put this together I would draw up a plan of it. A few years from now it may make a big difference in something if you need to make a change.

Depending on how you charge you might consider making two house banks and use a 1/2/both switch. With a limited charging ability you may do better using one bank at a time in rotation. You also have the issue that a bad cell or two could send the wrong signal for charging and you end up cooking the whole fleet. I do it with mine and I only have 4 Trojans. I combine them both all the time but if I detect one battery going bad I would switch out one bank. I've a friend with a bank of 16 all in one bank. If you have 8 you really need a lot of alternator to charge them up full again. You need to make that a goal when you charge.

I also have a 1/2/both with the starting battery. In case the starting battery can't start the engine. I've had it on both boats and used it twice. Each Tome was due to a problem. Nothing else would have worked. The good switches cost a lot. I wouldn't think to go cheap with that much battery out of you bank account.
It's not that you have to do it but if you recently bought these batteries you wallet got a lot lighter.

[bobfnbw]

Originally Posted by CharlieJ

There are two schools of thought regarding series/parallel battery banks. One view (mine!) is to use whips from the batteries to respective B+ and B- bus bars and then feed your loads from the B+ bus bars via appropriate circuit protection devices (CPDs). The second view is to connect the B+ and B- of each set to its neighbor until all are interconnected. From opposite ends of the bank, pull off the B+ and the B- to separate bus bars and then feed your loads via appropriate CPDs.

Regardless of how you do it, it is a high quality installation that ends up with a B+ and a B- bus bar to service the loads. Your I/C requires a Class T fuse. This is a very fast acting CPD and it protects the largest continuous electrical load on your boat. You should also install an isolation switch in the I/C B+ (Blue Sea 6006 is fine for less than 3.0 kW).


The battery switch is required by ABYC E-11 and surveyors will ding you if you don't have it. The Blue Sea 6006 is the candidate again, put one between the battery bank and the bus bar and you are in compliance. Note that if you use View 1 above, this will require four switches (about $25 each), whereas if you use View 2 above, you will only need one switch.

Thanks for the post Charlie.
What do you mean by a "whip"?

I also after a lot of research, and a recent thru hull electrolosis problem, to change from 6v golf cart batteries, to AGM's. I am going with the Sears branded odyssey batteries, and will only install 500 amphours.
I plan to add additional solar capacity (I have 2 100 watt panels now on a Xantrex controller) and a wind generator. And instead of a diesel genset, will put a honda on the aft deck, the new 3000 watt that weighs in at 75 lbs, due out this summer. That should bring everything up nicely.
Bob

[CorrinaCorrina]

I have a similar setup and this is what I designed:
Hook your batteries in series/ parallel. I used 2/0 between series connections and 4/0 for parallel connections (check out genuinedealz for wire prices). I attached my main positive wire from the battery (4/0) from one corner of my battery bank and my main negative (4/0) from the farthest end of the battery bank away from the positive draw. I then took my positive feed and ran it into an ON/OFF switch. Reason is for quick disonnect to depower the boat. From the ON/OFF switch I ran a 4/0 wire to a copper buss bar that I bought from Grainger ( http://www.grainger.com/Grainger/wwg/guideBrowse.shtml ) part number 2AAZ1.
I drilled several holes and some extras for ANL Fuse holders. These fuse holders would then supply to my DC Panel, Windlass, Solar Panel, Inverter and Alternator. The inverter you have would definitely require 4/0 wire for proper operation.
The negative coming from the bank I attached to a 600amp power bar from blue seas and made all my negatives ultimately attach here. If you have a shunt place it in the negative coming from your battery bank.
I also designed it to allow my house to crank my engine incase my engine battery died. This is done by simply running a cable from your on/off switch to position 1 on a 1/2/both switch. Position 2 is for your engine battery and your starter attaches to the Common post.
Hope this helps.

[CharlieJ]

I am not a big fan of 1-2-Both-Off switches. Too many times they are left in the wrong position. I prefer auto charge regulators that will combine two banks whenever a charging source is available. The Blue Sea ML series is a latching solenoid that takes no power to hold the ACR in position, does not generate any RF noise (like some ACRs with PWM) and have a manual over-ride. I use the Blue Sea 6006 On-Off switch (300 amp continuous) to isolate the batteries.

The whips I spoke of are the, usually short, lengths of cable that connect the batteries to their bus bars.

The Marine Rated Battery Fuses (MRBF) carried by Blue Sea are just about ideal for your application: correct AIC, ignition protected and you only need to make a single crimp.

[redcobra]

Just checking my rusty electric theory here..
2-220AH@6V bats in series = 220AH@12V so 8-6v@220AH each in series parallel yields 880AH@12V. Right?

[GordMay]

Originally Posted by redcobra

Just checking my rusty electric theory here..
2-220AH@6V bats in series = 220AH@12V so 8-6v@220AH each in series parallel yields 880AH@12V. Right?

Right.

[Sandero]

I use a series parallel system with a separate house and start bank and a blue seas 8080 switch. This has a 100amp breaker as the main for the house bank. I have a large buss which is connected to the house pos by a whip and on that buss are the windlass, the alternator output, a whip to the battery switch, the inverter. All large loads are fused of course. This system means that when the house bank is off the windlass and the inverter can still see the batt output (each has an on off switch.) The 8080 can combine house and start banks if the start batt needs some help. The charging sources, alternator, solar and inteverter charge the hosue bank and the start bank is charged by an Echo Charge. I use a Link20 to see what's up in the system. This seems to be a good system and much improved over the OEM 1-2-both.

The one-two-both system is a management nightmare and you need to remember and monitor which batts are on.

[CharlieJ]

defjef-
I agree with your system but would like to offer one small operational improvement...you won't have to spend a dime!

Here is a link to the circuit diagram for the 8080: http://bluesea.com/files/resources/i...tions/9862.pdf

It has been my practice for sometime to wire the "Emergency Start" switching device, be it solenoids or manual switches, in the manner shown. However, I instruct my clients that, if they need to use the house battery to start the engine because the engine starting battery has insufficient voltage, than the last thing they want to do is "parallel" the house with the starting banks. They must first isolate the inadequate starting battery, and then use the house bank to start the engine. I often accomplish this with two Blue Sea solenoids (9012, or better yet, the 7700) and a toggle switch for "Normal" and "Emergency".

Your 8080 will accomplish the same task if:

1. The instructions are modified:

"In the event that the house bank is needed to start the engine, first isolate the engine starting battery from the circuit by turning the Engine Battery switch OFF before turning the Emergency Start switch ON. This will preclude allowing the house battery from attempting to charge the low voltage engine start battery.

2. The label is changed from "Emergency Parallel Switch" to .Emergency Start Switch".

[redcobra]

I just changed my system to a two circuit Blue Sea battery switch that keeps the start and house systems separate unless in and emergency combine mode. The alternator output goes to the Start bats and the shore power charger goes to the house bats. An ACR connects the two bat sys. The switch allows paralleling the sytem for emergency starts.
Two questions.
1) As long as I switch out of the emergency start position after the engine starts why do I need to disconnect the start battery before using the house?
2) Why do many folks charge the house bats with the alt output then echo charge (or ACR) the start sys? Seems you would want the start bats charged first when powering.
Thanks, I have learned a lot here.

[CharlieJ]

Originally Posted by redcobra

1) As long as I switch out of the emergency start position after the engine starts why do I need to disconnect the start battery before using the house?

Refer to the Blue Sea circuit I referenced above.

If the initial condition is that you have a discharged or failed starting battery than by "paralleling" with the house bank, the house bank is going to attempt to charge the discharged starting battery and there may or not be enough energy in the house bank to also start your engine. By switching the defunct starting battery out of the system and routing the house bank current directly to the engine starter, you preclude this issue.

Originally Posted by redcobra

2) Why do many folks charge the house bats with the alt output then echo charge (or ACR) the start sys? Seems you would want the start bats charged first when powering.

For the answer to that; let's do some math. Assume that your engine starter requires 400 amps for 10 seconds to start your 130 hp diesel and that you are using a series 31 battery as your starting battery.

The total Ahr used from your starting battery would be:
400 amp x 10 s x 1 hr/3,600 s = 1.1 Ahr

Your series 31 battery has a nominal 800 marine cranking amp and 100 Ahr capacity so you are using about 1% of its capacity. Since the Ahr draw is so low, your charging source will bring it back to full charge quickly. It would therefore follow that the start battery should have the priority in charging. However; if you have an inverter/charger (I/C) with an echo charge capability installed, than the house bank will be connected to the main terminals and the starting battery is connected to the echo charger. So the I/C has muddied the logic.

I am a proponent of ACRs. The latest versions of these units from Blue Sea Systems does not favor one terminal over the other although I force the issue by connecting all charging sources to the B+ bus bar for the house bank. This system works well especially if you add a couple of BS 6006 on/off switches (or, more elegantly, two ML series solenoids) to provide the capacity for emergency starting from the house bank.

I hope this has helped.

[redcobra]

Here is what I ended up with. Comments?