battery monitor, one bank, no starting battery

[Maine Sail]

Ideally the Echo should be attached to each battery's positive post and fused with an in-line fuse but in the real world of boats this can sometimes be tough. Doing this will give the best performance and lessen the potential for voltage drop. Each termination carries a potential for VD depending upon the quality of the termination and its age.

This is not to say it won't work but without knowing the gauge or condition of your jumper wires I would tend to suggest going to the battery posts.


On my own boat I am currently using a Blue Seas ACR and it connects at the ANL fuse points for the banks but I am running 1/0 wire for the very short distance and these were terminated with a massive heavy duty lug crimper and then sealed with mil-spec adhesive lined heat shrink thus I know I have no voltage drop issues..

[barfwinkle]

I am sorry, but Maine Sail you should do an article on "How to Use a Multimeter". Just for dummies like me....

[chase]

Hi Maine Sail, et al, thanks for the great info, this has been an awesome thread.

I've just purchased a Prowatt 1000 from the place you posted, been waiting for a reasonably priced inverter. I’m going to go ahead and combine my two Grp 27's and add an inexpensive start battery for my Yanmar, which should only need 550 CCA. I like the charge the house bank approach and then Echo charge/ACR the little backup battery. I have some questions about wiring I'm not quite clear on.

1) I assume you terminate all your lugs yourself to get the shortest length necessary, do you have recommendation for affordable crimp tool? That's some serious cable, I guess I could do in vice but I just dont make battery cables to this standard in my shop. We use mechanical terminals and the vice for rings but always wished we could do a better job at re-terminating cables on equipment.

2) Does a stock alternator putting out less than 30A need a fuse such as the ANL installed in your boat? I know I need one for the Xantrex but I must admit there are no fuses on my boat between batteries and DC panel, etc, but now that I am doubling capacity, do I need two? One between house bank and inverter, another in between house bank and 1/2/All switch serving house loads? I presume 150A is sized right for two Grp 27's.

3) I don't have the skill to develop a wiring diagram for you to comment on, but perhaps this narrative will be comprehensible and you could check me out on my wiring plan:

***Two group 27's wired in parallel, with + and - jumpered with their own short cables, all 1/0? Hot from alternator goes to either hot in this bank. Either ground goes to block. Only thing direct wired here is fused bilge pumps. Hot wire to battery switch (Batt 1 position) fused with 150A ANL fuse to protect XAntrex inverter and DC panel with just one fuse? OR does inverter go straight to house bank bypassing switch and its own dedicated fuse and just gets managed with its own on/off switch? Xantrex XBM monitor wired just like it is now, to one of the house batteries and reprogramming monitor for double Ah? Or do you go to a hot of one of the batteries and negative of other? Then I get fuzzy with your installation with the ACR. I can’t make sense of that in the picture and wonder exactly where it goes? What I thought was between pos+ of house bank and pos+ of backup start battery with a fuse in between but yours looks like it is conected to the unprotected side of bank 2 fuse. Ground cable from Xantrex inverter to block? Do you use a bus for your grounds, so only one cable going to block?

***One backup start battery, wired to number 2 position on switch. Gets charged by ACR/Echo and gets exercised now and again just to make me feel better.

Thanks for any light you can shed on this for me, I’d like to accomplish the following:

1) Avoid burning my boat down
2) Maintain high level of conductivity with quality terminations/connections
3) Increase house bank to avoid running engine for many days at the time
4) Sail offshore to Maine in two years and meet new friends, have radar to find them, running off my robust house bank. I’ll owe you one by then-

Thanks for any contributions-

Chase

[Maine Sail]

Chase,

Fusing is up to you on your boat. I always try and wire to ABYC standards which is not always an easy task. The amp rating of the alt is not the question as they are self limiting by design. What you are protecting is the wire leading from the battery to the alternator in the event of a short. An ANL can also act as your switch when wanting to do work on the alt as pulling it can disconnect the alt from the batt in a direct wire situation.

With battery bank fusing you are generally protecting the wire from a dead short.

The three fuses on the left of that photo are "bussed" together because each item needing fusing, house bank, alternator and battery charger all have and need a different size fuse and one size does not fit all. Seeing as charger & alt all lead to the same spot, the house bank, it was easier to make a custom copper buss bar and tie them together and use one common wire from the house bank.

The fourth fuse in from the left is the 150 amp fuse for my inverter and the one on the right is for my starter bank.




Your wiring description sounds good except for ground or hot to either lug. You want to wire the ground to the opposite side of the parallel chain that the hot connections are. Your eng ground should come off one battery and all pos connections the other so the current is forced to flow through the entire bank. You may also consider the Blue Seas MRBF fuses, Defender sells them.


Single Post MRBF


MRBF Fuse


Dual Post MRBF




P.S. Don't worry about schematics I don't use them or bother to draw them. I just do the layout in my head and wire. I suppose I may draw a schematic for my boat for a new owner when that time comes but it is really pretty simple....

[chase]

Thanks Maine, very helful, never seen those little fuses, looks like a great option.

As usual, your crisp photography and descriptions are VERY helpful, thanks for the time.

Chase

[tjr818]

...First you'll want an automatic battery combining relay (ACR) or an Echo charger to keep the emergency bank topped off. I personally prefer the Echo Charger. These devices are reasonably priced and simple to install. They also remove the potential for human error while at the same time charging BOTH banks without the need to flip the 1/2BOTH/OFF switch.

Re-wire the alternator output:

One more change you'll want to make while in there is to run your alternators output wire directly to the house bank.

Most boats run the alternator the starter then over to the common post of the 1/2/BOTH/OFF switch. This allows for the switch to pass through the off position which can fry the diodes in your alternator if the motor is charging or running.

By doing this you will no longer run the risk of frying the alternators diodes by passing through the off position on the battery switch or having a guest flip the battery switch off, at the end of a sail, with the motor still running, thinking they are doing you a favor. You'll also put companies like "Zap-Stop" out of business. A product like "Zap-Stop" is only being sold because of DEMAND due to HUMAN ERROR. This upgrade may take all of 20 minutes to do and can save you hundreds of dollars in alternator repairs.

In summary using a 1/2/BOTH/OFF switch

1) House & emergency banks
2) Add an ACR or Echo charger to charge the "emergency bank"
3) Direct wire the alt to the house bank.

...

Ahoy Maine Sail,
Okay I would love to do this, and NOW is the time. I have all of the battery cables off of the battery selector switch. Where o where did they hide the alternator output wire? I would have thought that it would be a good size cable (10 gauge or 8 maybe) I don't see anything that heavy on the panel. Wouldn't it come up to the common terminal on the selector switch?

[hilbert]

Most boats run the alternator the starter then over to the common post of the 1/2/BOTH/OFF switch.

Tim,

Excuse me for budding in and Maine Sail can correct me if I am mistaken, but I'm not sure that the above explanation was clear.

In many cases, there is a relatively small wire running a short distance from the alternator to the positive connection on the starter.
The charge from the alternator runs back through the starter cable to the switch on the panel. There is no separate cable from the alternator to the switch.

[Maine Sail]

Most boats run the alternator the starter then over to the common post of the 1/2/BOTH/OFF switch.

Tim,

Excuse me for budding in and Maine Sail can correct me if I am mistaken, but I'm not sure that the above explanation was clear.

In many cases, there is a relatively small wire running a short distance from the alternator to the positive connection on the starter.
The charge from the alternator runs back through the starter cable to the switch on the panel. There is no separate cable from the alternator to the switch.

This is correct. In most factory installations the alt B+/output jumps over to the starter lug where it picks up the large gauge wiring back to the "C" post of the batt switch. Not ideal but it is cheap, easy and works.. In higher performance installations the alt is usually direct wired to the house bank.


P.S since this thread launched there has been some new developments in battery monitoring specifically the new Balmar Smart Gauge. MUCH EASIER!

[chase]

Hey Maine, haven't seen the Balmar yet. Can it show amperage like the victron and others? That's a great trouble shooting function, in addition to having decent battery monitoring functions too. I don't understand how they accomplish that with the Balmar without a shunt, but I'll check it out some time.

[Maine Sail]

Hey Maine, haven't seen the Balmar yet. Can it show amperage like the victron and others? That's a great trouble shooting function, in addition to having decent battery monitoring functions too. I don't understand how they accomplish that with the Balmar without a shunt, but I'll check it out some time.

The Balmar is a simple SOC battery monitoring unit that never needs synchronization or continual programing even as the battery ages. The longer it stays connected to the bank the more accurate it gets. This is just the opposite of an Ah counter.

SOC & your average DOD are all that really matter, in terms of battery monitoring, to getting the most cycles out of the bank. This device does not show amps as it is not designed for that. It is designed for the 98.9% of boaters who have trouble keeping an Ah counter accurate, and 98% of those don't even know their Ah counter is not accurate....

More info here:

http://www.pbase.com/mainecruising/smart_gauge

[tjr818]

This has been moved to a new Thread.

Okay, we are going to go with the idea of keeping the starter battery as an emergency only battery, so we are ready to install either a ACR or an echo charger. BlueSea makes what seems to be a very easy to install ACR. Which is the prefered way to go? What echo charger would be recommended? Sláinte will have a Group 24 "Emergency Start" battery for her little one cylinder Yanmar and a Group 27 Deep Cycle as Battery #1. Defender has a Battery Maintainer that seems like it would do the job. Here is the link to it : http://www.defender.com/pdf/259333_Sterling.pdf
Sláinte is kept at a dock where I have shore power available and she has a new ProMariner 10 charger on board.

Any ideas or recommendations would be appreciated.