Looking for Wiring Schematic for this Scenario

[KevinE]

My battery system is a complete mess do to many additions / changes made by the previous owner. I want to take it all apart and re-wire but am looking for a proper schematic before I start.

Heres my existing setup:
Link 2000 monitor w/ Zantrex charger / inverter (2500w)
4-6v golf carts wired into two 12v banks
separate starter battery
100 amp alternator
1 battery switch (1-2-all)
2 battery isolators (see below)

Problem
When the previous owner added another bank, he daisy chained another isolator into the circuit which has caused a voltage drop across the second set of batteries. When using both house banks concurrently, most of the current is taken from one bank and very little from the second. Converse is true with charging - I can't seem to get a full charge on one of the banks. This has caused one of my banks to sulfate up.

Questions
Do I need to abort on the isolators and go with a combiner?
Looking for a good schematic that can show me how to properly wire ALL of the above noted items. Most of the schematics I have found do not deal with all the various charging sources (alternator / shore charger).
I also a little confused as to how to set up the switch. Is bank 1 my house, 2 the starter?

Thanks in advance
Kevin

Kevin,

I suspect the problems you see in charging one bank is due to the voltage drop across the isolators. Putting two of them in series is a recipe for exactly the kind of serious problems that you see. It is difficult to be sure without a schematic of your current system, but that is my bet. In any event....

Current best practice for maximizing battery life and usability is to use a SINGLE house bank. Sounds like you have most all of the bits and pieces for putting together a first class system, but they are cobbled together in a less than optimal way. The 1-2-all system just isn't up to a modern boats power demands.

My recommendation would be to put all of your 6v batteries in one bank. Keep the starting battery seperate and use one of your isolators to hook that into your charging system.

Throw out the 1-2-all switch, and install three on-off battery switchs. One to turn the house bank on and off, on for the starting battery, and one that can cross connect the two banks in the event of a dead engine battery.

Nigal Calder's Boatowner's Mechanical and Electrical Manual will have the kind of schematics you are looking for.


Bill

[DeepFrz]

Blue Sea has some schematics for DC distribution and charging circuits such as the one at this URL

http://www.bluesea.com/Article_detai..._ID=291&id=303

Deep

[Sandero]

I can send you my schematic which is not exactly what you are looking for but works quite well. I use a blue sea 8080 which isolates (or combines) a house and start bank and includes a 100 amp breaker. I do not have separate banks for house batts.. but 2 8D in parallel. I have included link20, Trucharge 20, Inverter, Pulsator, solar panels w/ PV 14 reg...

PM me and I can send you an image file of the schematic

Jef
sv Shiva
Contest 36s

[Pblais]

I am redoing mine as well and have a similar setup. You can use a single isolator and then tweak the regulator voltage so you compensate the voltage drop.

They make cute gadgets (auto charge relays) that tend the starting battery and then you don't need an isolator. The one on mine was an Ample Power Eliminator. On paper they sound great and original owner of the the boat said it worked great - but it died between when he sold it and I got it. That is how my mess came to me after the most recent owner got the boat from a yard or did it himself. They can still bite you when you get into other situations too so in the end you are stuck with some scenario that can end run the plan. Personally staring batteries are cheaper and as long as anything is running I can start the engine.

You can attach the shore power charger directly to each bank (starter and house) The Xantrex supports an equalization cycle so you can take the 4 golf carts and make one bank. It's easier to do that. So on shore you have what you need all the time for each.

What I did with the switches is this. I have two (1,2,Both, or Off) switches. The first is used to put all 4 golf carts in a two banks but combined when in the (both) position. Now if I notice one of the batteries is acting funny in a cell or two I can switch that pair out (switch to 1 or 2) of the setup and not have the bad cell cascade to the good pair. That was always the reason you made separate banks of flood batteries. I can use the OFF position to just shut it all off so I can work on it (the solar panel is always on in the daylight).

The second switch is set to 1 so the starter battery starts the engine. Position 2 would let the house bank start the engine and both would maybe never be needed but if it came down to it everything can be used.

I also have a battery monitor on the two banks. The only hole is that the alternator regulator is based on the house bank sensor and the starter goes along on the same ride with the isolator. For about $400 you can get something to handle that instead of a $70 isolator. There are products from Balmer and others. Read all the details before you jump on board.

My solar panels are handled by the same regulator that handles the alternator so that input is properly regulated. The House bank has it's own shore charger regulation and so does the starter.

This all works pretty well since you never need to turn any switch under normal operations. You don't need to remember what to switch is off or on unless it's not normal.

You could stay with three banks but then you end up spending more money and have to remember to alternate the house banks regularly. Since you need to watch flood batteries any way if you can switch out a bad batter at least you have 1/2 capacity and that is all you could ever have in a three bank situation. If you let the bad cell cascade then you were not watching close enough any way and it's the same damage.

My last boat was set up similarly except with AGM's as the house bank. This setup is tuned more for flood batteries and since the regulator is a nice one and I have a spare brand new one it seemed a better choice than switching all the gear to handle AGM's (really are better).

[KevinE]

Bill,
Your thoughts are exactly what I have been thinking! Is there any loss in charging efficiency with all the house batteries on one bank? Also wondering about the zantrex charger and alternator - how do you wire them so that no damage is done to the battery if the engine is started or is this even an issue?

Kevin

[Rick]

Bill did a great job in his presentation of a good solution for you. Today's equipment is such that one can turn on/off any charge source and turn on/off any load without having to be concerned about damaging anything. One caveat, of course, is to not have a load that can cause overheating of an alternator...another discussion.

I am in favor in the use of automatic battery combiners to eliminate the use of any diode isolators. Diode isolators historically are not reliable in addition to the unnecessary waste of power with their use at high currents.

Originally Posted by KevinE

Is there any loss in charging efficiency with all the house batteries on one bank? Also wondering about the zantrex charger and alternator - how do you wire them so that no damage is done to the battery if the engine is started or is this even an issue?

There is no loss in efficiency, only gains, by switching to a single bank.

As for your question about the Zantrex and the alternator, there are two possibilities. If you are away from the dock and have no generator running, there is no issue at all. The Zantrex would have no way of knowing if the voltage being supplied to it was coming from the batery or alternator. If you are feeding 120VAC from shore power or a generator and the Zantrex is in charge mode, it would be good practice to avoid running the alternator at the same time, but I am aware of no damage that would occur. The best source of information about this would be the Zantrex owner's manual.

Rick's comment about being able to turn anything on and off without damage is generally correct, BUT....There are two situations that you should avoid. One is running an alternator without a battery connected. For most alternators this will result in fried diodes in the blink of an eye. You also should avoid running the Zantrex battery charger without a battery in the system. It won't hurt the Zantrex, but the voltage will not be well regulated and could damage other components in the electrical system. (ask me how I know...) In the best of all possible worlds, an electrical system would be designed to make doing these kinds of things impossible, or at least very difficult.

An additional comment on isolators, they have fallen in disfavor recently as reliable combiners have taken over, and for lots of good reasons. For the situation where you are charging a house battery with the main alternator, and use the isolator to feed the charge current to the starting battery, they are useful if not optimal. They will typically generate a voltage drop of 0.7 volts. This will not keep them on a proper charge while the main system is in "float" mode, but while the main system is in "bulk" and the voltage is ~14.4V you ought to be able to replace the relatively small amount of charge pulled out during engine starting. It might not produce the longest lasting starting battery possible, but they are fairly cheap to replace (compared to deep cycle batteries). If you get 4 years instead of 8 from you starting battery, is that worth the cost of a combiner?

What I use in my system is Blue Sea System's BatteryLink current limiting switch. Functions like a combiner, but has some additional functionality and self-limits the current flow so you can avoid the high capacity cable runs that would be needed if the starting battery is not close to the house battery.

Bill

[KevinE]

I think I am going to go the combiner route.

Found a good write up on combiners at http://www.yandina.com/combInfo.htm

Check out the projects sections also.

Cheers,
Kevin

[hellosailor]

Kevin, Yandina makes the "West" combiner. There's a solid-state combiner ont he market, hellroaring.com is the URL for it. I'm not sure that I would want solid state for this, as opposed to the tried-and-true technology of the relays in the Yandina though.

Combiners of any kind are further away from "KISS" than simple switches...but they are a nice way of accomplishing the goal. Just do make sure they are rated high enough to handle the amperage of your system, I think Yandina only stocks 75A and 150A models.

[Rick]

Having designed the PathMaker battery combiner series that Xantrex now distributes I am very famaliar with most of the solenoids that are affordable to use in battery combiner applicatons.

The best high current ones use the gray sealed solenoids made by Kilovac. You see them in Blue Sea Systems as well as the Xantrex "250A" battery combiners. Those solenoids are conservatively rated and I have tested them to over 600A for minutes even though that is not their rating.

I have not tested the Blue Sea Systems alternator combiner yet it looks good on paper to me.