Outback wiring question

[davidwigler]

Has no one yet found a solution to charging a separate starting bank from the Outback inverter? I can't find an Automatic Charging Relay or any other similar product rated for 32 volts. This would be perfect if it operated at 32 volts:

http://www.boatfix.com/shop4/store/v...idProduct=6222

[carolinacoast]

we apparently used the oem wiring including the inline fuses that protect from overcharging. when the starboard engine is started with a somewhat low voltage condition it is pulling amps from port through the fuses designed to protect one side, not 2 (and in the other direction). the outback is wired as the combiner. He likes the idea of just a charging solenoid instead of the expense of wiring the batts in parallel. I told him we wanted the charger at the end of the circuit with one set of wires on the single output, and to please price the 15'(or so) run of cable. does his solution have any merit or cause other problems? I'm sure the solenoid is cheaper, but he is defending the work he has already done. it seems that a heavy draw on the inverter would cause a problem as well.

[carolinacoast]

Rob- yes we are blowing a 50 amp 32 volt fuse on the output dc side. mal

[MikeP]

What the mechanic "likes" is not going to work. THe Outback does not have multiple battery charging outputs. It can only charge one battery (or bank). So the only way to use it as the only battery charger for the mains is to combine the two battery banks first and then wire the outback to the battery bank as per the outback instructions.

The only way that I can see to use the outback as the only charger AND be able to maintain separate battery banks is to use a battery combiner. These work great and I have one on a 12 v system but as far as I can tell, nobody makes a 32v battery combiner. Somebody here is probably smart enough to figure out how to make one! But I have to admit that even if they made one, I wouldn't use it because batteries/charging are more efficient as one large bank as opposed to two smaller banks.

Sometimes this stuff gets complicated because of the use of the terms "battery banks" and the associated number of batteries. Try to think of it in simpler terms - despite the fact that you have 4 8v batts in each bank, think of it as if you have ONE 32v battery on each side. Despite the fact that you have 4 batteries connected in series, you end up with ONE Positive and ONE negative battery terminal to connect to the system, just like a simple car battery. So you have one 32v battery on each side and you simply want to run them in parallel.

It's no different than doing that with a pair of 12v batteries. You simply connect a suitable gauge wire from the Pos on one of your "32V" batteries to the the Pos on the other "32V battery." Since both 32V batteries already have their Negs connected at a common neg buss, that's all that has to be done. The banks are now in parallel (combined). If you want, you can add a batt switch to that POS cable to return the batts to normal configuration (de combined) anytime you want.

After that's done, the Outback is simply connected to EITHER Battery's Pos cable connector and to that batts neg connector or the neg buss. That's it. The Outback will now charge both banks and take inverter power from both banks and it has NOTHING to do with any flow of power to any other system; it is totally transparent as far as 32v operation is concerned.

Re isolation diodes - You can't actually connect multiple banks to the outback as it is constructed since it is not designed to deal with multiple banks. So if you actually connect the pos wires from both banks it will naturally end up combining them because you've inserted the outback into the combine circuit. But the "cable" used is way too small because the DC charger/inverter cable is that #8 being referred to and it cannot possible carry loads associated with starting. The outback cannot accept a cable large enough to act as the actual combine cable; no battery charger does.

The setup to do this combine thing is really simple and it works flawlessly. As often noted however, if keeping the banks separate as originally designed is necessary, the Outback, with it's single charge circuit output, is not the way to go unless you use another one or some other 32v charger for the other bank (or figure out how to make a combiner)

Combining the oem banks into one single bank is more efficient for the batteries BUT as has often been noted it does create the possibility that you could draw down the batteries far enough to not be able to start the mains. That has never happened to us and we are on the hook anytime we are out but it is theoretically possible. SO I would suggest that if the boat has only a 32v system, combining the banks may not be a good idea. HOWEVER, many boats now have 12v gennys so they have a way to start the genny/charge the main batts even if the 32's are flat and that makes the issue pretty much go away since no matter how flat the mains are, you can charge them with the genny.

Obviously this is a matter of personal use/opinion. I think the Outback is perfect - it's extremely efficient, very smart, has settings available for everything in very fine increments (.1 V) and just does an outstanding job. It ran the fridge for 36 hours while the boat bottom was being painted and when dropped in the water, the engines spun at normal speed for starting. I'm constantly amazed at how efficient the inverter seems to be. At the same time, it can recharge the batteries two to three times faster than the old LaMarche did. BUT it can't charge separate battery banks. If that's critical then it's not a good choice.

[Jim saco]

Post #9 by mike P first paragraph is what I was touching on last night however it's explained better. I agree 100% with mike p. If the banks are not combined first then sent to the charger/ inverter you'll continue to blow that fuse. If there not combined first then it's wired wrong.
Jim

[carolinacoast]

we need to parallel the batts as suggested. the question I have been asked is can we do that with a 1 foot wire to bypass the "parallel solenoid" in the engine room and disable that function at the helm. this would save wire and am not sure if there is any negatives to it. thoughts?

[REBrueckner]

Mike:
"So the only way to use it as the only battery charger for the mains is to combine the two battery banks first and then wire the outback to the battery bank as per the outback instructions.

The only way that I can see to use the outback as the only charger AND be able to maintain separate battery banks is to use a battery combiner."

yes

Carolina:
" can we do that with a 1 foot wire to bypass the "parallel solenoid" in the engine room "

yes.

But I would not like to have all my starting batteries permanently cabled together.

(a) I'd follow Mike's suggestion and use a battery combiner instead...it automatically disconnects banks when the charger if off....

(b) OR think about placing a heavy duty battery switch in one of the outbank outputs...and one right at the "bypass" cable .....that way you can isolate the starting battery banks quickly and easily if you ever need to.

[MikeP]

Yes, you can do that with no issue at all. I thought about doing it and the only reason I didn't was simply because I didn't want to change anything in the oem wiring that I didn't have to - just for "originality."

But you will still need a separate DC fuse/breaker between the outback and the batteries (as shown in the Outback wiring schematic).

[carolinacoast]

decided to save the $250 worth of cable ($16/lf) and bypass the solenoid BUT adding a disconnect as you suggest. with the disconnect off the wiring will return to oem and the solenoid will function. with the batteries in parallel the solenoid function is not relevant anymore. Thanks for all of the great feedback. mal

[manderley]

Here is an idea of what might be happening.

You said the outback is now positioned in place of the LeMarche and it is blowing the 50 amp fuse.

If you look at the schematics, Hatteras has an ANL 50 amp fuse in the engine room breaker panel that is on the line out of the LaMarche output going to the battery.

In fact, by complete coincidence, I was changing the capacitors on my LaMarche and noticed that my fuse had been replaced with a wire and just last week I put a new 50 amp ANL fuse back in.

Since they mounted the LaMarche in the old location, I wonder if they used the existing wires (the old #8's) and are inadvertently and mistakenly running the Outback charger output through this fuse. This is not the right type or capacity and was strictly based on the wire size and the old LaMarche maximum 30 amp (on the 32v) charging output.

The correct wiring is for the DC charging output of the Outback to go by way of proper Battery cables (probably 1-0 or 2-0 depending on the length) through a Class T fuse of suitable capacity, (probably 200 amp or similar) to the batteries. No stops in between. (except if you add, as I did, a battery switch for emergency).

Similarly, when the inverter is on, those same batteries will supply power via those same battery cables, through the Class T fuse back to the inverter where it is inverted to AC.

Since the charging output can reach 85 amps on the VFX3232M, there should not be any # 8 wire anywhere in this circuit.

Don't forget, this is a long run and wires in engine room spaces have to be sized larger. The only fuse should be the Outback (and ABYC) recommended Class T-Fuse for an inverter installation. Check your own model specs for current loads; they are quite a bit higher for the 24v and 12v models.

You'd probably never notice this if didn't run the bank down and the charging currents stayed below 50a.

(By the way, the charging output can be limited on the outback in the setup mode to well below 50 amp by reallocating how much AC is available. Mine is set at 18 amps so that's about 2160 watts and at 34 volts, it's about 63 amps. Still above the Hatteras stock 50 A fuse.)

Hope that helps.

Larry
MV Manderley