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Frank C wrote: ...
I've decided that's my direction and just punt on the starting battery - ...
The only problem with creating a single bank is guaranteeing that the batteries are always on-line to the alternator ... means I need to assure that crew do not click-off the battery switch when the outboard's running???

TT's got it. As mentioned above, I'm planning to parallel my two batteries into a double-sized House Bank. I was convinced long ago (by Duane Dunn) that it's folly, in my case, to waste a full-sized battery just for starting the outboard. Most motorcycles with bigger motors use a tiny power pack for starting, about the size of a lantern battery.

The Sail Magz article explains why doubling the size of a bank can triple the longevity of the batteries. This probably means I don't need my existing battery switches, nor my West Marine combiner.
(Maybe I should include them in a "package deal" with my sun-beaten Winchers! )

I suppose I DO need ONE SWITCH, just to kill power to the DC panel, say if I ever smelled electrical smoke, eh? But I'm confused from reading about "alternator diodes." Apparently there's a requirement to keep some "electrical ballast" attached, like a battery bank, whenever the outboard is running. This means it would fry my alternator if an uninformed guest or crew switched OFF my new, single battery bank?

I think this is also related to the warnings that switches must always be of the "make-then-break" variety. Could the resident electrician pls explain? Thanks.

TT's got it. As mentioned above, I'm planning to parallel my two batteries into a double-sized House Bank. I was convinced long ago (by Duane Dunn) that it's folly, in my case, to waste a full-sized battery just for starting the outboard.

And I'm convinced that it's far greater folly not to keep your two battery banks fully isloated for safety reasons.

Comparing these systems to motorcycles or cars is folly as well. If you can't start your car, you call AAA or your buddy with jumper cables and retire to the nearest Starbucks or bar to wait for help to arrive.

I've started my Tohatsu 50 with a rope; I can tell you it's incredibly easy; and I can also tell you that having done it several times and knowing exactly how, it's even money I could do it in less than five minutes.

I won't insult anyone's intelligence by going through the litany of the really bad things that can happen in a boat without propulsion power in five minutes.

DLT wrote:To help clarify this, I believe:

The common terminal of the typical 1-2-N-B switch of wired to the motor starter, motor alternator, and DC panel. Of course, motor starters and alternators are often wired together, such that they use the same wire.

for the purpose of our discussion, use the outboard motor example in the link above that uses a 1-2-n-b switch and a combiner. you've gotta use the combiner for charging ease regardless if you use the 1 switch or 3 switches.

Thus, if you had the motor running, you could power your DC panel, even if the switch is in the None/Off position, or there were no batteries. Subject to charging capacity versus load issues, of course..

you're confused. switch to "1" and your starter battery is used exclusively to start the motor. switch to "2" and the house battery is used exclusively to start the motor while still running the house lights. switch to "both" and both batteries together are used to start the motor. however, "both" also uses the two batteries together to run the house lights which isn't necessarily good because you could drain your starter battery. switch to "none/off" and when you turn the key you will get nothing. however, you will still get house lights from the house battery even when it's in the "none/off" position. "none/off" only controls the amps to the motor.
but, never ever turn the switch to "none/off" while the motor is running. that is a no-no.

The "1" and "2" terminals are typically connected to the different banks.

yes!

So, most people switch to "1", which is typically the starter bank, and start the motor. Then, they may switch to both, to charge both banks off the motor

you are confused...most just leave it in "1". there is no need to switch to "both" because the combiner will take the charge from the motor and first charge the starter battery. then, once completely charged, will charge the house battery until fully charged. that's the beauty of the combiner.

After they shut the motor off, they switch to 2, to run the house off the second bank.

again, you are confused...you do not need to switch to "2" to run the house. the house battery is already connected as a seperate circuit for the house. you would only switch to "2" if your starter battery died and you now want to start the motor. by switching to "2", "2" now starts the motor and is also used exclusively as the house battery while the starter battery ("1") just sits by itself and receives a charge from the motor via the combiner.

There are all kinds of variations on this... For example, some motors may be wired directly to the starter bank. But, I believe this is the basic "traditional" method.

OK...

These charging relays/combiners simplify this somewhat by allowing you to wire the motor straight to the starter bank and only the DC panel to the switch. In this case, most people probably leave the switch in the "2" postion, relying on the relay/combiner to charge the house bank when the motor has charged (or is charging) the starter bank.

incorrect...again the combiner will charge both batteries regardless of what the switch is set to. when at "1", the combiner charges the starter battery first until it is fully charged, then switches to the house battery and charges until it's fully charged. when the switch is set to "2" and the motor is running, the house battery is charged first, then the starter battery

Chip wrote: True, but note that wired in this fashion, no matter where the switch is set, the house battery is permanently connected to the DC panel and cannot be disconnected without pulling one of the terminals off the battery or cutting the wire.

you are absolutely correct. the only way the starter battery gets on the house circuit is in the "both" position. then both are starting the motor and both are being drained by the house lights.
the starter battery can not ever be used to run the house exclusively nor the house exclusively to start (and not be attached to house lights).
but for me, that's OK. i have to protect the starter battery because there's no way in hull i can "pull start" my 90 TLDI.

in conclusion, i either use my starter battery exclusively to start the motor ("1") or when it's dead i've got a switch to use the house battery to start the motor("2").
but because i have a good starting battery, i rarely need to change to anything other than the "1" position. the combiner does all the work in charging both batteries while isolating the banks from each other.

am i being clear?

Chip Hindes wrote:

TT's got it. As mentioned above, I'm planning to parallel my two batteries into a double-sized House Bank. I was convinced long ago (by Duane Dunn) that it's folly, in my case, to waste a full-sized battery just for starting the outboard.

And I'm convinced that it's far greater folly not to keep your two battery banks fully isloated for safety reasons. ... .

Frank C wrote: ... just punt on the starting battery - the Suzuki's starting demand is so slight that the house can easily supply it, even when low. I always carry the jump-start battery too, so that's my backup.

because the combiner will take the charge from the motor and first charge the starter battery. then, once completely charged, will charge the house battery until fully charged. that's the beauty of the combiner.

No it isn't. What you are describing is a VSR, voltage sensitive relay. It first charges the priority battery (normally the starting battery); when that comes up to full charge, it switches to the other battery.

A VSR and a combiner are not the same thing. A combiner does just that: it simply combines the two batteries to charge both at the same time; then separates them again when they reach full charge.

A quote right out of the installation manual you provided "In all cases, both batteries are being charged when the engine is running". That is not true of the VSR, which charges each battery in turn. It's not just semantics, it's a fundamental difference between a combiner and a VSR.

Funny thing, West Marine used to recommend the VSR over the combiner before they quit offering a VSR.

I always carry the jump-start battery too, so that's my backup.

I get the same thing from my existing two battery setup, without the need for a separate jump start unit. One less thing to forget, or forget to charge.

Frank C - the older Alt's needed a voltage or they would fry with no voltage. That is the what happens when you switch to the off position. However the newer alt's have this solved.

AGM bateries- the problem that cruisers was having with the AGM's was that they was dieing too soon and the wet cells were not so the wet cells was a better deal in the long run given the proper protection.

Chip Hindes wrote:

because the combiner will take the charge from the motor and first charge the starter battery. then, once completely charged, will charge the house battery until fully charged. that's the beauty of the combiner.

No it isn't. What you are describing is a VSR, voltage sensitive relay. It first charges the priority battery (normally the starting battery); when that comes up to full charge, it switches to the other battery.

A VSR and a combiner are not the same thing. A combiner does just that: it simply combines the two batteries to charge both at the same time; then separates them again when they reach full charge.

A quote right out of the installation manual you provided "In all cases, both batteries are being charged when the engine is running". That is not true of the VSR, which charges each battery in turn. It's not just semantics, it's a fundamental difference between a combiner and a VSR.

Funny thing, West Marine used to recommend the VSR over the combiner before they quit offering a VSR.

before i agree with you, please read the section called "operation" beginning at the bottom of page 2 and comment.

battery combiner

i now recall someone (Duane?) saying that the bad thing about the combiner is that if you have a new/good battery and an old battery that the combiner will charge both batteries to the level of the old battery.
thus bringing the new/good battery down.

does that make sense? and, is that correct?

so i replaced both batteries at the same time...

Wow...

I just started this thread to mention a good article (to me at least) in SAIL. Just that the 3 switch idea seems to catching on...it is just not in the pages of the West catalog anymore. Is it the only or best system. No. It is the best system for ME though. YMMV.

I noticed too that west recommends a combiner vs a VSR. Guess it depends on what they are selling at the time.

Even if I decided to run both batteries together according to the sail article, I would probably still use the 3 switch method and just leave it connected with the emergency (jump start) switch switched on. You get 2 batteries on all the time..and if you need to separate them for whatever reason...you can.

Paul

Paul S wrote:... if I decided to run both batteries together according to the sail article, I would probably still use the 3 switch method and just leave it connected with the emergency (jump start) switch switched on. You get 2 batteries on all the time..and if you need to separate them for whatever reason...you can. Paul

Good idea

Hey Chip!

someone else has the same impression as i do of what the combiner does.
that is, when motoring the starter battery (or battery connected to the motor) is charged first, then the house battery is charged.

Night Sailor wrote:The start battery is combined to the house bank with a West Marine 50 amp battery combiner. When it has a full charge, then any charging current goes into the house bank until they are fully charged. Neither can draw from the other because of the combiner.
I haven't had a single issue with low voltage since I set that up. I highly recommend it.

also, on the dock or in my driveway my 110 volt charger is connected to my house battery. hence, with the combiner the house battery is charged first and then the starter battery is charged until they both reach 13.3 volts.

before i agree with you, please read the section called "operation" beginning at the bottom of page 2 and comment.

Note the paragraph heading "Battery Charger". This is talking about a single bank shore power charger, not the engine alternator, and it works that way only if you connect it (the charger) to the house battery, as stated in the paragraph.

Note also that by charging the house battery first (as you correctly stated) this works in the opposite manner which most people prefer; i.e., that the starting battery be charged first.

The difference between a combiner and VSR is frequently confused. It doesn't help that the West Marine advisor recommended first one, then the other depending on what they offer and don't offer.

My shore power charging system has a permanently installed two bank charger that does both batteries at the same time. It's the best possible situation, but it is fairly expensive and your system should work just fine most of the time.

i now recall someone (Duane?) saying that the bad thing about the combiner is that if you have a new/good battery and an old battery that the combiner will charge both batteries to the level of the old battery.
thus bringing the new/good battery down.

This is repeated fairly frequently in all the literature; I believe it's true generally whenever you have a two battery system; whether hooked in series or parallel electronically or with wires.

I did the same last year; though both of mine failed at pretty much the same time so there was no choice.

I maintain that a "real" starting battery (high CCA, non deep cycle) is a waste in a Mac. The deep cycle batteries have plenty of cranking amps for our little outboards. Both my batteries are identical standard Mac-size 80A-h deep cycle, and I intend to swap the "house" and "starting" batteries every spring to even out their usage patterns.

I considered going to larger than stock batteries, but there is a potential problem with a VSR in that it won't switch properly if the battery capacity is too high compared to alternator output. The standard 80A-h are already over the recommended limit for my puny 11A Tohatsu alternator, but so far it seems to be working properly. Won't be a problem when I go to the Suzuki 140HP with 40A alternator; guess I'll have to figure bigger batteries as part of the cost of the motor swap. Right

so...help me understand how the combiner works completely:

- with a 110 charger attached to either battery (house or starter), the charge goes to that battery first until it is fully charged, then to the other battery until it's fully charged.
we agree on this one...

- however, based on what you say based on your interpretation of the instruction book, when the motor is running it's quite different. that is, the charge from the motor goes to both batteries at the same time. this occurs even if (on a 1-2-n-b switch) the switch is at "2" where the house battery serves as the starter battery and the starter battery sits unattached to anything during that charging period.
I'm really struggling with this one...

that is...a charge is a charge. whether it comes form the motor or a 110 charger the combiner doesn't know the difference, does it?
if it doesn't, then the way the charge process works is that the battery attached to the charging "vehicle" would be charged first, followed by the "other" battery in all cases.

or they are both charged at the same time in all cases.

you and the instruction book say that it charges two different ways. at the same time when the motor's running and seperately when hooked to a 110 charger.

Some combiners connect both batteries in parallel as soon as they detect a charging voltage, regardless of the charge states of the batteries.

The ones I've looked at connect both batteries in parallel as soon as they detect a charging voltage on EITHER bank. But, I guess some could work off just one bank.

One thing to note here is that it is detecting a charge voltage. So, if the bank receiving the charge is really depleted, the combiner may not actually see a charge voltage until it has recharged that bank somewhat...

good point!
however the west marine combiner 50 talks out of both sides of it's mouth.
says it charges in parallel, and also says that one is charged first until it gets to 13.3, then the other is charged.

- with a 110 charger attached to either battery (house or starter), the charge goes to that battery first until it is fully charged, then to the other battery until it's fully charged.
we agree on this one

I believe this is correct, but note the charger paragraph states, "A single output charger can be connected directly to the house battery". Does this mean by inference, a single output charger cannot be connected directly to the starter battery? If not, why not? I don't know.

- however, based on what you say based on your interpretation of the instruction book, when the motor is running it's quite different. that is, the charge from the motor goes to both batteries at the same time. this occurs even if (on a 1-2-n-b switch) the switch is at "2" where the house battery serves as the starter battery and the starter battery sits unattached to anything during that charging period.
I'm really struggling with this one...

Not exactly, and I apologize, but my previous explanation was incorrect; I really screwed this up and should have kept my typing hands in my pockets.

I misinterpreted both the West Marine explanation "both batteries are being charged when the engine is running" and the implications of the switch position.

Wired as pictured, the battery which is switched into the starter circuit will be charged first.

If the switch is set to 1, the starter battery will be charged first. When the starting battery reaches 13.5V, the combiner will parallel the house battery and charge that. In this switch position it will function exactly as you originally described.

If the switch is set to 2, the house battery will be charged first, and the combiner will parallel the starter battery when the house battery reaches 13.5V.

If the switch is set to Both, both batteries will be charged simultaneously, and the combiner will have no effect.