Battery Wars

[rickalan35]

Hi Everyone,

Hope you all had a great weekend.

When Carver purchased the remains of the insolvent Trojan Corporation and then proceeded to manufacture their own Trojan 370 Express (the model that I own), I think they came up with a battery arrangement that may suit some people but sure doesn't suit me.

They have battery #1 for the Port engine, and Battery #2 for the starboard engines. They have a "spare" battery #3 for the Isolator button on the dash, to be used when both "engine" batteries won't start the engine. Plus there is a remote battery #4 for the generator.

In my previous Trojan, I had two starting batteries connected together to start the engines and identified them as Bank One. Then I had four "House" batteries connected together to power the DC system and identified as Bank Two. A separate isolated battery started the generator. When plugged in, the onboard AC battery charger, charged both banks plus the generator battery.

I have already run my batteries right down once while overnighting on the hook but thank goodness, the Isolator battery had enough juice in it to start my engines.

After load testing today, I found that two of the three batteries (battery # 1 and the balance battery) were toast. I have now replaced them.

But still, even with the new batteries I just installed, with the current system in place, about all I can think to do is run only Bank One (one battery) while on the hook to avoid the risk of not being able to start the boat. I don't like running the DC systems on one battery when I have four. Thoughts??

[captainmaniac]

Can't really speak to your specific configuration as I have one of the older 'original' Trojans, but battery layout used to be / in general should be : starting battery for port, starting battery for starboard, 1 or more deep cycle batteries as a bank for 'house' (for use while on the hook or under way to run DC stuff, lights, head, fridge on DC, etc... - that can be charged by battery charger and preferably also off of one of the engine alternators through an appropriate isolator), and separate battery for Generator.

Battery switches are helpful, but the cheaper ones should not be changed while engines are running (voltage regulators for the alternators freak out when there is momentary disconnect of any power source!! More advanced (expensive) switches have a way of buffering that to a degree.). You should also not share a starting battery between engines - you don't want two alternators / voltage regulators trying to charge the same battery.

Unfortunately, in my F32 either Trojan or a prior owner messed up and wired up the fridge to feed off of whatever power it could find, so with the fridge running for a few days without AC power plugged in drained house and both starting batteries (discovered this shortly after purchase, when I went to pick the boat up to bring it home... and all batteries were dead as broker moved the boat and left shore power unplugged as soon as the offer was accepted.)

In the older boats, the paralleling switch/solenoid puts both port and starboard starting batteries together, and doesn't include 'house' bank. One of these days I will get my wiring diagram for the paralleling box posted up to the forum.

Your charging system should address port, starboard, and house banks as separate circuits, and be an intelligent charger so it only applies what it has to for each bank. Usually, generator battery is not included in the charging system setup.

[Big D]

I agree with the above. Isolate every bank by use. Some installations now incorporate an additional bank strictly for sensitive electronics. This eliminates dangerous line spikes that will kill electronics quicker and brown-outs that'll cause all kinds of weird anomalies. Considering the cost of some electronic installations these days, it's a smart way to go.

...More advanced (expensive) switches have a way of buffering that to a degree...

The contacts inside simply make contact with one bank before disconnecting from another ("Make Before Break"). So when you turn away from one bank, it is still connected there and also connected to the bank next bank until you hear/feel the click on the bank you're switching to. The alternator always sees a voltage.

[rickalan35]

Hi,

So it looks like my current battery hook-up, is pretty much correct after all. Thanks for the info. Much appreciated.

Yet somehow my sense is that there isn't enough stored power for my house needs while on the hook. I can see having the two separate starter batteries for the engines though. Makes sense.

The 3rd battery though, doesn't appear to be used until I hit the parallel switch (which ends up connecting all three batteries according to the manual).

I'm wondering if maybe the parallel switch possibly connects the two starter batteries.... and maybe the house needs are handled by the third so-called "emergency" battery (as described in the manual.)

Thks Rick

P.S. The manual is also stating that I should turn the battery switch to either ONE or TWO while underway and not leave the switch on ALL. If left on ALL, the manual states that the alternators won't know which battery needs charging. Ever heard of that?

[Big D]

When you combine two or more banks through the switch, all the alternator still sees is one voltage, as far as it's concerned, it's just one battery and will charge according to the voltage it sees. In a twin engine application, you'd also have two alternators trying to charge the same circuit which can either result in only one doing the charging or driving the regulators crazy and neither charges. Because all the batteries combined into one circuit may be at different levels of charge to begin with, you may be overcharging one and undercharging another. If there is a bad battery in the bunch that won't take a charge such as an empty battery, you will overcharge and boil over all the other good batteries that are now part of the same circuit. I think over time, in a set of banks consisting of all good batteries, the batteries will eventually equalize as a combined circuit but each bank may revert to a different potential once disconnected from the rest, so the end charge may not be ideal.

One must also consider that differing battery types should not be combined such as crank and deep cycle batteries which is typically what happens when you put the switch on "ALL." This and the fact that it's a very common mistake to forget the switch in the ALL position and consequently kill your crank batteries while on the hook, is why I do not like the use of those switches. The only time banks should be combined is in an emergency for starting an engine due to a failed crank battery so you can get back to port. This should be done with a momentary emergency start switch at the helm that activates a solenoid to combine the failed cranker with a good battery for starting the engine. Once the switch is let go, the banks are isolated again.

All this requires some creative ways to charge but combining all the banks is not an ideal way to do that.

[rickalan35]

Hi Big D

So if you can, take me through what procedure you would use in my set-up (as you know it) For instance, right now it's in its slip and plugged into shore power. Right now I have the battery selector on ALL. I assume that's ok and that the battery charger can separate it's charging functions correctly (if it's been previously been wired correctly)


Then I come aboard and unplug the shorepower with the intent of powering up and leaving the slip. The battery selector is still on ALL. I turn on both Ignition Breakers and then start the port engine first. When it starts and is idling, I then start the starboard engine. Battery selector still on ALL.

Then - do I go over to the battery selector and move it back to ONE???? Then leave the slip and everything is fine?


Second question:

I cruise to my favourite bay and drop the hook. When it's set, I turn off the engines. What do I do then? Leave the selector ONE or possibly TWO?

BTW, the third battery (termed emergency battery in the manual), on the advice of the marina has now been replaced by a series 31 battery (deeper cell) while the new Port starting battery has been replaced by a series 27 battery I believe the Starboard battery is still a series 24. My sense is that the 31 series battery is a deeper cell and should be used for the house functions (leaving the starting functions to the other two batteries. But since I have now a 24 series, a 27 series and a 31 series all in the same damn boat, do you view that as an issue? Should I take a photo of the cranking power and the reserve hours of these batteries?

Thanks

Rick

[Big D]

Confusing! And the battery selector switch is what makes it so. To deal with charging at shore, if you have a 2 or 3 bank charger and the battery switch is on "All", you defeat the purpose of the charger's separate banks because you just combined them all with the switch. At shore, it makes sense to leave the switch in the position that will power up house loads off the house/deep cycle bank only.

Before you start the engines, you should turn the switch to the starting bank providing the switch also controls the source for the engines (likely).

When you get to your anchorage, the switch should go back to the house bank. But you MUST remember to do this or you will kill your engine start batteries, this is the most common emergency call because of this oversight. Unless you have the "Make Before Break" type of switch, don't do this with the engines running. Never leave it on "ALL", that should be reserved for emergencies only.

The only time it's an issue to have different types of batteries is when they are in the same bank or combined as when you put the switch on "ALL"

Don't like those switches, never have, never will. The older Trojans had it right; we don't have selector switches to worry about, we have an emergency start solenoid and that's it. All banks remain isolated at all times unless you momentarily push the emergency start button at the helm to "boost" the start batteries. I NEVER have to worry about managing a switch. When you're on the hook and your radio dies because the house bank is drained, that's it, your radio fun is over, but at least you can start your engines and go home or start the generator and know that all you have to charge is the house bank and that the engine batteries are still fully charged.

If you're handy with electrical, do yourself a favour and ditch the selector switch. It'll take some wiring and thought for charging strategies but it's the best setup and you'll be free of worrying about remembering to put the switch in the proper position. Even new boat manufacturers are doing it now because of the potential headaches selector switches pose.

The best strategy is a start battery for port eng., a start battery for strb. eng., a deep cycle battery/batteries for house bank. All should have "ON/OFF" switches only for servicing the circuit. ALL banks should be isolated from one another. There should be a method by which you can MOMENTARILY combine banks for emergency starts only, and a method to charge all batteries while maintaining bank isolation. And NO battery selector switch. That is a worry free system that does not require bank selection management every time you head out.

[Big D]

I should add that in most cases, there are only two banks and one of them is to start an engine and run house loads. Originally mine was the port bank. It started the port engine and supplied power for other on-board systems. Definitely not an ideal setup. Every stay on the hook is a potential emergency start as you diminish the ability of that bank you've been using to run your fridge, radio, etc. to start the engine hooked up to that bank. For this reason, the starboard engine was always the one to start first, then try starting the port. If the port wouldn't start, the emergency start solenoid was activated at the helm. Trojan got around this by introducing the "Black Box" to combine both banks automatically at start-up but it is still not an ideal set-up.

The other issue with utilizing one bank to start an engine and supply house loads is what type of battery do you use? A start battery would be great for starting the engine but definitely not what you want for house loads. A deep cycle battery while great for house loads is not ideal for engine starting. Some will install "dual purpose" batteries however one must remember that they are only a compromise between the two designs. The physical construction required to build a good start battery or a good deep cycle make it impossible to combine into one package. The result is a battery that will start an engine and run house loads but is not the best at doing either and typically don't last as long per my experience. If I had to go with one or the other, I would go with a large deep cycle bank in hopes that the higher capacity will provide a buffer for the heavy spike loads of starting the engine. Still not ideal though.

The best solution is to re-wire so there are isolated banks as noted in previous post. Not really all that hard to do.

[rickalan35]

Okay. Everything that you've explained definitely makes sense. It's common sense as well.

I asked some of the guys on my dock who are fairly experienced boaters about their battery system and two of them had a hook-up pretty much like mine on a Mainship and a Chaparel - with two starter batteries and advice from the previous owner to leave the battery selector switch on ONE when underway or when charging on shore power. Neither knew why (a fact which surprised me) The other two guys I asked simply said the'd given up trying to figure out what was what. One guy did comment on the fact that he had a "black" line coming off the positive terminal of one of his house batteries and then disappearing behind a bulkhead - (I suggested it might go to his windlass and now he thinks I'm a guru.)

I am going to see what I can do to trace the wiring on these three main batteries and see how they are hooked up.

But I am definitely moving that selector switch to ONE right away.

Thanks for clearing up the "How best to do it" question. Now I still have to get down in there and figure out how mine are hooked me up. Where it will confuse me for sure though is at the selector switch.

Rick

[Big D]

..... Where it will confuse me for sure though is at the selector switch...

There are a couple of ways you can find out which number on the switch belongs to which bank. The easiest way is to unscrew the switch from the wall and look at the back where the cables are connected. There will be "1" "2" "COM" The COM position is the load or the item you are supplying power to. And the other two positions are the sources; banks 1 and two. Follow the cables hooked up to "1" to the corresponding battery/bank and that'll tell you which is bank 1, then physically mark that bank with a label by tagging the batteries or the cables. The other bank will be bank 2. For the convenience of selection management, wright on the switch by 1 or 2 the one that is the start bank for starting the engines and wright "House" on the other. This will do away with the guessing/remembering, especially after a few brews have been thrown in the mix.

The other way to determine which bank is 1 and 2 is by disconnecting one of the banks then set the switch on "1". Turn on some loads and if nothing works, then you know that the bank you've just disconnected is #1. If things still work, then you know you've just disconnected the #2 bank. You can confirm this by turning the switch to the #2 position. If everything remains off, you've confirmed the one disconnected is #2. Confused now?!! You'll figure it out. Again, mark things out at the battery end and at the switch. It'll help you later.

[rickalan35]

Thanks for the directions and advice, Big D.

Tomorrow is Friday and I'm heading up to the marina to put your plan into action.

I stopped by there yesterday (Wed) and switched the battery selector switch over to ONE.

Tomorrow I plan on unbolting the selector switch and checking out where the cables lead back to from the number ONE spot on the switch, hopefully report back to the forum by Sunday nite.

[rickalan35]

I have now replaced my "third" battery. It was toast. It was a deep cycle and the marina replaced it with another deep cycle.

The current wiring has been somewhat traced, with the help of the marina mechanic.

I have a separate "starter" battery for each engine. But these two "starter" batteries also handle the "House" functions.

The third battery (the new deep cycle) is used only in situations when a parallel switch is required.

The fourth battery remains only for the generator.

The marina isn't sure yet just how my three bank battery charger is currently wired up to the three batteries (port starting battery, starboard starting battery and paralleling battery). The generator battery is not connected to battery charger.

I have told the marina that I don't like the current set up combining the deep cycle battery with either of the two starting batteries when extra cranking power is required. From what I have been told especially by Big D is that it's not the best idea to combine a starting battery with a deep cycle battery yet that's what I have now.

I would like to see the deep cycle third battery re-wired to supply the house requirements. I would like to see each starter battery tasked with cranking its own particular engine, but connected together when the parallel battery switch is engaged.

I would like to see the battery charger wired to charge all three batteries as separate banks.

At least I'm no longer leaving my battery switch on "All"

[Flyboy]

I have a 1981 10 Meter, so pretty early in the production. My #1 battery starts the Port engine and supplies the DC needs of the left side of the DC panel, basicly the Port side of the boat. The #2 battery starts the Starboard engine and supplies DC power to the right side of the DC panel, everything on the Starboard side of the boat. The #3 battery is for starting the Gen. So far we have never had a problem running a battery dead. If we did we can still start the gen and charge the batteries.

[rickalan35]

My #1 battery starts the Port engine and supplies the DC needs of the left side of the DC panel, basicly the Port side of the boat. The #2 battery starts the Starboard engine and supplies DC power to the right side of the DC panel, everything on the Starboard side of the boat.

Hi Flyboy

Thanks for the reply. I haven't heard of your type of arrangement of DC power before. Seems to work fine for you, though.

I'm still not sure what I think about my starter batteries also being tasked with handling the DC power needs.

I have mentioned your left/right DC power arrangement to my mechanic, in case it will help him.

In your case, I see that you're not using a deep cycle battery in your system.

When and if necessary, you have the option to charge your two starter batteries with your generator should the need arise.

Like you, I'm quite willing to run my generator to charge my batteries but in my case, after doing so, my batteries were still dead and so I used the parallel switch on the dash and fortunately, the boat started up. At that point I returned to my marina and set about figuring out just what the heck happened (I had 4 batteries on board yet still ran the starter batteries down because the starter batteries also powered the DC requirements)

One important point for me is that I'd like to avoid running down my starter batteries, simply because I think its not good for them.

I also tend to stay out on the water for two or three days at a time.

My parallel switch connects to the deep cycle battery and that is the only time the deep cycle battery is apparently ever used. This makes absolutely no sense to me.

For instance, if a battery is going to be reserved only for those times when my starter batteries are too low to start the boat, why not make it a high cranking "starting battery" model - why insert a deep cycle into this mix? I don't see the reasoning.

Obviously more work to do on the whole arrangement Will get there eventually.

Marina currently is checking to see exactly how the 3-bank charger is connected to the individual batteries, then they will check to see what the generator is charging when it's running as it may be only charging its own starter battery.

Thanks, Rick

[jhalb]

I have a 1981 10 Meter, so pretty early in the production. My #1 battery starts the Port engine and supplies the DC needs of the left side of the DC panel, basicly the Port side of the boat. The #2 battery starts the Starboard engine and supplies DC power to the right side of the DC panel, everything on the Starboard side of the boat. The #3 battery is for starting the Gen. So far we have never had a problem running a battery dead. If we did we can still start the gen and charge the batteries.

I have the same setup as flyboy and have not have any problems. My starter batteries are dual purpose and gen
is a starting battery. My refrigerator is 120 volt with ice packs to keep cool while on the hook.