Marine Electronics Forum - Battery Question...

I searched a lot of battery related posts but didn't come across one that applies to my question....

Before I post it, though, is it better to ask here or on the regular Boaters Forum?

http://us.f1.yahoofs.com/groups/g_8548013/__tn_flag_white.gif?bc9xeH.AyhYTZeS9 KMA-IARF TSLTW

Shit, If I could put up a post about some clown selling a VW you certainly can post a battery question on an Electronics board.

Thom

"For every complex question, there's a simple answer. And it's wrong."
(--H. L. Mencken)

Thanks, Thom!

Here's my current setup:

Catamaran with two batteries per motor. All 4 are currently starting type Group27's. I have a Battery switch on each side w the usual OFF-Both- 1-2.
There is no common wiring to port and starboard.

For various reasons (stupidity, senility, forgetting to swith batteries,etc.), I have had the occasion where one pair (same side) gets severly run down or goes dead. When that happens, I have the choice of running a set of jumper cables from one side to the other or using the portable booster. Either maneuver requires that I open hatches that are on the outside of the transom, and run the cables across the stern platform to the other side. Needless to say, it never happens in a dead calm sea!

I am thinking of setting up a third switch that could be used to draw juice from the good side to the dead side without opening a hatch, and running cables or a booster battery outside the boat.

What would be the best way to do this ? Is it not recommended for any reason?

I am also considering replacing one battery on each side with a deep cycle. Any thoughts?

KMA-IARF TSLTW

What kind of engines do you have?? Do your engines have dual battery charge capability?? You are implying that you cannot run permanent wiring between the 2 sets of batteries. Is this true or did I miss something??

Twin DF 140 Suzuki 4 strokes (40 amp alt ea.), 2 batteries per side with their own switch. There is no problem charging 2 batteries at a time. To my knowledge, there are no common wires between the 2 sides. It's like a single engine/2battery instal ldone twice on the same boat. Twin breaker panels with separate Main BAtT switches for each side as well to control whatever auxiliary equipment/ electronics are on the boat. The bilge pumps are the only devices wired directly to the batteries on their corresponding sides.

KMA-IARF TSLTW

First off, I would not mix batteries. Use in pairs either the starting type, deep cycle or the dual function type. I like the dual purpose ones.

Second, many set ups have the kind of wiring you are proposing. I believe it is most commonly referred to as a parallel switch. It essentially links (temporarily) one battery to another via a momentary switch. I'm sure there are lots of ways to rig it but the batteries should be isolated from each other when the switch is not in use.

23 Regulator (2002) F225

Rather than useing jumper cables you could do the same thing by permanently wireing from one side to the other useing a marine electric solinoid switch with a momentary push button on the dash to use to jump start from one engine to the other by just pushing a button when needed. http://thehulltruth.com/infopop/emoticons/icon_smile.gif

Tim,25'SkipjackFB,Diesel
Reel Hungry

It sounds like you are saying that even your "house" battery system is split in two and feeding two different DC panels? If so that is kind of odd. I would bet then that the side that goes dead most often is the one providing power for refrigeration or other significant uses? At any rate, you could overcome your present problem of dead starting by switching both of your battery "1-2-Both" switches to "2" when you are anchored, to "Both" when you are underway (& charging) and to "1" when you are starting. That said, I would give some consideration to rewiring that set-up so that the 2 house batteries are permanently paralleled thus the DC panels become unitized and the loads spread out. I would then leave the battery switches on "1" and charge the house batteries through a couple of "combiners" - that way you don't have to think too much (no switches to keep track of or worry about). Also, it is fine to replace your "house" batteries with deep cycle as long as they are the same type of battery as your "start" batteries (usually lead/acid).

28' Maxcat w/twin Honda 225's (on the way!) http://www.binaryrhyme.com/ubbicons/thumb.gif

[This message was edited by Chaps on 01-10-03 at 02:29 AM.]

Thom,
Maybe you can explain this to both of us while you're at it. http://thehulltruth.com/infopop/emoticons/icon_confused.gif

file:///C:/My%20Documents/My%20Pictures/batteryw.jpg

http://members.fishingworks.com/scubaboys/PhotoImages/Thumbnails/sundown.jpg

Thom,
Maybe you can explain this to both of us. http://thehulltruth.com/infopop/emoticons/icon_confused.gif
file:///C:/My%20Documents/My%20Pictures/battery.jpg

http://members.fishingworks.com/scubaboys/PhotoImages/Thumbnails/sundown.jpg

First off, thanks for replies, so far.

Reel hungry has the idea, exactly. I am only looking for a way to "momentarily" draw juice from the "hot" side to the "dead" side for starting purposes only. I am trying to avoid using clamp on booster cables or a a portable battery jumper from outside the boat (remember, battery access is on the outer transom).

I can run wiring from one sponson to the other with relative ease. My goal was to put some type of switch, either on the console or in the cabin for those times when I need a 'boost'.

Part of the problem is that my port side takes the heaviest hit when running with a lot of circuits on. The electronic box has it is own buss bar and draws from the port side system. Additionally, the stereo and alarm system on the boat require a constant hot for memory and sensor purposes, so those 2 were wired directly (in line fuses) to the port side as well.

Late in the season, when I used the boat sparsely, I often found the port side severly discharged or dead due to drain from the stereo memory, alarm and the fact that the bilge pumps were cranking pretty frequently with all the rain and even snow that we had in the fall.

The solenoid that Reel Hungry suggests looks like an answer. Are there other methods? Are there pitfalls to look out for?

KMA-IARF TSLTW

Big E

A few thoughts. A friend had that momentary solenoid. It only worked half the time, a real PITA. I would not rely on it. Go with a Perko type on/off switch and hook one positive to each post so that ON connects the two positives together.

Then go read the posts about connecting common grounds. If you connect the positive, and don't have a ground, it will not work. Gotta have a good common ground.

To draw down two group 27 batteries you must be running all kinds of stuff. Have you thought of just switching to one battery when you stop to keep the other charged for starting?

Casey

Beg E
Can you not see the diagram that I posted?

http://members.fishingworks.com/scubaboys/PhotoImages/Thumbnails/sundown.jpg

Casey P-

Your suggestion was my first thought. Just not quite sure how to do it, or if it is something that would backfire.

As far as running down the batteries, it is a combination of things. I am going to rewire the stereo memory hot lead to one of the switch panels. It seems that although it is supposed to draw a negligible amount it is one of the culprits for having the batteries die if not recharged for nearly a week( windy fall with abnormally low temps as well). I'll live without having my 3 favorite stations in memory!

The 2 batteries that I want to replace are the ones in the port sponson. They were fully discharged several times and we all know how that degrades storage capability. My thought was to get 2 deep cycles and place one on each side.

The few times that I have run them down were during night fishing trips with nav lights, cockpit/cabin lights, spreader lights, 2 baitwells, FF, Radar, VHF, GPS occasional windlass, etc. running. Sometimes, you forget to start and fast idel a motor to put some of the charge back. Sometimes (nasty nights) you say to yourself that it won't kill the battery if I leave it set to BOTH or 1 or 2... but it does.

DANNY- In your diagram, do you run the ground from the sky to the water or do you also run a lead to the land as well? (LOL). It is a nice sunset, though! For some reason, your diagram is not showing (at least to me).

KMA-IARF TSLTW

Just re-read your reply.

First off, thanks!

Not sure if I fully understand how a "House Battery" set up functions. No need to explain right now, since I believe you are correct in your statement that "my house battery is split in 2".

Each motor and some of the auxiliary and electronic equipment is part of eather the port or starboard "system". I can not, at present select to use my starboard motor to start or charge either of the 2 batteries on the port side,(or vice versa). Like wise, my port bilge pump, cannot draw from the starboard "system". It is the same for the other electricals. I believe even my navigation lights draw from one side or the other and cannot be redirected to either or both sides.

KMA-IARF TSLTW

BigE - battery wiring is a simple thing and you would do yourself a great service to set things up right. A simple paralleling lead so you can jump dead batteries with good batteries is a band aid approach IMO. Better to set things up properly so you never have to deal with dead systems.

28' Maxcat w/twin Honda 225's (on the way!) http://www.binaryrhyme.com/ubbicons/thumb.gif

From your earlier post as follows;


"I can run wiring from one sponson to the other with relative ease. My goal was to put some type of switch, either on the console or in the cabin for those times when I need a 'boost'."

If you can do the above including running a pair of heavy duty wires like #1 guage between the starboard and port battery switches, I think you can solve your problem. However, I have to check the wiring of my Bat switches which I will do this weekend. Will get back to you on Monday.

Gil-
Thanks for the effort, it is appreciated. http://thehulltruth.com/infopop/emoticons/icon_wink.gif

Chaps-
I can't agree with you more. I am taking the steps to "fix it right". First is to get rid of those things that cause a constant drain. The other is to improve upon (if possible) the way my boat is wired now. Some of it is just human error (IMO).If my solution seems like a "band-aid", please let me know what you think is the correct approach. http://thehulltruth.com/infopop/emoticons/icon_smile.gif

KMA-IARF TSLTW

With all the drain & recharge you may consider taking those batteries to the autoparts store and have them run a dynamic test on each.

I had a similar prob with Ships Battery pulled down from continuous drain by radio's memory wire & powered GPS antenna. Had to replace the battery.

How are your panels connected? e.g. #1 Panel connected to #1 Battery of Bank 1 and #2 Panel to #1 Battery of Bank 2. That type of connection would require both SWs to be in Position 1 or Both to recharge the loaded battery, Running SWs in position 2 would never allow panel batteries to recharge.

[This message was edited by HookMan on 01-10-03 at 02:27 PM.]

Big E,
I've got a diagram that came with my Grady that shows you how to do exactly what you're talking about. I've got what sounds like the same setup as you. If you wish, I will email it to you as a pdf file if you have acrobat reader. I would also like to send it to Thom so he could explain to all of us how it works.

http://members.fishingworks.com/scubaboys/PhotoImages/Thumbnails/sundown.jpg

Try this link

http://members.fishingworks.com/scubaboys/PhotoImages/batteryp.jpg

http://members.fishingworks.com/scubaboys/PhotoImages/Thumbnails/sundown.jpg

2 batteries in Parrallel on each 140hp OB motor?? That's really not suggested. That alone could be part of your problem. See, there is only so much amperage output from your motors, and they are probably not putting out enough to charge both batteries in parellel (on both sides). It takes alot more juice to charge two batteries in para than just one as it is designed for. So maybe your just never charging your batteries more that 50 or 60%. And THAT is the problem?

Anyway, I don't underwstand why it is so complicated above. All you need to do to accomplish the emergency "fix", is to put a 1' cable between the negative terminals of the port and stbd battery banks. Then, run a red 8 or 10 gauge wire from port batter to an on/off switch (located near the batterys), then run another 8 or 10 guage wire from the sbd battery to the on/off switch. Done. When switch is in OFF position (normal use), the two battery banks (port and stbd) are separate. If one side is dead and you can't start that motor, turn the switch to ON, which connects the two banks. Start the motor and then turn the switch back off. Done.

I'd also suggest the use of a combiner or battery Isolator if you don't have one. The way it works is simple, instead of running the outputs from the motors to the separate batteries, you run them to the combiner. Then you run wire from the combiner (which will have 2 or 3 output terminals deptending on which one you buy for the # of banks you have, your case 3) to each battery separately. NOW, the combiner decides which battery is the most drained and directs ALL the motors outputs (both motors) to that battery until it is charaged. It then swtiches the output to the next least drained battery..... That will solve your problem of your one side draing faster and more often than the other because the combiner will direct the needed extra energy to that side.

PS- Your stereo memory is NOT draining your battery. Your talking Mili amps which would take months to drain a battery.

Birdman, Capt of
http://members.aol.com/ccarrara/fishing/sig1.gif

Danny-

That diagram needs to be larger and bolder for me to see it. I saved it on may hard drive and will play around with it to see if I can enhance it. It looks like it should work! Thanks!

Birdie- Interesting statements! Makes me think that this is the problem all along. Got to check out your theory. My question to you, how are you counting 3 battery banks on my boat?

HOOKMAN- Appreciate the repy! My dealer replaced both port batteries in September, because of that precise reason. They failed a load test, according to them, because they weren't holding a full charge. By December they look like they were chewed up again!

KMA-IARF TSLTW

Big E,
A battery bank is defined as a single battery "feed", which could be made of a single battery, or multiple battery's strapped together. In other words, in your case, you have two batteries strapped together for your port motor. That is ONE battery bank(call it the port battery bank). You have two batteries strapped together for your Stbd motor which is ONE battery bank (call it the stbd battery bank). Finally, you have a house battery (or more than one, can't remember, whatever..), that is also a battery bank (call it the house battery bank). They are called battery bank because for example sailboats sometimes have 5 or 10 batteries strapped together, making one huge battery bank. Essentially, it just means one battery but that "one battery" could be made up of many seperate batteries all connected together. And by the way, all the batteries in any battery bank, should be the same size and type batteries, VERY important. Do NOT mismatch them in ANY case.

So, what needs to be considered, is how much energy is needed to charge any one particular "battery bank". Unforetunetly it is not linear when looking at charging current. Meaning, if you have a battery that needs 1 amp to charge, then connecting two of those batteries together(making a battery bank), it does not take 2 amps to charge the bank, it takes more than 2.

Anywho, so you have three battery banks, port, stb and house. What I would do in your case is this:

Use one single deep cycle battery as your "Port bank". Use one single deep cycle as your "Stbd bank". Use two batteries (of the same size and type) strapped together as your "house bank". Get a two terminal input and three terminal output battery combiner or battery isolator (very simialr devices doing the same thing in different ways). Connect the two motors to thw two input terminals on the isolator, then connect each battery bank to each of the ouput terminals on the isolator. Lastly, put a on/off type battery switch (as I instructed in last post) between your Port and Stbd banks. So if either bank fails, you turn on the switch to start the 2nd motor. Basically you are paralelling the two battery banks. You can also add a 2nd on/off switch from either the port or stbd bank to the house bank. That way, if both the port and Stbd banks fail, you turn on that swtich to parallel the house bank as well.

To recap, your combiner/isolator will keep all the banks charged properly, you will have the proper size bank connected to each motor (1 deep cycle battery), and you will have emergency connections between all yoru banks with the flip of a on/off knob.

Here is Guests website and link to isolators I'm refering to. In your case, you'd need #2403 for 2 alternators(1 each motor) and 3 batterys (each bank is a "battery").

http://www.guestco.com/isolators.html
#2403

Another link to guest: (GREAT site)
http://www.guestco.com/installation.html

PS - Just for the record, I didn't just make all this up, I just studied my boat. And that is how it is set up. I then researched here and on the respective manufacturer sites on how they suggest to use their parts best, and thats how they all say to do it. Did it suprise me Scout did it that way, the right way? Nope.

Birdman, Capt of
http://members.aol.com/ccarrara/fishing/sig1.gif

Birdie-

I will look at that site and digest what you and everyone here has offered. Might take me right into the fluke season!

It looks like I may have to buy some hardware and gizmos, though.

From what I'm grasping, although I have 4 batteries, presently I DON"T have 3 banks, but 4. Each engine is hooked up to separate batteries that are bolted to separate trays under (in?) my transom, with a Batt SW that allows me to run off/charge either one or both? I could have a bad battery on one terminal of the switch which is killing the other battery, but I have nothing that is keeping either fully charged. Also, the alternator output may not be adequate to keep them fully charged, even if they are in perfect condition, which is another kick in the pants.

When something goes pffffft to both batteries on either side, I don't have a "house" bank(battery) in reserve OR the ability to tap from the other system (circuit)? Basically, like I described earlier, 2 independent systems. And it looks like one is carrying more of a load than the other.

WOW!
Do I have this straight? http://thehulltruth.com/infopop/emoticons/icon_confused.gif

KMA-IARF TSLTW

Yep. Sounds like ya do. Get to work!! http://thehulltruth.com/infopop/emoticons/icon_wink.gif

Birdman, Capt of
http://members.aol.com/ccarrara/fishing/sig1.gif

Big E

I have had same problem with my cat w/f225's. I think a lot of my drain is autopilot pump, when it works a lot I have had electonics to shut down.

I am thinking about installing a "house" battery under the console and a switch to charge off either engine???

haven't thought it all out yet.

jim

Wow, after reading some of the posts that have transpired since last week, I can understand why you need therapy. Later today I will post my suggestions on how to solve your "jumper problem". I presume that that is still what you are looking for.

Big E, the approach described below should work for you. You may want to test things out with jumper cables before permanent installation.

You will need a heavy duty ON/OFF switch and a pair of heavy wires say #1 guage (red and black) that are run between the compartments. The ON/OFF switch can be mounted in either the port or starboard battery compartment, whatever is most convenient. Connect the black wire to the negative terminals of both the starboard and port batteries. That will link the grounds of all 4 batteries and a good idea anyway. (See below)

If you mount the ON/OFF switch in the starboard compartment, run a heavy jumper from your existing starboard Bat switch common or engine connection to one side of the ON/OFF switch.
Connect the red #1 wire to the other side of the ON/OFF switch. Now connect the port-side end of the #1 red wire to the port Bat-switch common or engine connection.
You may want to use a Hi-amp circuit breaker rather than an ON/OFF switch. I would guess a 50 amp would work OK. West Marine has a line of surface mounted breakers from 25 to 150 amp.


When the switch is ON, you have connected the Charge-start circuits of the starb and port engines together. You have also made all 4 batteries available to either engine, depending upon the port and starb Battery switch selections.
If your port batteries are rundown and cannot start the port engine, start the starboard engine and select starb-bat-1 after starting. Select port-bat-1 with your port bat switch and throw your ON/OFF switch to ON. You will now be charging starb-bat-1 and port-bat-1. If you select bat-2 or Both on the port bat switch, then you will be charging bat-2 or both. Note that the selection of starb-bat-1 after starting is arbitrary, but it is always safer to have one of it's own batteries connected to the running engine.

If you wish to start the port engine, you can do so at any time. Running both engines with the ON/OFF switch ON will not cause any damage. However, the ON/OFF switch should be returned to OFF when both engines are running.

BATTERY GROUNDS
Regardless of whether you decide to use the suggested hookup or not, you should absolutely find a way of linking the negative terminals of all 4 batteries with a heavy wire. With the port and starb hookups isolated the way you described above, the common ground connection point between the 2 systems is through your engines and the salt water, a potential problem with galvanic action.

Gil, thanks, so simple a fix. Ship's power would also be selectable between any combination of all 4 batteries.

BTW: Sorry for the confusion added by me, deleted those posts.

After considering Chaps advice about a "band aid" approach, Danny's schematics and Birdie's idea that maybe the batteries are not getting fully charged (isolators, house bank explanation , etc.) , I am strapping on the straight jacket! http://thehulltruth.com/infopop/emoticons/icon_redface.gif

It all makes so much sense, and sounds so good, I want to do it all! But Gil's setup for an emergenecy boost and the other set up with a house bank and isolators look like they will conflict and not work in the same system.

Oh, well, I'll have to get a second boat and have them set up with each variation! http://thehulltruth.com/infopop/emoticons/icon_biggrin.gif http://thehulltruth.com/infopop/emoticons/icon_biggrin.gif http://thehulltruth.com/infopop/emoticons/icon_biggrin.gif

Very helpful everyone! Thanks!

http://www.raiders.com/images/pics/samplefzthumb2.gif KMA-IARF TSLTW

I understand your setup as I am in the same boat, if you'll excuse the phrase. I have a cat with twins.... each engine has 2 batteries with a both/1/2/off switch for a total of 4 batteries and 2 switches. This gives me 2 completely independent electrical systems. What you are asking for is a way to combine them for emergencys ( i.e. when you can't start an engine because both batteries are dead on that side ) but only during emergencys, thus allowing you use the combined output of running side with its batteries to help start your dead side. But for normal running allow you to isolate the systems. Seperate systems allow you to isolate problems to 1 electrical system or the other. My setup is similer. I like Gils suggestions but I would probably make a small change. Since this is only for emergencys, and on/off switch may be overkill not to mention the space it may take up. I would use a battery master switch. They are around $20 and can take intermittent surges up to 500 amps. They come with a key switch so you are less likely to leave it on while at sea and have some problem creep up on you and drain both sets of batteries leaving you stranded.
Like I said I like Gils suggestion as well...but if you need the space and want to make it less accident prone ( i.e. make it an out of the ordinary thing to do...so guests wont think they are trying to help and turn the switch on ) use the master switch.

The two above are not very differrent from mine BigE. The ONLY difference is they do NOT address the charging issue. And your main problem here really is "CHARGING". You have more drain on one side. To address that, install a battery isolator. THEN, you can install on/off switches to parallel your banks, OR install 1/2/both selector type switches to parallel. On/off switches are MUCH safer and easier to understand and install. You do not have to be a rocket scientist to figure out what is happening when you turn them on. Selector switches can get tricky, espdcially if not installed properly.

Do yourself a favor, read the links I posted above.

Birdman, Capt of
http://members.aol.com/ccarrara/fishing/sig1.gif

Great information and diagrams. I read those and filed the URL' for future refence. I read all the posts here several times and made notes. As Chaps suggested, I just don't want to "band -aid" the problem. After reading all the help here, I talked to my dealer and a couple of friends who are more experienced than me, and it looks like your theory is favored.

Your suggested set up looks like it will keep all my batteries properly charged regardless of which side carries the bigger nut loadwise, as well as providing a "house bank(battery)" that I really don't have now. Once I get that straightened out, I should have far less incidents of run down, and at that point it might not be so bad just to break out the old standard jumper cables if needed. http://thehulltruth.com/infopop/emoticons/icon_wink.gif

http://www.raiders.com/images/pics/samplefzthumb2.gif KMA-IARF TSLTW

use an emergency parallel switch. This will connect either batery bank to each other. My hydra-sport comes with it from factory, i am running 2 banks (2 batteries each bank) with the normal off-1-2-all switch each bank plus the emgency switch that allows you to transfer power from one bank to another

jaycough-

Welcome to THT and thanks for the reply!

I am considering that as well as the isolator setup that has also been suggested. It looks like if i do both I should never have a problem!

Then again a generator with invertor would be good OR I could get a very long shore power cord and carry a battery charger with emergency jump feature as well! http://thehulltruth.com/infopop/emoticons/icon_biggrin.gif

http://www.raiders.com/images/pics/samplefzthumb2.gif KMA-IARF TSLTW

Maybe this will provide some additional information for you.

http://continuouswave.com/whaler/reference/dualBattery.html

My understanding is you have each outboard connected as shown in the first diagram, two separate dual battery systems for each outboard, and two seperate ship’s power panels, one from each bank of two.

Problem as stated in link 1 “In circuits with parallel connection of two engine charging circuits, it is likely that the voltage produced by them will not be precisely equal. If one unit has an output approximately one volt greater than the other, the effect of this will be to electrically disconnect the load from the lower voltage output engine. This may result in damage to the stator coil of the engine producing the lower voltage output.�

You said “Part of the problem is that my port side takes the heaviest hit when running with a lot of circuits on. The electronic box has it is own buss bar and draws from the port side system. Additionally, the stereo and alarm system on the boat require a constant hot for memory and sensor purposes, so those 2 were wired directly (in line fuses) to the port side as well�

One alternative is to consider doing a Ship’s power demand analysis to determine if you should split the load between banks more evenly.

http://www.sailnet.com/collections/gearandmaintenance/index.cfm?articleID=jeffre005&coll_cat=Electrical&Coll_name=Electrical

Another choice I prefer is to connect both motors as shown in first link (second diagram) “Dual Battery/Dual Engine Schematic� (the second diagram) but without any ship’s power panel connected. Providing each engine with its own separate start battery, and in an emergency set to both for starting only.

The other two batteries could be used to supply all ship’s power panels with your 1/2/Both/Off SW and kept in Both position for heavy ship’s power demand times. Ship’s power batteries would be charged via a combiner like Birdman recommended, using both engines charging systems. This will avoid the potential problem of parallel connection of two engine charging circuits, described in the first link.

Huh?

Birdman, Capt of
http://members.aol.com/ccarrara/fishing/sig1.gif

As stated above;

Problem as stated in link 1 “In circuits with parallel connection of two engine charging circuits, it is likely that the voltage produced by them will not be precisely equal. If one unit has an output approximately one volt greater than the other, the effect of this will be to electrically disconnect the load from the lower voltage output engine. This may result in damage to the stator coil of the engine producing the lower voltage output.�

THE ABOVE STATEMENT IS ABSOLUTE NONSENSE!!

Sorry cholly, a one volt difference in the charge output voltages from the 2 charging sources is not the same as the OFF position of the Bat switch. The OFF position of the switch allows the voltage output of the charge circuits to drift very high and voltage spikes eventually puncture one or more of the diodes in the reverse direction.

That's what is so great about this forum, exchange of information. At least the diagrams a clear in the links and provide some info. Right or wrong, don't know for sure.

Heck you talk to two certified Yamaha mechanics and it's hard to get two to agree. I struggle with trying to decide weather it's good or bad to decarb the Yamaha outboards when there is an O2 sensor involved. Is it safe to use seafoam or will it plug-up the O2 sensor screen. The service manuals say nothing about about it.

You would think something as basic as batteries and selector SWs would be easy to resolve. What does one believe.

To use a soinoid crossover,but after reading all the info here I believe it would be a band aid fix.What you really need is either new batterys or larger batterys deep cycle ofcoarse,and or a larger output alternator if possible.I read you have a cat with twins,I run a single diesel engine and I couldnt imagine haveing the problems you haveing with the one side.What output is comeing out of your alternators?

Tim,25'SkipjackFB,Diesel
Reel Hungry

I was planning on wiring my 4 batteries just like you suggested, one (on off 1 2) switch for each motor and one on-off switch to combine port and starboard in case needed. IS there a way to use isolaters(one for each side) on outboard two strokes in this set up?? I was planning on using one battery on each side just for starting and the other battery on each side would take approx 1/2 house load(lights,electronics, bilge and washdown pumps,etc.) but would like two charge all batteries with out having to switch from 1 to 2 on the switches.