Charging system

I have a Taiwanese trawler with dual Perkins Range 4 motors, dual alternators, Inverter with seperate charger and have an issue with the 4 position (off, 1, 2 or both) battery selector switch or maybe something else?

When running, regardless of the battery selector switch position, each battery is being charged. This was checked with a voltmeter on each bank and trying different selector switch positions. With the motors off, each battery is being charged by the charger. Engines off, the battery switch is set to #1, 2 or both, both battery banks discharge with a large load applied for many hours..

I have checked that the selector switch is functional with the battery banks disconnected using an ohmeter. I also checked that the battery banks were not somehow joined together, and did find an added battery cable between the battery banks and inverter. I removed this to no avail.

I have followed the wiring and do not see any type of isolator or cobiner installed anywhere. Please, what am I missing?

Mine had a common connection through the starting circuitry. Engine was replaced and who knows who had done what making that all possible.

I wound up rewiring everything anyhow, shorter runs, more fusing, etc...

Wasn't worth dealing with the homegrown rats nest.

What I found interesting was nothing really butchered, other than a jumper battery cable to tie the house and starter batteries through the inverter. It was not bad for a 30 year old boat.

I am going to continue looking and I may have to unwrap the harnesses to find out what goes where. I cannot find any wiring diagram, but do have 3 relays on each motor that I am not sure what circuits they attach. Guess I will find out the long and hard way!

Thank you for the reply.

Goldenstar38 said:

but do have 3 relays on each motor that I am not sure what circuits they attach. Guess I will find out the long and hard way!

Thank you for the reply.

Click to expand...

You might have a Combiner set-up...Usually done with solenoids/relays. If any charge is detected they combine both banks to accept the charge. The banks are separate per the Battery switch position when not charging.

Kind of a nice set-up to funnel charge amps without doing any manual switching..

psneeld said:

Mine had a common connection through the starting circuitry. Engine was replaced and who knows who had done what mķaking that all possible.

I wound up rewiring everything anyhow, shorter runs, more fusing, etc...

Wasn't worth dealing with the homegrown rats nest.

Click to expand...

I'm doing that right now. Even though I have a relatively simple system 40 years of amateur upgrades has made quite a hornets nest. I have all the pieces now and it's time for a little assembly.

Welcome aboard Goldenstar!

There are 3 sets of relays on each motor. I guess I should unwrap each wiring harness and check to see where the wiring goes. A lot of harness to go through! I do know one (1) relay seems to work for the fuel cut off solenoid on each motor.

I was going to add a combiner and have one already, but not installed yet. Is there a chance that such an arrangement was OEM installed? I was reading an article by Dave Pascoe recently that suggested something like this may have been common on some boats.

I'm still puzzled by the elector switch though. I have no control over which bank is selected with no AC available.

Nice to be here, as I do not often have the chance to visit. A lot of great people and information. Thank you.

One last question. The battery selector switch is made by Cole Hersee, #M705. It is marked off-1-both and 2AB. Although it tests good, does the AB indicate anything? Just hoping I missed something here. Thanks.

I'm having a little trouble trying to picture your layout
You have:
Only 1 battery switch?
2 engines w/ 1 alt each
1 house bank
1 start bank
1 batt charger
1 inverter

Can you post a pic of this "jumper" wire and its connections?

Of the top of my head it sounds like the inverter is drawing from all the batteries.

I cannot get a picture until tonight. However, the jumper battery cable I removed would have effectively tied the 2 battery banks together.
To describe: Positive house battery cable attached to a bulkhead on/off switch. Inverter positive cable attached here. The on/off switch output then went to the battery selector switch in the salon. At the first house bank switch, a heavy guage cable jumped over to the on/off switch to the positive starter battery cables which then went to the salon selector switch.

Yes, there is only 1 battery selector switch, 2 alternators. I have slowly been trying to find some type of isolation device, combiner, etc with no luck. The motors and charging system work fine, but I want to be able to use the selector switch to isolate each battery bank. I cannot image it being too hard to figure out, but I am stumped so far.

Is it possible that the OEM wiring (each motor has 3 relays on the side of the block) contains some type of isolation/combiner device? If so, I would not necessarily understand the need for a battery selector switch.

IF anyone would care to share/sell a Perkins Range 4 wiring diagram, I'm interested!

Thanks for the replies

Some Ocean Marine and some early Ocean Alexander twins were wired so that the house could be run off either bank and the starters could be run off either bank. The house switching was a "Off -1-1 and 2 - 2" switch at the DC service panel and the starter switching was done with 2 "off-on" switches on a separate panel.
The starter panel tied both starters to the bank that was turned on. If both banks were selected, the battery banks were tied together there and the house selector switch became an "off-on" switch.
Both battery banks had two cables connected to the positive terminals. One went to the house selector, the other to the starter selector.

av8r.
That is interesting. The DC panel is in the salon. The battery switch there has off-1-both-2AB (still not sure what the AB denoted).
There are 2 remote on/off switches on a bulkhead for both battery banks, but the bulkhead is under the salon floor (close to the selector switch/DC panel. Perhaps this is the arrangement
I will have to do some checking into this arrangement this weekend and see if this works for my set up.
Thank you so much for the input.

Was the cable you removed that seemed to tie the batteries together positive or negative?

Positive cable was removed. The way it is now, only draws from house bank.

My digital camera isn't working. I can try to get a picture with my phone, but cannot tonight.

I still want to look a little more into av8r's reply. It makes sense, except for having to get into the engine room to change the on/off switches.

With twin engines each with 2 alternators there are posts of charging path options. You need to trace the wires and make a diagram to get a handle on what is happening.

It's entirely possible that your selector switch is only for selection of what powers the DC panel (all of your DC system). That's how ours was in our '86 Senator (Taiwanese make too), however, I only had a single engine and alternator. FWIW, I did a extensive upgrade to our system to fix most of the shortcomings to the old rig. If it did nothing else, it gave me the ability to learn everything I needed to know about the boat's DC system and provided a huge peace of mind it would be exponentially more reliable. Here is the thread:

http://www.trawlerforum.com/forums/s4/winter-project-i-charging-system-upgrade-5641.html

Now, regarding the relays. There are three. One is the engine cutoff like you said. The other two are for engine start and for the preheater. Those too were upgraded on our old boat. Unfortunately, the wiring gets really sloppy and unreliable in these older boats and will, sooner or later, let you down. So I did a little upgrade on that too:

http://www.trawlerforum.com/forums/s4/little-relay-project-10094.html

Tom.B There is a lot if good info there, can't wait to be able to read it all. I actually have replaced all the relays and harnesses on the port motor already, even though it did not look as bad as yours did.

My biggest issue is tracking down why the battery selector switch will not allow me to switch the battery bank being charged. If out running and one alternator died, I cannot switch between banks.

I will read some more and start looking more closely tomorrow morning.

Thank you for the replies.

It's common for the battery selector switch not to control how a battery gets charged. If on a twin engine boat one alternator fails you just select the both or all postition on the switch and then the one working alternator will be charging both batteries. You have 4 alternators, so it get much more complicated. And God knows if the person wiring the system had a clue how to do it. Or what strange ideas they had of how it should be done.

Do you have 2 alternators, one on each engine
OR
4 alternators, two on each engine????

Last point made CaptBill may be right on , that the reason you cannot switch is because each battery is being charged by one of the alternators. It is common to run the alternator feed directly to the batteries and NOT through the battery switch. If one alternator or the driving engine failed then the battery sw would allow you to continue the charge from the still operating unit.

Alternator outputs are run directly to batteries to avoid blowing their diodes if someone forgetfully turns the battery switch to OFF while the engines are running. Lots of alt. have died from this action.

You need to find out by tracing the alternator output wire from each alt. to see where it goes. Don't worry about the small control wires at this time, just the big output wire.

Get some small write on tags and RED [pos.] and BLACK [neg,] Tyraps and label as you go about what the wire does/goes and trace those alt outputs. Proper labelling can come later.

That's a start. Let us know.

"I have a Taiwanese trawler with dual Perkins Range 4 motors, dual alternators,"

I guess I could have misinterpreted this. And he only has one alternator per engine.

The 2 remote switches may be the starter cut-off switches. Quick test is to turn both remote switches and the DC selector switch off and try both engine starters. Turn one one and see if only one engine cranks or if they both do.

If they both crank with 1 switch on, switch logic may be:
Switch 1 on, both starters powered by battery 1
Switch 2 on, both starters powered by battery 2
Both switches on, both starters powered by both batteries, the batteries are connected together at the switches.

To (maybe) split the banks, turn remote switch 1 on and DC selector switch to position 2. This may turn battery 1 into the starting bank and battery 2 into the house bank. Each alternator would charge its respective battery.

Sorry if I confused what I have. Each motor only has 1 alternator.
I am doing to do some digging tomorrow. I assumed that the selector switch allowed which battery to be charged. Maybe I have no problem at all? I will let you know.

Again, I truly thank everyone for the replies.

I have a twin engine two alternator Taiwanese trawler the alternators charge through a combiner. The battery charger charges the banks independently. I have only one selector and it is used to decide which set of batteries powers the DC panel or as some say the house bank. In other word with the selector I pick port or starboard or both battery banks to feed the house.

It is sounding more like I may not have too much of a problem after all?

Is the combiner "factory installed" or one added at a later time?

Have to walk the dog quickly and then time to dig in and figure this out.

A loy of good ideas to try. Thanks you.

A combiner can be a simple solenoid , or a transistor blue thing .

The solenoid passes the full voltage , the transistor gadget does not.

This may cause longer charge times at lower voltages when finished.

Purchase a good digital volt meter and learn how to use it.

FF said:

A combiner can be a simple solenoid , or a transistor blue thing .

The solenoid passes the full voltage , the transistor gadget does not.

This may cause longer charge times at lower voltages when finished.

Purchase a good digital volt meter and learn how to use it.

Click to expand...

I think you may be talking about the difference between a charge combiner and charge isolation diodes. Some diodes can cause a voltage drop.

Is there a separate house/inverter bank? How is this bank charged while underway? Is the alternator output wire split to go to house/inverter and starting batteries or does it feed into the AC charger? If it feeds into the battery charger does it go through an isolator/diode? If there is no isolator at the charger then charging current is being distributed to both house and starting banks. There are several places that charging current can crossover the battery switch. Start with the big wires (batt cables) Track them to the solenoids and then follow the current from there. Same with alternators.

Hope this helps. If not lets just keep between us.

Steelydon