What should be hooked to the starting batteries?

I am the new owner of a 1985 Marine Trader Sun Deck 43 and have a lot of things to sort out when I take possession Oct 4.

One thing came up during the survey. The surveyor turned on everything, so all switches on the panel were flipped on.

It was a 2.5 hour trip to the marina to pull the boat out and then the boat was out of the water for about an hour. When they put the boat back in the boat wouldn't start and we had to put a charger on it for about 15 min to get it started.

The Broker said of course the batteries were dead he turned everything on and left it on.

But I was thinking about it today. Nothing should run off the starting batteries except the motors/engines?

Shouldn't everything be hooked up to the house batteries and not the starting batteries?

The boat's generator isn't working and it has a new inverter which was on, running the fridge and other 110 items.

First congrats on your new boat. The only thing beside the starter on my start batteries is the windlass and that is only used when the engines are running. Sounds like you have some wiring to trace in your near future. Good luck.

Hard to guess anything other than you’ll probably be spending $XXX dollars on at least new batteries. Did the surveyor not have any comment?

The batteries are two years old and according to the motor survey/ mechanic were at 93%, but one of the alternators was an original.

The survey guy left before we boarded and did the 2 .5 hour trip back to the marina. He went home to do his report..the Broker and I took the boat back.

Anyway I'll do some looking around, I was just curios if maybe it was standard practice to run something other than the engines off the the starting batteries.

It is possible that you have an inadvertent cross over. Meaning despite all the battery switches both banks might be connected permanently. Talk to the surveyor, find out what he saw.

Is it possible that the house battery switch was on all.

The first question is: Do you have separate house bank & starter banks because many older trawlers incl. Grand Banks were originally set up with port & stbd battery banks which were controlled by the 1;2;both;off switch? All loads (incl. starting and house) were run through that panel & switch.
Most of us with that set up run on "both" then (after shutting down the engines) switch to #1 on odd numbered days & #2 on even numbered days so as to always have a charged battery for starting the next morning (we had a separate starter battery for the generator which charges itself off the gen. alternator). We cruised happily for several years with an 8D AGM on each side with no problems running a small fridge and modest house loads. Two caveats with this set-up - don't turn the switch while the mains are running, and, if you run an inverter, you really need a separate house bank.

People wire boats differently depending on whether they have a house battery bank or not and whether they dedicate one alternator to charging it.

On my boat, the only thing on the engine battery is the engine. House battery bank is separate with its own alternator.

Ted

Boats need two separate battery banks, one for starting, one for everything else as deep cycle.
Running all that stuff for a while could run down the batteries enough to not start if they are joined banks or only one bank. That was a lot of load on them. and you dont say how many or what configuration they are.
You also need a running gen to run to recharge batteries just in case you can't start.

And an ACR can join battery banks when engines run so the alternator can charge both banks, or even a high power relay can be used.
I simply got a continuous duty 80 amp golf cart type relay cheap off Amazon, wired it through a manual switch and wired it to always come on if the port engine ignition comes on. The manual switch lets me turn it off separating the banks, and of course they are not joined if the engine is off.

Derik said:

The batteries are two years old and according to the motor survey/ mechanic were at 93%, but one of the alternators was an original.

The survey guy left before we boarded and did the 2 .5 hour trip back to the marina. He went home to do his report..the Broker and I took the boat back.

Anyway I'll do some looking around, I was just curios if maybe it was standard practice to run something other than the engines off the the starting batteries.

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Have you done a quick calc of the load that was on the batteries? What’s the capacity of the house bank?

You guys are great, I can't go down to the boat and start working on it until I get my Insurance but, I am do remember seeing a switch that said Shore/ Batteries or something like that and I think it had a battery selection or both but am not 100 % sure.

I haven't done a load analysis yet but will. The two previous owners were campers and put 28 hours on the boat in the past 2 years. They were mostly hooked up to shore power and didn't mind the generator wasn't functional. I have a used Northern Lights Gen. that's been put in but not fully hooked up that will be my first order of business.

You should see what's drawing all that current. 2 1/2 hours even with everything on shouldn't deplete the batteries. Unless the batteries are bad, or you are trying to run the A/C from the inverter or something.

I am in the camp that you should have separate start and house banks and that the start bank should be used for starting only. My two battery banks are connected by an automatic combiner relay (ACR) so that both banks are charged by the alternator but separated when the engine is off.


My solar is connected to the house bank, but it does trigger the ACR so I get some solar charging of my start bank when solar pulls the house bank above the ACR voltage threshold (13.0 V).

Nothing should have drained good start batteries in 2.5 hours of non-running engines. Even with a spotlight turned on there should have been enough reserve to crank the engines. Especially sitting in a dock plugged in to shore power, assuming it has a functioning battery charger.
IMHO, the first order of business is sorting out the DC battery lineup and condition. Open up the battery boxes and tell us what size, quantity, and type batteries you have. Trace out the positive battery leads.
How many wires are connected to each positive terminal?

If the batteries have removable caps, are they properly filled? Be very careful because it is very strong acid.
With a digital volt meter, take voltage readings of each battery with the probe tips directly on the lead posts with the battery charger on normally. Write each of them down and post here.
Repeat with the battery charger turned off and all breakers turned on as in the survey and check voltages after 30 minutes.

I personally like to have some other load on my start battery to pull it down at least little so it doesn't develop a "surface charge". My engine starts immediately, so the load is small and quick and the battery isn't drawn down significantly.

I have my pot puller, and LED flood and spot lights wired into the start battery, those items are only used while the engine is running. Everything else is run off the house bank. I think only equipment run underway should be connected to the start battery. jmo

These guys all seem to have a good handle and good advice. But in your circumstances, before I started tracing loads on the battery I would first make sure the alternator was charging both banks when the engine is running. I would also confirm whether you have an ACR to combine the banks for charging or some other solution that may have failed.

If you've already done that, I'll sit down and be quiet.

Bkay said:

These guys all seem to have a good handle and good advice. But in your circumstances, before I started tracing loads on the battery I would first make sure the alternator was charging both banks when the engine is running. I would also confirm whether you have an ACR to combine the banks for charging or some other solution that may have failed.

If you've already done that, I'll sit down and be quiet.

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Yes agree. After re-reading post#1 it does not look like the alternators did anything on the 2 1/2 hour ride to the marina.
So with the engine running and the battery chargers shutdown, the voltage of the start battery for the running engines should rise above 12.8 VDC with the engine at about 1000 rpm. It should max out at about 14.5 volts when the batteries reach full charge.
Something is also wrong with the batteries themselves. I would bet they have never been watered in their short lives. It only takes 5 minutes to find out.

High Wire said:

Yes agree. After re-reading post#1 it does not look like the alternators did anything on the 2 1/2 hour ride to the marina.
So with the engine running and the battery chargers shutdown, the voltage of the start battery for the running engines should rise above 12.8 VDC with the engine at about 1000 rpm. It should max out at about 14.5 volts when the batteries reach full charge.
Something is also wrong with the batteries themselves. I would bet they have never been watered in their short lives. It only takes 5 minutes to find out.

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Good call on the alternators. My boat came complete with crap CarQuest alternator belts. Voltmeters on bridge ran about 12.4V. Switched to OEM Cat cogged belts, voltmeters immediately jumped to 14+V. Like so many things, false savings on the cheap belts, which were obviously slipping.

I'll know more soon but

Sorry I don't have more details yet, I'll get my insurance this week and will be able to go on the boat and do some things but not a lot since it's not my boat until Oct 4.

What I do know is that the Invert-er was on and the refrigerator was on, it's not a marine refrigerator and appears to be on the big size for a boat. There were some other breakers on that don't do anything but could draw power like Freshwater Maker ( it doesn't have one) Macerator pump. I am not sure if he used the microwave or not but had it on.

I am guessing at least one of the two alternators doesn't work and they the PO used shore power to charge the batteries full probably never turned the boat off. If this was a normal practice the batteries could be shot already. I'll check fluid and hope none of the cells are dry.

When we went to leave the haul out the motors did nothing but engage the starters the broker was able to get it going quickly by hooking the battery charger to the starter after it charged for a very short period. I am not sure what kind of charger they had but it wasn't something I had seen done before.

I am going to copy and paste everything here and bring it to the boat with me when I go next week.

Thanks all

Derik

" Nothing should run off the starting batteries except the motors/engines?

Shouldn't everything be hooked up to the house batteries and not the starting batteries?"


That is the safest method.

FF said:

" Nothing should run off the starting batteries except the motors/engines?

Shouldn't everything be hooked up to the house batteries and not the starting batteries?"


That is the safest method.

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What about windlass and thruster?
I wonder about those and can argue for having them on the start bank.
Both hi amp draw lo cycle time...
Only run when / after engines running...
Seems to fit start type batty use vs deep cycle house bank.

My MS is not an appropriate set up... IMO
Thrusters seperate 8D
Gennie seperate start batty
Dual 8Ds serve everything else... start windlass and house
Thinking about changing the batty type & wiring when its time for new battys
Am I off base or does above make sense?

Bacchus said:

My MS is not an appropriate set up... IMO
Thrusters seperate 8D
Gennie seperate start batty
Dual 8Ds serve everything else... start windlass and house
Thinking about changing the batty type & wiring when its time for new battys
Am I off base or does above make sense?

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Our set-up is similar, sans thruster. Depends on your situation, but in our case I think it's not worth the money/effort to change the basic design. We added battery capacity. See comments in the thread Toocoys started about their batteries.

-Chris

"Dual 8Ds serve everything else... start windlass and house"

8d are really heavy and not easy to find in deep cycle.

And if the 8D starts get down ,from house draw you might be dead in the water.

If you have the room (2) series 31 would be fine for engine service and 4 6V GC (golf cart ) deep cycles wired to 12V would be modest power for anchoring out.

This setup is fine for most folks ,with a SOC meter to observe the house bank.

If you are twin engine a 31 would be wired to each engine , with a rotary switch to help if one goes partially dead..

The house would be charged with the main engine alt(s?) as it keeps up the start.

KISS

Bacchus: Dual 8Ds serve everything else... start windlass and house
Thinking about changing the batty type & wiring when its time for new battys

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My 8D start battery (starts the generator and stbd engine ONLY) just died and I replaced it with 2 Group 31s. After wrestling the 8D out of the engine room, handling the 2 Group 31s was much more pleasant. I've used the new configuration and am very happy with the results. The 2 Group 31s also take less space if you can install them side by side, slightly wider but much less length.

Not sure what you mean about changing the wiring, but I suspect you mean as needed for battery type changes.

GregBrannon said:

My 8D start battery (starts the generator and stbd engine ONLY) just died and I replaced it with 2 Group 31s. After wrestling the 8D out of the engine room, handling the 2 Group 31s was much more pleasant. I've used the new configuration and am very happy with the results. The 2 Group 31s also take less space if you can install them side by side, slightly wider but much less length.

Not sure what you mean about changing the wiring, but I suspect you mean as needed for battery type changes.

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A start bank for me is one group 31, to start both engines.
I can join house bank to start or isolate start bank entirely to start engines.
So more than one group 31 for me is just a waste of space on the bank. And an extra group 31 is going to go down eventually and need replacing, which just doubles the costs with no added benefits. My start bank of one battery only starts engines, so the rest of the time is useless weight.

GregBrannon said:

Not sure what you mean about changing the wiring, but I suspect you mean as needed for battery type changes.

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His setup (as ours) doesn't completely segregate start and house functions. A battery starts one engine and runs approx half the house. Another battery, ditto other engine and other half of house. Wiring changes would be needed to disconnect those two functions (start and house) and to maybe combine both halves of the house.

-Chris

ranger42c said:

His setup (as ours) doesn't completely segregate start and house functions. A battery starts one engine and runs approx half the house. Another battery, ditto other engine and other half of house. Wiring changes would be needed to disconnect those two functions (start and house) and to maybe combine both halves of the house.

-Chris

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My boat used to be that way too. Makes more sense to have a dedicated start battery. It is too easy to run down batteries then your in trouble. I setup two battery switches to join banks if needed. My port engine charges the start bank, my starboard engine charges the house bank. And I have a combining relay that joins banks. I notice when I turn on that relay, both alternators equally share the load. The underused start alternator spikes up, and the overused house alternator drops down on the ammeters. My combining relay is a continuous duty 90 amp relay I got from Amazon for about $10. It is on if the port ignition is on, and I have a manual on-off switch also in series with the ignition wire. I leave it on all the time. When engine is off the banks are seperate. I did this to keep from flipping the big battery switches around so a lot more convenient to be automatic. I thought about an ACR but was a lot more money.


So if I crank the port motor first , the relay comes on and joins banks. But if I crank the starboard first, the house battery bank is not joined. But If I wait till port ignition is on, then starboard engine has banks joined. So every time I start an engine, I actually can have all the batteries in both banks supplying power to start either engine. Or if I turn off the combining relay by that switch, only the start battery cranks the engines, I never lack for cranking amps.

I suppose if the house bank is run down, just turn off the combining relay. I have not had the house bank run that low yet, might have no effect. on starting.

I really dont know if a fully charged battery joined to a severely depleted battery does much as the depleted battery will have a lot of internal resistance and needs a higher voltage to charge up. That situation happens constantly with cars and trucks needing a jump and it works fine, boat will be no different.

Here it is, but Amazon is not selling now. Something similar will work. I don't know if an ACR can be overridden to simply turn on manually with a manual switch.
https://www.amazon.com/gp/product/B00KGID0X0/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

Here is one with a higher amperage, low cost solution for combining banks.
https://www.amazon.com/CONTINUOUS-S...0BGTL9GI/ref=cm_cr_arp_d_product_sims?ie=UTF8

sdowney717 said:

My boat used to be that way too. Makes more sense to have a dedicated start battery. It is too easy to run down batteries then your in trouble.

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We haven't really had any difficulty running down the overall capacity.

We too have a parallel switch so the two big banks can be instantly joined for starting one or the other engine. And a genset so we can start that and charge everything if necessary. And a back-up battery in the dinghy in case we have troubles with the genst battery, and one of these days I'll probably get a pair of jumper cables to keep on the (diesel) boat to simplify that even more.

I think I've used our parallel switch twice over the last 13 years, and even that was in a situation known to draw down one of our banks severely... not at all a surprise.

I don't disagree with the common wisdom, but we don't have that setup... and the potential cost of reconfiguring our battery banks seems to me to exceed the potential gain.

-Chris

I think you want to confirm that you bilge pumps are wired directly to the batteries so that they function even if the battery switch is in the “off” position.

hooked to starting batteries

18 months ago a purchased a 1987 45' cruiser and brought it up from the Keys to Chesapeake bay. upon arrival and disconnected from shore power I found I had several dead/broken batteries. However, during my trip north I stayed in marinas each night and had no idea i had bad batteries.

However, my alternators put out enough voltage to mask my problem. We ran 1400 miles and she started every time. Once home I rearranged the wiring (on the new batteries) to keep it simple so even I could figure it out. Each motor has adequate and seperate batteries, plus house batteries and a seperate battery dedicated to the generator. Electricity/electronics is way above my pay grade but I keep it simple..so even I can figure it out. Good luck.

My arrangement is two 8D's. One is house and start. The other is Aux with windlass and thruster connected. When starting main engine I use a momentary switch to parallel the two batteries.