Dimming Electricity...

Summary:

1. We're on shore power
2. We have a Pro Mariner 20 battery charger
3. We have two starting batteries, which the house is also currently hooked up to.


On previous inspections of our boat, the yacht service stated that the cabin lights breaker was tripping after about 20 minutes. However we have not had that problem since moving aboard. In fact, we've had no electrical issues whatsoever.

Yesterday I installed a new stereo. I took the old one out, reconnected the new one to the same wires that ran to the old one, and put it back in the same hole. Played the stereo yesterday, played it all afternoon, no issues.

Today, my partner was home alone and cleaning the boat and listening to the radio. Apparently when he turned on the fluorescent light above the dining area, everything dimmed and the radio died. Wouldn't even turn back on.

This is concerning to me and I'm going to have an electrician come and check out the entire boat, but what can I do at this point to try and diagnose or identify problems?

Have you confirmed the charger is doing its thing?

BruceK said:

Have you confirmed the charger is doing its thing?

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It usually always says 13.3 volts and 4.5 amps of output.

Also, when he turned off most of the lights the radio came back on.

toocoys said:

It usually always says 13.3 volts and 4.5 amps of output.

Also, when he turned off most of the lights the radio came back on.

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What happens if you turn off the new radio?

What does it draw,that should be in the (desperation when all else fails) fitting instructions ?

BruceK said:

What happens if you turn off the new radio?

What does it draw,that should be in the (desperation when all else fails) fitting instructions ?

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Not sure.

That is one thing that I did change though.

The power wires on the boat had a red, black, and orange. Only the red and black were hooked up on the old stereo. I figured out that the orange was ALWAYS hot by using my volt meter. Even with the breaker flipped off at the panel, I was still getting 12v. So I hooked the memory wire on the radio up to that one.

I dont know what it draws. I'll have to figure out how to test that.

20 amp charger probably isnt enough if your fridge is working off DC.

Soulnds like very weak batteroes and without enough recovery charge time, all your loads are exceeding the 20 amp chargd and draining the battery. Switching off lights and regaining the stereo is possibly a tip off too.

Hmmmm.... fridge is 120 or 12v, but I'm fairly certain its running on 120 right now since that's the breaker that's on. We keep the 12v fridge breaker off.

So when we use 12v objects, electricity is coming directly from the battery, and the charger then replaces it. So its not like using an inverter where the the power comes directly from the charger? Interesting.

I really need to get a house bank, and get everything but the engines off those starting batteries.

The house bank sees X amps coming in, Y amps going out.....if its a negative number, the batteries make up the diffetence.

If your dimming occurs after periods of high light and stereo usage..pretty sure its limited capacity znd or weak batteries..

Just some general thoughts...

First, existing batteries could be old, may just need replacement.

Second, batteries could be small, and replacements with higher capacity could be an improvement.

Third, only two batteries -- one for each engine and each also services approx half of the house loads? -- could maybe be easily improved by just adding batteries to each bank. (Actually, maybe completely replacing one bank, making both existing batteries the other bank... or several other kinds of options.)

Fourth, a 20 amp charger isn't particularly huge... although if you're mostly at the dock it's probably "OK" if it's working and if you can balance everything else.

Fifth, replacing incandescent light bulbs with LEDs could significantly reduce DC draw.

toocoys said:

I really need to get a house bank, and get everything but the engines off those starting batteries.

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Note what I said about just adding batteries to each existing bank. Many designs favor separate house and starting banks, but probably the expected usage of your type of boat influenced your DC systems design... it probably works OK assuming you work within its limitations... and changing it could be a fairly expensive project.

FWIW, our setup is the same way, although the boat came with three G27s (or maybe they were G29s) per side so starting with a bit more capacity than you have. It was easy to replace dying batteries with better products at first (better G31s) and in one case I was later able to replace 3x G31s (approx 300 Ah) with four GC2s in series/parallel to increase capacity one one bank more significantly (approx 440 Ah). Much less expensive/less hassle in our case than splitting engine start banks off, creating a separate house bank, etc.

Maybe just depends on what kind of space you have available for batteries. Might have to revisit charger size afterwards, though...

-Chris

Sounds like the start batts may have been drawn down as if they
were deep cycle house batts,

Their DEATH is what you describe , the batts act like there 1/10 the size and die under minor loads.

Time for both a house set of deep cycle batts and some new starts.


Sorry,

ranger42c said:

Note what I said about just adding batteries to each existing bank. Many designs favor separate house and starting banks, but probably the expected usage of your type of boat influenced your DC systems design... it probably works OK assuming you work within its limitations... and changing it could be a fairly expensive project.

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I also meant to add you probably have a parallel switch, so you can combine both banks for starting should that be necessary after a major draw-down...

And you also have a genset I think, likely with it's own battery (and possibly with it's own alternator or other self-charging mechanism), so you could start that and then use your battery charger to bring the main banks back up if that were necessary...

IOW, the design of your battery system offers several options... and no huge downside to having the start and house functions combined... assuming you can work within current constraints, whatever they are...

-Chris

psneeld said:

20 amp charger probably isnt enough if your fridge is working off DC.

Soulnds like very weak batteroes and without enough recovery charge time, all your loads are exceeding the 20 amp chargd and draining the battery. Switching off lights and regaining the stereo is possibly a tip off too.

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You did not mention having a smart charger. You did say the 20 amp promariner mostly reads 4.5 amps.
Chances are it is the old style ferroresonant charger that starts at 20, lasts a minute, then drops off to its base charging rate of 4.5. Means you will take forever to recharge if your loads exceed 4 amps. That is way less charging than you need.
Get a proper charger, one that has at least 50 amps peak output, but much more important than peak output, get one that has a "smart" regulator, so you will get your peak output for as long as your new(I agree those batteries seem to be toast) batteries can accept a high charge rate, before dropping slowly to a float rate that will be just enough to keep the batteries from going lower.

A 20 amp charger is probably too small for a liveaboard. Mine is 60. It's like cars before alternators. If you stopped at a light at night and the heater was on, your headlights dimmed.

Folks, I am not the brightest bulb (pun) on the string of lights but, why dont you have a dedicated bank of house batteries, isolated from the start batteries?
I agree, the 20amp charger needs to be replaced to a larger, multi stage charger.

MY recommendation is to get a marine electrician on your boat, let him sort it out, follow his suggestions to the letter.

Changes are A. larger charger B. separate bank of house batteries C. isolations switches between the house batteries and the start batteries. D. larger alternators on the engines. Check the output of the stand alone generator. E. inverter?

A 20 amp charger is almost worth nothing.

NEVER cross connect (parallel) the start batteries house to starting batteries unless the starting batteries wont start the engines.

Do not mix the new and the old batteries together.

Amp/volt meter for the start batteries, amp/volt meter read out for the house batteries.
Amp meter/volt read out for the charger.

Best advice, follow the marine electrician's advice, bring the entire system up to snuff. If you have him do everything right, asking him questions as he works, you will not have any problems for a long time.

Dont do this half way. It will be expensive this time but if done correctly, you will have a very dependable system. If I read what you have correctly, you have an incomplete electrical system.

This is way outside my area of expertise, but... Successive previous owners of my last boat (a "project boat") were 12v gadget happy, and they installed most of it by just tapping into the nearest wires without regard for wire size needed or load already on that circuit, which not only caused lights to dim, but also some very interesting problems (i.e. the starboard engine turned over when I plugged a handheld spotlight into a chartlight receptacle!) I got rid of most of it, and then realized that the best solution was just to replace almost all the 12v wiring and install what I needed or wanted correctly. So it occurs to me to wonder if the same thing might also be at least part of the problem on your boat.
--Peggie

Sounds to me as a weak source of power. Not a big enough battery bank, inverter at 20 amps imo to weak, plus be nice to have a dedicated start bank and a house bank. Not a good idea to have the house and engine batteries together.

koliver said:

You did not mention having a smart charger. You did say the 20 amp promariner mostly reads 4.5 amps.
Chances are it is the old style ferroresonant charger that starts at 20, lasts a minute, then drops off to its base charging rate of 4.5. Means you will take forever to recharge if your loads exceed 4 amps. That is way less charging than you need.
Get a proper charger, one that has at least 50 amps peak output, but much more important than peak output, get one that has a "smart" regulator, so you will get your peak output for as long as your new(I agree those batteries seem to be toast) batteries can accept a high charge rate, before dropping slowly to a float rate that will be just enough to keep the batteries from going lower.

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Its brand new. The owner put it in a few months ago.

A trickle charger?

Take a quick visual check of the top and sides of each battery. Top look for bubbles in the cases and sides for bulging in the cases.

HeadMistress said:

This is way outside my area of expertise, but... Successive previous owners of my last boat (a "project boat") were 12v gadget happy, and they installed most of it by just tapping into the nearest wires without regard for wire size needed or load already on that circuit, which not only caused lights to dim, but also some very interesting problems (i.e. the starboard engine turned over when I plugged a handheld spotlight into a chartlight receptacle!) I got rid of most of it, and then realized that the best solution was just to replace almost all the 12v wiring and install what I needed or wanted correctly. So it occurs to me to wonder if the same thing might also be at least part of the problem on your boat.
--Peggie

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I'll bet when you rebuilt the 12vt system, you removed LOTS of unused and unnecessary wires and 12 pounds of wire ties.

toocoys said:

Its brand new. The owner put it in a few months ago.

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Too bad. New doesn't make inadequate any better.

koliver said:

Too bad. New doesn't make inadequate any better.

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So it's too small for our needs is what you're saying?

Brand was an indicator the charger was not an old ferro resonant type. And so it turned out. Assumption and presumption can be unhelpful.
The OP had no issues before changing the stereo, so it`s just commonsense the issue starts there.
Does it draw way more than the original? Could it be pointing to a lack of capacity in the system, or it could be the installation itself. 20A would run a lot of 12v house. Maybe the charger is defective, but the OP reported no electric issues running the hungry Jabsco dunny chasing issues there.Or other issues before changing the stereo.Maybe there were,but remain unreported.

toocoys said:

Its brand new. The owner put it in a few months ago.

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One of the best chargers on the market Can't say if it's too small or not as we don't know the size of your battery banks or your draw. Make sure it is properly programmed. This has nothing to do with your dropping voltage. You need an ABYC Certified Marine Electrician to look at your boat.

I'll bet when you rebuilt the 12vt system, you removed LOTS of unused and unnecessary wires and 12 pounds of wire ties.


I didn't measure it, but I wouldn't have been hard to convince if I'd been told it was about a mile of wire and at least a dozen pounds of wire nuts.


I spent a little more than two years turning a floating bag lady into a 2 yr old boat in a 20 yr old hull under the close supervision of a good friend (who passed away at nearly 90 a couple of years ago) who was one of the top marine surveyors in the country. I learned more about systems other than plumbing in those two years than I'd learned in the previous 20.



--Peggie

That is one of the best chargers on the market but it IS on the small side. It's reasonable to make sure it is set up correctly, but I think you have much more basic issues. 2 start batteries total is woefully underpowered and being such those batteries may already be trashed. Don't start pulling everything apart because that can accidentally cause issues. Work down the list of dealing with the most obvious problems first.

Ken

OldDan1943 said:

Folks, I am not the brightest bulb (pun) on the string of lights but, why dont you have a dedicated bank of house batteries, isolated from the start batteries?
I agree, the 20amp charger needs to be replaced to a larger, multi stage charger.

A 20 amp charger is almost worth nothing.

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Because that's the way his boat was designed, built, and delivered. It's actually a very common setup in that style boat. Undoing all that would cost a lot and only gain a little. (IMO, not enough gain to fool with it, if there are other easier options available -- and I've posted about those already, above -- especially since it's not exactly his boat.)

Too says he's only got two batteries, one for each side. If those are G27s (for example), they're dual-purpose batteries with only 80-90 Ah capacity each. A 20-amp 3-stage charger (as is his new ProMariner 1220P) is probably charging both those mains batteries and the genset batteri... and is
likely sufficient for the battery lay-out as it stands.

I would agree more battery capacity would be a good thing, and I posted about that above. Might call out eventually for a larger charger, and I posted about that above.

OldDan1943 said:

If I read what you have correctly, you have an incomplete electrical system.

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His system is likely fine, if still in keeping with the manufacturer's original design, and not hosed up afterwards by an unknowing or lazy owner, etc. The layout is quite common, and Mainship (AFAIK) followed all ABYC electrical guidance when it comes to installation, wire sizing, fusing, color coding, strain relief, etc etc etc

IMO, his only immediate problems are about age of current batteries, and minimal capacity.

-Chris

ranger42c said:

Because that's the way his boat was designed, built, and delivered. It's actually a very common setup in that style boat. Undoing all that would cost a lot and only gain a little. (IMO, not enough gain to fool with it, if there are other easier options available -- and I've posted about those already, above -- especially since it's not exactly his boat.)

Too says he's only got two batteries, one for each side. If those are G27s (for example), they're dual-purpose batteries with only 80-90 Ah capacity each. A 20-amp 3-stage charger (as is his new ProMariner 1220P) is probably charging both those mains batteries and the genset batteri... and is
likely sufficient for the battery lay-out as it stands.

I would agree more battery capacity would be a good thing, and I posted about that above. Might call out eventually for a larger charger, and I posted about that above.




His system is likely fine, if still in keeping with the manufacturer's original design, and not hosed up afterwards by an unknowing or lazy owner, etc. The layout is quite common, and Mainship (AFAIK) followed all ABYC electrical guidance when it comes to installation, wire sizing, fusing, color coding, strain relief, etc etc etc

IMO, his only immediate problems are about age of current batteries, and minimal capacity.

-Chris

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Sounds like his boat is not set up to live on the hook w/o starting at least one engine or his generator.

OldDan1943 said:

Sounds like his boat is not set up to live on the hook w/o starting at least one engine or his generator.

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Yes, I agree.

That one was built in Mainship's "non-trawler" days, so maybe their later DC systems designs evolved afterwards, when they "returned to their roots" (so to speak)...

But I think builder expectations were that those (and many similar) boats would likely be used primarily for day trips and marina hopping... and the design matches that mission fairly well at an affordable cost.

It's quite common in many brands with similar mission expectations... including ours.

-Chris

Thats an excellent charger from my experience with them.

Just too small for a liveaboard I am guesding.

That charger may be like mineand can be switched from power supply to charger.

If it is on power supply, and you exceed 20 amps load, you may be slowly depleting the batteries without ever giving them a good charging.