Battery Charge Alarm

[d4raffy]

Hey Keiron

I will probably get shot down but a few comments ..... With my limited knowledge... They may help ... Or not.

As suggested earlier, it still sounds like the alternator is putting out too much voltage.
I know some run high these days but isn't 16+ V to high for normal output ??
The lower voltage on the house bank is just because of the constant House load.
Constant 15+ volts on your sealed engine battery is bad and will cook it.

Question is, what's the reason and why now ?

I had issues eventually too with my Hitachi alternator - not sure what make yours is ?
The factory did a regulator tweak for external control.
The sense wire came off my Sure splitter also .. Doesn't yours ?
Something went wrong over time ( 4 years ish). I had an electrical voltage spike gremlin in the circuit causing all kinds of issues and the amps would drop off to nothing pretty quick (well known issue for Hitachi's)
I believe it was an alternator problem - over-heating issue - breaking the internal alternator circuits and / or the Sure splitter failing in some way.

I did a couple of things, removed the external regulator control and used another less intrusive method ( the cause of many heated forum threads , swapped the Sure isolator for a Sterling zero volt drop. I also got a more robust alt - but since I did these changes - all has been good for 2 years (touch wood) and I haven't fitted the new alternator yet. With my new setup I could monitor the temp of the alternator and protect it from over heating. I then also fitted alternator cooling. If this link works - http://www.cruisersforum.com/forums/...d.php?t=130609
It also looks after the engine battery - which is a different type to the house.

So my guess would be ...
Your Sure isolator is failing in some way - swap it out anyway - it's pants!
Your alternator is overheating / failing effecting the alt regulator or voltage output control circuits

You need to measure the alternator output when you get your voltage spike.

Put it down to the Croatian heat ! :-)
Or some anti-alternator Frapa death ray :-)))





Sent from my iPad using Cruisers Sailing Forum

[kas_1611]

Hi Damian,

Frapa Anti-Alternator Death Ray Anything is possible I guess

Answers to your questions:

- Alternator is a Mitsubishi 12v 115a. Fitted by factory when boat was built to a Volvo Penta D2-40
- Sense wire (labeled in German as control cable) is not connected to the Sure Power isolator but to the Anchor Windlass power cable (again from the factory).

I have isolated the starter battery to see what sort of voltage drop occurs over the next 24hrs to give me an idea of how well it is holding charge. As we are on mains it was being trickle/float charged from the mains regulator.

I sense a beer and electrics day next time we are both on our boats at the same time and in the meantime I will do some searching whilst I am bobbing around at work.

Keiron

[transmitterdan]

Originally Posted by kas_1611

Thanks for the advice.

I'll look into some form of smart alternator regulation system for future but right now I'm not thinking about making any alterations to the factory fitted electrical circuitry.

There are in line fuses in the smaller wires above the breakers but I cropped them out of the picture in order to focus on the alternator control wire (pink one).

The alternator is the original item and as far as I know has never been adjusted or modified in any way. Up to the last week or so it has performed as expected.

Starter battery is a sealed, maintenance free unit so no way to check fluid levels.

The question is now do I have a bad battery or is it a bad alternator?

Unfortunately I don't know any electricians here in Croatia to get the system checked out and with the language difficulties I don't want to start down the road of changing the system that works only to end up with a system that doesn't.

Cheers

Keiron

To know if your alternator is "bad" wait until the house bank is fully charged. Then measure the house battery voltage when charging from engine. If it is between 13.3V and 14.5 V then the alternator is ok. If you still measure more than 15V on the start battery in this case then the most likely thing is that the battery isolator has partially failed on the house bank side. If it has failed then don't buy anther one. Get instead a battery combiner also known as an automatic charge relay (see my previous post) rated for 120A. Blue Sea Systems make several types as do other companies. But you will have to replace something to fix this problem.

The fact that the factory installed a 1980's technology diode isolator on a model year 2011 boat is disappointing. No new boat should have these things given what is available today. ACR relays work better and cost less.

[kas_1611]

Originally Posted by transmitterdan

To know if your alternator is "bad" wait until the house bank is fully charged. Then measure the house battery voltage when charging from engine. If it is between 13.3V and 14.5 V then the alternator is ok. If you still measure more than 15V on the start battery in this case then the most likely thing is that the battery isolator has partially failed on the house bank side. If it has failed then don't buy anther one. Get instead a battery combiner also known as an automatic charge relay (see my previous post) rated for 120A. Blue Sea Systems make several types as do other companies. But you will have to replace something to fix this problem.

I'll try to check this tomorrow AM before heading back to work but if I don't have time it will be on the list of things to do when I get back. The house battery is currently on mains charge so reading around 13.8v to 14.2v and the starter battery is isolated but reading 13.2v on the multimeter.

So far throughout this I have never seen more than 14.4v on the house battery when on the engine but have seen 15+v several times on the starter battery.

The fact that the factory installed a 1980's technology diode isolator on a model year 2011 boat is disappointing. No new boat should have these things given what is available today. ACR relays work better and cost less.

Probably down to cost and KISS. The technology may be old but it does work and is "Simple". When you are bulk buying items to fit in hundreds of boats you want to keep it simple and they probably get a discounted price.

We still use chronometers after all and they are 1700's technology

Cheers

Keiron

[Maine Sail]

Originally Posted by sailinglegend

Split diodes can cause these problems, and Transmitterdan has explained why but let me add more detail so you can better understand what's happening.

Split diodes can have a voltage drop of 0.7 volts across each diode, maybe double this at high charge currents and maybe only 0.1v with no current. This can be compensated for by having regulators that sense the service battery voltage and boost the charger output. This can produce the right voltage at the service battery but can produce too high a voltage on the starter battery.

Consider a heavily depleted large service bank - and an almost full smaller starter battery. The voltage drop across the diode feeding the service bank increases with the current so may well reach 1.4 volts or more. The alternator senses the voltage at the bank and raises the output by 1.4 volts to say 15.8 volts to get 14.4v at the service battery. The voltage drop across the diode feeding the starter bank battery may be only 0.1 volts because the smaller service bank is taking a much much smaller current, so it will see the alternator output minus 0.1v = 15.7 volts.

Because your batteries are getting older they maybe taking more charge charge current than before which could be why you are now seeing this problem.

Bingo..! Old school diode splitters are no longer used by competent installers and this is just one of the many reasons why..

[DeepFrz]

The link to this wiring diagram was posted on another current thread by deblen and I am going to re-post it here.
https://www.dropbox.com/sh/bj4c5q4o4...9XQRIuUEa?dl=0

The only change I would make is that I would have the alternator charge the house bank and then be linked to the start battery by the VSR.

[transmitterdan]

Originally Posted by kas_1611

The technology may be old but it does work and is "Simple". When you are bulk buying items to fit in hundreds of boats you want to keep it simple and they probably get a discounted price.

We still use chronometers after all and they are 1700's technology

Cheers

Keiron

Keiron,

Actually this old diode technology does not work very well. It was used because it was all they had in the 1980's. If the diode isolator is in fact bad I strongly urge not to get another one. The ACR installs almost identically to the diode isolator. You will like the ACR much better I think.

[hellosailor]

Kieron-
A working kludge might be to disconnect your starting battery from everything but the starter, if that is possible. And then just use automotive jumper cables to connect it to the house bank (after that's charged well) and charge it from there. Obviously that is not a long term solution.
As said before, A BATTERY CANNOT CAUSE EXCESS VOLTAGE so there is no way that replacing your starting battery can fix anything. You can only waste money and ruin a second battery by doing that. Guaranteed.
What the factory did with the isolator and some type of voltage compensation for it, or why they would connect a voltage sense lead to the windless...that is all impossible to guess without a complete schematic. No doubt some engineer had their personal reasons for doing things that way, but without at least a schematic? There's really no way to fix the problem without risking greater damage.
You'll need professional help from someone who knows that system, probably an "authorized" repair ship, unless they can go through the entire system, essentially creating a schematic so they can make sure of what's being fixed.


I'm guessing it would be faster AND cheaper to simply gut the odd bits and everything to do with "isolator" and replace with a conventional modern "combiner" instead.


Of course you might just have some component that has come loose and become disconnected, but the danger with any charging system is that if something is "broken" and overheating--it can also be a fire hazard. Don't underestimate the need to fix this, or at least, find out what is wrong, quickly.

[kas_1611]

Quick update:

After nearly 24hrs isolated the starter battery was still showing 13.2v across the terminals on my multi meter which indicates it is still holding charge so hopefully no lasting damage done in the few instances 15+v were going to it.

Switched off the mains so to avoid any spurious charges and checked both house and starter voltages, both were good at 13.5v and 13.2v respectively. Fired up the engine and measured the voltage from the alternator and initially measured 14.7-15.0v on the multimeter with both batteries reading 14.2v After a few minutes the alternator reading actually dropped to 0v indicating the regulator was doing its job properly then as the fridge kicked in it resumed charge and never went above 14.8v even with 1500rpm on the engine.

So it looks like everything is working as it should at this moment in time. I hate transient or intermittent problems.

As I am off to work I have isolated the starter battery again to prevent it being mains charged for now and will check the voltage when I get home in a couple of weeks to see how well it has held charge.

In the intervening time I am going to research smart alternator regulators and the Combiners (ACR/VSR etc) to replace the isolator(s) we have.

Many thanks for all the input so far

Cheers and cold beers

Keiron

[hellosailor]

Keiron-
Something you should be concerned with, is that you still see 14.8 volts even with the fridge running.
Alternator systems are designed for "standard" voltage, and that would be 14.4 volts *absolute* maximum. That's an ironclad rule, 14.4 volts maximum. The electrical equipment is surprisingly voltage sensitive. For instance, any incandescent lights on your system are designed for 14.4 volts maximum. As the voltage increases, they get brighter but also burn out incredibly faster, from 10x faster to "just hours" of life.
Not much of a problem to change a light bulb, maybe. But in the RADIOS and ELECTRONICS many of them are using parts that are rated at 15 volts, the first (cheapest) standard above their intended maximum supply voltage. So your VHF or SSB may be designed to run at a nominal 13.8 volt supply voltage (see the manual) and the parts in it will in fact take damage once the voltage exceeds 15 volts, plus or minus another 10% of tolerance in the parts.


If your alternator is putting 14.8 volts into the power lines, PLEASE do consider that violates the standards for every piece of electronics aboard. Autopilot? GPS? Chartplotter? All may be burned out at any time. This is not a case of "close enough", this is a case where the operating standards are being exceeded, and with consumer goods today there is simply no extra tolerance for high voltage.


If you have to kludge it...I'd suggest turning on every high load on the boat, in an attempt to draw the voltage down under load, to not more than 14.4 volts.

[DeepFrz]

hellosailor posted: Alternator systems are designed for "standard" voltage, and that would be 14.4 volts *absolute* maximum. That's an ironclad rule, 14.4 volts maximum. The electrical equipment is surprisingly voltage sensitive. For instance, any incandescent lights on your system are designed for 14.4 volts maximum. As the voltage increases, they get brighter but also burn out incredibly faster, from 10x faster to "just hours" of life.
Not much of a problem to change a light bulb, maybe. But in the RADIOS and ELECTRONICS many of them are using parts that are rated at 15 volts, the first (cheapest) standard above their intended maximum supply voltage. So your VHF or SSB may be designed to run at a nominal 13.8 volt supply voltage (see the manual) and the parts in it will in fact take damage once the voltage exceeds 15 volts, plus or minus another 10% of tolerance in the parts.

This just is not so. Some batteries manufacturers state that they require 14.8 volts. However, the OP is measuring alternator voltage up current from a battery isolator which has a voltage drop. Voltage at the battery is 14.2. His alternator controller is sensing the voltage at the batteries and so kicks up the alternator to a higher voltage. This has nothing to do with his system voltage and is entirely fine. The only problem is with the isolator putting to high a voltage on the start battery and that has been explained in earlier posts.

[kas_1611]

Originally Posted by DeepFrz

This just is not so. Some batteries manufacturers state that they require 14.8 volts. However, the OP is measuring alternator voltage up current from a battery isolator which has a voltage drop. Voltage at the battery is 14.2. His alternator controller is sensing the voltage at the batteries and so kicks up the alternator to a higher voltage. This has nothing to do with his system voltage and is entirely fine. The only problem is with the isolator putting to high a voltage on the start battery and that has been explained in earlier posts.

Thanks for pointing this out. Yes I have NEVER seen more than 14.4v at the house battery and normally do not see any more than 14.2v under mains or engine charging.

The issue is purely on the starter battery side and I think I understand the issue and the solution.

Only potential complication is the bow thruster battery which is an AGM. But I think there ahould be a smart regulator / combiner out there that can accommodate all 3 batteries

Cheers

Keiron

[Stu Jackson]

Originally Posted by kas_1611

But I think there ahould be a smart regulator / combiner out there that can accommodate all 3 batteries

You'll need two combiners, or use switching manually to do that for the windlass bank.

I favor the Yandina combiner over the BlueSea ACR. Yandina has a LIFETIME warranty, they're still in business and actually od honor that warranty, although very few have been reported to have failed. Ours is 17 years old and still works just fine.

[hellosailor]

"Some batteries manufacturers state that they require 14.8 volts. "
I'd love to see a link to anything like that from any battery company, because I never have. Fifteen volts for equalizing, sometimes. 14.8 as a maximum the battery can tolerate, sometimes. But 14.8 as being necessary in normal operation? Or proper for any normal alternator power source? Never have seen it, from a battery or alternator data sheet.


Standard 15-volt electronic components, rated +-10%, are only good for service in systems running 13.5 volts, so some manufacturers are pushing the envelope just with "normal" use. (Even some of Icom's radios.)


As to the system voltage versus the starting battery voltage...we just don't know where the isolator(s) are, or where anything else has been connected, for certain. We DO know the alternator is putting out high voltage, and that if that has been improperly connected in one place...one has to suspect the possibility it is getting to other places.


Here, we know there is at least one failure in a system. Considering how frail electronics can be, it can be worth being suspicious. And worth ensuring excess voltage just isn't anywhere IN the system. If a second diode failed in short mode instead of open mode, the way the one to the starting battery apparently has? Not good. And the odds are that both diodes came off the same batch, same line, same engineering for the installation.


As the man said to Inspector Clouseau: Ah, but that's not my dog.
I don't trust sparky things, even when they are behaving.

[kas_1611]

Originally Posted by Stu Jackson

You'll need two combiners, or use switching manually to do that for the windlass bank.

I favor the Yandina combiner over the BlueSea ACR. Yandina has a LIFETIME warranty, they're still in business and actually od honor that warranty, although very few have been reported to have failed. Ours is 17 years old and still works just fine.

I can work with 2 combiners as long as it is a simple wiring job and it works

Keiron