Engine batterie dying too quickly

[Compass790]

Originally Posted by GILow

I'm not so sure about these rules about frequency of engine use and engine battery life.

My boat sat sometimes for months without the engine being run, when I was building the house it was often three or four months between boat visits. And for the two years the batteries were in the boat before I bought her, I don't know if the engine was run more than a few times a year.

And yet, the engine batteries lasted ten years. I only replaced them because I replaced the engine, though they were, as I noted, becoming a bit sluggish on cold mornings.

Sure, prudence says frequent use is good, but I just don't think infrequent use is the battery killer it is reputed to be.

Certainly I think there is another problem at play here, and I'd put equal odds on a buggered alternator vs a power leakage.

Matt

Nailed it!

[stormalong]

Again we are missing a lot of pertinent data. The OP says he uses the windlass off of the start battery and switches to the house battery after half an hour of charging.

No description of the charging system. Size of alternator? Internal regulator or smart regulator? Size of windlass?

From what little information given I suspect a small internally regulated alternator which is not up to the job of putting power back into the engine start battery after using the windlass. Engine start batteries are not up to the task of running a windlass and the battery is never fully recharged. They can only supply a lot of power for a few seconds to crank the engine, not for a few minutes to raise an anchor.

To find the right solution more information is needed.

[Cadence]

Originally Posted by kriskro

Hi,

It has been 5 years that I have my boat and I must have replaced my engine batterie 3 times... This looks to me a pretty poor performance and would be keen to hear from some experienced sailor what could be the problem.

Firstly, let me describe little bit my setup and how I operate

I have

- 1 Engine Battery ( Century Marine Pro )
https://www.supercheapauto.com.au/p/...060105#start=1

- 2 House Batteries (AGM GIANT)
https://www.aussiebatteries.com.au/b...BoCBIcQAvD_BwE

- A classic switch in between

The AGM are connected with Solar panel and Wind Turbine behind a charge controller.

I never use both house and engine battery at the same time. When starting and running the engine, I switch to engine batteries to start and stay on the engine battery for a while to ensure charging. It is usually at this time that I use the windlass to lift the anchor too. Once I turn off the engine, I switch back to house batteries.

Last time I was on the boat, I started the engine as usual with the engine batteries with no issues. After a a few hours sailing, I tried to start the engine and here, nothing, no power on the engine battery...

Do you see any issues with my way of operating the batteries ? Could the problem be my engine alternator that kills the battery ? Or is 1 or 1.5 year is the standard life of engine batteries on boat?

Cheers,
Chris

I'm probably as dumb as a rock but it sounds as though your only charging is the short time you are running the engine? The battery in good condition will restore itself over time. Starting and the windless are sucking the life out of it without a charging.

[roland stockham]

Yes I suggest you have a charging problem but there are many ways to solve it and you need to pick the best one for the boat.
Issues, sealed batteries are very prone to failure if the charge regime is not spot on. The start battery you have appears to be a dual use sealed one not dedicated start batteries.
You have 2 different types of batteries on one charge system. AGM setting give a very slow taper and low final voltage to prevent damage so the last 10% of charge takes forever (around 5hrs). Your engine battery never drops below 90% because you only take a few A/hr but still needs the full time as it's acceptance at 95%is so low. The result is that the start batt' is never getting to full charge so it dies. Each time it is left with only 95% charge it looses that 5% so rapidly looses capacity.
Solutions. You need to change things so that the start battery has a much longer charge period either continuously while the engine is running or from the solar system.
I would say ideally get rid of the 1,2,both switch and replace it with a proper charge distribution system and fit an external regulator. The only way I can see to charge both batteries on you current system would be always run the engine with it set to both which means you are loosing all the advantages of a separate start batt.

[dennismenace111]

A blown diode on the alter perhaps?

[IslandInfedel]

I’d check the battery and alternators health

If that’s good I’d isolate all the systems by flipping breakers and pulling fuses, test and check to see where the drain is coming from.

[hamburking]

Check your shore power battery charger. Sometimes an automotive type charger is foolishly installed . These chargers are built to be be disconnected from the battery after charging. If left connected, with no AC power, they present a substantial DC power drain to the battery. I kid you not!!!! This happened to me. My starter battery was constantly dead. After I disconnected the battery charger, everything suddenly worked great!

[Uncle Bob]

Originally Posted by donradcliffe

When my engine won't turn over, I start out by cleaning every connection with a wire brush wheel.Usually, that solves the problem.

+1 For what it's worth, I have only ever had one supercheap battery, it was not a happy experience.

[kriskro]

So, went on the boat and did a bit of measurements to understand..

The drain on the house battery is 0.11 amps with the few leds, a bilge pump and the wattmeter that is plugged full time (At the moment)

I did check the engine battery and there was a drain of 0.07 amps. Nothing was connected and still wondering what it was..

Now I checked the alternator.

It gives
- nothing at idle (no voltage change at the battery)
- 13 volts a 1000 rpm
- 14 volts at 2200 rpm

The alternator is supposed to be a 60 amps.

So my guess is that the 30 minutes engine to get out of the port is probably not enough to reload much especially if I play with the windlass after that. and if by mistake, i forget to switch to the house battery after docking the boat, then i may well have a flat battery after a few weeks with the drain of the bilge pump (and not solar to load the engine battery)

I think the solution will be here to load the engine battery and the house battery using the dual battery solar charger so that both gets loaded one after another when I leave the boat unattended.

Considering the alternator, do you think it needs replacement ? i would have thought they would give at least 14volt even on idle.. What do you think ?

[ranger58sb]

Originally Posted by kriskro

Now I checked the alternator.

It gives
- nothing at idle (no voltage change at the battery)
- 13 volts a 1000 rpm
- 14 volts at 2200 rpm

The alternator is supposed to be a 60 amps.

Considering the alternator, do you think it needs replacement ? i would have thought they would give at least 14volt even on idle.. What do you think ?

Some alternators are "self-exciting" and don't start putting out juice ("exciting?") until RPMs increase. OTOH, I think (but don't know for sure) that once they start juicing, they continue doing so even if RPMs decrease, even to idle.

I'd have thought you'd get a fairly standard 13.7-14.0V (once "excited") all across the board, not RPM dependent. I dunno that for sure, though; it's just based on our most recent experience (with much bigger engines and alternators). Others will know better.

-Chris

[GILow]

Originally Posted by kriskro

I did check the engine battery and there was a drain of 0.07 amps. Nothing was connected and still wondering what it was..

Now I checked the alternator.

It gives
- nothing at idle (no voltage change at the battery)
- 13 volts a 1000 rpm
- 14 volts at 2200 rpm

The alternator is supposed to be a 60 amps.

Those numbers feel a bit low to me. Of course I suppose it depends on the actual state of charge of the battery, but I'd expect more. 14.7 or so by the time you get to 2200.

Any chance of getting an ammeter on the charging circuit?

The 0.07 amp discharge is a problem. It translates to 10 amp hours per week, which is certainly enough to ruin a battery.

[Wotname]

Originally Posted by kriskro

So, went on the boat and did a bit of measurements to understand..

The drain on the house battery is 0.11 amps with the few leds, a bilge pump and the wattmeter that is plugged full time (At the moment)

I did check the engine battery and there was a drain of 0.07 amps. Nothing was connected and still wondering what it was..

Now I checked the alternator.

It gives
- nothing at idle (no voltage change at the battery)
- 13 volts a 1000 rpm
- 14 volts at 2200 rpm

The alternator is supposed to be a 60 amps.

So my guess is that the 30 minutes engine to get out of the port is probably not enough to reload much especially if I play with the windlass after that. and if by mistake, i forget to switch to the house battery after docking the boat, then i may well have a flat battery after a few weeks with the drain of the bilge pump (and not solar to load the engine battery)

I think the solution will be here to load the engine battery and the house battery using the dual battery solar charger so that both gets loaded one after another when I leave the boat unattended.

Considering the alternator, do you think it needs replacement ? i would have thought they would give at least 14volt even on idle.. What do you think ?

A constant drain of 0.07A is about 50AH per month. That is not good for the battery and is part of the reason for the shortened battery life.

The alternator numbers do seem a bit low but it depends on the alternator / regulator type.

What engine and/or alternator do you have? Some older ones will only be around 13.8V.

EDIT - Opps - I note GILow raised the same points - sorry for the duplication!

[GILow]

Originally Posted by Wotname

EDIT - Opps - I note GILow raised the same points - sorry for the duplication!

Not duplication, reiteration.

[GILow]

Originally Posted by kriskro

...
So my guess is that the 30 minutes engine to get out of the port is probably not enough to reload much especially if I play with the windlass after that.
...

Regarding the windlass. Yes, they suck a LOT of power. Even my old thing draws UP TO 150 amps. But that's peak, if I stall it. Lots less if I am just letting the boat run up to the anchor.

AND, I only run it for under a minute to lift the anchor. Probably 30 seconds.

So, that's less than 2 amp hours to lift the anchor.

Trivial. Sure, the wiring has to be good enough to handle the peak current, but the alternator can put that power back in moments.

[Compass790]

Sounds like you hit the jackpot, parasitic drain & dodgy alternator but to reiterate what GILow said: Can you put a clampmeter on the B+ cable & see what amps its pushing out?
Dont touch the alternator fan when engine is running.
Don't ask me why I know this is a bad idea
Post #20 may be barking up the right tree I'm guessing
Yes definitely get solar charging on engine battery as well as eliminate parasitic drain if poss.

Disclaimer: I'm an electrical novice but have had to learn a little bit about our boats alternator.