House battery life

[dalee62]

So my 2 golf cart batteries have packed it in. They were installed in March of 2012. They are U.S. Battery brand which I thought we're good. They have not been run dry or mistreated to my knowledge. It has worked out to $100 a year to own them. I know there are many factors that contribute to battery life but is this a little short? I had expected 4 minimum and that I would replace them at 5 years. Maybe this is normal and I am expecting to much.

dave

 

[knotflying]

Dave,
There are many variables that affect battery life, including the quality of the battery to begin with. Three to five years is a normal range. It looks like you are at the lower end. Keeping your batteries up to full charge is the most important thing. Sulfation of the plates prevents deep charging and hence shortened battery life. Golf cart batteries have deeper charges and more amp hours, but that does not mean that they will last longer. As I am sure you have seen before in my posts, Walmart, $90.00 and replace every three years regardless and you can't go wrong.

 

[NorthernFocus]

...Keeping your batteries up to full charge is the most important thing. Sulfation of the plates prevents deep charging and hence shortened battery life...

Knotflying said it. Deep discharging batteries wears them out much quicker. The higher you keep the charge in them, the longer they will live. In our last boat we had really light house loads when at anchor (just heater and laptop) and ran the engine a few minutes every night before bed. The original set of batteries which weren't even "deep cycle" lasted seven years. And then I only replaced them on general principles. They were still functioning fine.

As a general rule, any time lead-acid batteries drop below about 12.4V without current running into them, they're being damaged. So why all the hype about "deep cycle", high capacity, etc.? Good question. I follow the same philosophy as Knotflying. I use decent quality, inexpensive batteries, try to treat them well, and replace them at the first signs of age.

 

[dalee62]

Thanks for the responses. The guy I bought the batteries from sells a gizmo that passeses a pulse of electricity through the the batteries to deal with sulfation The name of it escapes me at the moment. I will nvestigste the Walmart route, for me I don't see the point in buying good batteries now. thanks again.

dave

 

[sheral]

We live 'off grid' and have some experience, personally or through others, who have used various 'desulfators' etc. Personally I have not seen any increase in battery life using the desulfators, although others will disagree, I am sure.

The two things that seem to make a real difference in stretching out battery life is keeping a trickle charge on a battery and depending on the type of battery, checking SOC and doing an EQ when necessary.

My first choice, both for simplicity and proven usefulness, would be keeping a good quality trickle charger on batteries when not in use.

 

[SGIDAVE]

Hello Dave

Does your charger allow for an "equalization " charge? My 21EC came with pro mariner pronautic charger which can be set to do this. It seems to keep my 6V batteries working better.

Trying an equalization might be worth a try before trashing your current batteries.

dave

 

[NorthernFocus]

...My first choice, both for simplicity and proven usefulness, would be keeping a good quality trickle charger on batteries when not in use.

Ditto. The long lived batts that I mentioned previously were treated so. Trickle charge between trips and over the winter. There is a school of thought that small levels of sulfate can be removed that way thereby preventing a heavy, performance killing layer from ever developing. Based on my own experience I'm a believer.

One thing to think about on this topic, how long does a battery survive in an automobile? Personally I haven't replaced one in a car/truck in the last twenty years. During that time we've had a couple of vehicles that we kept for 10 years or so. My wife's Jeep is now ten years old with the original battery. For those of us with a few years behind us, one must ask, "what has changed?". In my youth it was typical to replace a car battery every two or three years. What has changed is that most modern vehicles will shut the lights off for us if/when we forget to do so, leave doors open, etc. The hardest thing on a lead/acid battery is slow, deep discharge. The only thing worse is letting them go dry.

 

[dalee62]

The boat came with a Charles 5000sp series charger. The manual only mentions bulk,absorption and float stages. Nothing about equalization. The only time I am not plugged in is when Im using the boat. the guy who sold me the batteries also does charging systems. I've got a pretty good idea what he will say if I ask him about my charger.

When I left the dock this evening I was at 13.3 volts. 2.5 hours later I was just under 12.5. that's with only the fridge on.

I will investigate a different charger.

Dave

 

[Dog Islander]

I may have missed it, but did you check to see how your alternator is functioning? That might be a reason for your voltage drop during your cruise. If you have a clamp on amp meter, check the amp flow out of the alternator to the batteries (house and start). I suppose there is some sort of relay that switches the batteries during the charging cycle too. If your start battery maintains a charge while the house doesn't, I'd look at that switching mechanism. I won't attempt to try and verbalized how that all works as others on this site can more eloquently describe that system than I.

 

[SGIDAVE]

The boat came with a Charles 5000sp series charger. The manual only mentions bulk,absorption and float stages. Nothing about equalization. The only time I am not plugged in is when Im using the boat. the guy who sold me the batteries also does charging systems. I've got a pretty good idea what he will say if I ask him about my charger.

When I left the dock this evening I was at 13.3 volts. 2.5 hours later I was just under 12.5. that's with only the fridge on.

I will investigate a different charger.

Dave

Hello Dave,

Whilst underway, your battery 'voltage' should invariably read HIGHER than 13V IF your alternator/voltage regulator system are working right. Maybe I'm misconstruing your post above, but I'm taking it to mean you where underway and had voltage of 12.5. So, Dog Islander has a good point, put your clamp-on style DC voltmeter on the charging wire from the alternator and see whats going on. There will be ONE wire (red), probably AWG 6-8 in size running to the starting battery. This is what conveys the alternator's charge to the boat's batteries. The Blue Seas ACR should provide a connection between the start/house batteries and allow the alternators juice to fairly quickly get to the house bank.

When I start my Yanmar, I can 'hear' the extra alternator load on the idling engine about 1-2 minutes after starting. At that point the 'start' battery has reached the set voltage to allow the ACR to connect the house bank and allow the charge to go to that much larger bank as well. Hence, my comment that, while underway, your house battery voltage should be greater than 13V because it is receiving continuous juice from the alternator.

Fair winds and charged batteries,

dave

 

[dalee62]

When the engine is running I have 13.4going to the batteries. the low reading on the house batteries came a couple hours after I had shut off the engine and was not plugged in.

Dave

 

[walldog]

That may not be too far off normal. 12.5 volts is still about 90 %.

My magic number is 12.24 volts which we never let our house batteries drop below.

 

[sheral]

That may not be too far off normal. 12.5 volts is still about 90 %.

My magic number is 12.24 volts which we never let our house batteries drop below.

Bingo. Yes I agree. Staying at or above 12.2v for a 12 v system or 24.4v for a 24 v system will keep your batteries healthy for a long time. Every time you let your charge drop below those numbers you will be taking weeks/months/years off of their total life.

 

[bakerboat]

Hi,

I apologize in advance if I am pointing out the obvious here but, these voltage/state of charge charts are really only intended for use when the batteries are 'at rest'. Meaning there is no charge or discharge going on and the battery's chemical reaction has had a chance to become stabilized after an hour or two. Only then can you get a reasonably accurate state of charge from the voltage.

This doesn't happen very often which is why there are amp hour counters and algorithm based voltmeters out there to try to give you some kind of an average. Not the perfect answer but, I don't think there is one yet.

Not going below 50% is certainly important. Some battery mfrs like Surrette are brave enough to actually tell you how many cycles down to 50% their batteries will take before they start to degrade. Going below that, you're on your own.

Last comment (I promise), please don't try to equalize AGM or Gel batteries. At 15.5 volts, the electrolyte will vaporize and disappear - it cannot be replaced. Flooded cell batteries can obviously handle this situation.

Regards,
Ken
O'Meara
R27

 

[dalee62]

What alerted me to this situation was that I was on a over night trip on Saturday night. on Sunday morning I discovered that the fridge was not running. I didn't have a volt meter with me at the time but as soon as I startedup the engine the fridge started up. I am going to shut off the master this evening and see if the batteries drain over night. I'm wondering if there is some othere problem robbing me that I'm not aware of. I still suspect the batteries are shot though.

Dave