Am I killing my batteries?

I asked this qustion a few years ago and responses were mixed. My problem persists and I would like the forum to have another shot at it.

My start and house batteries only last about two years before a cell goes bad - normally a cell close to the positive battery post. Can it be that I am not charging and discharging them enough? In other words, do batteries like to be "worked"?

They have an easy life and are always fully charged. The main engines start first swing and the generator runs when the mains do in order to power the a/c's etc.

The batteries are maintained by an 85 watt HQRP solar panel with HQRP Duo-Charge controller when the boat is not in use. I built a manual switching system which connects the duo-charger to both house batts or both start batts or the genset batt. I cycle the batteries roughly three days in each position. The LED's on the charge controler indicate that it is doing what it should. The batteries need topping off with water every two months. Consumption feels reasonable and the plates are always submerged.

Further information
Twin diesels plus 6.5 KW genset , each with own battery.
Two house batteries.
All Deka Marine Master lead acid #27's - link below.
Deka Marine Lead Acid 12V
Solar panel: https://www.amazon.com/gp/product/B002OSAB32
Location is the Caribbean so temps are high.

Strange. Being low on water every two months is a little on the high side. What rate of max amperage do they see on a bulk charge? What amp hour is the bank? How many amp hours do you pull out of them before recharging, and what mechanism tells you your level of discharge? Finally, what is the float voltage they live at between use?

Two years is not enough.

check the voltage when fully charged but on the charger. You may be overcharging.

Shoalwaters said:

The batteries are maintained by an 85 watt HQRP solar panel with HQRP Duo-Charge controller when the boat is not in use. I built a manual switching system which connects the duo-charger to both house batts or both start batts or the genset batt. I cycle the batteries roughly three days in each position. The LED's on the charge controler indicate that it is doing what it should. The batteries need topping off with water every two months. Consumption feels reasonable and the plates are always submerged.

Click to expand...

My guess -- and it is only that -- is that you are overcharging. Sure sounds like it anyway. If I understand it, you are charging them with a solar panel. Most good battery chargers will go into "float" mode once the battery gets charged, so that they do not get overcharged. But unless you have a really fancy controller, the solar panel is going to keep pumping the amps in whether or not the battery is already fully charged.

The eagle had six wet 8 D batteries, 3 house, 3 for engine and gen set. They last 5 to 7 years. They sit unused for 3 to 6 months per year with little or no drain. Have to added water every 3 months. They are charged with the original 1978 Pacific marine 65 amp charger which charges all 6 at the same time. The water level is about the same in all cells.

So my guess is the solar is not charging high enough so the discharge is less than 12.2 volts Batteries should not be discharged below 50%.13.1 is fully charged, 12.8 is 75 %, 12 4 is 50 %. So it sounds like the charge is not high enough or discharged be low 50%to often.

85 watts is 7 amps 12 volts, which is not much for 5 batteries. 1 amp per battery.

Make sure you understand ac and dc calculation convetsions. 1 amp 120 volts is equal to 10 amps 12 volts. Volts X amps= watts.

Shoalwaters said:

I asked this qustion a few years ago and responses were mixed. My problem persists and I would like the forum to have another shot at it.

My start and house batteries only last about two years before a cell goes bad - normally a cell close to the positive battery post. Can it be that I am not charging and discharging them enough? In other words, do batteries like to be "worked"?

Click to expand...

Certainly isn't right whatever is going on.

I run nothing but regular 4D LA batteries in three banks and they last 7 or 9 years. I check the water monthly when in use, but only end up adding water maybe twice a year. I usually take them out of service after 8 years, just because of their age, and they end up powering things in my shop for a few more years.

I run a Xantrex 40 amp smart charger continuously, which maintains the batteries at float and it cycles them every 21 days.

Since you're adding water regularly sounds like they are being continuously charged, maybe too much. Nothing will kill an LA battery quicker than keeping them too hot or drawing them down too hard.

Are you running a load on the batteries, like refrigeration or an inverter, when the boats not in use? Shouldn't be using much water when they're not in use and the charger is at float.

Read the instructions on your charge controller. Most of them have user adjustable set points. For lead acid batteries the float charge should be 13.8-14.2 volts. If it is higher, the batteries will be damaged. I would hook all the batteries up to the solar system and let them rest at float charge, instead of using the "manual switch". I used a 200 watt solar system with a Zantrex C40 automatic charge controller on a cruising sailboat for 7 years and never did loose a battery. I set the charge controller when I installed it. Solar panels put out about 21 volts and if unregulated, they will eat batteries.

Take a look at this site:
SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank

There are ways, better ways and best ways to connect parallel batteries.

Your note that the cell next to the positive battery post dies each time indicates that the cell first in line is worked the hardest.

How are the batteries connected? Did you run the take off conductors to the same battery? If so that may be part of the problem, one battery gets worked harder than the others.

In the link above If you have connection #1 then change it to #2 at least.

Better would be #3. Each polarity must be the same length, the same wire size and the same type of wire. Failure to achieve that will result in different Vdrops in the wires resulting in one battery suffering.

Both #2 and #3 will feed and draw more evenly than #1.

Photos?? of the connections as you have them showing the wiring might help us see if there are any other possible improvements.

Shoalwaters said:

I asked this question a few years ago and responses were mixed. My problem persists and I would like the forum to have another shot at it.

My start and house batteries only last about two years before a cell goes bad - normally a cell close to the positive battery post.
Location is the Caribbean so temps are high.

Click to expand...

My experience in high heat is on a Motorhome. I replaced my start batteries on purchasing a used MH in March 2011. I left the MH in the southern Cal desert for only about 5 months over the next 21 months, but had them both go bad at that age. I had bought them at NAPA, so went there for replacements. To my surprise the replacements were free, as their guarantee was 24 months unconditional, and the tech there told me that "in the desert you will rarely get more than 2 years out of a battery like these."

My boat batteries never see anything above ambient BC water temps unless the engines are heating up the ER. The last set of Golf Cart house batteries went 10 years. The 4D Start battery went 12 years.

Draw your own conclusion.

Celectric's comments in post 8 are spot on for install related double checks. As mentioned by several, your charging system is cooking your batteries. Can't tell you why. You are sure the HQRP equipment is suitable for the job? You mention you switch charging output every few days, are you charging "full batteries" especially the 3 starts.

Did I read it right, your house bank is two 27s? Does your genset have an alternator? If so, is that alternator charging the other batteries when genset on and how is that specific output regulated?

I'd say you are killing your batteries and your charge controller is the problem. You are using too much water for banks that are not being worked hard even in your hot climate. Make sure your controller's float voltage is reasonable and lower it if possible. Some battery makers even specify slightly different float voltages from each other. Any time batteries are in parallel, and not charging, they are, in effect, working against each other especially if they are different ages or brands. The fact that the failed cells are nearest the + terminal must say something to someone. I have read that it is better to charge a bank of parallel batteries from one end and discharge from the other end ??

My house bank lasts 8 years normally and 6 if I cruise a lot. I have a simple system. K.I.S.S. Keep It Simple Stupid.

I learned early on batteries have a determined number of charge discharge cycles. You can burn those up fast by keeping a charger on them or you can stretch them out by turning off your chargers when they get fully charged and turning them back on only to recharge.

I know you know more and are going to tell me you have a smart charger and it goes through 4 stages etc. etc. So do I. I still turn it off.

I need water maybe twice a year or less. It's a choice you have to make and I suggest you try it. Make sure the solar isn't making electricity with nowhere to go as I think that isn't good.

I' started this system in 1983 and it works great. Think about it. You don't put a battery charger on you car everywhere you park and in your garage overnight and your car battery somehow is able to last that way so why do you think your boat batteries are any different?

Same experience as Capthead. You are killing your batteries with "kindness. Float still means charge. I have never harmed a battery by leaving it slightly discharged, not deeply but slightly.
Boatyards in my cold climate used to remove batteries in the winter, bring them inside and put them in a "trickle" charger room, destroying a lot of batteries in the process not to mention the labor, space, mess, danger. Now knowledgeable yards charge and load test them in the fall, disconnect them, discard the bad ones so they won't freeze, and leave them alone through the winter finding that they are getting better life from them.

A few bits of info:

The batteries are not paralleled except when a master switch is set to "both". I have not yet had to do this.

The genset alternator charges its own start battery only.

The charge-controller is designed to charge and maintain two lead acid batteries. I tested today and it performs within specs: float 13.8v charge 14.2v.

I am inclined to vote with Brooksie and others: "Float still means charge" and "I am killing my batteries with kindness". The new regime will be to charge each battery for a full day once every two weeks and see how that works.

Thanks all for your input.

Shoalwaters said:

The charge-controller is designed to charge and maintain two lead acid batteries. I tested today and it performs within specs: float 13.8v charge 14.2v.

I am inclined to vote with Brooksie and others: "Float still means charge" and "I am killing my batteries with kindness". The new regime will be to charge each battery for a full day once every two weeks and see how that works.

Thanks all for your input.

Click to expand...

Are you using an inverter when the engines aren't running? Or running a refer on the batteries when you're off the boat? There's got to be a reason for your short battery life.

I've had three different chargers over 40 years on this boat. The last two were smart chargers, which have been switched on continuously. The battery life has exceeded 8 years on every set and I buy standard off the shelf batteries.

Turn your charging system off for at least 24 hours and see what the batteries actually float at. My charger float level is adjustable and that's how I determined the baseline. I'm pretty sure mine is set below 13.8V. If I'm off the boat, my charger doesn't even come on between 21 day maintenance cycles.

If your boat is in the water and not checked daily, turning your charging system off could be a big mistake. Have a hose pop off or another serious leak source and down she goes. A boat sank here even though the owner had all the valves shut off. The muskrat camping out in an exhaust tube chewed through the tube.

No, everything is turned off except the bilge pumps each time I leave the boat. The solar charging system is just keeping the batteries topped off.


It may well be that the batteries' natural float voltage is less than 13.8 volts but I can't adjust the charge-controller to a lower voltage. Hence the plan to top off every two weeks.


I'm at the boat every couple of days and leave all seacocks turned off. I'm comfortable with the general integrity of the boat. However, one can never be too careful. A conspicuous notice "NO RODENTS, by order the management" can't hurt.

I've never seen a float charge requirement at that high a voltage. I checked the Trojan manual and they recommend 13.2. I checked Crown and they recommend 13.5. (Just 2 I happened to have handy) So it does look like you're overcharging them.

Ken

FWIW, I checked the flooded battery specs for a new Mastervolt Chargemaster smart charger I just installed. They are:

• Bulk 14.4V
• Absorption 14.25V
• Float 13.25

The charge voltage is temperature compensated when the remote sensor is in use.

Shoalwaters said:

It may well be that the batteries' natural float voltage is less than 13.8 volts but I can't adjust the charge-controller to a lower voltage. Hence the plan to top off every two weeks.

However, one can never be too careful. A conspicuous notice "NO RODENTS, by order the management" can't hurt.

Click to expand...

I just checked the data sheet on my last 4D battery purchased, recommended float voltage is 2.25v per cell which is 13.5v for the battery and my charger is set for 13.4v. Depends on the battery, but I think you are correct, at the higher float voltage your batteries never rest.

We should post a sign like that too! But then we'd have to get a government grant to teach the rodents to read.

The EPA would declare them a unique and protected species

The rodents would demand recognition, citizenship and medical coverage under Affordable Health Care Act. . . . . .

Never mind, they can just have my boat and I'll move into a homeless shelter.

Just read in another thread that you should add Tang orange drink powder to your battery for long life. Either that or you feed it to the rodents... Not really sure which.

Yes - I too believe you are over charging your batts.

BTW - Are your house bank batts: "starter" batts, or - "dual purpose" i.e. 1/2 starter - 1/2 deep cycle batts, or... as they should be... beefy, full-on "deep cycle" batts?

If your float voltage is being held at 13.8 in real life, you have you almost certainly have your answer. It's now just a cost benefit of replacing batteries.

I was curious not having put solar on yet and did a little investigating. quick like. First, I found quite a few charge controllers that had higher than typical in the charging world float values of 13.7+. I also noted that charge controllers that are shipping in the boxes tend to be pretty basic. The one yours came with was worth about $16 on Amazon , retail, by itself. That's not much money in a device that controls your charge curve, and the life of a battery bank that could be worth thousands depending on its size. I went to Victron and found that sophisticated charge controllers can cost hundreds.

So I suspect that you may be able to upgrade your charge controller for less than the price of the opportunity cost of a shortened lifespan. I also copied this blurb out of one of their charger brochures.

"
When a solar charge controller is not able to recharge the battery to its full capacity within one day, the result is often that the battery will continually be cycled between a ‘partially charged’ state and the ‘end of discharge’ state. This mode of operation (no regular full recharge) will destroy a lead-acid battery within weeks or months.
The Battery Life algorithm will monitor the state of charge of the battery and, if needed, day by day slightly increase the load disconnect level (i.e. disconnect the load earlier) until the harvested solar energy is sufficient to recharge the battery to nearly the full 100%. From that point onwards the load disconnect level will be modulated so that a nearly 100% recharge is achieved about once every week.
"

A lot more research is needed, but quite obviously there is room for improvement.

One of the benefits of a solar panel system is the ability to charge the batteries when the boat is stored without cooking them. With two 140 watt panels and 12 Trojan 105 six volt batteries the two solar panels more than charged the batteries. (Caribbean summer sun) so I had to make a cover to block half of the panels.

Batteries now stay at about 12.6 volts and water is needed to be added once in seven months of storage.

Art said:

Yes - I too believe you are over charging your batts.

BTW - Are your house bank batts: "starter" batts, or - "dual purpose" i.e. 1/2 starter - 1/2 deep cycle batts, or... as they should be... beefy, full-on "deep cycle" batts?

Click to expand...

That's my [post 21] quote above... for some info as to my batt MO...

I have my batts at 100% charge each time leaving boat for any length of time. I always flip on charger to bring batts back to 100% when arriving again. We live 100 miles away from dock. Normally we visit for three to six day cruise and anchor out about every six weeks or so. Due to circumstances we've needed to stay away for up to four months during the last couple years [sometimes we do get to visit more often].

Important note #1: I do not leave our boat electric line hooked into dock while away and being under covered dock our small solar panel is no use. This means the batts sit completely dormant while we are away. The leaving boat unplugged from dock with all batts completely isolated via Perko main switches considerably thwarts corrosion of any sort on metal portions in or out of water.

Important note #2: For house bank we employ four hooked in parallel, group 31, LA wet cell "deep cycle" batts... manufactured by East Penn (Batteries Plus chain stores sell them at great price under different brand name). Our house bank is also starter batts for both engines. 7.5 Kohler gen set has its own group 27 "starter" batt that its alternator charges and the solar panel charges when out and about. Also have one completely isolated (in its own black box) group 27 "starter" batt that receives 1 amp trickle charge each time AC electricity is on - from dock or from gen set. It's always ready to be placed into service if emergency arises.

Important note #3: I do not at all recommend using dual purpose batts that claim to be "starter" as well as "deep cycle" capable. IMO they are no good and from experience can say they are lucky to last a couple years under any service requirements.

Fun note: Due to quality and models of LA batt brand used for different purposes, as well as 100% charge/dormant-hold for duration method I use... our house bank is now eight [8] years old with seemingly plenty of life remaining. Of course it's important to keep distilled water cell level up to bottom of slotted channel in each cell. Filled higher that that (i.e. almost to top of per cell opening) is a waste of time... as during top-over charge sequences the extra water simply overflows or gasses out. I fill our batts' cells annually.

Happy Batt-Use Daze! - Art

Shoalwaters said:

The charge-controller is designed to charge and maintain two lead acid batteries. I tested today and it performs within specs: float 13.8v charge 14.2v.

Click to expand...

But without regard to what the charger is doing (for a minute)...

What float charge do your batteries want? IOW, what does that specific manufacturer recommend -- bulk, absorption, and float -- for those specific batteries? You can look that up.

Shoalwaters said:

It may well be that the batteries' natural float voltage is less than 13.8 volts but I can't adjust the charge-controller to a lower voltage.

Click to expand...

Now back to the charger: Really? Seems odd, these days; most charging products I've shopped on recently offer setting or profile options to match charger to batteries. If it's exceeding what the batteries are designed for... and it offers no way to control that, maybe shopping on chargers would be slightly more important than shopping on batteries every two years or so.

FWIW, if you can match the two systems (batteries and charger), I don't see much utility in turning the charger off and on all the time. Our oldest bank right now is just finishing up it's 11th season, without damage from being on the charger whenever we're at the dock (which is much of the time). That bank is indeed getting a bit long in the tooth and it looks like next year is replacement year, but still... that's a lot different from replacement every 2 years.

-Chris

ranger42c said:

But without regard to what the charger is doing (for a minute)...

What float charge do your batteries want? IOW, what does that specific manufacturer recommend -- bulk, absorption, and float -- for those specific batteries?





Now back to the charger: Really? Seems odd, these days; most charging products I've shopped on recently offer setting or profile options to match charger to batteries. If it's exceeding what the batteries are designed for... and it offers no way to control that, maybe shopping on chargers would be slightly more important than shopping on batteries every two years or so.

FWIW, if you can match the two systems (batteries and charger), I don't see much utility in turning the charger off and on all the time. Our oldest bank right now is just finishing up it's 11th season, without damage from being on the charger whenever we're at the dock (which is much of the time). That bank is indeed getting a bit long in the tooth and it looks like next year is replacement year, but still... that's a lot different from replacement every 2 years.

-Chris

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Hey Chris - what brand/model/type batts do you have? 11 yr plus life span is a good number! - Art

Art said:

Hey Chris - what brand/model/type batts do you have? 11 yr plus life span is a good number! - Art

Click to expand...

Odyssey, PC-2150 (Group 31) AGMs, 3x in each of two large banks, 300 Ah each. Each large bank is both start (one main engine) and house. The "house" load is actually about half of the boat, so that bank runs one fridge, some lights, the fresh water pump, etc., our whole electronics suite on the bridge, and it now runs a 2000W inverter for the TV/sterso, electric recliner controllers and short loads like the microwave and coffee maker.

For years, I charged twice/day at anchor (using the genset) but now I'm finding we have to charge (because of that bank) 3x/day... and even then, we still don't have enough juice in the early morning to make coffee without starting the genny. Time to fix it.


Happens my current plan is to replace that bank with either 4x Lifeline 6V golf cart batteries (440 Ah) or maybe 3x Firefly Carbon Foam 12V G31s. Haven't done the cost analysis on the latter, yet, but 4x GCs or 3X G31s is pretty much what I can fit in the space. (Didn't realize I could probably get 4x GCs in there until a couple years ago.) Staying with AGMs because access for service is painful, and I like the reduced off-gassing.


-Chris

Bay Pelican said:

One of the benefits of a solar panel system is the ability to charge the batteries when the boat is stored without cooking them. With two 140 watt panels and 12 Trojan 105 six volt batteries the two solar panels more than charged the batteries. (Caribbean summer sun) so I had to make a cover to block half of the panels.

Batteries now stay at about 12.6 volts and water is needed to be added once in seven months of storage.

Click to expand...

Shoal waters -- BP's post seems spot on for your panel induced overcharging situation. Possibly some Trojans would help too.

Thanks for the additional input. All read, digested and under consideration.

My charge controller is identical to the Victron BlueSolar PWM-DUO. Only the sticky label on the front is different. Pics and data sheet on the link below.
https://www.victronenergy.com/upload/documents/Datasheet-BlueSolar-PWM-DUO-Charge-Controller-EN.pdf

Start and house batteries are of the correct type(s).
Starting Battery Sealed 24M7 1000 MCA 12V
Deep Cycle Battery Wet DC27 715 MCA 12V

LarryM said:

FWIW, I checked the flooded battery specs for a new Mastervolt Chargemaster smart charger I just installed. They are:

• Bulk 14.4V
• Absorption 14.25V
• Float 13.25

The charge voltage is temperature compensated when the remote sensor is in use.

Click to expand...

The guys that are heavily into off grid stuff use adjustable chargers that you can set all four (including equalize) voltages as well as charge rates and you set it to to what the battery manufacturer recommends. Most chargers do not go high enough on absorption (sometimes needs to be 15+ volts) to get a really good charge.

I would disagree on the point of letting them discharge because Float is charge - its not if you have the right voltage and *any* discharge will cause wear on the plates. (albeit perhaps less than overcharging them...)

Also FWIW the cheaper solar charger I have on my RV will occasionally not realize the batteries are floating and give them an extra cycle which is not good for them at all.