Dead Batteries After 8 Months? Surely Not!

[Pelagic]

Sometimes batteries have been on the shelf a long time before being sold.

If you bought them at any major discount, that may be part of the problem.

[mbianka]

Steve:

I use electric propulsion for auxiliary power. So batteries are kind of important to me. So when one of the 12 volt 210 amp AGM batteries in the 48 volt series string would suddenly not complete taking a charge I began to investigate why. This battery had a Paktrakr Battery monitor connected to it drawing a 25 ma load and 150 watts of solar panels and a controller keeping it charge up over the winter. I removed the Paktrakr load and at first the battery would still not complete a charge cycle. But, after repeated charge cycles it kept improving and finally got to pretty close to where the other batteries were in terms of capacity and load testing. It has caused no further problems this year. You can see the process I went through in these posts:

THE BIANKA LOG BLOG: BATTERY INVESTIGATION PART 1: ASSAULT ON A BATTERY
THE BIANKA LOG BLOG: BATTERY INVESTIGATION PART 2: MORE BATTERY TROUBLE SHOOTING OF A 48 VOLT STRING
THE BIANKA LOG BLOG: BATTERY INVESTIGATION PART THREE: Overnight Charge & Battery Analyzer Test
THE BIANKA LOG BLOG: BATTERY INVESTIGATION PART FOUR: USING THE CENTECH BATTERY ANALYZER
THE BIANKA LOG BLOG: BATTERY INVESTIGATION PART FIVE: Some Good News!
THE BIANKA LOG BLOG: BATTERY INVESTIGATION PART SIX:
THE BIANKA LOG BLOG: BATTERY INVESTIGATION PART 7: Much better balance
THE BIANKA LOG BLOG: BATTERY INVESTIGATION PART 8: LOAD TESTING

My point is others may have trashed the AGM battery as soon as it failed to complete a charge. But, with a little TLC I was able to bring it back. I suspect the Paktraker was loading down my battery so it really never got a full charge compared to the other batteries in the string. Which may be a similar condition to your alternator only charging to 14.2 volts.

[Artif]

Originally Posted by mbianka

Steve:

I use electric propulsion for auxiliary power. So batteries are kind of important to me. So when one of the 12 volt 210 amp AGM batteries in the 48 volt series string would suddenly not complete taking a charge I began to investigate why. This battery had a Paktrakr Battery monitor connected to it drawing a 25 ma load and 150 watts of solar panels and a controller keeping it charge up over the winter. I removed the Paktrakr load and at first the battery would still not complete a charge cycle. But, after repeated charge cycles it kept improving and finally got to pretty close to where the other batteries were in terms of capacity and load testing. It has caused no further problems this year. You can see the process I went through in these posts:

Always a bad idea to pull a load from an individual battery, of a battery bank.

A whole lot more info required from the OP to diagnose the problem though.

[mbianka]

Originally Posted by Artif

Always a bad idea to pull a load from an individual battery, of a battery bank.

A whole lot more info required from the OP to diagnose the problem though.

Agree on both counts. As I found out even a little load can cause the battery to look bad at first blush. I no longer have the load from the Paktrakr on the battery in my case and the battery is now charging as well as the other batteries in the pack. I wonder how many batteries are left for dead when they may still come back to life with a little TLC as long as they are not discharged too severely. Which sounds like may be the case with the OP's batteries.

[stevensuf]

The batteries are elecsol carbon fibre agms, pure snake oil.. from the very start they did not match the supposed rated capacity, but by the time i noticed i was over 1000 miles from home so could do very little about it bar live with it.

they rapidly lost capacity with every long motor run,i am certain the valves released the gas too quickly loosing electrolyte or perhaps the seals were of poor quality in the beginning.

[Artif]

Well Elecsol batteries come with a 7 year warranty.
I'm not a great fan of them, but the ones I had did last 5+ years of very hard abuse, I have heard of problems with them, but it is usually just one battery that will drop out.

I'll say it again, to knock out 2 banks of batteries in a relatively short period suggests you have problems elsewhere.

Check your charging voltage at the battery posts with a good quality Voltmeter, check your Amps with a good quality clamp on Ammeter, obviously you need to check these throughout the charge cycle. Do the same during the discharge cycle as well.

[stevensuf]

Artif, I have checked everything, they are only holding about 40ah max capacity, no dead cells etc, i can only assume degassing is the cause, i doubt they are sulphated, as they were never deeply discharged

[twistedtree]

As a first step, you should isolate each battery and measure it's voltage with a good meter. This might reveal one bad battery, not two. If the voltage measurement doesn't reveal anything, try charging and running one one battery at a time to see how each performs on its own. This might again show one bad battery, not two.

You should also methodically check all your charging. Are the bulk/absorb/float voltages correct on each? Are the chargers properly set up for AGMs?

If your batteries have failed, you want to be darn sure it's not your charging system that caused it or you will just wreck the replacements too.

[Maine Sail]

Originally Posted by stevensuf

So, my super dooper - piece of excrement batteries died after only 8 months of use, never taken below 50% charge bar the last week or so, and only because the whole 500amp hours were only lasting 2-3 hours and i did not have enough fuel to waste running the engine all night on an Atlantic crossing.

My question is, the shore power charger is 3 stage and fine, the solar charger 3 stage and fine, the alternator is a dumb regulator sits at 14.2v and gives the batteries whatever they will absorb at this voltage and holds them there, now i knew this could have been a long term problem on long motoring journeys, but when the batteries were charged it showed only 10-15 amps at 14.2v surely this should not have fried (ie degassed the batteries so quickly) ???

(bear in mind the boat was probably consuming 10 of those amps, ie the alternator was only pumping 5 amps into 500 amp hours of batteries for longer periods once they were charged)

I am thinking the batteries have been below par since the day i got them.

Answers on a postcard please..

Steven,

We really need more info. How do you know the alt sits at 14.2V? Has this been physically measured at the batteries AND at the back of the alternator? Has this been measured in both locations at differnt states of charge?

Have you broken the batteries apart, let them rest for 24 hours and looked for any differences in open circuit voltage? If these batteries were in parallel, and connected correctly to the "loads" then they should be all within a few hundredths of a volt after resting.

My gut on this is chronic under charging not over charging. IIRC the Elecsol AGM batteries should be charged at 14.4V so 14.2V can undercharge them, if the batteries even see the 14.2V at the terminal posts.. I can't recall the last time I saw a bank "cooked" on a cruising boat due to "over charging". Remember most automobiles are pushing 14.2V - 14.6V every time the engine runs. Sears here in the US puts the longest warranty on their Die Hard AGM battery and the majority of cars are charging in excess of 14.2V constant...

With most factory alts you will have very poor factory wiring, a case grounded alt, and usually a voltage drop between the batteries and alternator, especially in BULK or early ABSORPTION charging. Some factory alts won't even hit the voltage set point until the batteries are pushing 95% SOC or better due to voltage drop.

14.2V should not damage typical AGM batteries but we really need to know how and where this was measured and with what? How are the banks physically wired? A picture? Is there a diode isolator to route charging to multiple banks?

Going on your second bank with short life I would strongly suggest you get this sorted out then invest in a battery monitor. What you think may be happening may not be happening or happening differently than you assume. A Victron BMV-600 is well under $200.00USD and worth every cent..

Below is a prime example of a factory alt chronically undercharging due to voltage drop issues.. Remember you need to measure the voltage at the batteries and at the back of the alternator.

It is good to also know how much current the alt is putting out at the time the voltage readings are taken. In this case 1.0V of voltage drop at 10A of alternator output is 150% unacceptable.. These batteries were chronically undercharged, not over charged, despite an alternator with a 14.4V set point. Essentially these batteries never saw much more than a very low float voltage... This is VERY typical of factory alternator issues....

Voltage Drop From Factory Alternator Wiring - YouTube

[stevensuf]

The voltage has been measured at the battery terminals, the solar/ shore both kick in to 14.4 then drop and hold at 13.4/13.6 floats..

When motoring down from the canaries to the cape verdes i could measure the time they lasted between full charges, and it deteriorated after every motor same across the atlantic, till we got to less than 3 hours runs time on them, i would bet money it is an electrolyte thing, maybe bad valves set at too low a pressure?

[Maine Sail]

Originally Posted by stevensuf

The voltage has been measured at the battery terminals, the solar/ shore both kick in to 14.4 then drop and hold at 13.4/13.6 floats..

When motoring down from the canaries to the cape verdes i could measure the time they lasted between full charges, and it deteriorated after every motor same across the atlantic, till we got to less than 3 hours runs time on them, i would bet money it is an electrolyte thing, maybe bad valves set at too low a pressure?

When was it measured at the batteries? In bulk, absorption, early absorption or when near full with no loads on the system? What was the current when measured? Your alt may be regulated higher than 14.4V, very common, but in bulk or early absorption you measure 14.2V - 14.4V but as the banks reach full the voltage could climb higher.

In order to know your voltage set point you need to measure at the back of the alt with the batteries accepting less than 2% of capacity with all other system loads off. You may find you are over the 14.4V when measured this way so when the batteries are full you are exceeding the safe charging voltage of your batteries.

[Nicholson58]

Originally Posted by stevensuf

So, my super dooper - piece of excrement batteries died after only 8 months of use, never taken below 50% charge bar the last week or so, and only because the whole 500amp hours were only lasting 2-3 hours and i did not have enough fuel to waste running the engine all night on an Atlantic crossing.

My question is, the shore power charger is 3 stage and fine, the solar charger 3 stage and fine, the alternator is a dumb regulator sits at 14.2v and gives the batteries whatever they will absorb at this voltage and holds them there, now i knew this could have been a long term problem on long motoring journeys, but when the batteries were charged it showed only 10-15 amps at 14.2v surely this should not have fried (ie degassed the batteries so quickly) ???

(bear in mind the boat was probably consuming 10 of those amps, ie the alternator was only pumping 5 amps into 500 amp hours of batteries for longer periods once they were charged)

I am thinking the batteries have been below par since the day i got them.

Answers on a postcard please..

Many of us swear by our smart charge regulators. I have one on the main an another on the generator. I have one Balmar and one Xantrex.

I suggest you find HANDY BOB SOLAR blog and read a lot about living off of the grid. In your situation, I suspect your systems have been chronicly under-charging. Bob hasn't much nice to say about the charge voltage normally set for lead-acid batteries by the makers of most charge controllers. Also, he rails on about undersized wires and poor placement of battery monitors etc. Its a good but long read. I review it from time to time.

HandyBob's Blog

[zeehag]

firt thing i do with batteries that act as if dead is to either drop em from one foot altitude to desulfate em then try a charge at higher amperage, or i will take a mallet to them with reasonable force (dont puncture em) then try to charge em. if that fails, go for the warantee....

(i was taught this by a battery expert...works.)

[Maine Sail]

Originally Posted by zeehag

firt thing i do with batteries that act as if dead is to either drop em from one foot altitude to desulfate em then try a charge at higher amperage, or i will take a mallet to them with reasonable force (dont puncture em) then try to charge em. if that fails, go for the warantee....

(i was taught this by a battery expert...works.)

Works until the battery blows up in your face and you are permanently disfigured due to acid burns... Just ask Roger Long over on SBO & Wooden Boat about his good friend whom this happened to.... There's always an expert for everything, even one who will tell you to jump off the Golden Gate bridge...

Seeing as Elecsol says these batteries can't and won't sulfate, yeah we've heard that before, then this is not going to help....

[stevensuf]

Ive replaced the batteries with a couple of exide marine batteries, checked everything, both solar/shore charger/alternator are all topping out at 14.2v at the terminals, a bit low i know, but the batteries were also periodicaly desulphated using a sterling desulphator.

When i removed the batteries i could see too small what looked like screw driver marks on the casing cover, i have a feeling i have been sent returns that have been refilled or something very not right!

I am absolutely certain that undercharging leading to heavy sulphation was not the issue and that the batteries were loosing electroltye while under heavy charging, most likely the pressure valves or seals failed.