AGM Battery Failure - Two Sets in Two Years

[Jammer]

Originally Posted by sailjumanji

2) Both the MassCombi and the Solar Chargemaster have temperature compensation probes. The two separate probes, are connected to the top of the batteries - one on each battery. We have run tests with temp probes removed, to check the base voltages. And run tests with them connected, to test the correction. Our downfall is that we measured ambient temperature, instead of battery temp. I posted some numbers on this earlier, but overall it appears the voltages are being overcorrected. In some instances, the correction is exceeding the 0.30 volt limit that Mastervolt states.

I would expect the batteries to be warmer than ambient while charging. Since the ambient temperature is above 72 or 74 or whatever Mastervolt uses as a reference I would expect to see a larger adjustment based on battery temperature than ambient, because the battery is warmer than ambient.



Most battery temperature probes are designed to attach to the battery terminal since the terminal is typically closer to the plate temperature than the top of the case. Is that what you have done?

What is your thought on that? If we are in an undercharge situation, isolating the outboard charge to the start battery as they are now proposing, would be the wrong direction? Mastervolt said they were not concerned about the 14.1-14.2 volts we are seeing after hours of motoring ICW with full batteries. Would you be concerned?

I would not be particularly concerned and would not be at all concerned unless the batteries were showing physical signs of overcharging, such as bulging cases, audible venting, signs that electrolyte was being discharged, etc.

ANother question. We have trashed two sets of house batteries. The start battery is still original. It gets the outboard current same as the house batteries when the VSR is on. Either the outboard current is not an issue, or the larger batteries are more susceptible to overcharge than the smaller start battery. Comment?

Well there are one of four things going on:
1) The house batteries actually are of defective manufacture (it does happen)
2) The house batteries are overheating due to the nature of the installation while the start battery is not.

3) The VSR isn't doing what it is supposed to be doing (unlikely)
4) The problem is on the discharge side of the curve rather than the charge side of the curve (unlikely given other data you have provided)

4) Yeah, Mastervolt said the same thing about temp. I replied to them that my Deka AGM's - albeit only group 31 size - lasted 12 years in this Florida and Texas heat on our previous Seawind. The saloon on the Lite though is closed up, whereas the previous boat saloon was open. So it gets hotter - probably over 100 deg F in August. That might be issue for second set of batteries. But first failed with a month of marina air con, and Apr-June of being at anchor in Bahamas.

I'd really be interested in your thoughts on 3) remarks. THANKS

Typically this sort of thing becomes a problem with car batteries in Texas, Florida, etc., where the high ambient temperature, plus the solar gain inside the underhood environment, plus the elevated temperatures from operating the engine, lead to a really hot battery. Cop cars and courier's cars that are running all day are the worst for this, and yes they can go through a battery in six months.


That isn't your environment and I don't think that failure due to high ambient temperature while on float is plausible.

[Jammer]

I really don't think there's anything wrong with your electrical system. There are two possibilities that remain:


1) The batteries are becoming too hot during charging due to a lack of airflow or conductive cooling. You indicate that the batteries do not become excessively warm to the touch, so I believe this does not fit the facts of the situation.


2) The batteries were defective at the time of installation.


Mastervolt doesn't make batteries, of course, they private-label ones made by somebody else. There are only a handful of battery plants in the USA, far fewer than brands of batteries.


There are all kinds of shenanigans that go on in the battery industry that could have affected your situation. I want to emphasize that I have seen these things happen with other OEMs (NOT Mastervolt) and offer them as possible examples of what can happen in the industry in general.


It's possible but unlikely that your batteries were defective in some way at the time of manufacture, possibly due to a metallurgical problem with the plates, or the way they were assembled, or the way the electrolyte was mixed. I think the chances of this happening with four batteries is remote, but it could happen.


It's possible that the batteries were old. The battery industry is organized around FLAs, and the way they handle FLAs is they ship them and warehouse them dry and then the distributor (usually) or the dealer (less often) adds electrolyte to them before they are sold. FLAs don't age while they are dry so it works out well even if the batteries were sitting on a pallet on the top shelf of a warehouse in Texas all summer.


Obviously, AGMs will deteriorate when subject to that sort of treatment. But I don't know how good the industry is about that now.


I have seen other manufacturers sell, at full price, as new, gel-cell batteries that were salvaged from a pallet that had been sitting in a warehouse for a year, so that they had self-discharged -- half of them were completely shot and were sent for recycling, and the other half were sold as "new" to someone who never knew the history.


Again I don't know if that's anything like what happened here and even if it did, it could have happened before Mastervolt got the batteries, so they may not have known.


It is also possible that there was some sort of specification mixup and you got batteries intended for some less demanding application that somehow got the Mastervolt sticker on them anyway. Often the brand stickers are applied by distributors so that they can pool otherwise identical stock, and a mistake could have been made.


I think you have checked all the obvious things and believe that you're doing the right thing by making this Mastervolt's problem.

[Captain Bill]

I'm not sure what the op is talking about when referring to "bulk Voltage". Bulk charging is all about amperage. Bulk charging should be putting in as many amps as it can until the internal resistance of the battery causes the voltage to rise to the absorption voltage at which time the charger should hold the voltage constant as the amps in tail off. I have to admit that i've probably only worked with a half dozen or so three stage chargers, but I've never read even read a manual that refers to "bulk voltage. Mastervolt is kind of known for going their own way on things and may do things differently than any other manufacturer. Can anyone point me to a reference on bulk voltage. Even then it seems odd that a bulk voltage would be higher than a absorption voltage.

[sailjumanji]

Originally Posted by Captain Bill

I'm not sure what the op is talking about when referring to "bulk Voltage". Bulk charging is all about amperage. Bulk charging should be putting in as many amps as it can until the internal resistance of the battery causes the voltage to rise to the absorption voltage at which time the charger should hold the voltage constant as the amps in tail off. I have to admit that i've probably only worked with a half dozen or so three stage chargers, but I've never read even read a manual that refers to "bulk voltage. Mastervolt is kind of known for going their own way on things and may do things differently than any other manufacturer. Can anyone point me to a reference on bulk voltage. Even then it seems odd that a bulk voltage would be higher than a absorption voltage.

Is the OP me? Here is a manual for the solar controller. Look on page 5, and there is a diagram. It is as you explained, whereas in the bulk stage, the voltage works its way up to the absorption voltage, and then limited to that, and amps begin to drop off as the battery continues to fill. In real life though, with temp comp off, the voltage in the bulk stage works up to a peak of 14.4 volts. And then it drops to absorption voltage of 14.25 volts.

https://images.mastervolt.nl/files/1...MPPT_MB_EN.pdf

For the MassCombi - the shore power charger - in the bulk stage the voltage continues to increase until the bulk voltage of 14.4 is reached, and then it immediately drops to absorption voltage of 14.25 volts. Here is a link to that manual. Look at the diagram on page 7. It works as I explained above. The bulk phase voltage limit and the other phase voltages are listed on page 40.

https://images.mastervolt.nl/files/M...bi070717EN.pdf

Yes, Mastervolt does things different.

[sailorboy1]

Originally Posted by sailjumanji

Is the OP me?

Yes it is you.

Just from my point of view:

1 - if you want me to consider your data you need to answer my questions not refer me to a manual or a graph, others of course maybe willing to dig
2 - till you have good batteries I don't feel there is anything else to to do

good luck

[sailjumanji]

Originally Posted by Jammer

I really don't think there's anything wrong with your electrical system. There are two possibilities that remain:


1) The batteries are becoming too hot during charging due to a lack of airflow or conductive cooling. You indicate that the batteries do not become excessively warm to the touch, so I believe this does not fit the facts of the situation.


2) The batteries were defective at the time of installation.

.

The original batteries were installed by Seawind Vietnam. I think they had a manufacture date of sometime in 2017, the boat was completed in Dec 2018, and we commissioned in Feb 2019. When they failed, Mastervolt's immediate reaction was that they were not stored correctly by Seawind, too hot, not charged while stored, etc. As we were stuck in Miami dealing with this on the way home, Seawind stepped up and arranged for us to get new batteries from West Marine. Went to the huge Ft Lauderdale store, and went thru about ten they had there, and picked the newest set they had. That was in June 2019, and the battery build stamp was June 2018.

When these failed, I went back to West Marine, and rather offer to test and replace them, they said I had to ship them back to Mastervolt. I contacted a regional distributor for MV, and she helped me get replacements under warranty. We upsized to 270 AH AGM's, and had them shipped directly from MV. They have date codes of 4 May 2020 - so only four months since build. I have a start battery coming as well, direct from MV for the same reason.

Mastervolt reviewed the install location and said it was fine. Their instructions call for "a finger width" between the batteries. Because of the heat, I am going to add another inch or so between them for air circulation. The batteries have a bit of a V-shape, whereas the stock install has the top of the batteries touching, but space in between. I just need to engineer a spacer that keeps them separate at top as well, but doesnt point load. Plus with more space, the aluminum bar hold down they were using doesnt fit. Will have to come up with something. Keeping them from moving fore and aft is relatively easy. Coming up with something to keep two 160 lb batteries in place in an inverted boat, is probably next to impossible. Plus these are super 8D batteries. Never seen any hold down for anything bigger than a regular 8D.

[sailjumanji]

Originally Posted by sailorboy1

Yes it is you.

Just from my point of view:

1 - if you want me to consider your data you need to answer my questions not refer me to a manual or a graph, others of course maybe willing to dig
2 - till you have good batteries I don't feel there is anything else to to do

good luck

Huh? Actually, my question - as per the included quote - was to CaptainBill. He asked for a reference to a manual. I was answering HIS question.

In your last post, you specifically said I didn't present any amp data. I replied that it was included in the graphs that I posted here already. But I looked it up for you. The graphs of voltages and current data are in post 32, 33, 35, 38 and 56.

[sailjumanji]

Originally Posted by Jammer

Most battery temperature probes are designed to attach to the battery terminal since the terminal is typically closer to the plate temperature than the top of the case. Is that what you have done?

Actually, I left them where Seawind put them, which is on the top of the case. Mastervolt reviewed that as well. And they sent me new probes for the new batteries. The probe attachments are flat, rectangular shaped. Here is a link:

https://www.mastervolt.com/products/...re-sensor-15m/

What you say makes sense though. I will ask them again. Specifically.

[Captain Bill]

Originally Posted by sailjumanji

Is the OP me? Here is a manual for the solar controller. Look on page 5, and there is a diagram. It is as you explained, whereas in the bulk stage, the voltage works its way up to the absorption voltage, and then limited to that, and amps begin to drop off as the battery continues to fill. In real life though, with temp comp off, the voltage in the bulk stage works up to a peak of 14.4 volts. And then it drops to absorption voltage of 14.25 volts.

https://images.mastervolt.nl/files/1...MPPT_MB_EN.pdf

For the MassCombi - the shore power charger - in the bulk stage the voltage continues to increase until the bulk voltage of 14.4 is reached, and then it immediately drops to absorption voltage of 14.25 volts. Here is a link to that manual. Look at the diagram on page 7. It works as I explained above. The bulk phase voltage limit and the other phase voltages are listed on page 40.

https://images.mastervolt.nl/files/M...bi070717EN.pdf

Yes, Mastervolt does things different.

Thanks. With your recent data regarding the manufacturing dates and the installation dates my guess is that neither set was stored or maintained properly. I make it a practice to never buy a sealed battery over three months old. These probably went a year without a recharge. You can get away with older FLA batteries that are stored dry. I would ask West Marine to show you their battery charging/maintainer system in Miami. I'ld be surprised to find out that they were stored in air conditioned space as well.

[s/v Jedi]

Originally Posted by sailjumanji

Is the OP me? Here is a manual for the solar controller. Look on page 5, and there is a diagram. It is as you explained, whereas in the bulk stage, the voltage works its way up to the absorption voltage, and then limited to that, and amps begin to drop off as the battery continues to fill. In real life though, with temp comp off, the voltage in the bulk stage works up to a peak of 14.4 volts. And then it drops to absorption voltage of 14.25 volts.

https://images.mastervolt.nl/files/1...MPPT_MB_EN.pdf

For the MassCombi - the shore power charger - in the bulk stage the voltage continues to increase until the bulk voltage of 14.4 is reached, and then it immediately drops to absorption voltage of 14.25 volts. Here is a link to that manual. Look at the diagram on page 7. It works as I explained above. The bulk phase voltage limit and the other phase voltages are listed on page 40.

https://images.mastervolt.nl/files/M...bi070717EN.pdf

Yes, Mastervolt does things different.

Figure 3 on page 5 shows a correct charge diagram. It is very clear, leaving no room for doubt, that the charge voltage never exceeds absorption voltage. As your unit does, it is faulty.

[Jammer]

Originally Posted by sailjumanji

Actually, I left them where Seawind put them, which is on the top of the case. Mastervolt reviewed that as well. And they sent me new probes for the new batteries. The probe attachments are flat, rectangular shaped. Here is a link:

https://www.mastervolt.com/products/...re-sensor-15m/

What you say makes sense though. I will ask them again. Specifically.

I think Mastervolt products are good ones and are, on the whole, well thought out with a focus on quality. That said, I do not believe that the battery temperature sensor's design is a wise one. It is easy and intuitive to adhere the sensor to the top of the case, and to be sure, that's better than no sensor at all. But the top of the case is not in contact with the electrolyte, or the plates, and will typically have a temperature somewhere between the electrolyte/plate temperature (which is what matters) and the ambient temperature in the battery compartment (which doesn't).


See for example the approach taken by these competing products, all of which are designed to fit under the head of a terminal bolt or nut:

Magnum energy


Xantrex


Victron


These designs may show elevated readings from resistive heating near the terminals, which will depress the charge voltage. I don't think that is a bad thing, because properly connected and torqued terminals should show only an insignificant temperature rise.



In the automotive world, when there is a battery temperature sensor it is usually underneath the center of the battery, as batteries are typically mounted in the fender area and this space is available:


Dodge Ram truck


But due to cost constraints, many cars and light trucks just use an ambient temperature sensor (which they need anyway for managing the fuel injection system) and apply various adjustments in software to estimate the battery temperature.


Anyway, that may be contributing to the problem, but I don't think it is the problem.

[Jammer]

Originally Posted by sailjumanji

The original batteries were installed by Seawind Vietnam. I think they had a manufacture date of sometime in 2017, the boat was completed in Dec 2018, and we commissioned in Feb 2019. When they failed, Mastervolt's immediate reaction was that they were not stored correctly by Seawind, too hot, not charged while stored, etc.

I agree with Mastervolt's analysis.

As we were stuck in Miami dealing with this on the way home, Seawind stepped up and arranged for us to get new batteries from West Marine. Went to the huge Ft Lauderdale store, and went thru about ten they had there, and picked the newest set they had. That was in June 2019, and the battery build stamp was June 2018.

I am increasingly skeptical that the batteries were in good condition when installed. If stored in hot, warehouse conditions for a significant portion of the one-year time between manufacture and installation, they would have been drained due to self-discharge, and then deteriorated due to the combination of low SoC, heat, and the passage of time. If they were on the air-conditioned showroom floor the entire time, well, that's better, but still not great.

I just need to engineer a spacer that keeps them separate at top as well, but doesnt point load. Plus with more space, the aluminum bar hold down they were using doesnt fit. Will have to come up with something. Keeping them from moving fore and aft is relatively easy. Coming up with something to keep two 160 lb batteries in place in an inverted boat, is probably next to impossible. Plus these are super 8D batteries. Never seen any hold down for anything bigger than a regular 8D.

Wood doesn't conduct electricity and is relatively resistant to damage from electrolyte. That said, you may be overthinking it. A larger gap doesn't always mean better cooling due to the fluid dynamics of the moving air. If you have some gap, and don't have batteries getting hot, you may be trying to solve a problem you don't actually have. I've watched iterations of heat sink designs and have given up trying to predict whether it is going to help matters to add fins, remove fins, make fins deeper, make fins more shallow, etc etc. It's harder than trying to understand voodoo.

[CarlF]

Yikes - you’ve worked hard at this.

When totally stumped by something I revert to “When you hear hooves, think “horses” not “zebras”

Untold numbers of AGM batteries have had short lives on cruising boats because of PSOC. The only people I know who are really happy with their AGM’s are plugged in almost every night. While your failures seem way too fast for PSOC damage, the symptoms are right.

I finally gave up on AGM’s and switched to Fireflys. If your problem is PSOC, that will fix it.

[sailjumanji]

Originally Posted by s/v Jedi

Figure 3 on page 5 shows a correct charge diagram. It is very clear, leaving no room for doubt, that the charge voltage never exceeds absorption voltage. As your unit does, it is faulty.

Yeah, but the MassCombi has a different profile, whereby the bulk voltage is 14.40, and the absorption is 14.25 volts. It's tough to say that the solar controller should be limited to 14.25 to prevent battery damage, whereas the MassCombi shore power charger specifically allows 14.4 volts bulk. In real tests, the 14.4 volts is almost instantaneous, and then the charge drops to absorption voltage. It's not at 14.4 volts for hours, but just a minute or so. It ramps up so quickly, and then drops, you really have to watch it to catch it.

[sailjumanji]

Originally Posted by Jammer

I think Mastervolt products are good ones and are, on the whole, well thought out with a focus on quality. That said, I do not believe that the battery temperature sensor's design is a wise one. It is easy and intuitive to adhere the sensor to the top of the case, and to be sure, that's better than no sensor at all. But the top of the case is not in contact with the electrolyte, or the plates, and will typically have a temperature somewhere between the electrolyte/plate temperature (which is what matters) and the ambient temperature in the battery compartment (which doesn't).


See for example the approach taken by these competing products, all of which are designed to fit under the head of a terminal bolt or nut:

Magnum energy


Xantrex


Victron


These designs may show elevated readings from resistive heating near the terminals, which will depress the charge voltage. I don't think that is a bad thing, because properly connected and torqued terminals should show only an insignificant temperature rise.



In the automotive world, when there is a battery temperature sensor it is usually underneath the center of the battery, as batteries are typically mounted in the fender area and this space is available:


Dodge Ram truck


But due to cost constraints, many cars and light trucks just use an ambient temperature sensor (which they need anyway for managing the fuel injection system) and apply various adjustments in software to estimate the battery temperature.


Anyway, that may be contributing to the problem, but I don't think it is the problem.

Wow, thats something to think about, when so many others do it different.

Funny that just last week, the battery on my Ford truck failed. I brought it in for replacement, and the tech asked if I ever planned to take the truck to freezing conditions. Because the stock battery had a blanket surrounding it to keep it from freezing. And because in south Texas, heat is a much bigger issue than cold. The blanket stayed on the removed battery! New installation is sans blanket.