Battery Woes...

[skipgundlach]

Battery Woes...

Well, Dang!

I installed new Deka L16 batteries (4x370AH, bank 740AH in April 2014. They
appear to be at the end of their lives at ~30 months in. We have been
diligent in keeping them watered with distilled water, and have battery
saver caps to minimize water loss.

We charge with a Honda 2000 connected to our shore power, which feeds a
Xantrex 70A/1500W temperature-probed inverter-charger. That has a design
issue which makes it not float out well, so we transfer to our 40A
stand-alone charger for the last of it.

We monitor everything through a Trimetric battery monitor. We fully charge
once a week or more often, through, also, our 370W solar feeding a Blue Sky
6024H MPPT controller, and our KISS wind generator, and equalize once a
month (using the Honda and the Xantrex).

When we're motoring, our alternator keeps up with it, but doesn't seem to
have a good control/regulator; even though the output shows low net incoming
amps after a long while, our cumulative AH shows positive values (20-40AH
typical) which, of course, goes away the moment the engine is off, but our
battery is certainly fully charged, if not equalized.

All charge sources are fed to a single buss protected by a 500A in-line
fuse. Our typical charge is at 25-30% discharged, so the battery doesn't
work very hard. It has been to 45% discharged a few times, and once to 55%
(Hurricane Matthew, with the KISS disabled, and not much sun in the 4 days
we were off the boat).

In the last few weeks, I have gotten up in the morning to ~220AH used - less
than 30% discharged - and found voltage at 11.3. Not good at all - whassup?
So, I've been wrestling, with no solutions or even clues.

We've been fully charging about every 2-3 days of late, due to work we've
been doing which requires the Honda, and yesterday I fully charged (one hour
at 14.1V or better) and equalized (2 hours at 15.2V or better), and
immediately read the batteries with a temperature-compensated hydrometer and
also our voltmeter, at the end, while still charging, the individual battery
voltages (ya, I know - they weren't disconnected).

The 4 had divergent readings at the end of the equalization cycle: 8.0,
7.3, 7.33 and 6.68 volts. The banks/pairs are 1/4 and 2/3, and,
cumulatively, the banks had the same readings, but with very different
single readings. I suppose that could be laid to the fact that I couldn't
effectively disconnect them, but it's still pretty weird...

Temperatures were very different between banks one and two (read down each
water-fill hole; I've averaged the 3 readings per battery) immediately after
equalization:75, 98, 100, 73F - from which I gather/intuit that bank one
(1/4) got much less amperage, somehow, or there was some problem in bank 2.

Specific gravities were lousy. All the cells read in about the same range
per battery, with bank 1 faring much better than bank 2: Bank one averaged
about 1.227 and bank two, temp compensated for 8-10 added, averaged 1.220 -
but that included one cell in 2/3 - at both ends; cells 5-8 read 1.220, but
had 1.235 and 1.260 in cells 4 and 9.

None of them was better than fair, and many of the cells were in the edge of
the "charge" range - immediately after equalizing.

So, clearly, something is amiss.

Beyond just bad luck, are there any ideas of how this might have occurred,
given the above? And, my presumption, are these batteries toast?

Thanks.

L8R

Skip

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[a64pilot]

Fridge ate your batteries?
Sorry, poor joke, but couldn't help myself

[skipgundlach]

Originally Posted by a64pilot

Fridge ate your batteries?
Sorry, poor joke, but couldn't help myself

No, but it IS the reason we run the Honda so much; if it's fully sunny and a nice 15-20 breeze, we keep up, solar topping up the evening - if any - shortfall...

[transmitterdan]

The only way to know if the batteries are ok is to individually charge each battery then do a load and discharge test. Takes a long time (days) to do one at a time.

Amp counting meters kill a lot of batteries. They say 100% when it really ain't so. Few cruisers want to charge to true 100% because it can take up to 6-8 hours for a big bank. Heck it can take 4 hours for a small bank. But not charging to 100% is the most likely cause of early battery death.

[skipgundlach]

The most current info I have comes from a former Tech Support guy at Rolls/Surrette; he suggests several cycles of long equalization after charge, then deep (50%) discharge.

He agreed with the possibility of chronic undercharge, though we do a fair amount of charge to what we think is full (hours of floating and an hour or more at 14.1 or more), as well as equalization - but he thinks both are way too short.

MAYBE we'll find these just needing a good stiff shaking, so to speak and a sharp speaking-too, metaphorically

[brianlara 3]

I have 4x120ah AGM's = 480. The Engel ( @ minus 15C ) 38L freezer runs 12 hours @ 2.75 amps. The TV often runs 7 hours @ 5 amps.
So I have to run the 2kv=1600W genny for two hours a day minimum which runs a Sterling Pro Ultra 12/60 charger. I never let the loaded voltage (pulling 8 amps) drop below 12.4V.
Even recharging a well charged bank I'm often on 'bulk' for 40 minutes until it cuts back to varying levels of "absorbtion' which is what really takes the time as mentioned by another poster.
Only smart chargers and smart alternators will take a battery to a true 100% .
Solar regs, I believe, don't have the brains of a proper charger.
People THINK they are on 'float' but my professional quals cause me to suspect otherwise.
I have a 135W panel which does a bit, three would do more but i suspect 10 wouldn't bring the true s.o.c. to 100%.
There are better professionally qualified experts here on CF who might energetically disagree with my " no smart charger= not proper charged " theory. I respect their greater marine experience but I won't be biting at disagreements.
I suspect there is probably nothing wrong with the OP's DEKA batteries but as mentioned here already, the only way to definatively test a battery is to isolate it, fully smart charge it and then load test with a carbon pile tester noting individual cell gasing.
Hydrometres are really useful but because of stratification, individual cell sulphation etc they aren't the proper tool for assessing an expensive batteries true suitability for the task.
IMO, there is no way 4 fairly new Dekas are faulty.

[skipgundlach]

Thanks for that; I had assumed that equalization un-stratified the acid, and in part, was the reason to do so.

Certainly, in looking down the holes during charging, there's bubbling which would suggest movement of the acid.

Where do you get a monster carbon pile tester? Even the tech who did the installation with me didn't have one suited to the task and had to get it sent from another store; at that, I am convinced that he never did properly test them; I had him out for a service call as I was suspicious of the new installation, and then later, of the charge level after they had been in for a month or so.

Makes me wonder if I got a bad set, despite their having been made mere days before installation...

[Dockhead]

Originally Posted by transmitterdan

The only way to know if the batteries are ok is to individually charge each battery then do a load and discharge test. Takes a long time (days) to do one at a time.

Amp counting meters kill a lot of batteries. They say 100% when it really ain't so. Few cruisers want to charge to true 100% because it can take up to 6-8 hours for a big bank. Heck it can take 4 hours for a small bank. But not charging to 100% is the most likely cause of early battery death.

Yep -- I'm guessing it's not the fridge, but the bloody amp-counting battery monitor, which ate the batteries.

It's not just that they say 100% when it ain't so, it's much more that they say 60% when you have 11.3 volts

It doesn't take running them down that far too many times, to kill a set of batteries.

Throw away the battery monitor and get a SmartGauge, or learn to read voltages. You CANNOT just read the % SOC output of an amp-counting battery monitor, and assume that it's right. Normally the battery will be more discharged, than it says -- the error tends to go that way. Sometimes a LOT more discharged -- and this gets worse and worse, as the battery's capacity is diminished.


Concerning capacity: You don't necessarily have to do a load test. You can do impedance spectrography with something like this:

http://forex.hu/images/pdf/ARGUS500.pdf

I have one and it is really great for keeping up with your battery condition.

[sailorboy1]

I think you are charging at too low voltage. The nbattery monitor doesn't care if it thinks there is 5 amps at 14.1 or 14.6 but to your batteries there is a big difference

[btrayfors]

Skip,

You have two problems:

1. Determine the actual condition of the batteries (each one);
2. Determine which changes, if any, are needed.

You can play around all day....or all year....with #2 and still not have your answer to #1. This is critical.

The ONLY way to determine the condition of the batteries is to test each one individually. The best way is to do a controlled 20-hour discharge test. A reasonable proxy can be done with a sophisticated conductance tester, like the Midtronics series, which can give you an indicative though not definitive indication of battery capacity. This last is useful for comparisons between batteries.

Based on your original post I'd guess that the problem(s) you are seeing which are not related to battery condition may be the result of:

1. erroneous indications of SOC from your battery monitor;
2. failure to reach a truly full charge because of too low charging voltage and inadequate charging time; and/or
3. poor connections at and between the batteries.

These batteries like to be charged at 14.8 to 15.0VDC. Equalization voltages should be on the order of 15.5 - 17.0VDC.

Unless you really like to have the Honda running most of the time -- or you routinely do very long passages under power, or spend lots of time plugged in at dockside -- you are very unlikely to get the battery bank fully charged. Also, check the output voltage of your solar panel.

A clamp-on ammeter is invaluable in poking around and determining what is actually going on during the charging process.

FWIW,

Bill

[skipgundlach]

Watching, agreeing, and doing several high charge/discharge cycles (now in the first).

I have some distrust of the TriMetric and need to get smarter about other ways of verification - and maybe ignore the "+XXX AH" (more amps in than full) during some of these...

[a64pilot]

Only way I know to tell if it's fully charged is either by specific gravity, or watching the acceptance at absorption voltage.
If I were you, I wouldn't let my Solar Charger ever get into float, I'd leave it in absorption, especially this time of year

[Maine Sail]

Originally Posted by Dockhead

Concerning capacity: You don't necessarily have to do a load test. You can do impedance spectrography with something like this:

http://forex.hu/images/pdf/ARGUS500.pdf

I have one and it is really great for keeping up with your battery condition.

While the Argus is a nice piece of equipment, and tells you lots of good data for cranking it fails miserably at predicting the state of healthin terms of Ah capacity.

I own both the Argus 500 (they were successfully sued out of business for stealing Midtronics proprietary data) and a Midtronics EXP-1000HD KIT and a cheap Harbor Freight Chinese version.. Lucky for me the Midtronics offers many other capabilities because I bought the BS, hook line & sinker..

Are Battery Impedance Testers Worth It? (LINK)

[bdbcat]

Skip...

Yep -- I'm guessing it's not the fridge, but the bloody amp-counting battery monitor, which ate the batteries.

It's not just that they say 100% when it ain't so, it's much more that they say 60% when you have 11.3 volts

I agree with this.

Suggest you adjust your battery monitor's "Charge Efficiency Factor" downward a few percentage points, so that it will do a more accurate job of compensating for the understanding that AMPS-in never gives the same as AMPS-out.

Or get Lithium cells, where AMPS-in does equal AMPS-out.

Dave

[Dockhead]

Originally Posted by Maine Sail

While the Argus is a nice piece of equipment, and tells you lots of good data for cranking it fails miserably at predicting the state of healthin terms of Ah capacity.

I own both the Argus 500 (they were successfully sued out of business for stealing Midtronics proprietary data) and a Midtronics EXP-1000HD KIT and a cheap Harbor Freight Chinese version.. Lucky for me the Midtronics offers many other capabilities because I bought the BS, hook line & sinker..

Are Battery Impedance Testers Worth It? (LINK)

I think this is the right link:

Are Battery Impedance Testers Worth It? Photo Gallery by Compass Marine How To at pbase.com


I'm going to send you the bill for my Argus, since I bought it after reading your original article on these testers

Just kidding.

Actually, I understood almost immediately that it can't really measure deep cycle battery capacity, and I don't think it's even made for that -- it's for measuring cranking capacity.

However, I have found it to be very useful for tracking the change, and especially, consistency between different batteries in the bank, over time. I do think that it accurately shows the change of capacity over time and I think that if you could calibrate it, you could even get this data from it.

I'm now on the second set of batteries I've been tracking over their whole lives with this device. I test every time I water the batts and keep a log. I believe I will see very clearly what happens with the second set as it starts to deteriorate, by comparing the readings kept from the first set. And perhaps most valuably, I see when things have really gone downhill when I start to see one or two batts (out of the 8 in my bank) start to get way out from the rest.

I don't count amps anymore and don't really care about AH capacity, so I haven't bothered to try to calibrate the Argus.