Is my inverter dead?

[ttubravesrock]

In short, my battery bank no longer lasts more than 20 seconds when it used to last days.

So, this past summer I bought new batteries (Trojan L60 x 4) to run my home. I was replacing sealed batteries which still worked, but not as well as they used to. I taught my wife the maintenance procedures, but I neglected to tell her how important it was, especially for the first few months. So, she went ~4 months without ever checking the batteries with the hydrometer. At this point, the batteries only lasted for about an hour before they needed to be charged again. Initially, one charge lasted 3 days as long as she didn't vacuum or run the big desktop computer. I spent a whole weekend running an equalization charge and while the ph levels improved, they never fully equalized. After this, the battery life did not improve.

Since then, I have only tried one thing for troubleshooting. I hooked up the old batteries (that worked before the 'upgrade') and they also would not hold a charge.

To me, that tells me that the batteries aren't the main issue. Yes, it was bad that we let the batteries go 4 months without maintenance, but something is wrong with either the inverter or charger, or that there's a wiring issue somewhere.

I'm not at home right now, so I can't answer specific questions or provide pictures, but the great thing about forums is that I don't have to be immediate.

Do any of you amateur/professional electricians know where I should start with troubleshooting?

[mountainmoma]

The old batteries, after sitting for those months, are most likely also no longer be any good.

I doubt it is the inverter as that sounds too coincidental to the known ruining of the batteries. Because, you have checked the batteries and you know they are toast ( I am assuming ?)


Have her bring the old sealed batteries in to the battery store to be tested to see if they are any good.

Sorry about the batteries. Expensive, I know.

[Carl]

  I must also say that batteries tend to be abused and I doubt that your inverter/charger is at fault. While sulphation and strangle a battery ,neglect will often leave cells non-recoverable. There are methods of rebuilding cells,new acid etc that may bring them back to service if the plates are in good shape.

More detail is needed to answer charge current and voltage while bank is charging and voltage while under a set load to compare input/output power of the electronics and also battery capability.Something sounds odd as even 4 months should not so effectively kill the batteries. Bad cables or corrosion in your harness can be at fault. I only use small scale solar,sub 500 watts...but the problems are the same.

LOOK FOR HEAT...this will be a good indication of trouble .

[mountainmoma]

I have solar with batteries, and it generally used to take me more than 4 months of forgetfullness to kill batteries, this is true.

But, You have tested the batteries to see if dead ? If you are not sure if you have checked them correctly, put them in the trunk and take them to a battery store and get a second opinion.

[ttubravesrock]

Well i've tested to see if my old batteries work in my current system. I don't know if both sets of batteries are dead or if they just aren't charging anymore.

[Carl]

Well i've tested to see if my old batteries work in my current system. I don't know if both sets of batteries are dead or if they just aren't charging anymore.

A volt meter should answer that question as battery at rest should be 12.6 or so and less under load ,while when charging it would be 13.6 to 14 plus volts depending on you charge controller setting and the sun.

[ttubravesrock]

A volt meter should answer that question as battery at rest should be 12.6 or so and less under load ,while when charging it would be 13.6 to 14 plus volts depending on you charge controller setting and the sun.

x2 (it's a 24V setup).  While charging, I read ~28V (I think I get 27.6), but as soon as the generator turns off, it dropps to the dead range (IIRC, around 21-22V). That's why I'm suspicious as to whether it's even charging the batteries. The voltage is running through the batteries, but maybe not charging.

[Carl]

x2 (it's a 24V setup).  While charging, I read ~28V (I think I get 27.6), but as soon as the generator turns off, it dropps to the dead range (IIRC, around 21-22V). That's why I'm suspicious as to whether it's even charging the batteries. The voltage is running through the batteries, but maybe not charging.

The voltage is in the range that batteries 'should' be charging. If cables and fuses are all proper the batteries are suspect.

[mountainmoma]

x2 (it's a 24V setup).  While charging, I read ~28V (I think I get 27.6), but as soon as the generator turns off, it dropps to the dead range (IIRC, around 21-22V). That's why I'm suspicious as to whether it's even charging the batteries. The voltage is running through the batteries, but maybe not charging.

The voltage applied to the batteries means that the charging is working. The batteries not "taking" the charge means the batteries arent working right. Not an inverter problem

[Carl]

The voltage applied to the batteries means that the charging is working. The batteries not "taking" the charge means the batteries arent working right. Not an inverter problem

Thanks MM,I still question the cables and fuse as a bad connection or cable can still be a fault as 4 months abuse should not be a full death blow to an otherwise healthy battery bank. I would move to test EACH battery and cable/connection before giving up on the batteries.I think a battery problem would not be so 'immediate' though a cable or connector would act this way and prevent charge/discharge and a voltmeter could find this problem. I use a load meter for my small setup and the battery tester is still a good way to load and test cables too.

https://www.amazon.com/Schumacher-BT-100-Battery-Load-Tester/dp/B000AMBOI0/ref=sr_1_5?s=automotive&ie=UTF8&qid=1490941792&sr=1-5&keywords=battery+tester

[FreeThinker]

Put a bulk charge on the batteries then immediately disconnect the wiring between them so each battery is isolated.  Check the voltage on each battery a few times for the next few hours. Quick way to find a bad battery (cell) that might be bringing down the whole series string.  If all hold the same voltage level hours after being charged at least it's further confirmation the batteries aren't the issue.  Hope you find something simple/inexpensive as the cause, but really sounds like a bad battery (cell) showing a false charge state to me. 

If the batteries check out good it might help to describe your system and what test equipment you have in more detail to come up with more tests.  Some inverter/chargers have built-in meters that might be useful to see what's going on, or if you have a main DC breaker/disconnect it could be used to (easily) isolate the batteries from the rest of the system to help isolate the failing component.

[Carl]

KARMA freethinker,great ,helpful ,idea.

[mountainmoma]

Thanks MM,I still question the cables and fuse as a bad connection or cable can still be a fault as 4 months abuse should not be a full death blow to an otherwise healthy battery bank. I would move to test EACH battery and cable/connection before giving up on the batteries.I think a battery problem would not be so 'immediate' though a cable or connector would act this way and prevent charge/discharge and a voltmeter could find this problem. I use a load meter for my small setup and the battery tester is still a good way to load and test cables too.

https://www.amazon.com/Schumacher-BT-100-Battery-Load-Tester/dp/B000AMBOI0/ref=sr_1_5?s=automotive&ie=UTF8&qid=1490941792&sr=1-5&keywords=battery+tester

yes, of course could be cables or fuses, and 4 months isnt that long to die from misuse, as I would know, I was so forgetful I went to a different battery technology finally. But, still could be, these things happen. hopefully it is only one like freethinker says, and freethinker has a good idea of how to further check on your own

[ttubravesrock]

Put a bulk charge on the batteries then immediately disconnect the wiring between them so each battery is isolated.  Check the voltage on each battery a few times for the next few hours. Quick way to find a bad battery (cell) that might be bringing down the whole series string.  If all hold the same voltage level hours after being charged at least it's further confirmation the batteries aren't the issue.  Hope you find something simple/inexpensive as the cause, but really sounds like a bad battery (cell) showing a false charge state to me. 

If the batteries check out good it might help to describe your system and what test equipment you have in more detail to come up with more tests.  Some inverter/chargers have built-in meters that might be useful to see what's going on, or if you have a main DC breaker/disconnect it could be used to (easily) isolate the batteries from the rest of the system to help isolate the failing component.

I'll try that this weekend and see what happens.

If that doesn't work, I'll wait until the ice is gone from my driveway and bring them to town like mountainmoma said. I'd hate to slip while lifting a 120 lb battery.

Worst case scenario, I keep doing what I've been doing all winter and run the generator full time until I can afford new batteries/cables/fuses/etc. Best case scenario seems like if I were to only need to replace one battery. I've learned my lesson that with me being gone all summer I need maintenance free batteries. However, if I can milk a couple of years out of them before I have to replace them, that would be great.

[ttubravesrock]

Well I didn't get a chance to mess with batteries this weekend because my outhouse fell over due to snow load... I spent all weekend getting the outhouse back up.