Batteries Dead After Reinstall Due to New Roof

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Camino Francisco
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Posts: 4
Joined: Tue Jun 21, 2022 4:13 pm

Batteries Dead After Reinstall Due to New Roof

Post by Camino Francisco »

Hello all,
I have a real problem. Here is my Grid tie configuration:
- 1x 3648 vented GT inverter
- 2x MX60 Charge Controllers
- Hub
- Mate
- FlexNet DC
- FlexWare hardware
- 8x 400 AH AGM (Sun Extender) Batteries 6v in series

The system was running great for 10 years. I just had my roof replaced I had to take the panels down during the install. I made what I now know is a horrible mistake and left the system running. Then one day during the roof replacement, it all just switched off. I figured the low limit on the batteries kicked in. What I found out was the batteries were drained down to 9v (from 48). Now they are completely dead and useless. I cannot get any of my chargers to even see them as viable batteries.

Here is the killer. I put the panels back up and I took some Headway 8AH batteries I had lying around and wired them up to act as a stand-in until I can figure out what I want to do with the big batteries. I hooked them up and kicked on the system, it sold all day long and everything was great. Then at 3AM the system once again shut down. Again my batteries were completely dead. While I could revive all but two, I cannot figure out why my system will not protect my expensive batteries.

I have always assumed the batteries only kicked in when there was a grid outage. Apparently, the system will drain them down to zip. So, on to my questions...

- How can I make the system not drain the batteries at night beyond the appropriate low voltage cutoff? I want Grid-Tie sell all day, battery backup all day and night.
- Is it possible to regenerate my horribly expensive batteries? Any suggestions?

I have some new 100AH batteries on order and cannot even start the system at this moment, so I cannot say more about my current configuration until I get them in and installed. I am hopeful someone out there has experienced this and has overcome the problem. Maybe you can give me some configuration suggestions for when I get the new batteries and help me protect the new investment.

Thank you,
Gordon
fcwlp
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Joined: Wed Jan 22, 2020 9:40 am
My RE system: GS8048A, FM80 w/3,600W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed.

I install and maintain grid-tied and off-grid systems in my area and consult on solar system design/operation.
Location: 80 miles NE of Phoenix at 5500'

Re: Batteries Dead After Reinstall Due to New Roof

Post by fcwlp »

What is your LBCO (Low Battery Cut Out) setting?

Your original string is likely toast with a string voltage of 9V. It is likely that some of the batteries in the string have reversed polarity to get that low.
raysun
Forum Emperor
Posts: 8024
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01, (2) FM80, MATE3s, FlexNetDC
6 SimpliPhi 3.8-48 (48v @ 75AH. 450AH total)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: Batteries Dead After Reinstall Due to New Roof

Post by raysun »

fcwlp wrote: Wed Jun 22, 2022 9:16 am What is your LBCO (Low Battery Cut Out) setting?

Your original string is likely toast with a string voltage of 9V. It is likely that some of the batteries in the string have reversed polarity to get that low.
This is an unsparing, but very likely accurate diagnosis of the battery condition. 10 years is old age for AGM, so at least the battery had a good life. Chances are there was age-related degradation prior to the failure event, and the extreme drain drove the final nail in the coffin.

The 10 year old system includes a VFX3648 inverter? The inverter has a built-in low battery cutout of 42V, which is essentially a dead battery. The internal setting is to protect the equipment, not necessarily the battery itself. There is also a Battery Protection section in the inverter's Battery Charger menu which features an adjustable Low Battery Cut Out parameter. It can be set to a value that will be safer for the battery. Setting it is a bit of an art, as battery voltage varies by both State of Charge (SoC) and Rate of Discharge. A good starting target is the voltage that is measured above 50% SoC at typical inverter loads.
fcwlp
Forum Emperor
Posts: 1016
Joined: Wed Jan 22, 2020 9:40 am
My RE system: GS8048A, FM80 w/3,600W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed.

I install and maintain grid-tied and off-grid systems in my area and consult on solar system design/operation.
Location: 80 miles NE of Phoenix at 5500'

Re: Batteries Dead After Reinstall Due to New Roof

Post by fcwlp »

raysun wrote: Wed Jun 22, 2022 9:50 am This is an unsparing, but very likely accurate diagnosis of the battery condition. 10 years is old age for AGM, so at least the battery had a good life.
I inherited a system today using Iron Edison's NiFe batteries in a 24V system. System is about 85% complete and then sat for 5+ years. Measured string voltage was 7.48V with each cell at ~0.37V versus 1.2V. So at least all cells were equally nearly totally discharged. After speaking with tech support, I need to find a battery charger with enough amps and will likely need to split the string to get the recommended 1.65V. Fortunately one of my customers has heavy equipment and likely has a charger I can borrow.
raysun
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Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01, (2) FM80, MATE3s, FlexNetDC
6 SimpliPhi 3.8-48 (48v @ 75AH. 450AH total)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: Batteries Dead After Reinstall Due to New Roof

Post by raysun »

The Edison batteries are a different breed, to be sure. Not especially charge-efficient.

Better hook that charger up in front of the meter. 😉
Camino Francisco
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Re: Batteries Dead After Reinstall Due to New Roof

Post by Camino Francisco »

Thank you all for the information so far. :-) If the VFX3648 shuts down @ 42 volts, why did it drain my batteries (two sets) down to nothing? Haven't received my new batteries yet, but as soon as I do, I will look for the setting on low battery cutoff. Any suggestions on a complete setup configuration given my hardware?

I am out looking for a HD charger to see what can be done with my big set, if anything. :-/

Thank you!
raysun
Forum Emperor
Posts: 8024
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01, (2) FM80, MATE3s, FlexNetDC
6 SimpliPhi 3.8-48 (48v @ 75AH. 450AH total)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: Batteries Dead After Reinstall Due to New Roof

Post by raysun »

why did it drain my batteries (two sets) down to nothing
It may be more a case of internal failure in one or more of the battery blocks that caused the drain. Hard to say for certain.

That, or some sort of partial short in the DC circuitry.

What is the 2nd set? The 8AH battery blocks? How did those get charged? With one of the MX60s? Was charge current limited to a safe rate for such a small capacity battery? If they are gel cells and were overcharged, they were likely damaged in the process.
Camino Francisco
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Joined: Tue Jun 21, 2022 4:13 pm

Re: Batteries Dead After Reinstall Due to New Roof

Post by Camino Francisco »

raysun wrote: Wed Jun 22, 2022 2:02 pm
why did it drain my batteries (two sets) down to nothing
It may be more a case of internal failure in one or more of the battery blocks that caused the drain. Hard to say for certain.

That, or some sort of partial short in the DC circuitry.

What is the 2nd set? The 8AH battery blocks? How did those get charged? With one of the MX60s? Was charge current limited to a safe rate for such a small capacity battery? If they are gel cells and were overcharged, they were likely damaged in the process.
The second set are Headway LiFePO4 cells. They were fully charged when installed so I had to force the charge cycle initially and, of course, they fell through to float then the system started selling. I will need to wait until I get things back up and running to get any details on the settings, but I have had the system setup to sell all day then act as a power backup should the grid fail. Since the system didn't make it past 3AM, the system didn't even try to charge the batteries in the morning so I don't think it would have been a charge related failure.

On the 400AH Sun X-tender battery front. After sitting there for a few weeks, the 6v batteries show 3v. I tried every charger I own and they all refuse to actually charge them. However, I have a hobby charger capable of providing constant current/voltage. So I looked up the battery tech manual and they have a "deep discharge recovery" section stating to charge using constant current @ 5% of the capacity. For my batteries this would be 20 amps. My charger maxes out at 10 amps per connection with 4 connections. I toyed with the idea of using two connections and attempting to draw the 20 amps, but since I do not know the internal wiring of the charger and cannot count on any level of isolation, I figure this will blow something inside the charger letting the magic blue smoke escape ;-).

I have a 12v @30A power supply hanging around I could use but I would need a constant current/voltage circuit to control it. Any favorite circuits out there that use common parts (I have tons of electronic parts laying around)?

Any thoughts on where I am heading?

Thanks!
raysun
Forum Emperor
Posts: 8024
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01, (2) FM80, MATE3s, FlexNetDC
6 SimpliPhi 3.8-48 (48v @ 75AH. 450AH total)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: Batteries Dead After Reinstall Due to New Roof

Post by raysun »

My charger maxes out at 10 amps per connection with 4 connections.
Is this a 4 bank Noco Genius?

I wish I had some insight that would offer a ray of hope for the Sun X-Tenders, but all my experience with VRLA/AGM tells me the sun has set on this battery.

There is one trick you can try, if you have a functional 12V lead acid battery of any size.
Using the existing 4 bank charger (one 10A lead only, you are right not to parallel the outputs), a 12V "jumper" battery that holds a charge, and 2 of the 6V monoblocs wired in series:

Procedure

Connect the batteries in parallel using the jumper cables. (Positive to positive, and negative to negative.)
Do not have the charger connected to the battery or turned on at this stage.
Connect the charger leads to the terminals on the good battery.
Turn on the charger.
The charger will "see" the voltage of the good battery, and start charging.
Charge the batteries for 1 hour.
Turn off the charger.
Disconnect the charger from the good battery.
Disconnect the jumper cables from both batteries.
Check for warmth.
The battery will get warm.
If it is hot to the touch, STOP CHARGING IMMEDIATELY!
Excessive heat is an indication that there is something wrong with the battery.
Check for a hissing sound coming from the safety valves.
If it's hissing, STOP CHARGING IMMEDIATELY!
This is an indication that the battery is overheating internally.
Check the voltage of the AGM battery.
If the battery has less than 10.5 volts, repeat steps 1-10.
If the battery has more than 10.5 volts, connect it to the charger as you normally would and complete the charging cycle.

With 10A of charge current, the 1 hour time may need to be increased substantially. Be patient with the process.

Good luck!
Camino Francisco
Forum Junior Member
Posts: 4
Joined: Tue Jun 21, 2022 4:13 pm

Re: Batteries Dead After Reinstall Due to New Roof

Post by Camino Francisco »

raysun wrote: Sun Jun 26, 2022 10:28 am
My charger maxes out at 10 amps per connection with 4 connections.
Is this a 4 bank Noco Genius?

I wish I had some insight that would offer a ray of hope for the Sun X-Tenders, but all my experience with VRLA/AGM tells me the sun has set on this battery.

There is one trick you can try, if you have a functional 12V lead acid battery of any size.
Using the existing 4 bank charger (one 10A lead only, you are right not to parallel the outputs), a 12V "jumper" battery that holds a charge, and 2 of the 6V monoblocs wired in series:

Procedure

Connect the batteries in parallel using the jumper cables. (Positive to positive, and negative to negative.)
Do not have the charger connected to the battery or turned on at this stage.
Connect the charger leads to the terminals on the good battery.
Turn on the charger.
The charger will "see" the voltage of the good battery, and start charging.
Charge the batteries for 1 hour.
Turn off the charger.
Disconnect the charger from the good battery.
Disconnect the jumper cables from both batteries.
Check for warmth.
The battery will get warm.
If it is hot to the touch, STOP CHARGING IMMEDIATELY!
Excessive heat is an indication that there is something wrong with the battery.
Check for a hissing sound coming from the safety valves.
If it's hissing, STOP CHARGING IMMEDIATELY!
This is an indication that the battery is overheating internally.
Check the voltage of the AGM battery.
If the battery has less than 10.5 volts, repeat steps 1-10.
If the battery has more than 10.5 volts, connect it to the charger as you normally would and complete the charging cycle.

With 10A of charge current, the 1 hour time may need to be increased substantially. Be patient with the process.

Good luck!
Excellent info and I will definitely try it. :-) My hobby charger is a EV-Peak CQ-3. Funny now that I look at the box, it clearly states "Four Independent Output" But I am not gonna try doubling up anyway. Just feels wrong. :-)

I will report back when I have anything new to report. Thank you for the info and suggestion! :-)
raysun
Forum Emperor
Posts: 8024
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01, (2) FM80, MATE3s, FlexNetDC
6 SimpliPhi 3.8-48 (48v @ 75AH. 450AH total)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: Batteries Dead After Reinstall Due to New Roof

Post by raysun »

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