abnormalities in morning functions and battery charging

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randallxski
Forum Member
Posts: 24
Joined: Thu Jul 27, 2017 6:03 am
My RE system: Primary System:
Radian 8048A Inverter
24 Rolls S-1860 2v Batteries
3 FlexMax 80 Charge Controllers
42 250W AmeriSolar Solar Panels
Mate3s / Outback Hub / FlexNet DC
CAT C3.3 55KW Generator
Occasional Power from Electric Company (~5 hrs every 48 hours)
Location: Jacmel, Haiti
Contact:

abnormalities in morning functions and battery charging

Post by randallxski » Wed Sep 23, 2020 6:44 pm

I could use some insight into some issues I'm having with our system. Since returning to Haiti early this month, the batteries lose power overnight every night about 2 hours after the generator or local electric turn off. Before February of this year, they lasted closer to 4 hours. In the morning after first light, the power comes back on automatically (~7:30ish) but then it repeatedly turns on and of, sometimes in very short amounts of time (e.g. off for 30 seconds to 1 minute then back on again). I raised the Low Battery Cut In Voltage from 50v to 51.2, and that seemed to help somewhat, but it continues to cycle power 10-15 times every morning before stabilizing. Nothing is noted in the event log about these outages, so it's not clear what's going on.

I also lowered the Low Battery Cut Out Voltage from 46.8 to 46.4. That has resulted in the generator turning on briefly during the night. I'm guessing that's because the battery voltage can drop enough to reach the AGS 2-Minute Start Voltage. I'm not sure this is helping!

The last 3 nights when the generator turns on automatically at 7:30, all the lights turn off for 5-10 seconds about a minute after the generator starts. I've also seen issues where the generator and EDH are not charging the batteries. The log shows the battery charging starts and then stops immediately. In the Inverter controls, the charging must be re-enabled manually for battery charging to resume. How can I get the batteries to charge automatically again?

I'm still new at this. Even after reading through all the manuals I could find, I still have a ton of questions!

raysun
Forum Emperor
Posts: 2997
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
Suniva 330 watt panels (12 - 6 strings of 2 in series)
Hyundai 355 watt panels (6 - 3 strings of 2 in series)
Honda EU7000is gas fuel generator

Re: abnormalities in morning functions and battery charging

Post by raysun » Wed Sep 23, 2020 11:05 pm

The first thing to check when there's odd system behavior is the health of the battery. The 2V Rolls cells are flooded lead acid, so a check of the specific gravity (SG) of each cell is the place to start. Checking specific gravity requires a hydrometer. Are you familiar with this device?

Measure and write down the SG of each cell.

If a hydrometer is not immediately available, a "quick and dirty" health check is to measure the voltage of each cell.

Place the battery at rest, no charging or discharging:
• Disconnect the solar charge controllers, by disconnecting the PV arrays FIRST, then disconnect the controllers from the battery.
• Disconnect the inverter load, by starting the generator, ideally by fully bypassing the inverter. If there is no full inverter bypass in the system, then the inverter should switch the loads to the generator and go idle. Disable the inverter chargers by setting their Mode to OFF.

Measure and write down the voltage of each cell. Ideally, each should measure the same, around 2 volts. If there is a good deal of variance between cells, there may be an issue. Note especially any cells that read lower than average.

Next, place a load on the battery by re-enabling the inverter and shutting down the generator. Take a second set of voltage measurements of each cell. Write them down. Under load, each cell voltage should drop. Ideally they will all drop the same amount. Any that drop substantially more than the others are suspect.

Post the SG and/or Voltage measurements here.

To re-enable the solar charge controllers, connect them to the battery FIRST, then connect the solar panel arrays.

Two basic instruments, a hydrometer and a voltmeter are essential tools for every flooded lead acid battery owner. If not in your toolkit, post back for recommendations.

randallxski
Forum Member
Posts: 24
Joined: Thu Jul 27, 2017 6:03 am
My RE system: Primary System:
Radian 8048A Inverter
24 Rolls S-1860 2v Batteries
3 FlexMax 80 Charge Controllers
42 250W AmeriSolar Solar Panels
Mate3s / Outback Hub / FlexNet DC
CAT C3.3 55KW Generator
Occasional Power from Electric Company (~5 hrs every 48 hours)
Location: Jacmel, Haiti
Contact:

Re: abnormalities in morning functions and battery charging

Post by randallxski » Thu Sep 24, 2020 6:20 am

Thanks for that explanation. Thankfully, I have both a hydrometer and a voltmeter, so I'll go ahead with the specific gravity test. The voltage test sounds a bit more complicated!

The details about the voltage drop of the battery cells under load is helpful. I've checked cell voltages before, but never considered whether the batteries were charging, discharging or dormant.

raysun
Forum Emperor
Posts: 2997
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
Suniva 330 watt panels (12 - 6 strings of 2 in series)
Hyundai 355 watt panels (6 - 3 strings of 2 in series)
Honda EU7000is gas fuel generator

Re: abnormalities in morning functions and battery charging

Post by raysun » Thu Sep 24, 2020 6:33 am

Charging current tends to "prop up" weak cells, making voltage measurements less if an indicator.

A simpler method of voltage measurement is to take them just before sunrise. The charge controllers are idle, the inverter load is usually low(ish), and the cells fairly depleted. No need to turn anything on or off to get a quick "sanity check" on the relative cell voltages.

Specific gravity can be measured any time, but is most meaningful after a charge cycle has completed. Any cell that varies by more than 0.030 merits investigation.

Are all the water levels above the lead plates in the cells?

randallxski
Forum Member
Posts: 24
Joined: Thu Jul 27, 2017 6:03 am
My RE system: Primary System:
Radian 8048A Inverter
24 Rolls S-1860 2v Batteries
3 FlexMax 80 Charge Controllers
42 250W AmeriSolar Solar Panels
Mate3s / Outback Hub / FlexNet DC
CAT C3.3 55KW Generator
Occasional Power from Electric Company (~5 hrs every 48 hours)
Location: Jacmel, Haiti
Contact:

Re: abnormalities in morning functions and battery charging

Post by randallxski » Sun Oct 04, 2020 9:28 am

Some VIPs just visited and I had to prep for them, and now I finally had a chance to check the battery specific gravity levels. I have 24 2v batteries in series to make up a 48v system. I have 1 weak (dead?) battery. Here are the values:

Code: Select all

1.3             1.3
1.3             1.29
1.3             1.3
1.3             1.3
1.3             1.275
1.3             1.3
1.1 **          1.3
1.28            1.3
1.3             1.3
1.26            1.3
1.3             1.285
1.3             1.3
What's my best course of action for the battery with the 1.1 SG? Can it be rejuvanated? Cleaned? Can I just replace 1 battery in my string of 24?

randallxski
Forum Member
Posts: 24
Joined: Thu Jul 27, 2017 6:03 am
My RE system: Primary System:
Radian 8048A Inverter
24 Rolls S-1860 2v Batteries
3 FlexMax 80 Charge Controllers
42 250W AmeriSolar Solar Panels
Mate3s / Outback Hub / FlexNet DC
CAT C3.3 55KW Generator
Occasional Power from Electric Company (~5 hrs every 48 hours)
Location: Jacmel, Haiti
Contact:

Re: abnormalities in morning functions and battery charging

Post by randallxski » Sun Oct 04, 2020 9:35 am

Also, for some odd reason (politically motivated, perhaps???), we've been getting hours upon hours of power from the electric company in the last week! We've gone from 5 hours of every 48 hours to around 30 hours of every 48 hours! So the anomalies haven't been as noticeable. :grin: It would be great if that continues!

raysun
Forum Emperor
Posts: 2997
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
Suniva 330 watt panels (12 - 6 strings of 2 in series)
Hyundai 355 watt panels (6 - 3 strings of 2 in series)
Honda EU7000is gas fuel generator

Re: abnormalities in morning functions and battery charging

Post by raysun » Sun Oct 04, 2020 10:02 am

randallxski wrote:
Sun Oct 04, 2020 9:28 am
Some VIPs just visited and I had to prep for them, and now I finally had a chance to check the battery specific gravity levels. I have 24 2v batteries in series to make up a 48v system. I have 1 weak (dead?) battery. Here are the values:

Code: Select all

1.3             1.3
1.3             1.29
1.3             1.3
1.3             1.3
1.3             1.275
1.3             1.3
1.1 **          1.3
1.28            1.3
1.3             1.3
1.26            1.3
1.3             1.285
1.3             1.3
What's my best course of action for the battery with the 1.1 SG? Can it be rejuvanated? Cleaned? Can I just replace 1 battery in my string of 24?
The first thing to try is an equalization charge. If the low-reading cell can be brought up to proper SG, well and good. If not, replacement is likely in order.

How old is the battery?

randallxski
Forum Member
Posts: 24
Joined: Thu Jul 27, 2017 6:03 am
My RE system: Primary System:
Radian 8048A Inverter
24 Rolls S-1860 2v Batteries
3 FlexMax 80 Charge Controllers
42 250W AmeriSolar Solar Panels
Mate3s / Outback Hub / FlexNet DC
CAT C3.3 55KW Generator
Occasional Power from Electric Company (~5 hrs every 48 hours)
Location: Jacmel, Haiti
Contact:

Re: abnormalities in morning functions and battery charging

Post by randallxski » Sun Oct 04, 2020 12:22 pm

raysun wrote:
Sun Oct 04, 2020 10:02 am
The first thing to try is an equalization charge. If the low-reading cell can be brought up to proper SG, well and good. If not, replacement is likely in order.

How old is the battery?
Okay, thanks. Equalize is set to 62v for 3 hours. I'll kick that off tonight when I know I'll have either generator or city power (via Must Run time in the Mate).

I have equalize set to run every month, but I don't think it ever successfully starts, and I've never seen a single equalize complete. What parameters would prevent an equalize from starting, and what would prevent it from completing?

The batteries are almost 3 years old. They go through 2 full charge -> use until cut out voltage cycles most days.

raysun
Forum Emperor
Posts: 2997
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
Suniva 330 watt panels (12 - 6 strings of 2 in series)
Hyundai 355 watt panels (6 - 3 strings of 2 in series)
Honda EU7000is gas fuel generator

Re: abnormalities in morning functions and battery charging

Post by raysun » Sun Oct 04, 2020 12:29 pm

randallxski wrote:
Sun Oct 04, 2020 12:22 pm
raysun wrote:
Sun Oct 04, 2020 10:02 am
The first thing to try is an equalization charge. If the low-reading cell can be brought up to proper SG, well and good. If not, replacement is likely in order.

How old is the battery?
Okay, thanks. Equalize is set to 62v for 3 hours. I'll kick that off tonight when I know I'll have either generator or city power (via Must Run time in the Mate).

I have equalize set to run every month, but I don't think it ever successfully starts, and I've never seen a single equalize complete. What parameters would prevent an equalize from starting, and what would prevent it from completing?

The batteries are almost 3 years old. They go through 2 full charge -> use until cut out voltage cycles most days.
Not sure about the autostart issue.

For EQ in this case, it may need to run longer than 3 hours. Keep an eye on the ailing cell. Measure SG hourly, it should show steady increase. Stop EQ when the SG no longer changes.

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