diy solar

diy solar

Batteries drained!!!

Greasyrick

New Member
Joined
Mar 21, 2022
Messages
67
Hello everyone, hope all is well, finally decided to put my system together, took me a while because we moved to a house outside the city, having a bit of an issue here, let me first state what my system is set up like:
4 AmpereTime lifepo4 12 volts 200AH with a 200 BMS in series to get 48 volts.
10 200 watts panels, two strings of 5 in series then both strings in parallel Into the combiner box 100 feet away with a 4awg HTTN cable to a Epever MPPT 150V 60A controller
Reliable 5k 48v 120 volt inverter.
I was able to program the charge controller in the user battery feature with the MT50 remote as per the battery manual specs, (multiplying the values times 4, of course)
After charging all batteries individually with a dedicated Lifepo4 charger and connected to the system, everything was fine, I have a load of about 3 to 4. 5 amps at night, the first night everything was fine, all worked fine, I believe I was at 89% battery capacity when I started, the next morning I was down to about 65%.
After a full day using some lights, a coffee maker and all 3 fridges, sometimes momentarily Going about 12 amps the batteries were at 70%, but that night I was starting with 70 % battery capacity, I was down to zero charge bars in 5 hours, of course had to switch to grid power, but my question is, I’m I doing something Wrong?
I‘m I pulling too many amps?
are batteries that bad that they last so little when you start the night with 70% charge?
Do I need more panels?
Its 9:45 am and the charge controller is getting 86 volts and 6.46 amp Its a bit cloudy.
The controller is sending 52.12 volts and 15.15 amps to the batteries, with no loads and the inverter off just today since I was down so far in charge, yesterday at noon I got about 40 amps going to the batteries, with loads on, I thought that was decent.
The batteries already show at 70% capacity with only about 4 hours of early morning sun, again, with no loads and the inverter off.
I don’t get it.
This is a head scratcher to me, any ideas will be appreciated.
Thanks in advance for your responses.
 
Last edited:
What are you basing the % of charge on? The first night 89%-65% used 24% of 200Ah = 48, the next night used 70% = 210. Do you have a shunt meter, they give a pretty good indication of SOC. At this point I would measure each of the batteries voltage to be sure that they remain balanced.
 
After a full day using some lights, a coffee maker and all 3 fridges, sometimes momentarily Going about 12 amps the batteries were at 70%, but that night I was starting with 70 % battery capacity, I was down to zero charge bars in 5 hours, of course had to switch to grid power, but my question is, I’m I doing something Wrong?
If you are not reaching full charge before noon, then you don't have enough solar.
Do I need more panels?
I have 48V system, and I have 5500W of panels connected to it.
4 AmpereTime lifepo4 12 volts 200AH with a 200 BMS in series to get 48 volts.
10 200 watts panels, two strings of 5 in series then both strings in parallel Into the combiner box 100 feet away with a 4awg HTTN cable to a Epever MPPT 150V 60A controller
I think you also need a larger battery. 400Ah instead of 200. But, don't add more battery until after you've upgraded the solar.
The controller is sending 52.12 volts and 15.15 amps to the batteries, with no loads and the inverter off just today since I was down so far in charge, yesterday at noon I got about 40 amps going to the batteries, with loads on, I thought that was decent.
The batteries already show at 70% capacity with only about 4 hours of early morning sun, again, with no loads and the inverter off.
With a 60A charge controller, feeding a 48V battery, most likely you can easily add 60A X 50Vcharging X 1.175 fudgefactor = 3525W. So, right now today, you could add an additional 1500W to help keep your batteries at full charge. With my own system, running the whole cabin overnight, I am at 85% in the morning, and get to full charge before 10:00am. You'll be able to expand more if you upgraded to a larger/second charge controller.
 
Really comes down to math. You can of course buy parts to throw at it until it works right.

First a power audit for the highest time of year, and a power audit for the shortest day of the year. A kWh requirement for each and also a max wattage. Power bills can help if you don’t have a kilawatt meter to track.

With this kWh calculator, decide if you’d like to last through a cloudy day with charge from the day prior or just turn grid power on during cloudy days. If so double or triple your power requirement.

Next, go to a solar calculator, like in my signature block, put in your lat long, panels, batttery size and battery discharge depth and see what production looks like. Look to see if you have enough in the summer, And the same for the winter.
 
Look at your reports to see if the inverter is producing the power at night, or if the batteries are self discharging.

If inverting power, then you need to find out what is using power overnight.
 
What are you basing the % of charge on? The first night 89%-65% used 24% of 200Ah = 48, the next night used 70% = 210. Do you have a shunt meter, they give a pretty good indication of SOC. At this point I would measure each of the batteries voltage to be sure that they remain balanced.
I have a shunt meter on the ac load center I’m averaging 5.5 amps during the day.
the average % of charge I’m basing is looking at the app info coming from the little Epever eBox-WIFI-01
after all was drained last night I checked the batteries and each had about 10.7 pretty evenly.
that’s after I disconnected the main switch from the battery bank to the system, before that, with everything connected including the inverter on but no loads one of the batteries was showing -29 volts, but it got back to even with the rest of batteries voltage the moment I turned the main switch off isolating the batterie bank from everything.
 
If you are not reaching full charge before noon, then you don't have enough solar.

I have 48V system, and I have 5500W of panels connected to it.

I think you also need a larger battery. 400Ah instead of 200. But, don't add more battery until after you've upgraded the solar.

With a 60A charge controller, feeding a 48V battery, most likely you can easily add 60A X 50Vcharging X 1.175 fudgefactor = 3525W. So, right now today, you could add an additional 1500W to help keep your batteries at full charge. With my own system, running the whole cabin overnight, I am at 85% in the morning, and get to full charge before 10:00am. You'll be able to expand more if you upgraded to a larger/second charge controller.
It’s 11:45am and I’m at 85% capacity, this is with no loads, not even the inverter on. But it’s cloudy today, Perhaps I might need a few more panels.
 
This is right now, it’s cloudy out.
 

Attachments

  • BE217B0A-8CEA-4E25-A5ED-CE73FF799F89.jpeg
    BE217B0A-8CEA-4E25-A5ED-CE73FF799F89.jpeg
    134.5 KB · Views: 27
If you're using the SOC information on the Epever, know that it's notoriously inaccurate. It doesn't know what you're drawing from the batteries, and bases it's calculation on your voltage, which is not an accurate way to do it. You probably started with a lot less than 70% the night you only got 5 hours out of it.
Get a shunt/meter on the batteries, then you'll know where your SOC really is.
 
Putting 60 amps into a 200 amp bank that was down to near zero and then showing 70 charge doesn’t add up I think your meter is off

you can also test each battery for capacity separately with a 12 volt load to verify each battery is getting the rated amp hours this will help troubleshoot by eliminating a potential battery issue
 
If you're using the SOC information on the Epever, know that it's notoriously inaccurate. It doesn't know what you're drawing from the batteries, and bases it's calculation on your voltage, which is not an accurate way to do it. You probably started with a lot less than 70% the night you only got 5 hours out of it.
Get a shunt/meter on the batteries, then you'll know where your SOC really is.
Just ordered the Victron Energy SmartShunt 500 amp Battery Monitor (Bluetooth), it’ll be here tomorrow morning.
 
Putting 60 amps into a 200 amp bank that was down to near zero and then showing 70 charge doesn’t add up I think your meter is off

you can also test each battery for capacity separately with a 12 volt load to verify each battery is getting the rated amp hours this will help troubleshoot by eliminating a potential battery issue
I never had 60 amps going into the batteries, the most I had yesterday during the peak full Sun hours was fluctuating between 38 and 41 amps, also must of the day was cloudy on and off but this full Sun lasted for just a couple hours. This is right now
 

Attachments

  • 1496249F-C521-4880-9F86-B622FB9F3591.jpeg
    1496249F-C521-4880-9F86-B622FB9F3591.jpeg
    126.5 KB · Views: 6
Last edited:
4 AmpereTime lifepo4 12 volts 200AH with a 200 BMS in series to get 48 volts.
10 200 watts panels,
4 x 12.8V x 200Ah = 10240Wh

10240Wh capacity / 2000W solar = 5.12h to recharge from empty operating at 100% efficiency

After a full day using some lights, a coffee maker and all 3 fridges, sometimes momentarily Going about 12 amps the batteries
You really NEED to figure out the power usage for these items to figure this out.

Guessing your fridges average at 100W each:
3 x 100W x 24h = 7200Wh (about 70% as you mentioned)

The controller is sending 52.12 volts and 15.15 amps to the batteries,
This sounds wrong. Your charger should be sending about 56-58V to the batteries.

Can you post a pic of your charge settings?
 
4 x 12.8V x 200Ah = 10240Wh

10240Wh capacity / 2000W solar = 5.12h to recharge from empty operating at 100% efficiency


You really NEED to figure out the power usage for these items to figure this out.

Guessing your fridges average at 100W each:
3 x 100W x 24h = 7200Wh (about 70% as you mentioned)


This sounds wrong. Your charger should be sending about 56-58V to the batteries.

Can you post a pic of your charge settings?

Absolutely
 

Attachments

  • 35406EA7-0BFA-4D20-B347-7DD85439C2B5.jpeg
    35406EA7-0BFA-4D20-B347-7DD85439C2B5.jpeg
    134.5 KB · Views: 18
  • A583A587-CD84-4119-AF2C-2D474EB1D2A0.jpeg
    A583A587-CD84-4119-AF2C-2D474EB1D2A0.jpeg
    133.7 KB · Views: 18
  • 4E29D52A-6A30-4744-8C74-76F689EF4E8D.jpeg
    4E29D52A-6A30-4744-8C74-76F689EF4E8D.jpeg
    136.1 KB · Views: 17
  • A5290423-D9F8-40CE-8AD3-62CA0D73C11E.jpeg
    A5290423-D9F8-40CE-8AD3-62CA0D73C11E.jpeg
    136.9 KB · Views: 18
  • 8741E00C-48A8-4C15-9BF1-7249AFAAAA9B.jpeg
    8741E00C-48A8-4C15-9BF1-7249AFAAAA9B.jpeg
    138.2 KB · Views: 16
  • 945F969D-F2C6-4F3C-9603-CFB5EE1CC88E.jpeg
    945F969D-F2C6-4F3C-9603-CFB5EE1CC88E.jpeg
    128.6 KB · Views: 16
  • 8D6B840C-645C-43F2-93A5-963A61161F2A.jpeg
    8D6B840C-645C-43F2-93A5-963A61161F2A.jpeg
    130.4 KB · Views: 14
  • 4F1D62EE-EE59-41FC-AA2D-B3CE90E5D30D.jpeg
    4F1D62EE-EE59-41FC-AA2D-B3CE90E5D30D.jpeg
    127.8 KB · Views: 14
  • F707C560-2E4F-41F0-85A8-ACD7A6FA4881.jpeg
    F707C560-2E4F-41F0-85A8-ACD7A6FA4881.jpeg
    129.2 KB · Views: 17
Looks reasonable.

The charge voltage 55.2V is likely lower than recommended voltage but 120 minute boost (absorb) time should fill your batteries nicely. Maybe bump up to 56V for a couple days to see if it helps.

Does your boost charge cycle actually finish and drop into float? If not, you are likely not fully charging your batteries.

Where do you see/measure "The controller is sending 52.12 volts and 15.15 amps to the batteries,"?

Can you post a pic of your battery wiring? (grasping for clues...)
 
In my opinion you do not have enough battery storage. I was running a full sized refrigerator and a chest freezer on two 12v 300ah batteries. Every now and then it would shut off before morning, especially when it was cloudy the day before. I added two more 12v 300ah batteries and now i run the refrigerator, freezer, and an additional extra large freezer without any problems. When it comes to refrigerators and freezers, it is difficult to estimate because the compressor is not running 24 hours. I read some articles that say 30% is a good estimate. But in my experience if you want to be certain that you won’t run out of power, do your estimates at 100%. Obviously the compressor won’t be running 100% of the time. But doing the estimate at 100% gives you a lot of room for error and various weather conditions.
 
Looks reasonable.

The charge voltage 55.2V is likely lower than recommended voltage but 120 minute boost (absorb) time should fill your batteries nicely. Maybe bump up to 56V for a couple days to see if it helps.

Does your boost charge cycle actually finish and drop into float? If not, you are likely not fully charging your batteries.

Where do you see/measure "The controller is sending 52.12 volts and 15.15 amps to the batteries,"?

Can you post a pic of your battery wiring? (grasping for clues...)
Here, I’m looking at the numbers under the battery emblem on the monitor (last pic), as you can see it shows 53.4 volts, amps are low at 8, it’s very cloudy right now. But when it’s not cloudy the amps go way up but the voltage stays around the 53 mark., sorry, the site double posted when I went back to take the last pic
 

Attachments

  • 7BA8AB72-4A97-4DBD-B85F-11AEFED38739.jpeg
    7BA8AB72-4A97-4DBD-B85F-11AEFED38739.jpeg
    286.8 KB · Views: 29
  • 127FAF4A-EB34-42FF-8637-2B6B2183988D.jpeg
    127FAF4A-EB34-42FF-8637-2B6B2183988D.jpeg
    258.4 KB · Views: 29
  • 0DE18B8E-5889-4575-A25E-7B39ADD89343.jpeg
    0DE18B8E-5889-4575-A25E-7B39ADD89343.jpeg
    290 KB · Views: 28
  • 49F319B0-13DB-487E-AD7C-3435615BD0A0.jpeg
    49F319B0-13DB-487E-AD7C-3435615BD0A0.jpeg
    286.8 KB · Views: 28
  • 0EAB628F-3586-4549-B047-04D7421670C6.jpeg
    0EAB628F-3586-4549-B047-04D7421670C6.jpeg
    258.4 KB · Views: 28
  • 7CC5E086-33CA-44D9-A5EF-8A3EE83CB091.jpeg
    7CC5E086-33CA-44D9-A5EF-8A3EE83CB091.jpeg
    290 KB · Views: 29
  • 8EAF99B9-7A45-4370-BD68-1CAD44BE18DB.jpeg
    8EAF99B9-7A45-4370-BD68-1CAD44BE18DB.jpeg
    243.1 KB · Views: 30
Looks reasonable.

The charge voltage 55.2V is likely lower than recommended voltage but 120 minute boost (absorb) time should fill your batteries nicely. Maybe bump up to 56V for a couple days to see if it helps.

Does your boost charge cycle actually finish and drop into float? If not, you are likely not fully charging your batteries.

Where do you see/measure "The controller is sending 52.12 volts and 15.15 amps to the batteries,"?

Can you post a pic of your battery wiring? (grasping for clues...)
Just made these changes from 55.2 to 56.0
 

Attachments

  • 4A9D17FF-5AA5-4912-9145-4C689A65A0CB.jpeg
    4A9D17FF-5AA5-4912-9145-4C689A65A0CB.jpeg
    226.6 KB · Views: 8
as you can see it shows 53.4 volts,
I am not sure what the 53.4V represents. It does not make sense to display the charge voltage so i'd think it is the battery voltage (with charge being applied so a mix between charge voltage and resting battery voltage).

That big inverter stands out as a possible energy hog. Any idea how much it consumes?

Can you determine you daily fridge usage watt hours? Actually all daily usage numbers for a sanity check on battery size.

Everything else looks good to me.
 
Back
Top