fjcone
Solar Newcomer
Posts: 3
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Post by fjcone on May 2, 2019 0:23:01 GMT
I have a Renogy 2000W inverter connected to two (Parallel) Renogy 170AH Lithium batteries with 1/0 cable (Approx 12" distance.) When I use a heavy load, such as the instant pot (1100 to 1300w) the voltage drops from the 13.6 starting to usually 12.1 or so.
This startled me at first, but its never been a serious issue as it bounced right back when we turn off the instant pot. However, the other day it dropped under 11v. I turned the Instant pot off and it continued to drop. It bottomed out at 4.8v according to the battery monitor. This was with no load, I pulled everything before goingt to sleep that night.
In the AM it sat there not charging. I disonnected the batteries for an hour and a hand and cut the solar panels from the 20 MPPT. I then reconnected the batteries and brought the panels back online. The screen on the mppt had "acr" on it. Its been raining and overcast everyday this week, but its been slowly bringing the batteries up. After 48 hours its at 12.56.
I tried calling support, however, after 2 hours I was disconnected, so I thought I would post here.
Couple of questions:
Should a 2000w inverter with 340AH of lithium always drop voltage under load? Why the heck did the BMS in the batteries allow them to drop all night and hit 4.8v?
Thanks in advance, Frank
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Post by tattoo on May 2, 2019 1:02:36 GMT
It sounds to me like you have killed your batteries that's why your voltage dropped........ I know people disagree with me but that's a poor use of solar to heat water that's what propane is for....
Yes I agree it's a waste of time to call Renogy support...... Why I have no idea.....
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Post by Admin on May 6, 2019 23:36:26 GMT
I have a Renogy 2000W inverter connected to two (Parallel) Renogy 170AH Lithium batteries with 1/0 cable (Approx 12" distance.) When I use a heavy load, such as the instant pot (1100 to 1300w) the voltage drops from the 13.6 starting to usually 12.1 or so. This startled me at first, but its never been a serious issue as it bounced right back when we turn off the instant pot. However, the other day it dropped under 11v. I turned the Instant pot off and it continued to drop. It bottomed out at 4.8v according to the battery monitor. This was with no load, I pulled everything before goingt to sleep that night. In the AM it sat there not charging. I disonnected the batteries for an hour and a hand and cut the solar panels from the 20 MPPT. I then reconnected the batteries and brought the panels back online. The screen on the mppt had "acr" on it. Its been raining and overcast everyday this week, but its been slowly bringing the batteries up. After 48 hours its at 12.56. I tried calling support, however, after 2 hours I was disconnected, so I thought I would post here. Couple of questions: Should a 2000w inverter with 340AH of lithium always drop voltage under load? Why the heck did the BMS in the batteries allow them to drop all night and hit 4.8v? Thanks in advance, Frank
You will see voltage dropping and then stabilizing when utilizing high loads. What could be happening is when you're reading 13.6, it' important to note whether that's a stable battery voltage or a charging voltage indicating the actual voltage of the battery is lower. It is strange that the battery hit 4.8V and is now needing to be activated. Best case would be to let it continue charging to full and checking to see if it loses charged voltage when no loads are connected. -Renogy Team |
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terracore
Solar Advocate
Chillin at EZwineKIT.com
Posts: 50
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Post by terracore on May 13, 2019 0:07:12 GMT
A voltage drop is to be expected, but it shouldn't drop below 10.5 or so before the inverter automatically shuts off.
Under heavy clouds you batteries may not charge appreciably. The charge controller (and inverter if you have it on, even under no load) consume power even if they look like they aren't doing anything, these loads may match or exceed what your panels produce under less than full sun, with continuing drains at night.
Contacting Renogy tech support is a waste of time. In the unlikely event you actually reach a human being they will only respond with nonsense.
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Post by tattoo on May 13, 2019 0:42:34 GMT
Contacting Renogy tech support is a waste of time. In the unlikely event you actually reach a human being they will only respond with nonsense. Or what they are reading off of to answer your questions...... Which is usually the wrong answer.... At least that has been the case the 3 times I have called them when I first got started in solar..... |
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fjcone
Solar Newcomer
Posts: 3
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Post by fjcone on May 13, 2019 18:03:09 GMT
Thanks for the responses. I did successfully speak with support. I went over how the batteries and inverter are cabled and what is connected. They gave me an RMA for the batteries to come in for testing. The next day we had a sunny day and the batteries came back up, to 12.9v. I did not use them much, and they were 12.79 at night.
The following morning they were 10.9v. The only things connected were the 6 puck lights. (Almost nothing) and a fan for the Natures head, also almost no draw. Before the issue arose, I had these and a Wynter 65q fridge and would not lose more than a volt overnight.
This past Saturday was sunny, batteries were reporting 13.4v. I wanted to test a heavy draw again so I turned on the electric water heater. (Checking screenshots now for exact numbers)
13.4v start, heater pulled 1645w. Water heater shutoff when it hit temp, batteries at 12.72v They dipped to 12.51 under the 1645w load. This is consistent with how they behaved for months.
Left the batteries at 12.72, in the AM it was down to 11.4 again. Inverter off, water tank off, the fridge still removed.
The Van sat unused, again with just the lights (not on) and the 40mm fan running. Today the batteries were 10.5v. It's a rainy day, they have, however, come up to 12.66.
It's very odd, they charge when there is sunlight, but they discharge when not charging, even when disconnected from any load. (Switch)And discharge an insane amount.
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terracore
Solar Advocate
Chillin at EZwineKIT.com
Posts: 50
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Post by terracore on May 20, 2019 2:31:03 GMT
It is normal for the voltage to drop overnight even with no load (the charge controller has a parasitic draw) but what you are describing sounds excessive for lithium batteries. If you are sure all the loads have been eliminated then I would suspect one of the batteries has a problem. Usually your best battery is only as good as your worst battery when they are hooked together. You could isolate them as a test and determine which battery is having a failure and run the system off of one battery until you get a warranty replacement.
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