Battery Drain no load

[Mybudfoster]

We have 4x 100 Renogy solar panels (2x100 set up in parallel and then those are connected to the other 2x100 parallel panels and then those are connected in series - running into 2x100ahLiFe Renogy batteries (set up in parallel), Renogy Rover 30amp cc and a 1000 watt inverter (you guessed it - Renogy).

All seems to powering up beautifully with sunshine in Georgian Bay, Ontario. It is an off grid cottage on an island - so accessibility to get stuff is challenging.

We are using a Sunfrost DC fridge which uses 20amps on start up and then 8-10 while running. It does not run through the CC, just to the batteries. (Thru a fuse panel)
We charge phones, tools , etc - nothing else major (and only during sunlight)

The fridge is now turned off at night because even with the 2x100ah batteries, it was draining the fully charged batteries down to 0 and we had a ACR warning on the cc.

We have turned off everything at night now. Night before last, there was no load on the cc (not even the inverter) and all was fully charged upon going to bed. (77ah stored and 100% battery). In the morning the cc showed 0 AH.

Last night, again, no load (except for the inverter). From 10:30pm until around 5am , the reading was consistent. 13.1, 97% battery and 27ah. But by about 6am, the AH had dropped to 0 - still no load.

What might be causing this battery issue? Is it possible we damaged the batteries somewhere in this situation?

We are installing another 4x100w panels today - but truly, the issue does not seem to be with charging.

We are using all of the correct gauge wiring and have confirmed proper connections throughout

Also, we will be attaching the Renogy BT module for “battery monitoring” and I am ordering an actual battery monitor with shunt today - but won’t get it up here for another week or so.

Welcome your expert thoughts. The batteries are still under warranty (purchased last Summer and brought home for the winter to go into “shelf mode”

We watched many YouTube videos, have Will Prouse’s book - but are very much “newbie’s” with this. So much so that I have to read many of the posts, which may have similar issues, over and over again to see if I can decipher the language.

Thanks!!
Signed, “Solar is sapping my sanity”

 

[rodrick]

You inverter has enough of a idle consumption to drain battery most likely

 

[Mybudfoster]

You inverter has enough of a idle consumption to drain battery most likely

I did wonder that, but we disconnected the inverter the night before last and the battery drained from 77ah to 0ah?

Oh, and thank you for your reply!!

 

[Mybudfoster]

We have disconnected the batteries now and have confirmed fully charged (external battery charger). We are going to reconnect them (in parallel) - should we be resetting any of the parameters on the Renogy Rover?

 

[mikefitz]

How are you measuring Ah in the batteries?
If you are monitoring battery state with the Renogy Rover it can deliver incorrect values.
Renogy batteries can go into a 'rest' mode if not receiving or delivering current.

reading was consistent. 13.1, 97% battery and 27ah

This set of readings make no sence. If we assume the battery voltage is 13.1 volts, that's around 40% SOC not 97%.

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Night before last, there was no load on the cc (not even the inverter) and all was fully charged upon going to bed. (77ah stored and 100% battery). In the morning the cc showed 0 AH.

'No load on the cc' suggests youare powering loads from the load terminals, is this the case? The diagram shows all loads connected to the battery.

77Ah stored in a 100Ah battery is not 100%.

The arrangement of the solar panels is possibly suspect, as shown in the diagram.
Two 100 watt panels in series connected in parallel to a further two 100 watt in series is OK, and
would present about 36 volts to the controller ,and a maximum of 400 watts in ideal conditions.
The addition of the 'old' panel could cause issues unless it's voltage is near 36 volts.

Summary.
The reported values are confusing and do not accurately indicate battery state.
Charging may be less than optimum, due to panel layout and/or charger setup.
Renogy batteries may be going into sleep mode and/or not fully charging.

 

[Rednecktek]

Also, some of the pre-built batteries BMS's default to 20% reserve, so your 100Ah is really only 80Ah before it's dead. You're definitely not fully charged if you're only showing 77Ah in a 100Ah battery and mostly dead if you're only seeing 77Ah between 2 batteries!

Ignore the 100% number, that's going by voltage and is pretty much useless for LFP batteries.

Make sure the voltage settings in your SCC are set for LFP. They come default for lead acids which are a much lower voltage. If the SCC thinks the batteries are full because it's looking for lead acid voltages, it's not gonna send any more power to the batteries. 13.1v is full for lead, mostly dead for LFP. You may have to go in and set up a USR profile with the appropriate bulk and float voltages.

It sounds like you've got 800w of panel on there, you're going to need about 80a of SCC to utilize that. That 30a Renogy is nerfing capacity, time to upgrade. A pair of 30a (one for each 4x100w set) is a must at minimum.

What's that "Old Panel" in the drawing? Take that out of the loop unless it's a close match to what your pair sets are.

Yes, it's a charging issue. There's a really flat curve and the capacity difference between 14.2 and 14.4 is about half the battery.