Battery drain with sun

[reiters]

I have 3x ES5000 and 30k EG4 batteries. I have fine tuned everything to my liking over a year. The last thing that bugs me that I haven't found a solution for is battery drain with full sun. On a sunny day my batteries are full by 1-2pm. Lots of sun left. The moment they hit 100% it switches to float (I assume) and runs the house from sun but the batteries immediately start to drain at roughly 4% per hour. So by 5pm when there is no longer enough sun to run the house the batteries are already down to 88%. What I would like to happen is to hold the batteries ate 100% as long as there is enough sun to power the house. That 12% loss is enough to run my house for 3-4 hours at night unless I'm using a lot of heat or cooling.

I am aware that es5000 are really bad about idle consumption but should the be draining the batteries with full sun?

 

[Mattb4]

Although it might seem odd a second array and SCC connected to your batteries seems to help in this situation. If its settings are such that it comes back on while your main AIO is waiting for battery recovery voltage set point to be reached, after being fully charged, it can hold your batteries at a higher state of charge and supply loads in the meantime.

Other than that is finding loads to run near the full charge point to stretch out your AIO's time in operation. For instance I am going to run a hot water heater whenever I find that I have more power than needed to charge up. It is on a MTS (manual transfer switch) plus a on/off switch so source and time of operation is under my control.

 

[reiters]

Would raising the float voltage a tiny bit help hold the charge up while solar is available or is this just normal? Would I do adding undo wear on the batteries.

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1drv.ms

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[reiters]

If the es5000 detects that the batteries are at 100% is it designed to disable charging until the lower charge limit (set to 30% by me) is hit before doing any charging again?

 

[Sojourner1]

If the es5000 detects that the batteries are at 100% is it designed to disable charging until the lower charge limit (set to 30% by me) is hit before doing any charging again?

You answered your own question. Raise your float to allow the batteries to be held at certain voltage while covering loads . If it's still draining the battery while in float you need more solar.

 

[reiters]

There is PLENTY of solar. It's just that the inverters stop charging once the batteries are full and allow the batteries to start discharging. I typically have 7-9kw of available solar when batteries hit full but they start discharging. I will try increasing the float to see if that helps while monitoring the battery temps. See images above. You don't need to set up a onedrive account to see the pics. See the SHARP cutoff of solar. That's when the batteries hit 100% and it stops using the available solar energy.

 

[Sojourner1]

If you are saying that you have the parameters set to stop charging till x amount of soc then you need to change the parameters to allow a float at 100% soc so solar is carrying loads and when the sun goes down your batteries are starting full.

 

[Mattb4]

Would raising the float voltage a tiny bit help hold the charge up while solar is available or is this just normal? Would I do adding undo wear on the batteries.

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1drv.ms

Depends. Some units do not run float in lithium battery type. Once they reach full charge (CC and CV) they shutdown til recovery voltage is reached. Some AIO's will have a recovery setting that can be pushed higher to allow that to happen quicker.

Regarding the batteries health. Solar charging is not ideal. Unlike charging from the grid where a known rate and level of charge can be done PV is always going to present a varied rate of charge based on solar intensity, amount of loads and level of charge reached during a charge cycle. Does this impact them? Likely. but it is going to be a balance between max life and PV output to operate your system.

 

[reiters]

Depends. Some units do not run float in lithium battery type. Once they reach full charge (CC and CV) they shutdown til recovery voltage is reached. Some AIO's will have a recovery setting that can be pushed higher to allow that to happen quicker.

Regarding the batteries health. Solar charging is not ideal. Unlike charging from the grid where a known rate and level of charge can be done PV is always going to present a varied rate of charge based on solar intensity, amount of loads and level of charge reached during a charge cycle. Does this impact them? Likely. but it is going to be a balance between max life and PV output to operate your system.

If that is the case then I'd be better off grid-tie all my solar and then use grid battery charger and leave the inverters in grid mode. Sorta what I have been moving to. I originally had 4 es5000 and 21k panels. I have since moved half the panels to grid-tie and shut off one inverter. I have 3 inverters but one has no pv coming to it. It's there for covering high loads.

The 4th AiO is now a dedicated battery charger hooked to the generator. If batteries are low and grid is down I can run the gen to charge batteries and run the how off battery power. I can charge faster than I use in that scenario. If the grid were down for multiple days (it's happened) I could run the generator for 3-5 hrs a day and have power all day.

As for charge rate I play pretty conservative. I cap it at 0.3c (180amps).

Much of this may be moot once summer hits and charging will slow when AC is running. I may not have full batteries until 4ish. I haven't had the system for a summer use yet.

 

[reiters]

Chatting with my wife and made me think that maybe it's the inverter with no input that is causing the drain. It's providing 1/3 of the house power but has no source other than battery. The other 2 are generating exactly what they need but not making up for the 3rd.

If this is the case I could take one string of panels (6/2) and split it so that 2 inverters have 3k solar and one has 6k solar rather than 2 having 6k and one having none.

I appreciate all the input. I get great information from this forum. Helps me to talk it out with others that have experience.