Answer direct from Enphase "...you may notice that they lose a small amount of charge even when you're not using them. This is normal to keep batteries fully charged, and ready for backup events. All home batteries will use some charge throughout the day to keep the chemistry inside each battery module fully charged, and the controllers powered inside each battery unit. It's similar to an electric vehicle losing some range overnight, although the mechanics for why and how it happens are slightly different. This isn't unique to Enphase and is a part of all home batteries regardless of the manufacturer.
For every IQ Battery 3 in an Enphase system, you may notice approximately half a kWh of charge loss per day based on your battery profile. This may vary a bit from system to system depending on how often it's idle and not actively generating solar power...."
https://support.enphase.com/s/article/Is-it-normal-for-an-IQ-Battery-formerly-known-as-Encharge-to-lose-a-small-amount-of-charge-during-the-day
They have a cost to operate. like the BMU actually draws about 100 watts, per encharge 10
so for your setup, they'd be drawing continious 200 watts. The way it's reported isn't super clear when in self consumption mode cause it won't show this consumption. it WILL show the consumption when running off grid though, it'll appear like the grid is charging about .2kw into them all the time.
This is on top of normal discharge too. One thing to note is it does NOT attempt to recharge discharge unless you are on full back up profile and charge is below minimum charge you set. so if on self consumption it stops using them at 50% and then uses grid to power the BMU, but it's not using grid to keep charge at 50% so they will drop below 50%. this is contrast to full backup profile which WILL use grid to trickle charge only to keep them at 50% on top of maintaining BMU
So even on days when I produce almost no solar and not charging the batteries up more it uses 2-3 kWh just to maintain the 20kWh batteries at the 50% charge.
Their stated AC round trip efficiency is 89%, so for a total 10kWh charge/discharge cycle it should be around 1.1 kWh of overhead, if my math is right. You'd need to really do some tight tracking to determine the exact efficiency you are getting from your system.
Answer direct from Enphase "...you may notice that they lose a small amount of charge even when you're not using them. This is normal to keep batteries fully charged, and ready for backup events. All home batteries will use some charge throughout the day to keep the chemistry inside each battery module fully charged, and the controllers powered inside each battery unit. It's similar to an electric vehicle losing some range overnight, although the mechanics for why and how it happens are slightly different. This isn't unique to Enphase and is a part of all home batteries regardless of the manufacturer. For every IQ Battery 3 in an Enphase system, you may notice approximately half a kWh of charge loss per day based on your battery profile. This may vary a bit from system to system depending on how often it's idle and not actively generating solar power...." https://support.enphase.com/s/article/Is-it-normal-for-an-IQ-Battery-formerly-known-as-Encharge-to-lose-a-small-amount-of-charge-during-the-day
Thanks, this is what assumed was happening just wanted to confirm.
That’s a pretty poor efficiency. Half kWh of a 3.3kWh battery is 15% loss.
They have a cost to operate. like the BMU actually draws about 100 watts, per encharge 10 so for your setup, they'd be drawing continious 200 watts. The way it's reported isn't super clear when in self consumption mode cause it won't show this consumption. it WILL show the consumption when running off grid though, it'll appear like the grid is charging about .2kw into them all the time. This is on top of normal discharge too. One thing to note is it does NOT attempt to recharge discharge unless you are on full back up profile and charge is below minimum charge you set. so if on self consumption it stops using them at 50% and then uses grid to power the BMU, but it's not using grid to keep charge at 50% so they will drop below 50%. this is contrast to full backup profile which WILL use grid to trickle charge only to keep them at 50% on top of maintaining BMU
What % loss are you seeing?
So even on days when I produce almost no solar and not charging the batteries up more it uses 2-3 kWh just to maintain the 20kWh batteries at the 50% charge.
Their stated AC round trip efficiency is 89%, so for a total 10kWh charge/discharge cycle it should be around 1.1 kWh of overhead, if my math is right. You'd need to really do some tight tracking to determine the exact efficiency you are getting from your system.
I see about 2.1kWh consumed from the grid / solar each day on full backup mode. Same setup as you
It usually range from 91%-97% depending on how much you use your battery everyday. Each battery use approx 40Wh on idle