What is your battery % drop during Bypass Output with AC ON and DC Off?

I’m curious what everyones’ battery percentage drop when you use your system as time control or standby.

My current setting is for Time Control UPS w/ AC ON and DC OFF the whole time:
Charge: 8am to 4pm
Discharge: 4pm to 9pm

My battery percentage drops 1% per hour between 9pm to 8am during Bypass Output, so if I have 70% left at 9pm, by 8am, it would have dropped to around 58-59% (so drops about 11-12%). During recharge, when it hits about 84-85%, it will jump to 100%. I’ve already tried draining to 0% then back to 100%, but the issue persists where the battery percentage drops too fast during Bypass Output from 9pm to 8am. Instead, it should drain about 1% every 3 hours. Looks like I may have a defective system, since it shuts off at 0% even though my voltage still reads 52.4.

So my question is, how fast does your battery percentage level drop with the same settings?


For me its dropping about 10% over night when the unit is in standby. So around 1 - 2% per hour should be a valid value

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I normally leave my AC500 unplugged from the wall outlet, but out of curiosity I put a Kill-a-watt meter on the ac plug and plugged it in. It showed that the unit will draw a few watts from the outlet (fluctuates from 0 to 4), but it doesn’t show up on the app. (It’s in PV Priority Mode).

My guess is it’s for keeping the various monitoring/sensor circuits up and running. A lot of appliances have this parasitic power draw; microwave, TV, home theater, anything with a remote control (so it can detect the remote), along with ipads, iphones, laptop, etc. So if it can’t get that power from an outlet it’s no doubt getting it from the batteries.

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@Spyris which mode do you have? AC300 or AC500? I can provide the no-load consumption data for your reference. Also, you can check if there is a latest firmware to update.

Since we are in the EP Forums i think he is reffering to EP500 or EP500Pro. Didnt see anything about AC300 or AC500

@Selfmadestrom Sorry, I saw the comments as well. For EP500Pro, attached for your reference. Kindly notice that the data are derived under laboratory conditions and there may have differences under actual use conditions.

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@Spyris @BLUETTI_CARE I’ve noticed the percentage drop per hour could be reduced greatly depending on how you leave the pack voltage resting at night. Please see this post. For example, on one EP500P I’ve automated a small six minute grid charging when EP500P pack voltage drops below 53.12v (3.32v per cell) at specific time during the night. I did this by adjusting “battery range end” temporarily high (98%), then back to my usual value at 85%. After a single six minute charge, the pack drops only 1% almost every 3hours in bypass mode.

Each pack may be different, so I suggest studying the resting voltage and the percentage drop/hour and automating just like this after finding the ideal cell resting voltage. This will minimize the percentage drop shown by the BMS.

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