question

marky644 avatar image
marky644 asked

Excess power to heat water - issue with battery power

Hi, I have a New system of 2x MultiPlus II 48/3000/35-32, SSC MPPT 250/100, BYD battery box and Venus GX. The system is currently set up that any excess energy (after batter is fully charged) is used to power a water heater. This is done through relay ( between 100% to 96% of SOC the solar energy is used to power up the heater).


However I run an issue when the solar power is not sufficient to power up the heater or the whole system, the excess energy is taken from grid, not from battery - even though there is sufficient battery capacity. As a result I’m running quite substantial grid consumption when there fluctuation in solar power. Could you please advise what could be the solution to also use the battery power to help during the solar fluctuation?

ESS
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

2 Answers
boekel avatar image
boekel answered ·

It should only use power from grid when your inverter cannot supply enough power.

What ESS mode are you using?
what is the power rating of the heater?
how big of a battery do you have?

1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

marky644 avatar image marky644 commented ·

Thanks Boekel,

I’m running maximum Lifetime mode on ESS (if that’s what you mean). Heater is c 1.5kw / 230V and battery should be sufficiently big - 7,5kwh.

Does this help.

Thanks again

0 Likes 0 ·
Michael Riley avatar image
Michael Riley answered ·

@marky644@gmail.com

I have a similar setup but am unable to find the logic (in the Venus) to make the correct switching. I do not have a BMV but use the Lynx Shunt 1000.

We live on a boat and am happy for energy to be drawn from LiPo so long as SOC is > say 80%. I have an AC water heater so have a 230V relay which I currently switch manually via the Venus-Relay manual mode but want to automate when not on the boat at the time of appropriate solar window.

1. What hardware has the logic relay (96% < SOC >100% etc). If it is the Venus can you post your settings in detail.

Thanks

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.