Using AC out2 on a multiplus 3000/12/120 for dumping solar in to water heater

DIY
,
1

Hi Guys - Marine install

We have had a multiplus v1 3000/12v/120a installed for a few years. Works great. I have a 326ah lifepo4 connected to it, 600w of solar on the flybridge into a victron SmartSolar Charger MPPT 100/50 - I dont yet have the victron dc-dc chargers as i use enerdrive ones - but that will be changing soon. I have a BMV and also a venus OS raspberry PI3 with all devices connected via MK3 (multiplus) and VEdirect

I know its not a lot of solar but it generally peaks at around 500w and we are fully charged by around lunch time each day in the summer.

We have a 6.5kw generator on board also.

I would like to dump the exess solar if possible to the hot water heater (1500w i think) and have been trying to nut out how to do this. I then with some reading see that ACout2 is controllable and can be used to dump solar.

My question is that I seem to remember that when using ACout2 you were still limited to a total of 3kw even when using shore power? is this correct or when shore power / generator is available can you run xxamps into ACout2 and also run up to 3kw via the inverter? The genset is 6.5kw but we only have a 15a shore power which is fairly standard here in Western Aus - and is sufficient for our needs

If I can use ACout2 to dump the load - I was looking at the following logic

Battery = 100% - ACout2 ON to heat water - continue until SOC is say 80% then ACout2 OFF - rinse and repeat.

When genset / shore power starts then ACout2 will turn ON anyway. My concern with the power rating is there may be a time where we would use the Kettle at 2kw while shore power is heating the hot water and than you could almost throw battery charging into it also which is another 1.5kw - its unlikely - but in that instance - is it possible to override the ACout2 also and switch it OFF to stop the water heating until the load has passed?

At the moment the Hot water is fed from a non inverted circuit so I would need to run another line from ACout2 to the RCD and note that as an inverted and none inverted load…

Also open to suggestions of better ways to do things..

Steve

2

Do you feed in solar power to public grid ?
if so you could use a simple Node-Red flow to check wether you have excessive power or not an then
use the relais on the cerbo to controll a electric contactor to switch on / off your water heater.
i did this on several customer sites so its definitly possible.

if you want a smart device i’d suggest the AC Elwa 2. It has several options and is fully victron compatible so you only
need a wifi signal and a setpoint and it will automaticly heat up your water if you have excessive solar power.
( AC ELWA 2 )

hopefully this is what you are looking for.

//Edit
Okay i just figgured that its a marine Installation.
Cant help you there im sorry

3

I’m very curious about this. Hope someone smart see this post.

4

It would be really helpful if you used the convention for describing ACOUT2 switches/relays, “open” = OFF and “closed” = ON… :wink:

I have an immersion heater connected to ACOUT2, and use a simple assistant running on the Quattro to turn ON at 99% SoC (53.9V) and OFF at 95% SoC (53V) – FLOAT voltage is set to 54V. This dumps excess solar power into the heater. But if I’m running off shoreline or generator I turn this off (physical switch in feed to heater).

5

Thanks for the info - I have edited the post with the on off terminology.

Good to know that ACout 2 is controllable and you do similar - any feedback on the passthough power being limited to the inverter capacity when running on external AC?

I just need to work out now if an assistant can be used to switch off ACout2 should the inverter encounter loads on ACout1. I’m trying to avoid a physical switch as we are generally distracted when returning to the boat with 2 young kids!

Steve

6

Thanks for the reply anyway - no doubt the info will be useful to somebody with a non marine install… :slight_smile: