Epever Load Current Question?

[yorkwils]

Been using my system for a while without any active data or data-logging so it's about time to sort that out. Off-grid for most of the year so usually let the bulk-charge finish before any heavy loads, then overnight on batteries.

The Epever Tracer AN 100A MPPT solar charger is different to previous models in that it only has solar-in and battery-out cables so the connection to inverter is external. The Epever display has graphic and values for load current but no obvious way of informing the charger what the value is so it's always shown as zero. I am using the MT50 remote display installed next to the charger as it's easier to change settings for the charger with that than the buttons on the charger itself. The MT50 does have a ModBus RJ45 socket but I'm struggling to work out if I can feed inverter data into the charger to make charging independent of other loads.

I'm not particularly familiar with Ethernet and WiFi so I suppose that explains my hesitation in the first place but, it also seems possible to spend a fortune on clever little boxes with no real idea if they will actually talk to each other!

Victron documentation is very good but Epever just serves to confuse me. Victron say that the VE-Bus for the Quattros are "mission critical" so there is no third-party option to connect directly to that bus. I can see that the Victron Color GX display can connect to the Quattros' VE-Bus and also appears to have ModBus capability. What I really need is for someone to reassure me that has possibly done something similar before I fork-out hundreds on the bits that I think I need.

So it all boils-down to whether the Color GX can tell the Epever what the load is so that the Epever can make the best job possible of charging the batteries?

I did install everything myself including the solar panels (literally on my own) and the system is working really well but, I'm getting-on a bit in years and it's not so easy now to learn all of the new stuff that I need to know.

Many thanks if you can help me.

 

[Symbioquine]

I am skeptical that you'll be able to get the Victron hardware to talk directly to the Epever hardware.

What are you actually trying to accomplish with the (hypothetical) communication between the inverter or Color GX display and the solar charge controller?

So it all boils-down to whether the Color GX can tell the Epever what the load is so that the Epever can make the best job possible of charging the batteries?

The charge controller is already going to do the best it can to maximize the power from the solar panels to fill any available loads - including charging the batteries - but it can't prioritize between charging and other loads.

Even on the smaller Epever charge controllers (or any charge controller for that matter) it won't be able to supply less power to the loads in favor of charging the batteries. It will either power the loads or not. (This is a property of how electricity works, not some missing feature.)

If you need to reduce power consumption based on the battery charging status, that needs to happen on the load side. e.g. you could have a fancy relay or smart plug that turns on/off certain (optional) loads when some conditions are met. Some loads might even be able to have intermediate states like a heater running at half power, but again, this would happen at the device/load level (and only involve the solar/battery hardware insofar as it would use those to get the current charging status).

 

[yorkwils]

Thanks for the reply. Yes, I realise that the charge controller will always satisfy the demand from batteries and load combined and that arrangement works well for me. My concern was that the charge controller may not remember what stage it had reached in charging the batteries if there was a temporary load, say a kettle for example, that pulled the battery voltage low for a short while but then allowed the voltage to rise again afterwards - would the charge controller continue the charge cycle from where it had got to or start again at an arbitrary point? Ideally it should remember but I suspect not from the observations I have made.

 

[Ellcon123]

Charge controller has no need to remember. Voltage is all that matters.

 

[yorkwils]

Thanks
Initially I thought the same and it does make sense but occasionally I've seen the charger go back to bulk voltage again for much longer than expected once a temporary load is removed, I suppose it doesn't matter because the current draw will be low but I was slightly concerned with the batteries sitting at a higher voltage for longer than necessary - I'm probably just over-thinking it!

 

[Symbioquine]

I was slightly concerned with the batteries sitting at a higher voltage for longer than necessary

I think that may be more of an issue with some battery technologies than others.

Sealed lead-acid batteries - and GEL/AGM styles - would presumably be some of the most sensitive to that since lead-acid in general takes an initial bulk charging phase at a higher voltage, but the sealed style batteries are hard or impossible to reverse the damage that would occur if that higher voltage charging goes on too long. (With flooded lead-acid batteries, the main downside in my understanding to bulk charging too long is that you use up some of your water and need to top it up sooner.)

occasionally I've seen the charger go back to bulk voltage again for much longer than expected once a temporary load is removed

This is likely due to the "boost reconnect voltage" setting which in my understanding is the voltage that causes the controller to reset it's charge cycle/timer and start the boost phase of charging again. If you reduce that value, the controller should be less aggressive about restarting the boost charging phase.

If you have LiFePO4 (LFP) batteries, the following thread and resource might be helpful;

• https://diysolarforum.com/threads/lifepo-epever-settings.42895/
• https://diysolarforum.com/resources/general-lifepo4-lfp-voltage-to-soc-charts-tables-12-24-48v.109/

 

[yorkwils]

Good point, thanks for that, will re-check settings...