What, only four wires?

yorkwils

New Member
Joined
Sep 20, 2022
Messages
7
Using the Epever Tracer AN 100A charge controller. It only has 'solar in' and 'battery out' cables!! How on earth is it supposed to know what the load current is to charge the batteries correctly?

In other words, what additional magic box do I need to tell the Tracer AN what current the loads are taking, it always shows zero in the display?

I'm using two daisy-chained Victron Quattros to give 10kVA inverter output but the VE-Bus on those has no third-party output possibility as Victron say that is "mission critical" to synchronise the inverters so I need some other way to tell the Epever AN what the load is. I'm trying to avoid forking-out for a Victron Color GX for what would seem to be such a simple requirement, can anyone help with a simpler solution?

Many thanks...
 

400bird

Solar Addict
Joined
May 23, 2020
Messages
1,241
A charge controller only need to see battery voltage and be properly programmed to function.

It doesn't matter if you have a load on the battery on not battery voltage is going to be enough.

If you're pulling 10 amps or 200 amps DC and the battery voltage is still in the bulk phase, the charge controller is going to give everything it's got if the charge controller only puts out 5 amps, then those 5 amps will support the load and the reminder will come from the battery.
 

yorkwils

New Member
Joined
Sep 20, 2022
Messages
7
Thanks for that and yes, that's how I've been running my system for some time but, it does beg several questions:

1) Why have Epever bothered to put the load current icon in the display with a permanent zero value?
2) If a load is placed on the battery during bulk charge that pulls the battery voltage down does that interfere with the time left to run on bulk charge when the load is removed? (I note the Epever booklet says that it remembers but I think it possibly resets the timer to start all over again when the voltage returns to bulk value.)
3) Once bulk is finished and battery is on float and then a load pulls the battery voltage below float, I've noticed that the charge controller sometimes goes back to bulk charge again once the load is removed - potentially that's an awful lot of bulk charge?

Maybe I'm missing the point but, it seems to me that the charge controller could make more sense of what condition the battery is in if it could take account of the load current history, hence my point of why they have bothered to put load current in the display in the first place?
 

400bird

Solar Addict
Joined
May 23, 2020
Messages
1,241
Thanks for that and yes, that's how I've been running my system for some time but, it does beg several questions:

1) Why have Epever bothered to put the load current icon in the display with a permanent zero value?
It may be for a "load" terminal or to show when an external load relay is enabled.
2) If a load is placed on the battery during bulk charge that pulls the battery voltage down does that interfere with the time left to run on bulk charge when the load is removed? (I note the Epever booklet says that it remembers but I think it possibly resets the timer to start all over again when the voltage returns to bulk value.)
I wouldn't trust the time remaining for anything. I don't know how it calculates the time and I have my doubts it is documented in the manual.
3) Once bulk is finished and battery is on float and then a load pulls the battery voltage below float, I've noticed that the charge controller sometimes goes back to bulk charge again once the load is removed - potentially that's an awful lot of bulk charge?
That's called re-bulk among other terms. On some, higher quality, charge controllers this is adjustable.
Maybe I'm missing the point but, it seems to me that the charge controller could make more sense of what condition the battery is in if it could take account of the load current history, hence my point of why they have bothered to put load current in the display in the first place?
Sure, you're charge controller could better track the battery state of charge, but I'd rather rely on a BMS (for lithium batteries)

For the most part, in bulk the charge controller just throws everything it's got at the battery and the load can do whatever.
Once in absorbtion, the charge controller tries to hold a constant voltage and the battery slowly accepts less and less current while maintaining that voltage. If a load pulls current the charge controller would see this as the voltage starting to fall and increase charge current. Then when the load turns off, the opposite happens.
 

Symbioquine

Solar Enthusiast
Joined
Jul 6, 2021
Messages
176
1) Why have Epever bothered to put the load current icon in the display with a permanent zero value?

...

Maybe I'm missing the point but, it seems to me that the charge controller could make more sense of what condition the battery is in if it could take account of the load current history, hence my point of why they have bothered to put load current in the display in the first place?

I believe this is an "vestigial feature" that exists because the smaller Epever charge controllers have "load terminals" which allow those controllers to measure the amount of power flowing to the load.

The larger controllers get rid of those load terminals in favor of relay contacts which can be used to turn on/off a load, but the actual load current doesn't pass through the controller so it can't tell how much power us being used.

Basically once you move up to the larger controllers the idea is that you've put on your "big boy pants" and are using enough power that you wouldn't want to be limited by passing it through your solar charge controller. This is similar to how (at pretty much any size of system) you would wire your inverter directly to your batteries since the inverter has its own low voltage cutoff - and likely monitoring functionality - and you wouldn't want the current limits of the charge controller to limit what the inverter could draw.

If you still need to measure/monitor your power usage for something like DC loads, you should use a shunt.
 

yorkwils

New Member
Joined
Sep 20, 2022
Messages
7
Thanks for the replies. I suspected the load icon and value for load current in the charge controller display might now be redundant and that's no problem as I can find another work-around to monitor everything and realise that the charge controller will always try and match the battery charging and load demand combined as best as it can from the array power available. If the Victron Color GX is unable to talk to the charge controller or, there is no point in attempting to achieve that, I think my best, and cheapest plan, would be to construct my own monitoring panel to do the job. Shunts would be the obvious solution as they would have known calibration but I think it will be easier for me to monitor the voltage drop across various cables and build-in a facility to calibrate the panel for each.
All comments have helped to clarify my thinking so many thanks for that.
 
Top