Alarm & cut out on fully charged batteries

[Harry Diculous]

Hi All

I'm having a problem with the alarm on the inverter going off & shutting down when the batteries are full. I've noticed that the Voltage shoots up to 15.5 volts. I believe that this happens when a heavy user of the power shuts down, like the washing machine or freezer. I've set the POWMR VR to 14.5 volts absorption but I don't think that it's taking a lot of notice. I have checked the batteries with a cat111 Multi tester & recorded 15.3 volts. This voltage is very brief. The Inverter is 3500 Watt Pure Sine Wave.
This Off Grid System :- 8 Panels, four in series x 160 W each panel. Total 1280 Watt. Leads from panels to the connecting wire are 1.5mm Dia. The Connecting wire to the Shunt 3mm Dia. From the Shunt through the VC (60 Amp) & Batteries are 3mm X 2 wires.
Batteries are 4 x 100 Amp Hr Flooded & 1 x 200 Amp/h AGM. It's grown a bit like "Topsy" over time so liberal use of Anderson Type Plugs.

There is in addition a wind turbine but it's too low to provide much power. It's connected to the batteries via it's own VR.

Thanks for any advice.

 

[svetz]

Is there any message associated with the alarm, possibly a display code you could look up in the manual and tell us?
Did the manufacturer have any suggestions (e.g., add a capacitor to smooth the surges)?

 

[Harry Diculous]

Thanks for the Reply svetz.

It's a Chinese inverter (EDECOA). I haven't had any issues with it. The increase in voltage (I was there be in front of the system to see it shoot up as indicated by both the Inverter & VR.) I also manged to get a similar reading on the multi tester. (I should have looked at the AMPS.)

It's all over pretty quickly but, of course, the Inverter has shut down and needs to be switched back on. (After waiting for a few minutes.)

It's set to (according to the instructions) indicate by a sound and flashing light that 15v has been exceeded and shuts down. This seems to be the case.

It's quite a few years out of warranty.

With the addition of the extra two panels (320 Watts) the system's performance has really improved. Except for this problem, of course.)

* I actually thought that the VR would regulate the input voltage.

 

[Harry Diculous]

OK. I think I know what the problem is. The VR doesn't have a cut out when the voltage exceeds a certain level.

I think that because the VR that's attached to the Wind Turbine does. When 15 volts is hit, it shuts down the wind turbine. When the voltage drops to a certain level, it will restart. I know that this happens by simple observation.

So this mechanism should be available in the Solar VR. I've checked the instructions & I can't see that that is available. So I need to install something or replace the VR.

A search on the net doesn't specifically turn up a VR that will do this.

I'm trying to avoid Chinese at present because they have it "in for us" here in Australia and service & communication might be jeopardised in the future. (We do have a "re-birth" of Solar Technology here in Oz at present which is very satisfying plus a couple of Lithium Battery plants under construction.)

 

[Hedges]

I think some people have had an issue with charge controller seeing high voltage when inverter load cut off.
Charge controller was wire to inverter end of cables, moving to battery end may have helped.

There can be a brief voltage kick due to inductance, don't know if that is fast enough to trip anything.
Try twisting positive and negative cables together, which reduces "loop area", the area of empty space between them. That reduces inductance.

More likely, issue is the charge controller was delivering full current when voltage was pulled down and takes a moment to stop doing that.
A brief spike to 15.5V ought to be tolerated by the electronics.
Maybe connecting charge controller to opposite end of wires paralleling batteries, so any such spike has to travel past them. Maybe that will put their capacitance in the right place, at least IR drop could help.

 

[Harry Diculous]

,,,,,Maybe connecting charge controller to opposite end of wires paralleling batteries, so any such spike has to travel past them. Maybe that will put their capacitance in the right place, at least IR drop could help.

Thanks Hedges. I'm not sure what you mean by the above?

 

[Hedges]

My idea was something like this:



At east the voltage due to IR drop of charge controller feeding batteries won't be seen by inverter.
Inductance, if it causes an effect, would be short; it only reacts to change in current, not steady-state current.

 

[Harry Diculous]

It seems that the panels are going directly to the batteries?

(I'm just reading up on Inductances & Steady State)

The symbol is the Inverter but I can't seem to find an exact replica on the net. Does it include a Voltage Regulator ?

Thanks again

 

[MisterSandals]

It seems that the panels are going directly to the batteries?

Yea, the panel wires go to the SCC. Otherwise, it correctly shows the charge leads going to opposite ends of the parallel cells.

 

[Harry Diculous]

My apologies if I'm not quite "getting it." I do appreciate your help, though.

So the wires from the Panels got to the Inverter/Voltage regulator then to the batteries?

That's how I've got it set up.

There's 44 volts coming from the Panels.

 

[Hedges]

Is this the inverter?

3500w pure sine wave inverter 24V

Off-grid tie inverter and voltage transformer,pure sine. Our product have 24v DC of input voltage, 7000W of max output power, AC 190-240v of output voltage. With our off grid tie inverter, pure sine wave inverter, you save money and you always keep your d

edecoa.com

You mentioned voltage regulator - is that a separate charge controller? Have a link?

44 Voc from the panels should be at least sufficient to start working. Vmp may or may not be high enough for full power with an MPPT charge controller, need to see specs of panels and charge controller. Have a link for the panels?

Assuming "Inverter" and "Voltage Regulator" are two separate boxes, not all in one,
Panels would go to charge controller, which then goes to batteries.
Inverter would separately wire to batteries.

Some all in one or hybrid have terminals for PV, battery, and AC, but I don't see that for the EDECOA models.

 

[Harry Diculous]

The inverter I have is the DPP35 but it doesn't appear on the net The unit I have is 3500 Watt, 12 volt to 240 Volt. Strangely enough, in the instructions which include other models, it doesn't mention a 3500 watt unit or the 5000 watt. Only goes to 3000 watt.

The system did grow like over time. All panels are 8 x160 watt in series of 4 x 320 watt. I'm stuck with 12 volt because I have a 200 Amp/hr AGM included with 4 x 100 W as well as the Inverter. This means that the original panel is about 5 years old.

I'm pretty sure that the cabling is OK because I've had this problem before but "solved" by removing the battery cables & replacing with bus bars over the batteries & a 12.7 mm diameter cable from the batteries to Inverter. This problem arose when I added the extra 2 x 160 watt. After adding the AGM, it seemed that I wasn't getting enough charge. This has improved. I have photographed the system as it is now, but I can see the connections from the panels to the VR is somewhat less that professional, making rather overuse of Anderson Plugs.