Conversol A9 3KW 24v

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ZeroIn
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Conversol A9 3KW 24v

Post by ZeroIn »

Hi Guys i hope you are all well and safe

Newbie here - pleased to find you via the AICC Pi website

I have recently bought this hybrid / off grid inverter and its up and running well, nearly. Im using some Rolls AGM batteries until my LiFePO4 cells arrive

Anyway I have the floating AC output issue where half the voltage is on the neutral when running off batteries. I would like to bond the neutral to earth, as it is on the grid (TN-S supply). I got one zap and thats enough!

While on bypass mode, clearly the input and output neutrals are firmly earthed. The manufacturers have told me to bond the neutral of the inverter out to earth but surely this is a second N-E bond which is bad. How do I get a temporary bonding to take place so that I have a zero volt neutral when on batteries?

Linked to the above is the RCD issue on AC in. With no earth bond, the (incomer) rcd is happy. If I have the ac out N-E bond in place, the moment the inverter switches over to bypass, the (incomer) RCD waits a second and then trips out. Assume this is the leakage casued by the 2nd N-E bond.

After reading up, I know the older models have an 'option 38' that could make the dry contacts have a logic that would drive a relay that could temporarily make this bond for me. The newer 3rd Gen models dont have this - mine is the 450V SCC, Bluetooth, batteryless one if that makes sense.

Could bonding Nin to Nout work or will that let the black smoke out?

Much obliged
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coulomb
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Re: Conversol A9 3KW 24v

Post by coulomb »

ZeroIn wrote: Fri, 22 May 2020, 01:56 I have the floating AC output issue where half the voltage is on the neutral when running off batteries.

Linked to the above is the RCD issue on AC in. With no earth bond, the (incomer) rcd is happy. If I have the ac out N-E bond in place, the moment the inverter switches over to bypass, the (incomer) RCD waits a second and then trips out. Assume this is the leakage casued by the 2nd N-E bond.
Yes. Some of the neutral current will flow through the earth wires, which means that various RCDs will trip.
Could bonding Nin to Nout work or will that let the black smoke out?
That should work; I do that myself with my PIP-4048MSs. I'm a little uncomfortable with this because it shorts one of the safety relays, and the firmware doesn't always seem to switch the two safety relays (connected to AC-in) at the same time. But I don't seem to have any ill effects from this. It seems by far the easiest way to solve your problem.
Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
1.4 kW solar with 1.2 kW Latronics inverter and FIT.
160 W solar, 2.5 kWh 24 V battery for lights.
Patching PIP-4048/5048 inverter-chargers.
ZeroIn
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Re: Conversol A9 3KW 24v

Post by ZeroIn »

coulomb wrote: Fri, 22 May 2020, 11:40
ZeroIn wrote: Fri, 22 May 2020, 01:56 I have the floating AC output issue where half the voltage is on the neutral when running off batteries.

Linked to the above is the RCD issue on AC in. With no earth bond, the (incomer) rcd is happy. If I have the ac out N-E bond in place, the moment the inverter switches over to bypass, the (incomer) RCD waits a second and then trips out. Assume this is the leakage casued by the 2nd N-E bond.
Yes. Some of the neutral current will flow through the earth wires, which means that various RCDs will trip.
Could bonding Nin to Nout work or will that let the black smoke out?
That should work; I do that myself with my PIP-4048MSs. I'm a little uncomfortable with this because it shorts one of the safety relays, and the firmware doesn't always seem to switch the two safety relays (connected to AC-in) at the same time. But I don't seem to have any ill effects from this. It seems by far the easiest way to solve your problem.
Thanks coulomb.

What could potentially, worse case, happen if tied the neutrals in terms of safety while relay is shorted ?

Also think i picked the wrong inverter with this high voltage scc. I might need another panel with the hot weather in UK at moment. The mpp isnt tracking so well between 120-130v although it says 120. In cooler weather im up near 140v. The perturb and observe algorithm is interesting to watch at the lower end of the range.

Got my Pi on order and looking forward to running AICC or something like that.
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coulomb
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Re: Conversol A9 3KW 24v

Post by coulomb »

ZeroIn wrote: Fri, 22 May 2020, 21:46 What could potentially, worse case, happen if tied the neutrals in terms of safety while relay is shorted ?
All I can think of is something like this. Your neutral connection to the grid goes high resistance, and you have a non-inverter load running (oven, hot water system, etc). That brings all the house neutrals up to lethal potential. You realise something is wrong, hit the big red switch on your inverter system, and expect the outlets in the home to be dead. As you investigate, you get careless and touch the neutral while earthed; it's only neutral after all, and besides it's all switched off. But because of the neutral-in to neutral-out connection, you get shocked. If that connection wasn't there, the safety relay would have prevented the shock.

It's quite contrived, but not impossible.
Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
1.4 kW solar with 1.2 kW Latronics inverter and FIT.
160 W solar, 2.5 kWh 24 V battery for lights.
Patching PIP-4048/5048 inverter-chargers.
paulvk
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Re: Conversol A9 3KW 24v

Post by paulvk »

The method I used was the generator start relay when it goes to grid (generator) it operates the relay this takes an earth off the neutral
so I used the normally closed contact to keep the earth relay operated but there can be a slight problem if the relay is slow it may trip
the protection relay before the inverter so I have my ones on the output of the inverter.
The addition of the earth relay in the inverters and the new setting in firmware for older units was because I pointed out the problem to them!
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