Axpert invertors

Johnny_Q said:
Ok thanks

This is my load calculation please correct me and advise on the battery setup I need

House lights 100W
Garden Lights 300W
Alarm 20W
DStv 75W
Home Enter 200W
LCD TV 200W

Total Watts 895 X 2.5 Hours = 2237.5

All above lights are LED

Thanks again all for your help
Click to expand...

Ahhh... okay, there the problem... Your load is only 895 W (Watts, as in power). Don't multiply by 2.5h :) The amount of energy that you need to survive the load shedding is 2237.7 Wh (Watt hours)

Also, did you actually measure those appliances? My measured load is 150W for lights (pretty much whole house using LED and a few CFLs). TV + DSTV + Home Theatre = 220W. Maybe look into lower power garden lights?

So you only really need a 1kW inverter... or maybe 2kW to be safe.

The usable energy (50% DOD) from a 12V 100 Ah battery is 600 Wh.

So for your 2200W requirement, 4 batteries is fine. Or if you can reduce your load, then 2 batteries is fine.

I'm running a 800W inverter and 2 batteries. My load is only about 400W in a normal evening - inside/outside lights + TV/entertainment and alarm, etc.
 
Thanks Greg_SA , So for now the 4 batteries are good , or should I get 200ah batteries ?

Lights are correct as I added up the LED watts of each one, the Alaram and Dstv etc used the calc from Sintech page.

Reason for the bigger inverter I will next year add solar panels and in the interim be reducing other appliances consumption.

Once again appreciate all the help from ppl here on the forum
 
Depending on the decoder, I think its 35w for the HD-PVR and 45w for the Explora.

Also 200w is high for an LED TV, unless its 60"+
 
For all who has build these systems, what have you put in place for safety?

I refer to fuse holders and fuses or circuit breakers between battery and inverter, battery and charge regulator, charge regulator and solar panels.
 
beatlexx said:
For all who has build these systems, what have you put in place for safety?

I refer to fuse holders and fuses or circuit breakers between battery and inverter, battery and charge regulator, charge regulator and solar panels.
Click to expand...

I was thinking that the electrician installing will put these in place? If you can share details will be helpful so I can let the Electrician know

Thanks
 
beatlexx said:
For all who has build these systems, what have you put in place for safety?

I refer to fuse holders and fuses or circuit breakers between battery and inverter, battery and charge regulator, charge regulator and solar panels.
Click to expand...

The Axpert has fuses on the battery and PV links. I guess you need to be aware of whether your inverter is fused or not. If you're running the output directly into your DB board then at least you have breakers on the output side. But TBH I'm not sure if this is sufficient.
 
Does anybody know if these units have a true neutral? Such that you can tie the ground and earth when wiring to your DB Board?

I've ordered one of these units and my plan is to isolate the house light circuits from the eskom supply with a changeover switch and a separate earth leakage breaker. The inverter will therefore be taken straight off it's own breaker for supply power and the power it delivers will go through a changeover switch to select eskom or the inverter (in case the inverter stops working I can revert to normal supply). From there the selected incoming power's neutral will be tied to the earth and then go through the separate earth leakage before powering the light breakers and "emergency" plug breakers.

If this system works, I can then essentially run my lights, tv, fridge and computer off the inverter in UPS mode and not have to worry about changeover. The changeover switch will only be used if the inverter fails and I need to go back to eskom power.
 
contrastflash said:
Does anybody know if these units have a true neutral? Such that you can tie the ground and earth when wiring to your DB Board?

I've ordered one of these units and my plan is to isolate the house light circuits from the eskom supply with a changeover switch and a separate earth leakage breaker. The inverter will therefore be taken straight off it's own breaker for supply power and the power it delivers will go through a changeover switch to select eskom or the inverter (in case the inverter stops working I can revert to normal supply). From there the selected incoming power's neutral will be tied to the earth and then go through the separate earth leakage before powering the light breakers and "emergency" plug breakers.

If this system works, I can then essentially run my lights, tv, fridge and computer off the inverter in UPS mode and not have to worry about changeover. The changeover switch will only be used if the inverter fails and I need to go back to eskom power.
Click to expand...

As far as I know, it is a floating neutral.

I wired mine according to this... http://www.4x4community.co.za/forum/attachment.php?attachmentid=333613&stc=1&d=1422940513

I route the output from the UPS as follows: earth wire to DB earth. Live + neutral wires through an isolator, then into an E/L. The neutral from the E/L goes to an separate neutral bus, for my UPS loads only. The Live from the E/L goes to a separate bus which feeds the breakers for my UPS loads. I didn't include a change over switch - I might add one later.

To bypass the UPS, you can remove the UPS by connecting the feed to the UPS to the output from the UPS?
 
greg_SA said:
As far as I know, it is a floating neutral.

I wired mine according to this... http://www.4x4community.co.za/forum/attachment.php?attachmentid=333613&stc=1&d=1422940513

I route the output from the UPS as follows: earth wire to DB earth. Live + neutral wires through an isolator, then into an E/L. The neutral from the E/L goes to an separate neutral bus, for my UPS loads only. The Live from the E/L goes to a separate bus which feeds the breakers for my UPS loads. I didn't include a change over switch - I might add one later.

To bypass the UPS, you can remove the UPS by connecting the feed to the UPS to the output from the UPS?
Click to expand...

Hi Greg,

I think it's probably unnecessary for the changeover switch, I just see the inverter breaking and the missus without lights while eskom is actually providing power going down really well :p. But you're right that it shouldn't take very long to just bypass the inverter.

Have you tested the earth leakage in your setup? I think that the inverter probably has an earth tie internally anyway - I just wonder if there is nothing tying the ground to earth then how would the earth protect you since the only path would be back to the inverter through neutral and the earth leakage would never trip? Maybe my understanding is flawed :erm:
 
FWIW the Axpert has a bypass setting but I guess if the whole unit packed up you'd be out of luck.
 
contrastflash said:
Hi Greg,

I think it's probably unnecessary for the changeover switch, I just see the inverter breaking and the missus without lights while eskom is actually providing power going down really well :p. But you're right that it shouldn't take very long to just bypass the inverter.

Have you tested the earth leakage in your setup? I think that the inverter probably has an earth tie internally anyway - I just wonder if there is nothing tying the ground to earth then how would the earth protect you since the only path would be back to the inverter through neutral and the earth leakage would never trip? Maybe my understanding is flawed :erm:
Click to expand...

The E/L devices are actually RCDs, and they detect a difference between the live and neutral currents. If there is a difference in the currents, it means that there is a current leaking. The leaking current doesn't have to travel via the earth wire.

Here is an explanation:

RCDs operate by measuring the current balance between two conductors using a differential current transformer. This measures the difference between current flowing through the live conductor and that returning through the neutral conductor. If these do not sum to zero, there is a leakage of current to somewhere else (to earth/ground, or to another circuit), and the device will open its contacts. Operation does not require a fault current to return via the earth wire in the installation; the trip will operate just as well if the return path is via plumbing, contact with terra firma or any other current path. Automatic disconnection and a measure of shock protection is therefore still provided even if the earth wiring of the installation is damaged or incomplete.
 
greg_SA said:
The E/L devices are actually RCDs, and they detect a difference between the live and neutral currents. If there is a difference in the currents, it means that there is a current leaking. The leaking current doesn't have to travel via the earth wire.

Here is an explanation:

RCDs operate by measuring the current balance between two conductors using a differential current transformer. This measures the difference between current flowing through the live conductor and that returning through the neutral conductor. If these do not sum to zero, there is a leakage of current to somewhere else (to earth/ground, or to another circuit), and the device will open its contacts. Operation does not require a fault current to return via the earth wire in the installation; the trip will operate just as well if the return path is via plumbing, contact with terra firma or any other current path. Automatic disconnection and a measure of shock protection is therefore still provided even if the earth wiring of the installation is damaged or incomplete.
Click to expand...

Hi Greg,

My understanding (which may be wrong : is similar to an electric fence, if the current leaks to earth/ground through you or an object, it is actually forming a conductor via the earth/ground to the neutral which is connected to the ground either at the utility station or through your plumbing etc.

In the case of the inverter, if your neutral is not grounded there is no path back from terra firma to the neutral and therefore the circuit is not complete via the earth. The reason an earth leakage device works is because the ground to neutral connection is before the RCD (normally at the substation), therefore if current travels via the earth, be it through the earth wire or the ground itself, it finds its way back to neutral but bypasses the RCD which then detects the current differential and trips.

I can only assume that the inverter has a tie internally to make this work? If not, I can't see a reason the live of the inverter would want to travel "to earth". This is all in battery mode that I am referring to, obviously in bypass mode the neutral will just behave like the supply. Sorry if I'm being dof :D
 
contrastflash said:
Hi Greg,

My understanding (which may be wrong : is similar to an electric fence, if the current leaks to earth/ground through you or an object, it is actually forming a conductor via the earth/ground to the neutral which is connected to the ground either at the utility station or through your plumbing etc.

In the case of the inverter, if your neutral is not grounded there is no path back from terra firma to the neutral and therefore the circuit is not complete via the earth. The reason an earth leakage device works is because the ground to neutral connection is before the RCD (normally at the substation), therefore if current travels via the earth, be it through the earth wire or the ground itself, it finds its way back to neutral but bypasses the RCD which then detects the current differential and trips.

I can only assume that the inverter has a tie internally to make this work? If not, I can't see a reason the live of the inverter would want to travel "to earth". This is all in battery mode that I am referring to, obviously in bypass mode the neutral will just behave like the supply. Sorry if I'm being dof :D
Click to expand...

Yes. That makes sense. The "leakage" current won't flow if there isn't a path back to neutral. But that means that you can't actually get a shock either, if you touch just one wire - live or neutral. You have to touch both wires to get a shock.

I'll look into this some more...
 
greg_SA said:
Yes. That makes sense. The "leakage" current won't flow if there isn't a path back to neutral. But that means that you can't actually get a shock either, if you touch just one wire - live or neutral. You have to touch both wires to get a shock.

I'll look into this some more...
Click to expand...

Thanks :) I'll wire to code but I'm just interested in how it works.
 
Hey , would this set up work ?

If I get 2 x 3kva Axpert inverters , and 4 batteries ( 2 series of 2 parallel )
1) could I connect two inverters to one set of batteries ?
2) could I connect solar panels to both inverters ?
3) could I connect one inverter to two seperate circuits on the DB ?

I want to connect one inverter to one circuit channel covering the lounge , and the other inverter to both lights circuits

EDIT - not asking about the sufficient power of inverters for the circuits - thats all worked out already , lights LED , lounge is just tv and stuff
 
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gimpex said:
Hey , would this set up work ?

If I get 2 x 3kva Axpert inverters , and 4 batteries ( 2 series of 2 parallel )
1) could I connect two inverters to one set of batteries ?
2) could I connect solar panels to both inverters ?
3) could I connect one inverter to two seperate circuits on the DB ?

I want to connect one inverter to one circuit channel covering the lounge , and the other inverter to both lights circuits

EDIT - not asking about the sufficient power of inverters for the circuits - thats all worked out already , lights LED , lounge is just tv and stuff
Click to expand...

You could, but it'd be a real las to wire. Because the 3kVa inverters can't be paralleled (sync the waveforms) you have to run them separately as you say. You can draw the power from the same batteries but I'm not sure how much the internal chargers would like competing with each other. Then on the DB board side you'd need to run two set ups like me and greg were talking about above isolating each inverter.

For the extra cost would you not want to just buy a more powerful inverter? if you are planning on running 4 batteries you can just as well connect them all in series and run 48V (better for current reasons anyway) and then get the axpert 5kva version - How much are you lights actually drawing? If I turn all my house lights on it uses like 800 watts. A modern TV, HiFi, blue ray and DSTV all running together will draw like 500watts so are you sure you would need the extra 800watts from running the two systems or is there a different reason you don't want the 5kva version?

Also it would be cheaper to buy just the one unit...
 
gimpex said:
Hey , would this set up work ?

If I get 2 x 3kva Axpert inverters , and 4 batteries ( 2 series of 2 parallel )
1) could I connect two inverters to one set of batteries ?
2) could I connect solar panels to both inverters ?
3) could I connect one inverter to two seperate circuits on the DB ?

I want to connect one inverter to one circuit channel covering the lounge , and the other inverter to both lights circuits

EDIT - not asking about the sufficient power of inverters for the circuits - thats all worked out already , lights LED , lounge is just tv and stuff
Click to expand...

If you do this, you'd have to completely separate setups - I wouldn't share anything.

Is this for load shedding? Its sees pretty extreme. I'd be worried if my lounge was drawing 3kVA!

You can connect ONE inverter to whatever you want... I have one inverter powering lights and some plug circuits. You just re-arrange your DB.
 
Thanks Greg and contrast flash

I was thinking 2 inverters instead of one , cause you could buy them at different times ,and when one fails you still have the other one to fall back on , albeit with some adjustments necessary.

Also being 24v means lower investment in batteries.

By the way lounge also included the kitchen ( fridge ). Yes all lights are under 1300w including outside lights , but of course you wouldn't have them all on at the same time.

Sounds like one bigger unit is the way to go , even if in terms of keeping it simple. Also when eventually installing solar panels.
 
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