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Inverter running without batteries (to do maintenance on the batteries)

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i have a Axpert King, and after going through what i think is the manual and looking elsewhere, i cant determine how to run it without the batteries connected to it (normal 80AH lead acid batteries i suspect is affected by sulfation), and i want to disconnect them and hook it up to a maintenance charger to repair the batteries.

is it possible to start up the inverter without the batteries connected to it?

 

The catch here is that i cant run the charger to repair the batteries if i cant get the inverter to power up without them.

 

3 hours ago, Andre Kruger said:

is it possible to start up the inverter without the batteries connected to it?

Short answer: no.

Slightly longer one: you can start it with a bench power supply provided that:

  • it supplies a slightly higher voltage than the inverter is set to charge at.
  • it can handle the initial surge current as the capacitors in the inverter charge up.
  • Author
3 minutes ago, Calvin said:

Short answer: no.

Slightly longer one: you can start it with a bench power supply provided that:

  • it supplies a slightly higher voltage than the inverter is set to charge at.
  • it can handle the initial surge current as the capacitors in the inverter charge up.

Thank you Calvin for the reply - currently i have 4 X 80AH batteries, do you think i can run it of two of them and repair the other two, and then swop the other two again?

 

6 minutes ago, Andre Kruger said:

do you think i can run it of two of them and repair the other two, and then swop the other two again?

If it is a 48V (5kW) King and the batteries are 12V, you certainly can not - you need all 4 in series (4 x 80Ah is VERY small for a 5kW inverter).  If it is a 24V (3kW) inverter and it won't start off 4 it is unlikely to start off 2.

Best bet is to get them charged up / desulphated separately.

  • Author
1 minute ago, Calvin said:

If it is a 48V (5kW) King and the batteries are 12V, you certainly can not - you need all 4 in series (4 x 80Ah is VERY small for a 5kW inverter).  If it is a 24V (3kW) inverter and it won't start off 4 it is unlikely to start off 2.

Best bet is to get them charged up / desulphated separately.

i was afraid of that..... sigh..

Yes, it is a 5KW inverter... (saving up at the moment for some pylontech batteries)

is there a way i can bypass the inverter altogether so i can get the batteries charged, seeing as i don't have any power when i do remove the batteries?

5 minutes ago, Andre Kruger said:

i was afraid of that..... sigh..

Yes, it is a 5KW inverter... (saving up at the moment for some pylontech batteries)

is there a way i can bypass the inverter altogether so i can get the batteries charged, seeing as i don't have any power when i do remove the batteries?

You should have a bypass/changeover switch installed by whoever did the initial installation. If not, you have to get that installed now. It’s a requirement for inverter systems, exactly for such situations - maintenance, inverter or batteries failure, etc. 

  • Author
11 hours ago, PowerUser said:

You should have a bypass/changeover switch installed by whoever did the initial installation. If not, you have to get that installed now. It’s a requirement for inverter systems, exactly for such situations - maintenance, inverter or batteries failure, etc. 

Hi @PowerUser - i spoke to the installer and i do have a changeover switch, but it has three settings, and i think i forgot that it has those settings, so i think i will be able to exactly what i need to do now.

  • Author
3 hours ago, 87 Dream said:

Short answer is yes. With the Grid available via the AC input, the inverter should startup. Unfortunately it will not be useful in a sense it can only be used as a conductor. Feeding loads from the grid. No solar will be used. This model does not support batteryless operations. Meaning you need a battery for it to be useful. The King has the smaller 145V solar PV input.

These models don't support batteryless ops. Only the 450V Solar PV input models support such a feat, the MKSll/lll/lV, VMIII and the MAX models do...Either way just better to use the Transfer switch onto the grid selection. 

87

 

Thank you @87 Dream - thank you for the feedback, changeover switch it is...

  • Author
3 hours ago, 87 Dream said:

If you suspecting issues with the batteries, it's the beginning of the end for those cells. When you get the Lithium technology you will wonder how you coped with Lead Acids. Lithium is really a game changer. Hopefully you can revive the 2 suspect cells...

87

Yeah, i think it was my fault, i might have pushed the batteries too hard while getting to optimum solar/battery config going... hopefully i can rejuvenate them, otherwise i will have to hold out until there is money for the pylons....

  • Author

I think i figured something out - it appears i have to put the inverter itself into ECO mode (bypass mode) in order for this to work, had a go at it just now, and i was able to remove the batteries and power up the inverter with the whole house powered

Never never never run your inverter with the batteries disconnected--magic smoke from the charger will escape--rather switch off the system and then work on the batteries.

Startup would be

1 connect batteries

2 Connect mains

3 Connect PV

Shutting down the system should be in reverse

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