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Charging batteries through inverter with small generator


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Hi guys, can I top up our batteries (20kWh) through our 8kW Deye inverter using a small e.g. 1 or 2 kW generator?


Will the inverter take what it can get or will it potentially draw too much from the gennie and kill it?


I'm thinking of getting a cheap small gennie just to top off our batteries in the very rare event we struggle to get our batteries fully charged (load shedding and bad weather combined)




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Hi Ant,

I'm using a old 5kw generator to that effect on my 8KW Deye inverter and it works fairly well.

In the setup one can specify how many watts the generator can handle (I had to set mine down to 3200W or else the load increases to much which causes the frequency to decay below 45Hz which then causes the Inverter to cut off the generator).

Note that when the generator is running the inverter switches over the whole essential load on to the generator and uses whatever is left over to charge the batteries.

So your generator would need to be big enough to carry the whole essential load, plus have some spare capacity for battery charging. So given this I suspect that you will need to look at a larger generator (unless your essential load is minimal).

Also I needed to play around with my generator governor to increase the Hz to an acceptable level before the Deye inverter accepted it.

Bearing in mind the above limitations it works really well, and I've even created a auto start routing using a Arduino board and a relay (that receives the start signal from the Deye inverter when the battery goes below a certain percentage).

Hope this helps.




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I would just use ESKOM to top off the batteries. It is the cheapest option. I had a 7kW generator. That thing gobbled up 25l of fuel in no time. Every second day I had to go buy more fuel. It is very expensive to run a generator, excluding the capital cost to buy the thing in the first place. If you live out on a farm or are determined to go off grid, it is a different story. Then you bite the bullet and pay-up. 

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So, two things,

You have settings ion your menu's for:

- Maximum Power load on Generator

- Maximum battery charge current from generator (different setting to charging from grid)


 If the load is more than what the max the generator can provide, it will pull the balance from the batteries (assuming you have power available in the batteries), otherwise the inverter will disconnect. 

If the inverter power load is less than the generator max and your "System Work Mode" settings are ticked to charge from the generator it will pull power from the generator to charge the battery up to a max of either the Battery Charge current or Max Generator Power load, whichever comes first. 

So, you can run a generator that is providing less power than your household load and it will work. 

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A bit two minded about this


I have converted to as green as possible in my house, All LED, cooking with Gas.. etc and my monthly electricity bill is roughly +-R1000 rand, the only big electricity user is most like the geyser


my question as following 


I am planning to install 5KVA backup system with Luxpower inverter and Greenrich 5kw battery, ( still deciding on UP5000 vs WM5000, both seem identical from the spec sheet )


I currently have a 5.5kw generator that I have been using during load shedding without much issues. I am now comtemplating whether is I should install 6X450w panels or if I just use generator to top up in the situation where Eskom becomes unavailable to charge the battery ,


any suggestion ? is it even worthwhile to consider fork out extra capital for solar panels taking into the consideration of my monthly electricity bill of +-R1000? I was quoted R24000 for 6 X450 panels supplied and fitted

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@turbochenAsk 10 people and you will get 10 different opinions.  At the end you need to decide for yourself.

Two points to consider:

1.  I don't know about the Luxpower inverters, but be aware that many inverters reject generator power due to their unstable output frequency.  Do not simply assume that you will be able to use your generator to top up the batteries.  Once you have your inverter installed, test to see if you can charge the batteries from the genie.  Also don't do a quick 1 minute test.  Load your generator with something like a kettle and switch it on and off.  See if battery charging is maintained as the genie's AVR battles with the load variation and the genie's speed hunts and wobbles.

2. Should the grid collapse completely the diesel and petrol supplies will likely run out in a few days.  In fact most things will stop and crash.  Water, sewage, communications, food supplies, etc.  In such a scenario I would rather huddle at home than to go out into the streets trying to buy fuel.


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