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What now???? 240v SPLIT PHASE inverters issues?

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Solar Wizard
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so you guys convinced me to do an inverter/charger with batteries instead of generator for well pump backup.

as a refresher its a 1hp pump that draws 22-25 amps startup and 9 amps run.

leading contender has been the growatt 6000. its low frequency so it wont have any problems starting the pump. it will only be used for emergencies.

so why am I now reading this (on watts247)and what the heck does it mean? and does it affect all 240v inverters with an autotransformer? educate me

Growatt 48V 6000T 6kW MPV (250V Solar Input) We no longer support this model due to potential Autotransformer issues feeding back to Utility.​


We no longer sell any units MPP/ Growatt or any other brand having (built in) or requiring an Auto Transformer on the output, If the inverter is in bypass mode, any Grid Imbalances will be fed through the inverter Auto Transformer

In some cases up to 60A has been seen

Even worse when more auto transformers are put in parallel, with some models.
 
I was hoping my mention of how easy it is to get more pump time with gas would sway you towards generator.

Some things to consider with that unit... While powered on, even if no loads are active, it will consume 100W all the time, and it's charger can't float like a typical charger. It's on/off like a tank float.

Utility/Generator Charger tips:
The generator charger is a different beast to the solar charger. (Does not utilize the Bulk and Float Charge settings)
It works on a float valve type principle. (triggers when battery voltage drops below that on setting 12 – set the voltage higher than current battery voltage to start charging right away)
Stops charging from Generator when setting 13′ s voltage is reached
Will not start charging the battery again until it drops below battery voltage – in setting 12.
Setting 01 set to SBU to activate setting 12 and 13.
Setting 02, is the Max charging current from Solar + Utility/Generator
Setting 11, is the Maximum Generator/Utility charging current @ your battery voltage (not at 120V)
Setting 14, make sure this setting includes the option to charge from utility/generator (see manual)
Note, setting Setting 11 too high for your generator may cause your generator to falter at startup, and cause the Inverter Charger to lose synchronization with the Generator (58 to 63Hz), if in doubt start small, and work your way up.
 
I was hoping my mention of how easy it is to get more pump time with gas would sway you towards generator.

Some things to consider with that unit... While powered on, even if no loads are active, it will consume 100W all the time, and it's charger can't float like a typical charger. It's on/off like a tank float.

Utility/Generator Charger tips:
The generator charger is a different beast to the solar charger. (Does not utilize the Bulk and Float Charge settings)
It works on a float valve type principle. (triggers when battery voltage drops below that on setting 12 – set the voltage higher than current battery voltage to start charging right away)
Stops charging from Generator when setting 13′ s voltage is reached
Will not start charging the battery again until it drops below battery voltage – in setting 12.
Setting 01 set to SBU to activate setting 12 and 13.
Setting 02, is the Max charging current from Solar + Utility/Generator
Setting 11, is the Maximum Generator/Utility charging current @ your battery voltage (not at 120V)
Setting 14, make sure this setting includes the option to charge from utility/generator (see manual)
Note, setting Setting 11 too high for your generator may cause your generator to falter at startup, and cause the Inverter Charger to lose synchronization with the Generator (58 to 63Hz), if in doubt start small, and work your way up.
well this new bit of information I learned about autotransformers might just push me BACK to the generator camp.
Damn. always something with inverters and batteries :)
 
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If it's for emergency use only and you're not connecting it to the grid, it is an absolutely splendid unit for driving difficult loads, but apart from that it's a bit crap.
 
If it's off grid, there's no problem with back feeding the grid. And if the pump runs on 240 volts, you don't need the autotransformer.
 
so you guys convinced me to do an inverter/charger with batteries instead of generator for well pump backup.

as a refresher its a 1hp pump that draws 22-25 amps startup and 9 amps run.
Could you explain in detail how exactly you got those numbers? I suspect you got them wrong? 9A is about right for 1hp, but a starting surge of only 22-25A is suspiciously low? Did you use a regular clamp meter to take your readings, or did you have a model that has "inrush current" capability? The numbers in the chart below closely match my own personal reading of my 1hp pump, which suggests to me there is an error?
1691338008796.png
 
Could you explain in detail how exactly you got those numbers? I suspect you got them wrong? 9A is about right for 1hp, but a starting surge of only 22-25A is suspiciously low? Did you use a regular clamp meter to take your readings, or did you have a model that has "inrush current" capability? The numbers in the chart below closely match my own personal reading of my 1hp pump, which suggests to me there is an error?
View attachment 161348
I used a meter with inrush. My question is, I tested one leg of 240v so should I be doubling those numbers since it's the same on the other leg?
 
I used a meter with inrush. My question is, I tested one leg of 240v so should I be doubling those numbers since it's the same on the other leg?
Which meter was that? No, you don't double the readings. Take a reading off either L1, or L2, and you should be good.
 
The SPF-6K is a Great off grid unit. I have one. Used for 2 1/2 yrs now. Starts well pump/ car hoist 220 circuits fine. If it is too much load it just shuts down. I also used mine to charge the batteries with Grid at times and turned off the utility breaker when not using. This is an example of how it should not be used now for safety. For off grid use, it's been good for me. Just don't update the firm ware after you get one, leave that alone other wise other issues could happen. I replaced mine with an 18kpv mostly for safety reasons. but the 6k is a good unit for the price of 1200. or less. If you buy one, make sure it is the 250v pv input model so you can hook up more voltage from your panels.
 
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