LG Chem and Storedge starting deep well pump?

Hey All,

We tested our customers backup system the other day(I actually was not there to witness it). It worked as it was supposed to except it would not start his well pump.

As soon as they flipped the well pump breaker the lights went dim and the pump wanted to start but would not.

I do not know all the specs of the pump, but I believe it is fairly deep, maybe 200 feet. My guess is it is 240volt.

I did not design this system and frankly this is not a surprise to me that it won't start. Anyone with experience with well pumps know if they draw too much startup current for the Storage? I know you're going to want more info, but maybe you not even need the specs to know.

thanks
 

gadfly56

Senior Member
Hey All,

We tested our customers backup system the other day(I actually was not there to witness it). It worked as it was supposed to except it would not start his well pump.

As soon as they flipped the well pump breaker the lights went dim and the pump wanted to start but would not.

I do not know all the specs of the pump, but I believe it is fairly deep, maybe 200 feet. My guess is it is 240volt.

I did not design this system and frankly this is not a surprise to me that it won't start. Anyone with experience with well pumps know if they draw too much startup current for the Storage? I know you're going to want more info, but maybe you not even need the specs to know.

thanks
Sounds like the inrush current is pulling the voltage so low it won't budge. More batteries and a bigger StorEdge are the probable solution.
 

GoldDigger

Moderator
Staff member
Sounds like the inrush current is pulling the voltage so low it won't budge. More batteries and a bigger StorEdge are the probable solution.
Another solution is to use a pump controller with active soft start technology (think VFD Junior). That might end up costing less than the Storedge expansion and work better.
 

Dzboyce

Senior Member
I’m in eastern WA, and am an O3 electrician/plumber.

your normal submersible pump’s Starting amps are about 6 times it’s running amps, for about a second. We can reduce that with an Intellidrive to not drawing more than running amps.
 
Thanks. I have more info.

The pump is 1HP at 240v. I found a table from Franklin Electric online for locked rotor current. It said this kind of pump could draw 48 amps at startup.

That seems like a lot for the Storedge if I remember right.

Are soft start kits reliable? Would that be an acceptable solution for this problem?

thanks
 

jaggedben

Senior Member
The surge capacity of the inverter and battery are on the spec sheets. From memory they are both around 7kw. That's surge, for 5-10 secs. Continuous is 5kw.

So 7kW is only about 30A so if you want to start a pump that pulls 48A at startup it ain't gonna happen, no surprise.

They (SolarEdge) specify a 25A breaker for the backup panel, which probably shouldn't trip on a 30A surge but is still below what it seems your pump would need. Simply put, if the pump breaker is larger than 25A or maybe 30A it's too big a pump.

There is no bigger StorEdge at this time.
 

jaggedben

Senior Member
Last shouldn't be taken to dismiss the soft start suggestions. I know nothing about that but am interested to learn.
 

kwired

Electron manager
Thanks. I have more info.

The pump is 1HP at 240v. I found a table from Franklin Electric online for locked rotor current. It said this kind of pump could draw 48 amps at startup.

That seems like a lot for the Storedge if I remember right.

Are soft start kits reliable? Would that be an acceptable solution for this problem?

thanks
Last shouldn't be taken to dismiss the soft start suggestions. I know nothing about that but am interested to learn.
Only "soft start" methods I am aware of for typical single phase submersible pump is Franklin's "Monodrives" or Pentiar's "Intellidrives, maybe some others that are similar. What they are is a VFD, specifically designed to take the capacitor and potential relay normally used out of the circuit and connect all three motor leads directly to the drive. It is not a three phase output, though the same drives can be programmed to run a three phase motor also. It will vary current and voltage as needed to the start and run windings, and as with any VFD, you get a "soft start" out of it.
 
The surge capacity of the inverter and battery are on the spec sheets. From memory they are both around 7kw. That's surge, for 5-10 secs. Continuous is 5kw.

So 7kW is only about 30A so if you want to start a pump that pulls 48A at startup it ain't gonna happen, no surprise.

They (SolarEdge) specify a 25A breaker for the backup panel, which probably shouldn't trip on a 30A surge but is still below what it seems your pump would need. Simply put, if the pump breaker is larger than 25A or maybe 30A it's too big a pump.

There is no bigger StorEdge at this time.

We have a 25 amp breaker before the backup panel and the pump is only on a 20. So maybe the surge amps are short enough to get by a 20 amp breaker but are still too much for the Storedge.
 

kwired

Electron manager
We have a 25 amp breaker before the backup panel and the pump is only on a 20. So maybe the surge amps are short enough to get by a 20 amp breaker but are still too much for the Storedge.
Correct. 1 HP motor should only draw about 8 amps (per NEC table). Breaker can be 2.5 times that which is 20.

Initial current upon energizing motor can be 6-8 times full load rating - so the mentioned 48 is about right on expectation. This level of current only lasts for milliseconds and rapidly drops, but there has to be significant rotation in the motor or else that current isn't going to drop all that rapidly either, and to make things worse (for starting the motor) your inverter is likely limiting the max current and voltage and just starving the motor of what it needs to get it started, where a similar undersized generator may take some time to start it but still will get it done.
 

Dzboyce

Senior Member
I’d retro fit a Franklin monodrive or Pentair Intellidrive PID10. The Franklin’s max input amperage is 11 amps. The Intellidrive should be about the same. With the Intellidrive you program in the max amperage. For a 1 hp sub motor, that’s just over 7 amps, depending upon the brand.

I don’t have any pumps running on solar. But I’ve seen people try to start sub pumps on too small of a generator. It drags the voltage down and they never come up to speed.
 

jaggedben

Senior Member
We have a 25 amp breaker before the backup panel and the pump is only on a 20. So maybe the surge amps are short enough to get by a 20 amp breaker but are still too much for the Storedge.
Correct. 1 HP motor should only draw about 8 amps (per NEC table). Breaker can be 2.5 times that which is 20.

Initial current upon energizing motor can be 6-8 times full load rating - so the mentioned 48 is about right on expectation. This level of current only lasts for milliseconds and rapidly drops, but there has to be significant rotation in the motor or else that current isn't going to drop all that rapidly either, and to make things worse (for starting the motor) your inverter is likely limiting the max current and voltage and just starving the motor of what it needs to get it started, where a similar undersized generator may take some time to start it but still will get it done.
I’d retro fit a Franklin monodrive or Pentair Intellidrive PID10. The Franklin’s max input amperage is 11 amps. The Intellidrive should be about the same. With the Intellidrive you program in the max amperage. For a 1 hp sub motor, that’s just over 7 amps, depending upon the brand.

I don’t have any pumps running on solar. But I’ve seen people try to start sub pumps on too small of a generator. It drags the voltage down and they never come up to speed.
This is all good for me to know! Thanks.
 
Update.

I went out with the homeowner today to test the well pump. We made sure to turn off every other load before we tried it. First try it started it right up. Second try it faulted, third faulted. Waited a little while to try again, started it again. Another try fault.

Seems like it it is right at its current limit. I don't want to make a habit of failed starts so probably is best to look into the soft start kit.

Pretty cool that it could start it at all though, I am pretty impressed with the system after today. It was sunny enough that it did not draw on the battery at all, everything was straight from the PV modules.
 

Dzboyce

Senior Member
Another feature to upsell the customer on a Pentair Intellidrive; the link2O module adds internet connectivity to the VFD, for monitoring and fault notifications.
 
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