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Soft start for mini Freezer Chest? 1.1Amp

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offgriddave

Solar Enthusiast
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I am trying to hook up a small 3.5cubic ft freezer chest to my Victron 375VA 48v. The Energy Star rating is "193kwh/year" or .52kwh a day. The inrush surge (not measured) EDIT: The Victron goes into PROTECTIUON MODE shutdown for 15 seconds. (Victron 375VA surge is rated at 700w).

I am assuming this unit pulls 110w-75w for 20 minutes every hour, after the initial inrush surge.

I am looking at soft starts. There's no way I'm paying $300 for a unit. I see some people have linked to aliexpress soft starts here for $40, but they are rated at 220V. I'm in USA at 115v.

Should I get a softstart? Will it work? Which one should I get?

Or should I get a new Victron? The 800VA claims a surge of 1500w. Will it work?

Cheapest softstart I can find:

GS10 Universal Soft Starter (15A max. Heavy duty) $159​


The ali express part linked that is 220v but I need 115v: $50

or a new Victron 48v 800VA $317?


I have a bigger inverter but the idle watts is 45-65w. That's unacceptable. I'm assuming the Victron 800VA has low idle watt like my 375va (13w)...

Any ideas? thanks
 
Last edited:
Can you read the Voltage and Amp sticker of the fridge to get VA rating?
Victrron 375VA 48V is 300W inverter, the chart does not say how long it can sustain the peak power draw, may be your fridge startup power draw is longer that the Victron can handle.

1664751150729.png
 
Thanks Bud Martin, I appreciate your post. Tough here living off the grid! *waves at moose*

The Victron 375VA tested with _just_ the freezer plugged in, gets a power fault almost immediately. If I recall the "700w" (700VA) peak rating is for the Victron 375VA/48v is an amazingly 2 minutes because of its LF design and it weighs 20lb. Sorry i can't remember where I saw the 2 minute figure..

Also I am running at 122v just to be safe (because I have a 400ft *10awg* 110v extension cord for my starlink , and starlink only, 70-180w)
I don't think this is an issue. This puts the 375VA at 3 amps max out. With peak surge at 5.7 amps if I get to "700va" for a moment. ... Lol I guess I could try underbolting to 109v? That might be a bad idea on the motor. Or wouldn't work at all. It would give me (700va/109 =) 6.42 amps. I don't think this would work this way. I guess the most insane thing I could do is undervolt the victron all the way to where it can go, everytime I start it? That's unrealistic and I won't test it unless somebody really insists.

The freezer does not say what the starting amps are, but I am guessing 12 amps based on my old one. Which is 10x what the sticker states.
Plugging it into a non-inverter generator the generator revs up -- but not completely -- for about 1 second and immediately goes back to idle (which is something like 200-300w for this no-name open frame genset) ... so I am guessing it's really is 12 amps or 1440 watts.

edited for clarity
 
Why not get the 1200 if it's in budget?

Idle power draw is only a watt or two more and efficiency is a percent or two higher as well.

Then you'd have 2200W surge capability.
 
Hi thanks, the Victron is fine I am using it right now to send this message. It just went into fault mode. BTW There's no internal fuse for the under 800VA units which sucks.
 
I edited it. I shouldn't have said blown up.

So soft start or bigger victron? What do you think?
 
Oh I already have a 5000w inverter ready to go for future needs. But the idle watts is 45-65 watts. I don't use anything that would need that.

The bigger Victron is $500.

How about this for $35?


Soft Start Single Phase 110V Motor Soft Starter Module 110V 2KW 4KW 6KW 8KW For Water Pump Belt Conveyor Blower Motor​


What I don't understand is it has the same part numbers for the 220V version. .... Somebody who can speak aliexpress ... does this mean the 110v version is the same as the 220v version? In theory would the 220v work on 110v? Or it is more aliexpress garbage?
 
I am not sure if the compressor will like the low Voltage ramp up period that may be considered as brown out condition.
And as you can see, you have to activate that switch every time you want to compressor to run, that means you will have to get to the thermostat and wire it up to that switch terminals so the compressor will soft start every time when the compressor comes on.

1664760225447.png
 
Can the switch be by passed? Is the statement "Can be used directly by default" ... somehow could means I could just run a jumper and by pass the switch?

Your talking about running a relay wire from inside the unit out to the soft start? I'm wondering if I could just skip that by a jumper.

This isn't a smart freezer, it's the cheapest one with manual defrost. I think it was $120. I don't care if it breaks. The one it is replacing works fine. At one point, a bear ripped the top off that one and ate 200 pounds of frozen meat. Then it sat in a field for two years and got full of water. It ran outside again in an area with 30" of rain. I think I paid $150 for it. It still works, I just wanted another one. I can't actually destroy it, I've tried everything.
 
This is how it functions:
1) You can have that small switch in the ON position but you will switch the AC power to the module, so every time you power up the module it will perform compressor soft-start, when the fridge reach the temperature the compressor will stop but when the compressor comes back on again, thee soft-start will not happen unless you power cycle the module.
2) If you hard wire the AC input to the module, then you use that small switch to turn on the module and the compressor soft-start will perform, and when the fridge reach the temperature the compressor will stop but when the compressor comes back on again, the soft-start will not happen unless you power cycle the small switch to activate start function.

From the website:
There Are Two Ways To Use

1.Use Air Switch Or Circuit Breaker To Control The Main Power On And Off, When The Switch Is Closed, The Main Power Is Energized And The Soft Start Start Works

2.Use The Switch Terminal (Connect a Non-Power Contact Switch) On The Side Of The Starter To Control The Start And Stop ,The Switch Is Closed And The Soft Start Works, Stop When Disconnected (If R2 Type, Must Use This Way to Control The Starter)
 
I'm looking for similar approach as I want to have backup for a small freezer and small fridge in case of grid down for extended periods. Primary goal is to replace my 600W PSW Xantrex with as low a PSW inverter wattage as possible. Similar to your reasoning.

I posted yesterday on the MOES ATS thread but will capture here as well. If you are familiar with reading schematics I've attached one for a product I purchased yesterday on the 'Zon (type in their search window Salon soft start to find it). It uses Negative Temperature Coefficient devices (NTCs) which essentially act (pre-energized) like ~5-10 ohm (different values available) but go to very low resistance (~0.05 ohm) upon heating as current flows through. Though this device (per the vendor) is for audio amps I haven't figured out why it won't work on small compressors (like my freezer and mini fridge). But I will be hacking the compressor voltage supply to insert this device. First though will be just to plug in my minifridge from a warm state and then go from there. The cool thing about this circuit is there's a user selectable timer (1-10 seconds) that will then engage the onboard relay to essentially bypass those NTCs and thus minimize the ohmic losses/heat/wear-and-tear, etc on them. But yes, it will latch until disengaged and thus the hack at the compressor. This MIGHT work and it might be similar to that device you linked to...but as stated, that would need to be hacked at your compressor voltage. Also, if it doesn't have the 12 volt aspect could explain why it's either/or 120 V or 220 V. When I get it I will dink around and post results here. I'm a retired EE so (mostly) know what I'm doing. Before I discovered the MOES ATS I had designed, built and used (breadboarded) a LV cutoff but it didn't have adjustability as I just set it via resistor values to obtain a very low DoD as I was using my system primarily during the day and on FLA battery that I wanted to last a very long time.

BTW, the surge current (max) on fridge/freezers is called the Rotar Locked Current (RLA) and is generally stamped on the compressor. Impossible to find elsewhere as I've tried. Multiply that by 120 V and you'll find the inverter power needed...though I suspect it's the non-surge value listed as most inverter specs don't give surge durations. Also, you'll need that to work on top of whatever load you have running at any given time.
 

Attachments

  • soft start schematic.jpg
    soft start schematic.jpg
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Wow! There's all sorts of cool people here!

That's really interesting SunnySoCal. Please update us on what you're doing.

I went with the 1200VA victron. I haven't received it yet, but my plan is to have that in parallel with my existing 375VA. And the 1200VA only on the freezer chest, but in eco-mode. 3 watts standby, up to 2000W surge, and on only 20 minutes every hour with an average of 25wh per hour.
 
Get the AIMS 3000 watt PSW inverter) 6000 watt surge) for $450.00. 12 watt idle consumption.
 
Checkthisout said:
Get the AIMS 3000 watt PSW inverter) 6000 watt surge) for $450.00. 12 watt idle consumption.
Click to expand...

Oh sorry I forgot to mention I'm at 48v, cheapest I could find AIMS inverter near that size was over $1k. (unless you know something I don't). 48v has been a blessing and a curse at the same time. Expensive gear, but faster charge rate and smaller wires. Slight increase in safety.
 
offgriddave said:
Oh sorry I forgot to mention I'm at 48v, cheapest I could find AIMS inverter near that size was over $1k. (unless you know something I don't). 48v has been a blessing and a curse at the same time. Expensive gear, but faster charge rate and smaller wires. Slight increase in safety.
Click to expand...

My bad. Why has everyone gone to 48V? Just to save a hundred bucks on copper wire that goes from the battery bank to the inverter?
 
Checkthisout said:
My bad. Why has everyone gone to 48V? Just to save a hundred bucks on copper wire that goes from the battery bank to the inverter?
Click to expand...

For me, not just the wire size, but a 100 Amp 12v charger (very expensive and large wiring required) is only 1200watts, vs what I have 33 amp @ 48v is 1500watts (still expensive, but a lot safer because of the wiring size). I have two extra chargers to push that to 60+ amps but I haven't bothered to install them because I'm going to hydro here in a month.

The real zinger is the solar charge controller. The difference in the price is almost the same, but the charge ability is 4x.
 
offgriddave said:
For me, not just the wire size, but a 100 Amp 12v charger (very expensive and large wiring required) is only 1200watts, vs what I have 33 amp @ 48v is 1500watts (still expensive, but a lot safer because of the wiring size). I have two extra chargers to push that to 60+ amps but I haven't bothered to install them because I'm going to hydro here in a month.

The real zinger is the solar charge controller. The difference in the price is almost the same, but the charge ability is 4x.
Click to expand...

Yeah I guess I forgot about the CC if you have a big system.
 
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