What’s the best inverter?

[ShaneT]

Hi all,
I have a fairly small system, running 8 3.2V LifePo4 280amp hour batteries. I’m only running a few lights a refrigerator and a freezer. Everything has been working great, but I recently upgraded my freezer to an 18.5 cu. ft. My inverter is 3000 watt. I have the freezer on a timer to shut off at night and save batteries. But in the morning when it try’s to kick on the inverter alarms.
Is it possible that I have an inverter with enough watts butt the surge is to much for it on the start up?

 

[John Frum]

What system voltage?
What size wires between the inverter and the battery?
What BMS are you using?

 

[John Frum]

The "best inverter" depends on your requirements.

 

[sunshine_eggo]

Hi all,
I have a fairly small system, running 8 3.2V LifePo4 280amp hour batteries

8 cells arranged into an 8S 24V battery?

. I’m only running a few lights a refrigerator and a freezer. Everything has been working great, but I recently upgraded my freezer to an 18.5 cu. ft. My inverter is 3000 watt. I have the freezer on a timer to shut off at night and save batteries. But in the morning when it try’s to kick on the inverter alarms.
Is it possible that I have an inverter with enough watts butt the surge is to much for it on the start up?

Yes. Very common particularly with cheap inverters. If a 3000W inverter can be easily carried with one hand, it's a "high frequency" unit and doesn't have a meaningful surge capability.

Is your inverter pure sine wave? If it's modified sine wave, electric motors tend to pull more amps than they otherwise would.

What @smoothJoey is getting at is your wires between the battery and inverter may be inadequate (or you have poor connections at the terminals) causing the battery voltage to drop way off when the load is applied.

 

[John Frum]

@sunshine_eggo and I are working on a new 2 prong approach to supporting users.
Coherent cop, Confusing cop.
Its more humane than our previous methods.

 

[ShaneT]

Hi,
It’s a 24v system.
2gauge wires form the battery to inverter
Using the 100A 8s 24v XiaoxiangBMS

 

[sunshine_eggo]

@sunshine_eggo and I are working on a new 2 prong approach to supporting users.
Coherent cop, Confusing cop.

Are you implying that either of us is coherent?

Its more humane than our previous methods.

LOL

Hi,
It’s a 24v system.
2gauge wires form the battery to inverter
Using the 100A 8s 24v XiaoxiangBMS

Pure sine wave or modified?
Heavy as crap or easy to move?
Did you check that all your connections between battery and inverter are properly torqued?

 

[John Frum]

Hi,
It’s a 24v system.
2gauge wires form the battery to inverter
Using the 100A 8s 24v XiaoxiangBMS

3000 ac watts / .85 conversion factor / 24 volts low cutoff = 147.058823529 service amps.
You wire is adequate but your bms is significantly undersized for the inverter.

 

[ShaneT]

8 cells arranged into an 8S 24V battery?



Yes. Very common particularly with cheap inverters. If a 3000W inverter can be easily carried with one hand, it's a "high frequency" unit and doesn't have a meaningful surge capability.

Is your inverter pure sine wave? If it's modified sine wave, electric motors tend to pull more amps than they otherwise would.

What @smoothJoey is getting at is your wires between the battery and inverter may be inadequate (or you have poor connections at the terminals) causing the battery voltage to drop way off when the load is applied.

Yes it’s a pure sine.

 

[ShaneT]

Are you implying that either of us is coherent?



LOL



Pure sine wave or modified?
Heavy as crap or easy to move?
Did you check that all your connections between battery and inverter are properly torqued?

Pure sine.

 

[ShaneT]

How do I know the correct torque?

 

[MurphyGuy]

Get an Outback inverter.

 

[ShaneT]

3000 ac watts / .85 conversion factor / 24 volts low cutoff = 147.058823529 service amps.
You wire is adequate but your bms is significantly undersized for the inverter.

So my inverter isn’t the problem then?

 

[ShaneT]

So my inverter isn’t the problem then?

So we need more batteries?

 

[Supervstech]

Pure sine.

How heavy is the inverter?

The freezer shouldn't pull much startup amps, look on the data plate to see LRA...thats what your inverter has to have.
280Ah 24V should be 7KWh... so unless tou have a LOT draining the system you should be fine.

 

[John Frum]

So my inverter isn’t the problem then?

It still could be.
Is the inverter alarm the "low voltage" alarm?
Lets try to rule out the dc voltage at the inverter dropping to low.

 

[Supervstech]

How much solar do you have charging? What voltage do the batteries reach during the day?

 

[ShaneT]

So my inverter isn’t the problem then?

It still could be.
Is the inverter alarm the "low voltage" alarm?
Lets try to rule out the dc voltage at the inverter dropping to low.

Yes, when the freezer (on a timer) tries to kick on in the morning the inverter sounds an audible alarm and a red light comes on.

 

[John Frum]

Yes, when the freezer (on a timer) tries to kick on in the morning the inverter sounds an audible alarm and a red light comes on.

What does the red light signify?
It could be low voltage disconnect or it could be overload or it could be something else.

 

[ShaneT]

How much solar do you have charging? What voltage do the batteries reach during the day?

We have one string of 3 of 280w panels, they reach around 25 volts, showing 100% on the charge controller soon after the sun is up. No issues running things as long as there is sun. But the startup in the morning of the freezer on the timer is when we have the issue.