Charging LiFePO4 batteries through Growatt 24V 3000W

[Awsmits]

So, I have two 24V banks of LiFePO4 batteries on my boat, connected to a Growatt “all-in-one” 24 V 3000W inverter/charger/solar controller. As many have noted, the idle current draw of the Growatt when it is ON is considerable, so I like to leave it off, as I am away from the boat for days.

I have learned that I can charge my LiFePO4 battery banks using shore power through the Growatt with the Growatt turned OFF. So, that’s good. But, having yet to install my solar panels (planning on three 370W panels), I don’t know whether the solar controller will change the LiFePO4 batteries with the Growatt OFF. Anyone tried this or can tell me if that works or not? Obviously I’ll need to turn the Growatt ON to get the inverter to convert DC to AC. Thanks!

 

[Awsmits]

I meant to type “solar controller will charge the LiFePO4 batteries”

 

[Rednecktek]

So, I have two 24V banks of LiFePO4 batteries on my boat, connected to a Growatt “all-in-one” 24 V 3000W inverter/charger/solar controller. As many have noted, the idle current draw of the Growatt when it is ON is considerable, so I like to leave it off, as I am away from the boat for days.

I have learned that I can charge my LiFePO4 battery banks using shore power through the Growatt with the Growatt turned OFF. So, that’s good. But, having yet to install my solar panels (planning on three 370W panels), I don’t know whether the solar controller will change the LiFePO4 batteries with the Growatt OFF. Anyone tried this or can tell me if that works or not? Obviously I’ll need to turn the Growatt ON to get the inverter to convert DC to AC. Thanks!

There was another thread where one of our members was nice enough to try this and what he found was:

Growatt Off + Solar = Charging
Growatt On + Utility + Load = Charging
Growatt Off + Utility = NO charging

 

[DThames]

FYI, I am planning to do some more testing as soon as I can wire in a plug to jumper my house AC over to my generator input for the emergency inverter system. According to the manual, it should charge from the grid even if the inverter is "off" but the unit must be in "standby" mode. Black display is not standby, so need to see if AC power in the input will wake up the internal functions and light the screen the way that PV input does.

 

[Awsmits]

When my Growatt is off, meaning the rocker switch on the bottom is off, the display screen is dark. If I then apply AC in to the unit, the display wakes up, gives a long beep, and begins to charge the batteries (display shows that diagrammatic). So that works.

Based on the thread Rednecktec provided, it appears several Growatt users can get the unit to charge batteries via solar even when the Growatt if off. That’s good news for me, and others. I have not played around with the Power-Saving mode.

 

[Samcat]

What is the model number? I do see there are different models with same model number but one of them are specifically designed for US suppliers. So which one is it and is it bought overseas or from US supplier?

 

[Awsmits]

The one I have is Growatt 24V SPF 3000TL LVM – 3kW, purchased through watts247.com. I don’t know if it’s the “US” version.

 

[Samcat]

The one I have is Growatt 24V SPF 3000TL LVM – 3kW, purchased through watts247.com. I don’t know if it’s the “US” version.

Thank you.

 

[Herb]

Makes sense to me, the MPPT charger controller when supplied with a current should start working/charging if is enabled. If the Growatt is set to charge from solar then it should also. The DC to AC and inverter should work only when the Growatt power is on and the AC to DC charger should work when the power is on. Correct? I keep mine off unless I want to run loads, since I don't use it everyday. So a little off topic, according to Growatt the unit don't have a built in shunt, and you must have batteries with communications capabilities to be able monitor state of charge, can anyone add to this? So unless you have one of those server type batteries with communications at 1500 USD a pop, you can't monitor the SOC of just any regular LiPO4 battery? I do have a Smart Shunt, which I had from a previous setup, did I get lucky? All of a sudden the AIO unit is not AIO after all!

 

[DThames]

Makes sense to me, the MPPT charger controller when supplied with a current should start working/charging if is enabled. If the Growatt is set to charge from solar then it should also. The DC to AC and inverter should work only when the Growatt power is on and the AC to DC charger should work when the power is on. Correct? I keep mine off unless I want to run loads, since I don't use it everyday. So a little off topic, according to Growatt the unit don't have a built in shunt, and you must have batteries with communications capabilities to be able monitor state of charge, can anyone add to this? So unless you have one of those server type batteries with communications at 1500 USD a pop, you can't monitor the SOC of just any regular LiPO4 battery? I do have a Smart Shunt, which I had from a previous setup, did I get lucky? All of a sudden the AIO unit is not AIO after all!

Just an added note, my Growatt will not charge from generator until Growatt logic thinks the battery is less than 100%. According to the log, the battery is 100, 100, 100, then boom 75% and AC charging only starts then. Smartshunt is great.

 

[Herb]

OK got you, I don't own a generator but, do you hook it up to the AC input? Is it an inverter also?

 

[Rednecktek]

OK got you, I don't own a generator but, do you hook it up to the AC input? Is it an inverter also?

Yes. The generator or grid power in would go to the AC Inputs underneath.

Inverter converts DC from the batteries or solar into AC output to your household stuff. So yes, it's an inverter as well.

What I suspect you're thinking of is a Rectifier which changes generator or grid AC into DC voltage to put into the batteries.

 

[Herb]

Ohh, I was thinking that the generator you had converter DC to AC? But yeah a rectifier rectify DC into AC Correct? I has been a while since I retired but I think that's what is does? Something about half wave and full wave rectifiers and some ripples I recall.

 

[DThames]

Yes. The generator or grid power in would go to the AC Inputs underneath.

Inverter converts DC from the batteries or solar into AC output to your household stuff. So yes, it's an inverter as well.

What I suspect you're thinking of is a Rectifier which changes generator or grid AC into DC voltage to put into the batteries.

OK got you, I don't own a generator but, do you hook it up to the AC input? Is it an inverter also?

I said generator because I am not sure if AC charging off the grid behaves exactly the same or not but the generator is connect to the AC Input just like the grid would be. I expect charging off the line would be the same unless the Growatt can somehow sense a generator is different.

 

[DThames]

Ohh, I was thinking that the generator you had converter DC to AC? But yeah a rectifier rectify DC into AC Correct? I has been a while since I retired but I think that's what is does? Something about half wave and full wave rectifiers and some ripples I recall.

Generators can output DC or AC (depending on what they are designed to do). I guess some might call an AC unit an alternator.

 

[Rednecktek]

Ohh, I was thinking that the generator you had converter DC to AC? But yeah a rectifier rectify DC into AC Correct? I has been a while since I retired but I think that's what is does? Something about half wave and full wave rectifiers and some ripples I recall.

Backwards there...

Inverter goes from DC source to AC output.
Rectifier takes AC and turns it into DC.
A generator creates AC, that AC is RECTIFIED to DC going into the batteries. After that the battery DC is INVERTED into AC output to run the coffee maker and MargaritaMaster-9000.

 

[Herb]

Got you! Hey do you think is possible to add an active balancer to some Chins batteries I have, I got 8, 12v each 100Ah and their voltage drift, not too bad but i know it gets worse with each cycle, but do you know if this is possible, normally it takes 4 days to do it the usual way as recommended by Chins and is tedious, their batteries BMS don't do balancing according to them sadly.

 

[DThames]

Got you! Hey do you think is possible to add an active balancer to some Chins batteries I have, I got 8, 12v each 100Ah and their voltage drift, not too bad but i know it gets worse with each cycle, but do you know if this is possible, normally it takes 4 days to do it the usual way as recommended by Chins and is tedious, their batteries BMS don't do balancing according to them sadly.

Can you access the connections between the cells? I am not familiar with how you might get inside the battery case.

 

[Herb]

Can you access the connections between the cells? I am not familiar with how you might get inside the battery case.

Unless you take the top off, maybe, Will took one apart and dang it took some cutting and hammering, and then some, LOL, so not sure if I want to do that since it will void their warranty. I was thinking about an external balancer just to bring the entire battery of 4 cells voltage closer to the other battery voltage, to be honest I'm not too worry, but just wondering if one of those external battery balancers would help, just trying to avoid having to take the bank apart to re-configure, I hate to drop a wrench or something the more I mess around with these batteries. I think it will put some wear and tear on the terminals, I do torque them to spec, since my elbow was calibrated not long ago!

 

[DThames]

Unless you take the top off, maybe, Will took one apart and dang it took some cutting and hammering, and then some, LOL, so not sure if I want to do that since it will void their warranty. I was thinking about an external balancer just to bring the entire battery of 4 cells voltage closer to the other battery voltage, to be honest I'm not too worry, but just wondering if one of those external battery balancers would help, just trying to avoid having to take the bank apart to re-configure, I hate to drop a wrench or something the more I mess around with these batteries. I think it will put some wear and tear on the terminals, I do torque them to spec, since my elbow was calibrated not long ago!

You can buy some low end battery discharge protection devices. For your 12v battery that is higher than its buddy, set the protection device to the target voltage and then put a load on that battery that he protection device can then turn off. So it would drain one down to the voltage of the other one. Are any of your batteries in parallel?