Hi - I am unable to charge batteries 100% from grid overnight in 4 hour low rate period. Solar installer saying it is because house has low voltage supply but doesn’t make sense as we get the same charge of batteries (70%) when we turn everything off in house overnight as when we have a heavy night with heat pump. Have noticed the batteries will only charge by 3kw at any point and will only discharge at 3kw at any point, whatever else is happening. What might the problem be? The inverter? Many thanks
Batteries not fully charging
- Thread starter AndrewH71
- Start date
Daddy Tanuki
Solar Wizard
guaranteed its a setting thing. what inverter charger or what charger? list model and all your settings size of battery bank etc.
I had a company in to set it up so can’t tell you settings!! But it’s a growatt SPH 6000 and I have three 6.25kwh batteries. When I had two they fully charged, three get to around 70% so it’s like I never added the third battery. Where can I find settings ?
Thanks so much
Thanks so much
Kenny_
Solar Addict
This may not be much help, but after a couple of months I've not been able to 'fully' charge my 5 rack mount batteries from solar only. I have been able to do so a couple of times from the grid through the Sungold 10k inverter. I've been able to get most of the 5 up near 100% SOC but even via grid one battery is still only hitting 99% SOC. ... and I know that SOC is not necessarily a good/reliable method of evaluating so am not too concerned at this point.
Steve_S
Offgrid Cabineer, N.E. Ontario, Canada
Pure & absolute donkey pucks ! That shmuck is a fool, do not engage further!
I would not also completely doubt his work and have it rechecked by a real & credibly qualified person. Sorry but if someone bullshits like that, I would doubt everything else they say. That is an instant 3-Strikes your out !
Charger is capable of 60A Charge which is not bad and can service your two batteries.
You are describing a Standard Classic Case of overly aggressive charging parameters which sadly is ALL TOO COMMON ! We see this all the time, we suggest a proper profile (due to yrs of exp) and then get argued with about it by those that don;t know better. So one more time for a New Member.
1) a 48V system (legacy rating) is actually 51.2V nominal
2) LFP like ALL battery chemistries has TWO Voltage Ranges.
-- The Allowable Range is where the battery cells are safe where no harm more damage is incurred, this is from 2.500 to 3.650 volts per cell.
-- The Working Voltage Range which is where the Deliverable Amp Hours reside. This is from 3.000-3.400 Volts per cell. A VERY flat curve!
! Many companies like to push well into the Allowable range and that causes issues such as a runner cell hitting Hi Volt Disconnect which instantly stops charging on the battery pack. This can also reduce the entire bank capacity by becoming a "throttle" as the lowest cell rules the pack.
A proper 48V Charging Profile is below:
Absorb: 55.2V for 45 minutes (3.45vpc) (some call this boost) * never actually runs the full 45mins because of EndAmps/Tailcurrent.
Equalize: OFF
Float 55.0V (3.437vpc)
MIn Volts: 42.2V (2.650vpc)
Max Volts: 57.2V (3.575vpc)
Rebulk Voltage: 51.2V (3.200vpc)
End Amps: #.#A (*1) (** Allows for full Saturation at set Float Voltage)
(*1): End Amps is calculated IE: (100AH X 0.05 = 5A or 280AH X 0.05 = 14A.
EndAmps = TailCurrent The term varies with companies, it is the same thing.
Coulumbic Efficiency / Battery Status Meter Efficiency for LFP = 99%.
This gets the bank charged to full with high amps (Constant Current - Constant Voltage) and then float (Constant Voltage - Variable Current) tops off so the cells are at 3.47Vpc.
* Do Not forget to adjust for Voltage Offsets between Actual Voltage @ Battery Terminal & at Solar Controller.
Very Special NOTE: Floating & Saturating to 3.437vpc, accounts for the Voltage Settling post Charge of any kind which actually brings the cells to just below 3.400Vpc.
One of my handy references for you to have handy, download &/OR print.
Daddy Tanuki
Solar Wizard
sorry not a growatt person (nor AIO in general) but there are plenty here. this is the data they will need to help you. does it stop at 70% exactly? or approximately? exactly, once againj a setting issue of some sort. Approximately and it varies each day IE mon 69%, tues 73%, wed 65%, thur 70% then you do not have enough solar to fill them up all the way.
just spitballing but thats my ¥2.8 worth.
just spitballing but thats my ¥2.8 worth.
Thanks to both Daddy and Steve.
Steve - I’m not at all technical so don’t understand most of what you are saying. However, we have three batteries, not two, totalling 19.25 kWh. And they don’t stop charging at any point. They are just limited to 3kw import and 3kw export. I think the inverter won’t allow any more either way. I’m confirming this with Growatt. In which case, the system has been designed badly and this guy knows it and is lying to me. He’s trying to get me to go on a different tariff to get more hours of cheap rates instead of dealing with it.
Either way, I now don’t know whether (a) I am right and (b) the set up is damaging the batteries as you have suggested.
Are there companies that can come in to independently check the set up without trying to sell kit?
Steve - I’m not at all technical so don’t understand most of what you are saying. However, we have three batteries, not two, totalling 19.25 kWh. And they don’t stop charging at any point. They are just limited to 3kw import and 3kw export. I think the inverter won’t allow any more either way. I’m confirming this with Growatt. In which case, the system has been designed badly and this guy knows it and is lying to me. He’s trying to get me to go on a different tariff to get more hours of cheap rates instead of dealing with it.
Either way, I now don’t know whether (a) I am right and (b) the set up is damaging the batteries as you have suggested.
Are there companies that can come in to independently check the set up without trying to sell kit?
Varies a little bit each day. If there is some left in battery at end of day, it goes above. I have had it up to 100% because there was 30% still in there when started charging. It just feels like the inverter won’t allow more than 3kw at any point so never has a chance to fill batteries in 4hour period.
I don’t think I have articulated the issue well enough. Winter here in the uk at the moment so solar isn’t giving me much at all. I am trying to fill my batteries from grid in a 4 hour cheap rate period but can only get them to 70% in that time. I could keep charging and get them to 100% if I just used expensive electricity rate but that defeats the purpose of the batteries in the winter.
Daddy Tanuki
Solar Wizard
depends upon how many panels you have. but if it is being as you said "They are just limited to 3kw import and 3kw export. I think the inverter won’t allow any more either way. I’m confirming this with Growatt. " then its a setting thing, as you normally can drawn down to the LBCO and or fully charge as needed.
settings my man...
whoa thats differnt. so i just looked at the photos again. thats all you controller in the growatt unit can handle. 3000 watts max power. that times x hours gives you how much you can theoretically put in.
Thought so. So I’ll need a different inverter?
And, in your opinion, would the solar/batt installer have known this … and have been bullshitting me the whole time?
Daddy Tanuki
Solar Wizard
so 3 k max, you need to adjust it so that it can put more in. that may casue you to try and fill the battery during a high cost or high tariff time. you might simply need a larger unit that can charge faster. once again need to wait until some of the growatt guru's chime in. basically you can set that unit to cahrge, or not charge from XX:XX until XX:XX to avoid charging during high tariff times to save you money if your electric companies charges different rates for different times of the day. your installer may have (may have) set it to avoid these times and you might not have enough time to recahrge it...settings really matter.
Daddy Tanuki
Solar Wizard
possibly, you could also just buy and EG4 battery charger and plug that in to top them off.
and no comment on the installer as I have no clue what you know or do not know about solar, nor what you both spoke of.
Sounds like :
1. Voltage needs raising on float setting. You need to learn how to go thru the settings and write down what everything is set to. Then we can suggest what to change it to.
2. Max amps allowed for charging is set to low. Again need those settings to suggest what to set it to.
3. It may be set to only charge from solar and not the grid. Again another need for the current settings.
1. Voltage needs raising on float setting. You need to learn how to go thru the settings and write down what everything is set to. Then we can suggest what to change it to.
2. Max amps allowed for charging is set to low. Again need those settings to suggest what to set it to.
3. It may be set to only charge from solar and not the grid. Again another need for the current settings.
Daddy Tanuki
Solar Wizard
you got him Buddy? grow watt not my thing just trying to spitball with him
I don't have a growatt either but I have looked up so many growatt questions lately that I remember the settings are similar to my tp6048 and the stuff I posted will cause mine to act like his is why I suggested that.
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