Charging individual lithium04 battery packs in a bank

spacebass

I have 4 12v lithium 04  pre made plastic battery packs in a 48 volt bank can I charge each battery separately with the supplied 12volt charger obviously using the charge socket on each battery while connected as a bank or do I have to separate them. 
I have just run them overnight and they ran out of juice any tips on getting them charged up ?
The individual batteries are not at the same state of depletion . Do I need s BMS type device to balance the 4 battery packs if so what?
I also have a 24 volt system that I intend to switch to on the depletion of the 48 volt system (I hope) but have not put the switch in yet. I do that tomorrow .
Thank You.

BB.

What is the Amp*Hour ratings of your batteries? And what are you overnight loads (Watts/Amps@48 volts/etc.)?

Are those batteries (wth some sort of BMS) rated to run 4x in series @ 48 volts?

-Bill

spacebass

BB. said:

What is the Amp*Hour ratings of your batteries? And what are you overnight loads (Watts/Amps@48 volts/etc.)?

Are those batteries (wth some sort of BMS) rated to run 4x in series @ 48 volts?

-Bill

Hi Bill ,
The batteries are 120ah, it says on the battery has advanced protection (in Chinese).
I don't know if they are 'rated to run in series at 48 volts' , I have run two pairs at 24 volts for a couple of weeks with no problems. One pair runs my big fridge for 14 hours.
I am measuring tonight 12 hours main load which is 2 inverter fridge freezers one 7.7 cu ft one 14.2 cu feet. I also have two fans about 28'watts each and modem / router internet.

I will post tomorrow consumption of two fridges 12 hours overnight

Thank You.

mcgivor

Without knowing the chemistry it's impossible to answer a question with such vague details. The purpose of a BMS is to keep cells within a battery (a group of cells in series ) within  safe parameters, there is no BMS which monitors batteries connected in series, parallel or otherwise,  each would have its individual BMS unless it an engineered system with communication capabilities.

Be very careful when dealing with lithium batteries, some are very unforgiving should one venture outside safe parameters, if in doubt, don't, is the best advice I could offer at this stage.

Raj174

I would advise charging them individually to 100% then connect them in the series configuration. It's important that they all have very close to equal voltage.

spacebass

Raj174 said:

I would advise charging them individually to 100% then connect them in the series configuration. It's important that they all have very close to equal voltage.

I have been doing that so far and will continue Thank You.

spacebass

mcgivor said:

Without knowing the chemistry it's impossible to answer a question with such vague details. The purpose of a BMS is to keep cells within a battery (a group of cells in series ) within  safe parameters, there is no BMS which monitors batteries connected in series, parallel or otherwise,  each would have its individual BMS unless it an engineered system with communication capabilities.

Be very careful when dealing with lithium batteries, some are very unforgiving should one venture outside safe parameters, if in doubt, don't, is the best advice I could offer at this stage.

The question has become redundant as I have just ordered a 48 volt 5amp Lp04 charger .

As. a matter of nterest my 2 inverter fridge freezers 7.9 and 14.2 cu. ft used 11.5 kWh over 7 days.