New to Lithium batteries  ,  Gents Running 24v Lithium systems (myself 2000w) on a 105ah Lithium battery,  on a small load around 13-15% , what does your battery voltage drop to after let's say 15min or 30min into load shedding...
My Float is set at 27.0v , and Boost at 27.6V (1min)  , batteries are always full...
On taking load , will it go down to around 26.2V and stay there , or does it hover around the higher 26V level...or can I have an average 
on load around 15% capacity from anyone? On a good 65% (5min test) load pull it will drop down to 25.6v/25.7v and come back up to 26.2V on let's say 15% load on 2000w 

This is a Lithium battery pack that was build for me , not 100% sure on the exact voltages the batteries should be charged at , so we went for 27.0 Float , 27.6 boost for 1min
Thanks

Edited August 28, 20232 yr by TERS1983

2 hours ago, TERS1983 said:

New to Lithium batteries  ,  Gents Running 24v Lithium systems (myself 2000w) on a 105ah Lithium battery,  on a small load around 13-15% , what does your battery voltage drop to after let's say 15min or 30min into load shedding...
My Float is set at 27.0v , and Boost at 27.6V (1min)  , batteries are always full...
On taking load , will it go down to around 26.2V and stay there , or does it hover around the higher 26V level...or can I have an average 
on load around 15% capacity from anyone? On a good 65% (5min test) load pull it will drop down to 25.6v/25.7v and come back up to 26.2V on let's say 15% load on 2000w 

This is a Lithium battery pack that was build for me , not 100% sure on the exact voltages the batteries should be charged at , so we went for 27.0 Float , 27.6 boost for 1min
Thanks

Nothing wrong with your voltages. I just think your boost could be a lot longer than 1min. My 12V lithiums are normally around 13.2V each. If I draw 1500W then they do go down to 25.4V but like yours under lower say 200W they just bounce back. 

Float is not important if you have the boost a longer time at about 27.4V. In order to balance via the BMS you might want to charge up to 28.4V from time to time. This will depend on what make of BMS you are using. Some DIY BMS can balance at low levels. 

Your volts sound about right .

Like scorp 007 said it good to charge from time to time at 28.4v to help balance the cels 

Tested I have done on bms even the once that balance at low volts the bms  will  balance at 27v but the moment I pushed charge to 28.4v the cels went out of balance .

But be careful if you do charge up to 28.4 from time to time to monitor the cels so not to over volts one or 2 cels . Some times you mite have to manually balance the cels . 

I float charge at 27.4 and bulk charge at 28v 

8 hours ago, Scorp007 said:

Nothing wrong with your voltages. I just think your boost could be a lot longer than 1min. My 12V lithiums are normally around 13.2V each. If I draw 1500W then they do go down to 25.4V but like yours under lower say 200W they just bounce back. 

Float is not important if you have the boost a longer time at about 27.4V. In order to balance via the BMS you might want to charge up to 28.4V from time to time. This will depend on what make of BMS you are using. Some DIY BMS can balance at low levels. 

Thanks,  would you say I bump the boort up to 30min?

6 hours ago, GMAC said:

Your volts sound about right .

Like scorp 007 said it good to charge from time to time at 28.4v to help balance the cels 

Tested I have done on bms even the once that balance at low volts the bms  will  balance at 27v but the moment I pushed charge to 28.4v the cels went out of balance .

But be careful if you do charge up to 28.4 from time to time to monitor the cels so not to over volts one or 2 cels . Some times you mite have to manually balance the cels . 

I float charge at 27.4 and bulk charge at 28v 

Thanks , and maybe bump the boost to 30min?

11 hours ago, TERS1983 said:

New to Lithium batteries  ,  Gents Running 24v Lithium systems (myself 2000w) on a 105ah Lithium battery,  on a small load around 13-15% , what does your battery voltage drop to after let's say 15min or 30min into load shedding...
My Float is set at 27.0v , and Boost at 27.6V (1min)  , batteries are always full...
On taking load , will it go down to around 26.2V and stay there , or does it hover around the higher 26V level...or can I have an average 
on load around 15% capacity from anyone? On a good 65% (5min test) load pull it will drop down to 25.6v/25.7v and come back up to 26.2V on let's say 15% load on 2000w 

This is a Lithium battery pack that was build for me , not 100% sure on the exact voltages the batteries should be charged at , so we went for 27.0 Float , 27.6 boost for 1min
Thanks

Keep in Mind , this battery pack didn't come with a BMS , Will only be added later on , funds were limited at the time.

49 minutes ago, TERS1983 said:

Thanks,  would you say I bump the boort up to 30min?

Yes you can. Can't you set a voltage when it would switch from boost to float instead of a time value? 

1 hour ago, Scorp007 said:

Yes you can. Can't you set a voltage when it would switch from boost to float instead of a time value? 

As I understand the Microcare inverter,  it only has settings for Float & Boost & cut-off that one adjust,  so i presume it boosts the voltage to the setting selected for the time selected and then after the time selected it will go to float 

21 minutes ago, TERS1983 said:

As I understand the Microcare inverter,  it only has settings for Float & Boost & cut-off that one adjust,  so i presume it boosts the voltage to the setting selected for the time selected and then after the time selected it will go to float 

Have you got a BMS to protect those cells from under and over voltage? 

27 minutes ago, Scorp007 said:

Have you got a BMS to protect those cells from under and over voltage? 

No , not at this stage , funds was limited at the time.

37 minutes ago, TERS1983 said:

No , not at this stage , funds was limited at the time.

BMS does provide a high reward vs risk😀

46 minutes ago, Scorp007 said:

BMS does provide a high reward vs risk😀

Yes Sir , I do understand that.

It is on the bucket list.

37 minutes ago, TERS1983 said:

Yes Sir , I do understand that.

It is on the bucket list.

I'm no Sir as I don't wear a tie 😀

1 hour ago, Scorp007 said:

I'm no Sir as I don't wear a tie 😀

lol 

I am currently looking at the Daly 8s 60A BMS 

As I only charge my battery at 50% (20%) 

 

5 minutes ago, TERS1983 said:

lol 

I am currently looking at the Daly 8s 60A BMS 

As I only charge my battery at 50% (20%) 

 

My call will be the JK 8-20 cells in 100A coming with Bluetooth APP. 

 

55 minutes ago, Scorp007 said:

My call will be the JK 8-20 cells in 100A coming with Bluetooth APP. 

 

yes, 1000 time this. 

and it has a 600ma active balancer

The JK BMS's seem to work well and as advertised, I would suggest a JK as well.

I purchased 2x JK BMS's for the batteries I will be building for myself.

 

Running the battery without a BMS is not ideal or safe, although it seems you already know this.

On 2023/08/29 at 12:51 PM, Scorp007 said:

My call will be the JK 8-20 cells in 100A coming with Bluetooth APP. 

@TERS1983 I would second @Scorp007on that call... 2000W@24V=83A... a 60A BMS will be too small, 24V systems run high currents.

18 minutes ago, jumper said:

@TERS1983 I would second @Scorp007on that call... 2000W@24V=83A... a 60A BMS will be too small, 24V systems run high currents.

The problem remains that we can work out what load we intend connecting and by accident someone else might plug in a high load. It has happened with me that I forget my transfer switch is still on inverter.. 

On the other hand the lower current BMS if working correct should switch off at about 60A but the risk is that it might fail as well as all electrical goods can. 

Rather a 100A used at 60A and idling..