Hi, need some assistance, I have a Mercer 3Kva inverter, with 2 x Vision 12V Lithium 200Ah ( SP12-200 ) , The charging light is constantly flashing and I find that the batteries dont last when we have multiple times of loadshedding, are my settings incorrect

please assist 

Thank you 

Mahendra 

 

 

On 2022/12/08 at 8:08 AM, Mahendra said:

Hi, need some assistance, I have a Mercer 3Kva inverter, with 2 x Vision 12V Lithium 200Ah ( SP12-200 ) , The charging light is constantly flashing and I find that the batteries dont last when we have multiple times of loadshedding, are my settings incorrect

please assist 

Thank you 

Mahendra 

Hi Mahendra, we would need more information in order to assist you as there could be many possibilities.

What loads are you running during loadshedding?

What are your current settings for bulk/absorb and float and what is the cutoff set to?

Do you have any solar panels?

It could be incorrect charge settings or the battery could be too small or not getting enough time to charge between load shedding sessions.

On 2022/12/08 at 4:08 PM, Mahendra said:

are my settings incorrect

If you're using default settings, then yes they will be incorrect. As above, we need more information.

Hi … thanks for the prompt responses 

all default settings the installer says “no settings needed “ 

my load is low when I check hovers between 10-15% … have 2 fridges, my house lights (LED) and my TV and WiFi router 

no solar panels installed 

thank you 

 

46 minutes ago, Mahendra said:

Hi … thanks for the prompt responses 

all default settings the installer says “no settings needed “ 

my load is low when I check hovers between 10-15% … have 2 fridges, my house lights (LED) and my TV and WiFi router 

no solar panels installed 

thank you 

 

My 1st call is get another installer. All lithiums one need to do changes to the battery settings. To start off you need to go to USR to be able to adjust the settings. You cannot just use the default lead acid settings......... Accept what @Coulomb

Mentioned. 

It's possible your lithiums have not been balanced as the charge voltage has been too low if you use lead acid settings. 

Your current default setting to cutt off should be 21V.This means the lithiums are totally discharged. They would thus take long to charge due to the current high frequency of LS. To make things worse as the are 200Ah it will take so much longer to charge to a high SOC for the next LS period. I like 24.5V for this setting. 

Edited December 11, 20223 yr by Scorp007

On 2022/12/08 at 8:08 AM, Mahendra said:

Vision 12V Lithium 200Ah ( SP12-200 )

From the details I can find on your battery it can be charged at 50A, but it is recommended to charge at 25A. You need to check your settings to make sure the max charge amps is set to 25A and grid charge is also set to 25A... you can increase this for bouts of heavy loadshedding, but I would mostly leave it at 25A to save the battery or load shedding will kill it quickly.

Max discharge is 100A, so that is approx 2400W at 24V.

The battery is 4S2P, so with 2 in series you should be able to safely charge the battery to 28V bulk/absorb and float at 27V... write down what your current settings are and compare them before you change anything.

End of discharge voltage is 11,2V, so for 2 in series you can set the cutoff to 22.5V. If your current setting is higher then you will get longer runtime just from this alone.

https://www.batteryguru.com.au/product/bvllfpsp12-200/

Thank you much appreciated 

I see on the front of the battery, it says to charge to 13.6 - 13.8 V. That seems on the low side to me, although I personally charge my LFP to 13.8 V per 4 cells. So probably reduce the bulk/absorb voltage to 27.6 V. I personally float mine at 26.85 V per 8 cells, so you could use 26.9 V.