Hi, hoping someone can help me setup my Daly BMS with my 24V Mecer (Axpert) inverter/solar charger (SOL-I-AX-3MPLUS24).

I bought this last week, but didn't come with any documentation other than a very basic connection diagram: https://lithiumbatteriessa.co.za/collections/diy-kit/products/24v-200ah-8s-daly-smart-100a-bms-lifepo4-lithium-iron-phosphate-diy-kit-new-a-grade-cells

To start with I plan to take the batteries, check their voltages and pair up the ones with the closest voltages (since it's 2p8s). I've found some good videos on youtube on connecting up the batteries to the Daly BMS, so I don't think I'll have any issues there. Since this is the smart version of this BMS, it comes with the touchscreen and bluetooth etc, so first question is will I need to configure anything on the Daly BMS itself?

When it comes to my 24V Mecer (Axpert) inverter/solar charger what setting do I need to change for absorb, float, equalise (and equalise period - every 30 days)? At the moment I think I have 28.5V absorb and 27.4V float. Also, where do I put the temperature sensor for the BMS, is it supposed to read the battery temperature, or the ambient room temperature?

Thanks in advance 

Just to add to this, they are LiFePO4 cells

treat it like a lifepo4 battery charge up to the recommended voltage per cell .

Discharge to the recommended voltage per cell and carry on .
Making sure the pack is balanced .

2 hours ago, Zimnismoboy34 said:

treat it like a lifepo4 battery charge up to the recommended voltage per cell .

Ok, so how do I set up the Mecer and Daly to achieve that? Would I just need to set up voltages for absorb, float, equalise etc on the Mecer to apply the correct voltages for the Daly BMS and what would these voltages be?

I saw there was a thread from a bit over a year ago that

@Coulomb

assisted with, but I'm not sure what the final settings were that worked 😕

 

I know nothing about setting up the Daly BMS, but the recommended voltages for 15S LFP batteries are these [ edit: however, the OP has a 24 V battery, so these are not applicable. Sigh. ] :

Edited June 6, 20215 yr by Coulomb

@CoulombYour settings are for 15S however Lindsay has 8S battery/24V Axpert. I guess he could take your provided  voltage settings and divide by 15 and then multiply by 8 😃

@Linday - you have LiFePo4 batteries and not lead acid. Turn off Equalization as it is not required. 

Thanks guys,

@Coulomb, I found this quite old post where you approved of 27.6 absorb and 27.2 float for a setup similar to mine: 

 

This is what I've set mine to for now.

@GreenMan, thanks, yes, I thought no equalise, so I turned it off.

Also only set it to 30a maximum charge for now while I get used to things. My loads are quite low (and DC only) at the moment and I will only start using it properly next weekend.

Haven't changed any other settings yet from my old settings for lead-acid (and the inverter is still in standby), so don't expect them to drain too low overnight.

I only set up my batteries late this afternoon, so only charged a little bit, but will keep a close eye on the cell voltages tomorrow.

Thanks again!

Just to add, voltages of the batteries were between 3.261-3.268v on arrival (only 2 of the batteries were below 3.265). Here are the settings on the BMS, if you guys think I should change anything:

 

After the first night pulling around 2 amps continuously, the cells were all around 3.18V. Was sunny and they started charging at a bit over 20 amps, falling to 12-13 amps later in the day, but the voltage of the highest cell never got much over 3.35V. They charged around 80Ah, so the cells I got for my 200Ah battery pack must have only been around 50% charged when I got them (which I believe is normal). While charging the difference between the highest and lowest cell went up to around 15mV, but the BMS seems to be set up to balance only when it's over 50mV. Last night the difference went down to 5mV.

After another night of a 2A load, this morning before charging the cells were around 3.28V.

I'll probably increase the charger settings by 0.4V, so 28V bulk and 27.6V float, which is more inline with (as GreenMan said) taking Coulombs values and dividing by 15 and multiplying by 8. Hopefully this will get the cells closer to 3.45V, which is what I'm aiming for.