The Battery Thread (Solar / Inverter)

[wingnut771]

Multimeter arrived so I could check and all cells arrived charged to about 3.26-3.27.

Did some DIYing last night to get everything including the inverter stuffed into a crate. Got 2 PC fans moving 37-39CFM through the crate so there is more than enough airflow. The fans are connected with positive on the battery and negative between the BMS and inverter. I might just add an inline switch to the fans so I can switch them off when necessary.

Other than the DIY of chopping up the crate, building the battery and connecting everything up only took 20 minutes.

My main concern is that when I went to bed last night the battery was charging, but this morning it seems the inverter is sitting on float charge without having bulk charged to 14.1v as per the settings. I have a feeling I may need to do a load test to DC cutoff and then let the inverter try charge again.

After re-checking the manual, the bulk charge timer option is only for the larger inverters. Based on running the battery flat (down to 12v) and then recharging, if it doesn't recharge to 14.1v then I'll need to look at another in line charger.

Edit: For now I've just set the floating charge to 14.1 to get it there, once it hits 14.1 I'll drop it down to 13.5 again

Did you equalise the cells by leaving them connected in parallel before building the bank? What were the cell voltages in the morning? Are you able to turn float charge off?

 

[Slinetpixel]

Did you equalise the cells by leaving them connected in parallel before building the bank? What were the cell voltages in the morning? Are you able to turn float charge off?

I did not leave them in parallel (not enough bus bars and all voltages were within the recommended 0.02v). This morning the voltages were sitting at 3.39. It doesn't seem possible to set float charge off, but the voltage can go low enough to match the DC cut off at 12v.

 

[TheChamp]

Thanks for all the adivce and comment ut really has been great.

If I decided to buy the components over a couple of months (inverter, panels, batteries) my assumption is that I can find an installer and he will do the install. Is that fair or are there guys who will refuse and will only supply a full solution.

On a second point, any recommended installers in Cape Town? I have a slate roof and I believe they are a mission to install on (no spare tiles)

Plenty installers around, if you found one that refuse you know you have just avoided a scammet.

 

[thehuman]

Multimeter arrived so I could check and all cells arrived charged to about 3.26-3.27.

Did some DIYing last night to get everything including the inverter stuffed into a crate. Got 2 PC fans moving 37-39CFM through the crate so there is more than enough airflow. The fans are connected with positive on the battery and negative between the BMS and inverter. I might just add an inline switch to the fans so I can switch them off when necessary.

Other than the DIY of chopping up the crate, building the battery and connecting everything up only took 20 minutes.

My main concern is that when I went to bed last night the battery was charging, but this morning it seems the inverter is sitting on float charge without having bulk charged to 14.1v as per the settings. I have a feeling I may need to do a load test to DC cutoff and then let the inverter try charge again.

After re-checking the manual, the bulk charge timer option is only for the larger inverters. Based on running the battery flat (down to 12v) and then recharging, if it doesn't recharge to 14.1v then I'll need to look at another in line charger.

Edit: For now I've just set the floating charge to 14.1 to get it there, once it hits 14.1 I'll drop it down to 13.5 again

My 24v axpert type inverter also goto float rather fast ( believe there a premature float bug ) , i normally bump float up once a week to balance cells.

 

[insect]

Just ordered an RCT AXPERT VM 1000VA (3.5k) and a Mecer 200ah (6k) second life lithium after weeks of head scratching and indecision, hope I didn't make the wrong choice.

I have a 300w panel on the roof +100ah AGM, Victron charge controller and 370w Victron phoenix inverter - which powers the guest bedroom when load shedding strikes just fine.

This will be a fun new project for a more permanent solution that includes the main bedroom and now I can move the old stuff to the office.

 

[wingnut771]

Just ordered an RCT AXPERT VM 1000VA (3.5k) and a Mecer 200ah (6k) second life lithium after weeks of head scratching and indecision, hope I didn't make the wrong choice.

I have a 300w panel on the roof +100ah AGM, Victron charge controller and 370w Victron phoenix inverter - which powers the guest bedroom when load shedding strikes just fine.

This will be a fun new project for a more permanent solution that includes the main bedroom and now I can move the old stuff to the office.

Nice, think you chose well for that price range. Are you going to add solar to the RCT? What will you be running off the mecer 200Ah?

 

[TheChamp]

Just ordered an RCT AXPERT VM 1000VA (3.5k) and a Mecer 200ah (6k) second life lithium after weeks of head scratching and indecision, hope I didn't make the wrong choice.

I have a 300w panel on the roof +100ah AGM, Victron charge controller and 370w Victron phoenix inverter - which powers the guest bedroom when load shedding strikes just fine.

This will be a fun new project for a more permanent solution that includes the main bedroom and now I can move the old stuff to the office.

Looks like a decent starter kit.

 

[insect]

Idea would be to use this as a stepping stone to get totally off grid eventually - I live alone so my usage is minimal and changing usage habits + moving over to more efficient devices wont be a problem.

The RTC can only take 500w solar according to specs - I already have a 300w on the roof so for now that will have to do. I'm in the Northern Cape so lots of good sun hours/day.

Installed gas stove in the kitchen and looking at a gas geyser, although in summer I rarely switch on the geyser at all - but Ill move to gas before winter.

Ill only be running a 65" LED TV, optiplex mini i5 htpc + nuc i3 plex server & raspberry pi. Should be less than 300w - unsure about the Denon Receiver, have to test what it draws with the watt meter tonight Will add some small items, phone charger, google mini, cpap machine etc.

LTE modem and Unifi setup runs of a ratel, not sure if I should move that to solar (yet).

So its basically just the fridge and microwave that needs Eskom for now. The 200ah will help me through load shedding, but Ill have to grow the bank to get off grid.

Can I add another 200ah lithium say in six months, I know you shouldn't mix old and new lead acids but not sure about lithium.

 

[TheChamp]

Can I add another 200ah lithium say in six months, I know you shouldn't mix old and new lead acids but not sure about lithuim.

Yes.

 

[wingnut771]

Idea would be to use this as a stepping stone to get totally off grid eventually - I live alone so my usage is minimal and changing usage habits + moving over to more efficient devices wont be a problem.

The RTC can only take 500w solar according to specs - I already have a 300w on the roof so for now that will have to do. I'm in the Northern Cape so lots of good sun hours/day.

Installed gas stove in the kitchen and looking at a gas geyser, although in summer I rarely switch on the geyser at all - but Ill move to gas before winter.

Ill only be running a 65" LED TV, optiplex mini i5 htpc + nuc i3 plex server & raspberry pi. Should be less than 300w - unsure about the Denon Receiver, have to test what it draws with the watt meter tonight Will add some small items, phone charger, google mini, cpap machine etc.

LTE modem and Unifi setup runs of a ratel, not sure if I should move that to solar (yet).

So its basically just the fridge and microwave that needs Eskom for now. The 200ah will help me through load shedding, but Ill have to grow the bank to get off grid.

Can I add another 200ah lithium say in six months, I know you shouldn't mix old and new lead acids but not sure about lithium.

Don't think so as they advise this:

Don't know why this is so.

Mecer 200A 12V LiFePO4 BatteryDefault Title

Mecer 200A 12V LiFePO4 Battery The Mecer 200A 12V LiFePO4 Battery is a second life battery. 2nd LiFePO4 200Ah 12v Lithium Iron Phosphate 1.9kW of usable energy storage 1500 cycles @ 80% DoD 2 year warranty BMS included Perfect for lead acid replacement Dimensions : 521L x 237W x 217H (mm)...

thepowerstore.co.za

This is why I prefer these batteries as they allow for customisation:

Affordable Lithium Batteries

Putting the power back into your hands

lithiumbatteriessa.co.za

 

[wingnut771]

Yes.

Really?

 

[TheChamp]

Really?

Never thought of that parallel limitation.

 

[insect]

This is why I prefer these batteries as they allow for customisation:

Eish I was on that site everyday for the last couple of weeks, don't know how I missed that kit! now I have fomo!

Interesting thread on the powerforum regarding the Mecer batteries - I should be able to sell it if I can't grow the bank, hopefully it will teach me some things regarding lithium and solar.

I know a good sparky who does a lot of solar installations for the farmers in the area - he will probably scold me on my choices, but eventually assist me

 

[wingnut771]

I did not leave them in parallel (not enough bus bars and all voltages were within the recommended 0.02v). This morning the voltages were sitting at 3.39. It doesn't seem possible to set float charge off, but the voltage can go low enough to match the DC cut off at 12v.

How's it going? Did you manage to come right? Making it through loadshedding? Better than before?

 

[Slinetpixel]

How's it going? Did you manage to come right? Making it through loadshedding? Better than before?

Tested them for 4 hours last week at about 0.2C discharge with the voltage sitting at about 12.8v at the end. Haven't done a full capacity test yet.

It was an absolute pleasure this weekend when Eskom decided we didn't need power when waking up. The only thing I need to look at now is getting a gas bottle for making coffee in the powerless mornings.

I'm still playing around with the float value/C-rate because when I set it to 13.5v the batteries discharge to 13.4x/13.5v but I can't check if there's any current flowing.

 

[The_Librarian]

Convinced CEO to look at installing a PV system to power the server room during the day.

 

[thehuman]

Don't think so as they advise this:
View attachment 1007560
Don't know why this is so.

View attachment 1007562

Mecer 200A 12V LiFePO4 BatteryDefault Title

Mecer 200A 12V LiFePO4 Battery The Mecer 200A 12V LiFePO4 Battery is a second life battery. 2nd LiFePO4 200Ah 12v Lithium Iron Phosphate 1.9kW of usable energy storage 1500 cycles @ 80% DoD 2 year warranty BMS included Perfect for lead acid replacement Dimensions : 521L x 237W x 217H (mm)...

thepowerstore.co.za

This is why I prefer these batteries as they allow for customisation:

Affordable Lithium Batteries

Putting the power back into your hands

lithiumbatteriessa.co.za

I am sure if you limit charging current to 1 batteries, and don't do parallel connections on battery terminals should be fine.

 

[wingnut771]

I am sure if you limit charging current to 1 batteries, and don't do parallel connections on battery terminals should be fine.

Busbar?

 

[isie]

Busbar?

Metal (probably copper) bar to connect the 2 Battery terminals together (used instead of copper wires.)
looks something like this

if you check your DB board you might have something like this linking a few of the Trip switches
thats a Busbar

 

[wingnut771]

Metal (probably copper) bar to connect the 2 Battery terminals together (used instead of copper wires.)
looks something like this
View attachment 1014728
if you check your DB board you might have something like this linking a few of the Trip switches
thats a Busbar
View attachment 1014724

How is this any different than using the battery terminals?