Installed second EPEVER MPPT today and an earth rod!

[littlehuw]

Really pleased how easy it all went today. Thanks for your help all. I used 35mm cable for the earthing rod but had to separate into two to get it on the earthing bus bar. Will this be ok?

the two MPPT controllers are set at the same settings apart from the smaller 40a one I have zeroed the equaliser time as suggested.

all cables to the batteries positive and negative are the exact same length and 16mm.

I have a WiFi controller to view/amend the details of the controllers if needs be. They are controlling 4 x 220ah SLA batteries, 2S 2P for 24v.

solar panels are 4 x 375w at 2S 2P for 1500w 68v 22a into the 80a controller via 30a fuse pre-entry. DC breaker to battery @80a

then 3 x 150w 3S for 450w for 57v at 8a into the 40a controller with a 25a fuse pre-entry. DC breaker to battery @40a

anything humdingingly bad let me know! Am going to put 2 x fridge and 2 x freezers on it tomorrow

 

[SamDeleted]

I used 35mm cable for the earthing rod but had to separate into two to get it on the earthing bus bar. Will this be ok?

Yes no probs that's fine



Looking good. Like the inverter, I've had my eye on one


Let us know what you think of it

 

[SamDeleted]

What are you fridges and freezers using a day KWh ?

Mine use about 750wh a day each average , chest freezer and big fridge


1.5kw of panel will almost certainly power all 4 of them (and then some) 8 months of the year .... might well struggle over winter

 

[sunshine_eggo]

Based on connection sequence, that's technically 2P2S.

You have two 12V in parallel.
You have another two 12V in parallel.
Those are then in series.

When you parallel 12V in a series system, you mask potential issues.

They also appear to be different types - sealed (SLA) and flooded (FLA), unless those are fake caps.

You also appear to be drawing/charging at multiple points.

Best practice would be to:

Connect the two FLA batteries in series.
Connect the two SLA batteries in series.
Parallel the two at their main terminals - thus you can check the voltage of each individual 12V - no masking.

Additionally, you should have ONE main (-) and ONE main (+) on the bank. It doesn't matter which is which, e.g., your (-) would be on the FLA and your (+) would be on the SLA.

Conceptually:

 

[littlehuw]

Yes no probs that's fine



Looking good. Like the inverter, I've had my eye on one


Let us know what you think of it

Well, I blew up the 500w inverter not totally sure how lol so when looking at the washing machine which uses 0.8ah on an eco cycle, 1900w but drawers a big surge when spinning. This 3000w 24v inverter has capacity for 900w surge, just needed to swap the breaker to 180a. The other thing, because it will act as the charger too and pass through the ac whilst charging, I had to drop the charging amps from 56 to 42 to not throw the 13a fuse on the ring main! We live and learn…

it’s a great inverter/charger but I will need to change it if we go further in the future with lithium and/or 48v

 

[littlehuw]

What are you fridges and freezers using a day KWh ?

Mine use about 750wh a day each average , chest freezer and big fridge


1.5kw of panel will almost certainly power all 4 of them (and then some) 8 months of the year .... might well struggle over winter

Not 100% sure but working on an estimate of about 2000wh all 4. The inverter will also pass through and charge the batteries when required for the winter. Sucking up the offset of grid charging for now and will look again at upgrading the batteries and inverter when these SLA batteries give up in 3 - 5 years time. Fingers crossed. Might be able to add 2 x 300w panels on the smaller charge controller in the meantime too.

 

[littlehuw]

Based on connection sequence, that's technically 2P2S.

You have two 12V in parallel.
You have another two 12V in parallel.
Those are then in series.

When you parallel 12V in a series system, you mask potential issues.

They also appear to be different types - sealed (SLA) and flooded (FLA), unless those are fake caps.

You also appear to be drawing/charging at multiple points.

Best practice would be to:

Connect the two FLA batteries in series.
Connect the two SLA batteries in series.
Parallel the two at their main terminals - thus you can check the voltage of each individual 12V - no masking.

Additionally, you should have ONE main (-) and ONE main (+) on the bank. It doesn't matter which is which, e.g., your (-) would be on the FLA and your (+) would be on the SLA.

Conceptually:

I think the nobs on the front set are fake as they are all same make and model SLA.

gosh that looks a lot simpler than the plan I followed to get 24v and double capacity!

so if the loads go on there, where do the charging points go, on the same connection or the other one?

 

[sunshine_eggo]

I think the nobs on the front set are fake as they are all same make and model SLA.

gosh that looks a lot simpler than the plan I followed to get 24v and double capacity!

It's the same capacity either way you do it.

so if the loads go on there, where do the charging points go, on the same connection or the other one?

Same terminals. Yu may find that you need to run the battery wires to a bus bar where you can connect your chargers and loads.

 

[littlehuw]

E

It's the same capacity either way you do it.



Same terminals. Yu may find that you need to run the battery wires to a bus bar where you can connect your chargers and loads.

please could I trouble you to conceptually draw the set up with the bus bar, charging and loads on the set up. Many thanks. I’ll then have an idea of what I need and where it needs to go!

 

[sunshine_eggo]

https://www.amazon.com/dp/B08JKYCF1X

One lug for battery
One lug for charger(s)
One lug for inverter
One lug for whatever

 

[littlehuw]

Thank you! And I’m noting 400amp because of input and output added together, is that right?

 

[sunshine_eggo]

Thank you! And I’m noting 400amp because of input and output added together, is that right?

No. Just the ones I use. They all tend to have pretty high ratings.

 

[littlehuw]

View attachment 146067

https://www.amazon.com/dp/B08JKYCF1X

One lug for battery
One lug for charger(s)
One lug for inverter
One lug for whatever

Ok I had to visually mirror image this a bit, top to bottom but I think I have done it. Numbers can loosely be seen on the batteries.

 

[sunshine_eggo]

It looks right. I had to mentally rotate the batteries ±90° to see it.

You should be able to measure the individual 12V and likely show 4 different readings.

It is important to periodically check these batteries to confirm that they are at the same voltage when the bank is at peak 24V voltage.