Solar PV battery options

Bif

https://www.boards.ie/discussion/comment/118547277#Comment_118547277

It’s a hefty loss @ 20% adding significant impact to costs.

garo

It is what it is. Some people will give you better numbers but take those with a pinch of salt. If you are charging from PV (free) or night rate to use during the day you still come out ahead.

Bif

https://www.boards.ie/discussion/comment/118548109#Comment_118548109

You are right of course but is it correct to say it does diminish ROI / payback calculations on capital outlay on batteries? I’m thinking of increasing my battery capacity.

championc

https://www.boards.ie/discussion/comment/118548185#Comment_118548185

It depends on what it is you propose to increase.

You sound like you are hinting that you have Pylontech units. If so, do what Dr. Phil did and buy the CALB 200ah 16pcs from OYE or PWOD on AliExpress with a Seplos BMS and then sell your Pylontech units.

You could go from 2.4kW to 10kW for just a few 100 guid

slave1

So I'm onto balancing my third batch of 8 batteries from AE, I read on another forum to get balanced all the way, charge at 3.4amp until full, disconnect and then charge at 3.5amp, then finally disconnect and charge at 3.6amp so gonna try that with this batch and see how things transpire

Bif

https://www.boards.ie/discussion/comment/118549085#Comment_118549085

I have a Puredrive 5kwh and thinking of expanding. Maybe another of the same or DIY ok.

garo

https://www.boards.ie/discussion/comment/118548185#Comment_118548185

Correct! Definitely take that 20% inefficiency into account when doing your sums. It does alter the decision away from a battery expansion. If I recall correctly you have only had your system for a short while. I would recommend a few more months while you see how you get on during the summer before making a decision.

To echo what championc was saying, I went from a 2.4 kWh Pylontech to a 10kWh DIY with Seplos for around 600 extra. And now I am thinking of another 10kWh though the numbers probably don't make sense for me.

championc

We have all had the days where we export one day and import the next. Oh how nice and comforting it would be to have the capacity to last on battery over 2 days.

I really struggle to see how more than 2.4kW of the pylontechs et al can make sense after the grant. Buying extra seems illogical when we have the AE alternative

garo

But not everyone has the time inclination or confidence to do a DIY build.

championc

Maybe more exact to say that €2k on batteries is bordering on the tipping point ?

garo

I am too far gone as are you 😀

slave1

Sometimes it’s the challenge and the economics are set aside

garo

Yes and thats why I am considering a second pack. I've already done the hard work of getting the BMS wired and running, done all the crimping etc. Adding a second set in parallel would be a doddle. Also if we think in financial terms, the number of hours I spent working on this, if my job were paying overtime, I would have probably made more than the cost of two battery packs.

slave1

https://www.boards.ie/discussion/comment/118550521#Comment_118550521

5 days later, all cells are between 3.6406 and 3.6408 so obviously works

graememk

Finally got the bathroom done... So Got some time this afternoon to tear the old battery pack down (Merging the 2 older packs for my dads set, and keeping all the new ones together.

top balanced them to 3.6, Its been nearly a week since that was finished, All are over 3.45 but some are 3.5x, Close enough, As long as they are above 3.4 I'm happy.

Also have moved from 2 rows of 8 (the 9th cell would appear high on charge and low on discharge due to the extra cable linking the 2 rows) to 1 row of 32 (16s2p)

slave1

Single row of 32, snap, using this as a guide

Jonathan

Might be of interest to some here. Popped up in my YT subscriptions earlier.

https://www.youtube.com/watch?v=O-VX32g3Aeo

championc

After a month running on the Seplos BMS, I finally had thing dialed in pretty well I felt, until the end of month showed that I had used 29 day units. Something was definitely wrong.

I went investigating and began homing in on the possibility that I was importing a small amount of power permanently, based on a misreading of the CT clamp attached to the mains, and the 30m run to my Storage Inverter.

I finally copped that I could use my MyEnergi app and look at the Grid graph. Sure enough, I was importing about 10 - 15w all day and night.

So at 14:00 today, I changed the CT clamp offset from +10w to -10w and then, around 18:00, changed it to -15w

slave1

I think I understand that, I too will have a similar setup by the end of the month so must check back on this CT offset which I've never heard about before

Alkers

https://www.boards.ie/discussion/comment/118538623#Comment_118538623

And excuse my ignorance but are those clamps wireless? Which cable to they go on?

championc

https://www.boards.ie/discussion/comment/118573121#Comment_118573121

On the ME3000, it is item 15 - CT Clamp calibration in the settings menu

championc

https://www.boards.ie/discussion/comment/118573489#Comment_118573489

Generally wired and go around the positive / live wire. Used to measure current. The MyEnergi ones can pick up enough current through induction to power a connected Harvi, to send data wirelessly with radio signals to a Zappi or Eddi

Alkers

So would I have to run s CT clamp cable from my main fuse up to the battery pack?

championc

It's the inverter which talks to everything. So a CT clamp would be connected from the inverter to the incoming grid connection

graememk

https://www.boards.ie/discussion/comment/118573636#Comment_118573636

Doesn't have to be the main fuse, it can be from the consumer unit, as long as it's on the main incoming grid cable.

There's also a second CT used to monitor the solar but that's more for stats, it only needs the grid one.

It would(generally) need its own cable back to the consumer unit

Big Lar

Just wondering how long folks have been waiting for these batteries from the OYE store, feel like I am getting the run around from them. Ordered 6th Nov last, they extended purchase protection at the start of Jan but still nothing.

slave1

I was 6 working days, @DrPhilG was deffo very long time

garo

https://www.boards.ie/discussion/comment/118573020#Comment_118573020

Interesting. I didn't see that with my Growatt/Seplos combo. But what I did see was the BMS/inverter combo being a bit slow to respond to sudden increases in demand when solar PV has a sudden drop. This also means that every day around sunset (or half hour before) I end up drawing from the grid for 10-20 mins.

The other issue I have is the inverter losing it's connection to the BMS when the battery is 100% full. I've had the inverter firmware updated and cut wires 7&8 on the CAN cable as suggested but no joy.

Jonathan

https://www.boards.ie/discussion/comment/118575407#Comment_118575407

https://www.boards.ie/discussion/comment/118575118#Comment_118575118

Merged this over to the DIY Battery thread.

graememk

https://www.boards.ie/discussion/comment/118575407#Comment_118575407

I got mine about 2 weeks ago, ordered in Nov. (From pwod)

When did you get your ups tracking number?