Solar PV battery options

MAULBROOK

https://www.boards.ie/discussion/comment/118076537#Comment_118076537

Sorry I have just waisted your time,This for charging on night rate.

garo

https://www.boards.ie/discussion/comment/118076537#Comment_118076537

Leavethe discharge time at 0 as shown above. Set the charge time from 12-9 (11-8 after Sunday) and set the charge limit to 0A. This will do what you want. i.e. only charge from solar and not discharge at night. There may be a tiny trickle charge at night but that can't be helped - happens with some inverter battery combos. Something like 50W.

Jonathan

https://www.boards.ie/discussion/comment/118076709#Comment_118076709

A little counterintuitive, but makes sense. Will try that later.

Thanks all!

MAULBROOK

https://www.boards.ie/discussion/comment/118076709#Comment_118076709

Ah good thinking, that was a good school day. I learned something new. Thanks garo

garo

I think I am overdue an update. Here’s the battery bank sitting in its container. The top row was passive balanced for two weeks and now the bottom row is also a week into passive balancing.

Extended and crimped the BMS wires today and learnt a few things along the way. It is really important to have a good wire stripper and crimper. I initially tried with my old wire stripper but given that you are going to do it over 50 times I quickly decided that it wasn’t cutting mustard and decided to go with a Stanley Fatmax automatic wire stripper https://www.screwfix.ie/p/stanley-fatmax-automatic-wire-stripper-8-203mm/5934k Absolutely brilliant.

Also discovered that the 16mm2 is a pain to cut with usual diagonal/side cutters. Got a pair of these instead: https://www.screwfix.ie/p/irwin-vise-grip-cable-cutters-8-203mm/61667 Fantastic job!

Finally learnt that crimping with insulated ring terminals is awkward. Get yourself uninsulated ring terminals if you can and then use heat shrink wrap.

Geeyfds53573

https://www.boards.ie/discussion/comment/118086893#Comment_118086893

Thanks Garo - I wondered what container if any would be used? Good fit. The two weeks balancing is that an arbitrary figure?

garo

It's a 64 litre plastic storage container. Can't remember where I got it. Ikea or Homebase or one of those places. The plastic is relatively robust. But I put some foam from the packaging the battery came in underneath to make sure the weights was evenly distributed. The big attraction for me is the lid which makes sure I keep battery terminals isolated and safe from any objects that may drop on it.

garo

First half of BMS wires and batteries connected and checked. Bit messy right now and wondering if interest is worth trying to tidy up the wires. I think I extended the wires by too much but I wanted to be safe rather than sorry. Now the bottleneck is the NTC wires. I didn’t extend those as I wasn’t sure if I should. So they are quite short compared to the rest. @championc You think it is safe to extend those as well? I would need to make two sets of joins for each. So 16 in all. Bleh!

bullit_dodger

In theory since your dealing with very slight deviations in resistance, shouldn't they all be the same length?

boarduser01

Hi, quick question or three....

I have a hybridprime inverter with two 2.5kw batteries, and I want to upgrade to larger battery capacity. The crowd I bought from previously want 4000 euros to add another two 2.5kw batteries to the system. I want to know what alternatives I have?

Can I stick with the same inverter but change to a different and larger battery pack, or are inverters made to link with specific batteries?

Is there any cheapish way of increasing to a minimum of 10kw battery storage system?

If I needed to replace the whole inverter/battery system, is there a market for selling to people wanting a used inverters/battery system?

Thank you.

championc

Well you are on the right thread to build your own 10kW battery bank, which will cost you about €1500 from AliExpress. You could then sell your existing batteries and make a profit.

Generally, batteries aren't linked to specific brands of inverter

graememk

https://www.boards.ie/discussion/comment/118094412#Comment_118094412

What inverter and batteries do you have?

Some inverters only work with their own battery. Eg solax, givenergy etc. But if it's solis and others you can DIY it

S'

Hi,

I am awaiting my installation of my PV system (6.9kW) and was wondering how easy is it add a DIY battery to the existing 5kW Puredrive battery? I would like to avoid exporting back to the grid.

Has anyone done it.

MAULBROOK

https://www.boards.ie/discussion/comment/118103218#Comment_118103218

Sell the puredrive and buy what you need and have some change left over.

randomname2005

Apologies if this is not the right thread for this but I think I came across a link somewhere in this thread or the Solar Quotes thread to a meter but of course I can't find it now. Has anyone got a recommendation for an energy meter they have used and found reliable? Internet reviews are so varied it is hard to know what to go for.

Use case: Last week had a small (3kw) solar system installed and even with general appliances being run and water tank filled up we are exporting a few hundred watts to the grid during the day and would expect to be exporting a little more during the sunnier months. I am looking for a meter that will allow me to look at how much we are using, with an hourly or better resolution, so that I can figure out how much we energy we use outside of solar production times, and if we use enough to make (DIY installed) battery payback times reasonable.

graememk

https://www.boards.ie/discussion/comment/118112802#Comment_118112802

My option is a bit on the expensive side : emonpi, from openenergymontior. That has 2 cts. There is also the emon tx if you need more cts to monitor things.

*I'm using a wifi emontx and a raspberry pi I already had as the server. It does need a double socket beside your consumer unit, as it needs to be able to monitor the grid and solar feeds.

If your looking into automation that's a great stepping stone.

I have seen an owl system that is solar compatible, and I think that one has wireless (battery powered) communication with the base station. I have not used it so can't say how good it is, all I know that it exists.

bullit_dodger

I've got the OWL (non-PV) system for about 5 years and as a device for strictly measuring the current and performing some limited costings on the device, it's been pretty good to me over the years. Batteries in the transmitter attached to the CT clamp in the main box outside last 6-12 months and are a doddle to change. Batteries in the monitor last 4-5 months, but I use 2600mA rechargables so not a huge cost.

Update, reception and accuracy of the signal from the transmitter is pretty good through the house an all things considered fairly accurate. (CT clamps will never be as accurate as actual hardwired measurement but it's reasonably close as I've compared the readings to an actual socket based measurment)

Where the OWL fails is in the web monitoring. Despite my best efforts, I could never get the web based upload to work. Just _would not_ work. Opened ports on my router etc. No joy. Was looking recently in purchasing an OWL upgrade (PV version) so I'd have multiple CT clamps to work out PV generation etc but saw a review on Amazon that you can't change the battery without a subscription. Granted the subscription is fairly cheap (€10 a year or something) but when I heard that.....it sort of put me off it.

munsterfan2

Getting ready to bite on this, keeping an eye on AliExpress for singles day specials (11/11). (wont let me add URL)

As part of the build package solar panels, solis hybrid inverter was installed but battery couldnt be delivered. Will be back with some questions :-)

Ruairi

47akak

If you're putting 48v packs in parallel connecting to the Solis AC charger or similar what do you for BMS? Does each parallel pack need it's own BMS? Can you daisy chain BMS to connect to the canbus on Solis?

Or should I just balance each pack once with one BMS then just leave the BMS connected to one at a time?

I have batteries and inverter ordered, sorry for newb questions just struggling a bit with the BMS side of things, not sure even which one to order. It's mainly with safety in mind, the batteries will be stored in an external building along with the inverter (about 25ft cable run to consumer unit in the house). The electrician will connect the inverter to house grid he just doesn't know or want to know about the battery side of things.

randomname2005

https://www.boards.ie/discussion/comment/118114345#Comment_118114345

https://www.boards.ie/discussion/comment/118114390#Comment_118114390

Thanks to you both - it seems that OWL is the way to go. Will see what is in the budget!

randomname2005

https://www.boards.ie/discussion/comment/118116639#Comment_118116639

If I am doing my figures right on this, 640w (=200 * 3.2) per battery or combined to get 10kw battery for €1500?

unkel

https://www.boards.ie/discussion/comment/118116832#Comment_118116832

Yes all correct!

Best to get your units right though. Particularly as there are always new people reading this who might get confused.

200Ah capacity per cell as advertised * 3.2V nominal voltage per battery * 16 actual batteries = 10240Wh total capacity of the pack, so about 10kWh

graememk

https://www.boards.ie/discussion/comment/118116773#Comment_118116773

You can build separate parallel packs with their own bms

Or you can parallel pairs of cells in a string of 16 with one bms.

randomname2005

https://www.boards.ie/discussion/comment/118116639#Comment_118116639

This is a couple of quid cheaper, and seems to have the same spec (200A, 3.2V, 16 pieces)

https://www.aliexpress.com/item/1005002322953614.html?spm=a2g0o.productlist.0.0.54242137Et4rL1&algo_pvid=4e58cecc-3af2-4809-994c-c2a819e16de3&algo_exp_id=4e58cecc-3af2-4809-994c-c2a819e16de3-22&pdp_ext_f=%7B%22sku_id%22%3A%2212000021813763018%22%7D

championc

Keep searching AliExpress for "CALB 200AH 16pcs". That will find all sellers. The better recommended ones are PWOD and OYE.

randomname2005

https://www.boards.ie/discussion/comment/117987449#Comment_117987449

With this shopping list in mind, is there a source for storage inverters I have missed? I was hoping that a storage inverter wouldn't be too much but am only seeing full hybrid inverters on the wholesalers in Ireland, midsummer, solartricity etc. It would almost be better to take out the standard inverter I have and get a hybrid inverter installed, and sell the standard if anyone would buy it!

irishchris

Can't remember if somebody here said they were selling their pylontech batteries now that they have DIY one built. Currently I'm on 7.2kwh but interested in adding one or two more.

Stock coming back in on the 18th of this month so will add one then but if anyone here is selling theirs before that drop me a pm

garo

https://www.boards.ie/discussion/comment/118120755#Comment_118120755

I will have one. I have had a couple of other expressions of interest. I've just been too busy to get the DIY finished.

Blue4u

Going to buy the following: https://www.aliexpress.com/item/4001083766967.html?spm=a2g0o.productlist.0.0.518a6919Su3gHo&algo_pvid=06140001-61ba-4f9f-8db1-2d71f1c8b704&algo_exp_id=06140001-61ba-4f9f-8db1-2d71f1c8b704-0&pdp_ext_f=%7B%22sku_id%22%3A%2212000025806930327%22%7D

Decent value?

slave1

Yes, that's about as low as it gets these days