Ronski's Solar & battery DIY build with whole house backup
- Thread starter Ron-ski
- Start date
Yes the bottoms of the cells are still covered.
All the cells are physically good, there is no damage, only thing I have noticed is the terminals are welded on slightly crooked, some are worse than others though. I don't think this will cause any issues, as there is some leeway in the supplied busbars, but I may well use these flexible busbars - need to check hole spacing.
I've measured the voltage, and every cell is 3.295v, can't carry out any other checks as I don't have the equipment yet.
www.aliexpress.com
All the cells are physically good, there is no damage, only thing I have noticed is the terminals are welded on slightly crooked, some are worse than others though. I don't think this will cause any issues, as there is some leeway in the supplied busbars, but I may well use these flexible busbars - need to check hole spacing.
I've measured the voltage, and every cell is 3.295v, can't carry out any other checks as I don't have the equipment yet.
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Yes they came with studs, nuts and busbars - just the usual flat solid ones.
Just been looking at where I need to run the SWA, looks even worse to install than I thought.
Thanks for the eBay link.
Just been looking at where I need to run the SWA, looks even worse to install than I thought.
Thanks for the eBay link.
I've ordered 16, someone else in the thread ordered 8 for themselves and 8 for someone else.
One thing to consider if just going for battery storage is payback time, say you have a 14kwh battery, you fully charge it off peak at 7.5p per kWh, that costs you £1.05 to charge it, at the current rate, if you used that 14kwh instead of paying 30p per unit, it would save you £3.15. Probably easier to calculate pay back time though.
If you have a power cut, and draw more power than the inverter can supply it will trip and need resetting, which just means during a power cut you'll have to be careful, only problem I can foresee is unless you set up some kind of warning you wouldn't know there was a power cut.
As for the electrician, mine has said I can do the DC stuff, but he has to do the AC side of it, the tricky part is finding one thats OK doing that, and most don't get involved in solar, and most solar firms want to do a full install, be that just battery or battery and solar, and they want to fit what they want, not what the customer wants. If you're installing just a battery then you only need Part P certification, if you want paying for export currently you need MCS certification, and you only normally get that with a full install.
I've drawn the cell's and busbars, currently they don't seem to make the two that go across the pack - I'll probably need to crimp my own cable for that, or use solid ones. I've uploaded the cell to Sketchup warehouse, just search Eve LF280K.
PS If anybody spots an error in my cells order let me know - I think its correct.
One thing to consider if just going for battery storage is payback time, say you have a 14kwh battery, you fully charge it off peak at 7.5p per kWh, that costs you £1.05 to charge it, at the current rate, if you used that 14kwh instead of paying 30p per unit, it would save you £3.15. Probably easier to calculate pay back time though.
If you have a power cut, and draw more power than the inverter can supply it will trip and need resetting, which just means during a power cut you'll have to be careful, only problem I can foresee is unless you set up some kind of warning you wouldn't know there was a power cut.
As for the electrician, mine has said I can do the DC stuff, but he has to do the AC side of it, the tricky part is finding one thats OK doing that, and most don't get involved in solar, and most solar firms want to do a full install, be that just battery or battery and solar, and they want to fit what they want, not what the customer wants. If you're installing just a battery then you only need Part P certification, if you want paying for export currently you need MCS certification, and you only normally get that with a full install.
I've drawn the cell's and busbars, currently they don't seem to make the two that go across the pack - I'll probably need to crimp my own cable for that, or use solid ones. I've uploaded the cell to Sketchup warehouse, just search Eve LF280K.
PS If anybody spots an error in my cells order let me know - I think its correct.
@Journey @BUDFORCE That's really good news, they like to hide that info away don't they. I was hoping as I already have an existing MCS system that I'd just be able to switch to a decent export tariff, and it wouldn't be noticed that I had an additional system. At least I now know there's a way around it.
Thanks , those straddling busbars aren't available, I've messaged the manufacturer as they appear to have overlooked them, I may need to make some.
If you're on a capped rate you could switch to Bulb, they have an EV tariff (doesn't require an EV), I've just switched and I'm paying exactly the same rate, and when the time comes I'll switch to the EV tariff. Bulb may possibly be bought by Octopus. Unless changing to a fixed price contract most suppliers won't take you on.
Including the solar the panels the whole lot is at least £10k mark - I'm really hoping the electrician is kind to me as that's not yet costed.
If you took the panels, mountings and solar charge controllers out then that would save roughly £3.2k, but I am going with an inverter (Quattro 48/10000) that can supply 8kw and its an expensive make, so if you went with a smaller inverter you could reduce that a lot further. The 4kw one (Victron Multiplus II 48/5000) is £1272 inc vat.
Yes the battery will be about 15.5kWh
If you took the panels, mountings and solar charge controllers out then that would save roughly £3.2k, but I am going with an inverter (Quattro 48/10000) that can supply 8kw and its an expensive make, so if you went with a smaller inverter you could reduce that a lot further. The 4kw one (Victron Multiplus II 48/5000) is £1272 inc vat.
Yes the battery will be about 15.5kWh
I did, but it was that French site on eBay, so thats something I need to look into again.
Yes please, I believe I need two Smart Solar MPPT 140/45TR, that's according to data I entered at https://www.victronenergy.com/mppt-calculator
6 panels on each (3S2P), likely 405W JA Solar Mono PERC Half-Cell MBB Black Frame solar panel.
6 panels on each (3S2P), likely 405W JA Solar Mono PERC Half-Cell MBB Black Frame solar panel.
Thanks, I'll have an east / west panel arrangement so need two charge controllers
The shaded strings that are in parallel do not affect the voltage of the strings that are in full sun, so you have 2x 3 panels for your East strings and 2x 3 panels for your West strings, then use a pair of 4 to 1 solar branch connectors (about £15), plenty of info around that will confirm this for you if you are unsure.
I did find this on Victron site, which states two controllers is better
2 strings in parallel with diferent shading - VictronEnergy
community.victronenergy.com
and this which ultimately comes to the same conclusion
Series strings connected in parallel with different shading - VictronEnergy
community.victronenergy.com
Seems another of those situations where there is lots of differing opinions, so difficult to know which is correct, but two MPPT controllers will definitely work OK, just cost a bit more.
I will have some shading, but that will be early morning and late afternoon/evening, it will be worse in the winter as the sun's lower. The morning shading is caused by our tree, which needs trimming, evening shading is a neighbors tree.
Yes., 3S2P. If you refer to the picture in the first post there is four rows of three panels, each row will be a string, the two strings facing east on one CC in parallel, the other two strings facing west on the other CC.
I put the relevant info into the Victron MPPT calculator, and it suggested the 150/45. Hopefully I did it correctly.
Edit. I'll correct the error in the previous post.
I put the relevant info into the Victron MPPT calculator, and it suggested the 150/45. Hopefully I did it correctly.
Edit. I'll correct the error in the previous post.
Forgot to say, my BMS has arrived, only ordered it on 16th.
Here's what I calculated, presuming I've used the correct values
mppt.victronenergy.com
MPPT Calculator - Victron Energy
Use our Online MPPT Calculator for PV sizing calculations.
That's the plan, all this expense needs to save money.
I haven't tried yet, but my smart meters haven't worked since the end of July. I might try contacting Bulb to see if they will replace them.
Mine are actually faulty though, they were working.
I've ordered a set of flexi busbars https://www.aliexpress.com/item/100...on.0.0.448b3e5fPWkTaz&gatewayAdapt=4itemAdapt
Rather pricey, but I've lots to be making as it is.