Upscaling the solar generation on our property 2

[Joeboy]

Thanks, charger ordered, I can't run to a new pylontech battery yet and the electrician hasn't turned up today as expected but I should be able to have a trial run with some tractor batteries in series if I can figure out the charger controls.

The Victron app on the phone is easy to use there are slso rotary dial generic settings on the unit itself.

[openspaceman]

It is over a month since I bought stuff for this and my original installer has broken off contact, why do trades people do this rather than say they won't do the work. I never stilted him or questioned his price last time and never discussed it for this job.

So I started DIY of the mount system, it will start flat and I will raise it as time goes by until it sits right for me.

I will have to find a PV competent electrician to splice the MPPT charger into the cables joining the battery to the inverter, I expect this will confuse the inverter somewhat over deriving the SOC, I am still not sure what the data cable conveys twixt battery and inverter.








All the aluminium extrusions were wrongly supplied (or ordered) for the original 16 panels, I have kept them for 10 years just in case.

I am repurposing two of the mounting rails as toe retainers and cutting the adapters which carried the load onto the rafters and their Y-pieces to make the clamps for the Airy points as per OGB's advice so I have only had to buy SS U-bolts to clamp the scaffold poles and a few SS bolts so far. It won't be elegant but needs must...

If you see any glaring problems please pipe up


Next job is to get it on the roof

[nowty]

I will have to find a PV competent electrician to splice the MPPT charger into the cables joining the battery to the inverter, I expect this will confuse the inverter somewhat over deriving the SOC, I am still not sure what the data cable conveys twixt battery and inverter.

If you see any glaring problems please pipe up

You might find it difficult persuading someone to do the DC splicing as your doing something which its not officially designed for so you may have to do it DIY. Your just about within the max charging capacity of the batteries with the extra panels.

Your batteries Growatt GBLI6532 take 104 A.
Your Growatt SPA3000TL BL charges at 66 A.
If you've got 1.5kW of panels, your going to get a max of around 30 A out of the Victron charge controller.

66 A + 30 A = 96 A

As yet I haven't heard of a case where this does not work. The stats on the inverter will be all over the place, but with these things, there is no guarantee the Growatt's won't think there is something wrong and shutdown.

If you've got the nounce to get those panels up on the roof, run the cables, fit the charge controller, there is not much more to splicing the cables. Your DIY skills look OK so far.

[openspaceman]

Thanks Nowty, I only intend to charge the battery in winter months when the FITs system cannot fill them up. They will be left open circuit in summer.

I have about 10m of welding cable which I intend to use from charger to battery but the growatt battery has some sort of proprietary connector so I may have to peel back some insulation and make a join with a clamp of some sort.

Have you any suggestions for the wire from the panels to the charger, it's about 10 metres so could be quite lossy in cloudy weather?

Space on the roof is tight and I am not sure I have given myself working room so they may have to go on a shed near a public footpath.

[nowty]

Thanks Nowty, I only intend to charge the battery in winter months when the FITs system cannot fill them up. They will be left open circuit in summer.

I have about 10m of welding cable which I intend to use from charger to battery but the growatt battery has some sort of proprietary connector so I may have to peel back some insulation and make a join with a clamp of some sort.

Have you any suggestions for the wire from the panels to the charger, it's about 10 metres so could be quite lossy in cloudy weather?

Space on the roof is tight and I am not sure I have given myself working room so they may have to go on a shed near a public footpath.

For a 10 meter run from the panels to the charger, I would just use standard 4mm Solar cable, losses on a 10m run are only 1.5%, if you use 6mm the losses are 1%. If going on the shed, then I would use SWA if burying the cable.

[openspaceman]

[
As yet I haven't heard of a case where this does not work. The stats on the inverter will be all over the place, but with these things, there is no guarantee the Growatt's won't think there is something wrong and shutdown.

I'm busy making the clamps and drilling the party wall to take the unistruts.

Reading the manual for the Growatt battery it does say that the battery will be shut down 25 minutes after the data cable fails, oddly it also says not to parallel a new and an old (>300 cycles) battery.

Yet more reasons to avoid Growatt if one wants to expand even though it just works if left alone.

Trying to source the Growatt parallel cables for joining two batteries by a Google search is failing any ideas so I can avoid cutting into the current ones?

[Oldgreybeard]

Looking at the Growatt battery connectors they look to be very similar to the Pylontech ones.

These people seem to stock a range of Growatt cables, might be worth giving them a call: https://www.dragonsbreathsolar.co.uk/pr ... ry-cables/

Alternatively if it turns out that they are Pylontech type connector then there is a fair chance that people have some spares around that could be used to make up some special leads. Pretty sure I have a spare set of Pylontech connecting cables, the short ones, as I needed to buy a pair of longer ones due to the way my packs are arranged as two groups of three. No doubt others here may also have spares for a similar reason.

[nowty]

Rather than cut the wires, you could parallel up the leads onto an intermediate terminal block from the inverter end. If it did not work, then at least you have not damaged the original cable.

Something like this, note the wooden block to prevent accidental dropping of spanners and screwdrivers across the terminal blocks.

[openspaceman]

Rather than cut the wires, you could parallel up the leads onto an intermediate terminal block from the inverter end. If it did not work, then at least you have not damaged the original cable.

I will have to switch off the battery to look at the inverter connection, it is beyond a gland nut that is marked 2 holes, I had assumed it was a proprietary connection but yes if it is just an eye I can make up two cables and a terminal block/busbar.

[nowty]

Rather than cut the wires, you could parallel up the leads onto an intermediate terminal block from the inverter end. If it did not work, then at least you have not damaged the original cable.

I will have to switch off the battery to look at the inverter connection, it is beyond a gland nut that is marked 2 holes, I had assumed it was a proprietary connection but yes if it is just an eye I can make up two cables and a terminal block/busbar.

I had a look at the manual for your battery inverter and it does look like a screwed eye terminal within the gland cover.