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diy solar

UK Help needed with 5.5kw hybrid grid tied I'm old school C&G trained so would appreciate some help

Mikeholdom

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Joined
Oct 30, 2021
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IMG20211028162004.jpglittle help needed please don't laugh.
Right I'm old city and guilds guy so not all up to date. My question is how to tie in to the consumer unit correctly.
I'm going to be using a surge block on some 6mm cables to run back to board but does anyone have any pointers. The unit is a hybrid so I can add batteries. What AGM type do you recommend it says minimum of about 125ah at 48 v.
IMG20211029152226.jpg
I have 1 series string of 12 panels at 380w I have a voltage of about 480-500v DC so my pc voltage is about spot on. Just wanted some friendly advice please. I know I will have to do a g99 sign off hopefully my c&g qualifications is enough. But any general help and advice would be grateful

Thanks.
IMG20211030121810.jpg
 
If you measure near 500V already, may not have enough margin for higher PV Voc on a cold day.
Do the math with temperature coefficient of Voc from PV data sheet and record cold temperature of your location.

You can choose battery quality/price depending on how many cycles you expect.
I undersized my SunXtender AGM bank, expect 70% DoD overnight, because few power failures expected in 10 year lifespan.

In the U.S. we have breaker panels with a busbar. Concern is main breaker plus backfed breaker from PV delivering more current than it can handle. We are allowed to exceed busbar rating by 20%, but have to put PV breaker at far end so no part of busbar carries sum of the two.

Not sure if you have a busbar, or wires connecting breakers in that panel.

We also might be required a visible-blade disconnect, so utility can be sure they've disconnected our PV "generator". More recently, my utility said optional (they could yank the meter to isolate.)
 
Sorry not knowledgeable about UK electrical grid but attached may be helpful.
Cheers!
The for is a g99 over here I think my qualifications can sign that off. But was more interested in how to attach to the consumer unit. As in the tails from the AC part of the Inver. But yes I'm aware of the bits I have to fill in
 
Your vocabulary is a bit different from what I'm accustomed to.
When you say "consumer unit", I'm not sure if you mean electrical loads, or a product meant for general public rather than industrial customers.

We typically install a "protected loads panel" on output of a battery inverter, so they continue to receive power like from an uninterruptible power supply.
What I've also done is install a backfed breaker in the main panel, interlocked with the main breaker from utility grid. That lets me disconnect from grid and feed other loads in the house as well.
Of course, have to manage larger load to avoid running the battery down. Maybe operate them only when PV is producing.
 
Not full G99 but..

a) for my G98 DNO notification I wrote "N/A" under installer qualifications. I carefully provided all details requested, clear wiring diagram etc. It was all fine.

b) I am currently in the G99 fast track process and also wrote "N/A". A network engineer did actually call me earlier this week to discuss. He'd read my application in full but didn't say anything about my lack of qualifications and he hinted they'd probably approve.

Just be totally honest. They're not building control. They don't care if you burn your house down or electrocute your cat. They *do* care whether you will put any of their grid maintenance staff in danger or destroy any of their infrastructure.
 
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