Victron Multiplus, SMA PV, Honda EU20i generator + On grid. What Batteries?

[biff]

Hello Al,
         I have this thing about Ah claims.I don,t care what they say but a batt which weighs only 29kgs will not have 90ahs after a few discharges.
   I knackered a few AGMs in my time,great big brutes of 50kgs efforts, They start of ok but after a while they degrade and don,t hold the charge as well,
  I would put my money into the rolls or buy into good indestructible forklift jobs . A forklift battery will forgive you anything.
                                                                        Biff

[billi]

All these expensive machines are like a trap,once you get sucked into them you have to keep buying them compatible toys,,for that year,,for that model.
  The whole idea of renewable energy is that life can be more simple,more compatible ,more renewable.

Absolutely.

The simplest, cheapest and most sensible option for the OP is a bigger generator. It's only to cover a couple of power outages a year, which could probably be coped with without standby power at all.

Trying to fully integrate the original PV system is silly. If you don't lose FIT entitlement altogether, the system output will be lower with so the FITs will be lower - and the cost will be totally disproportionate.

Having said that, I like expensive toys myself so when I have bought the batteries and built the room to house them I'll be going mainly off-grid with a non FITted 12kW SunnyBoy/Sunny Island system to replace the UPS. The original 3.8kW FIT system will be unmodified and export 100%.

Trying to fully integrate the original PV system is silly

 Why ?

Pretty easy    to store   electricity   from a FiT harvesting system and reuse  later  without  loosing FiT payments , but gaining  monney because of avoided imported units  from Grid  

[al_uk]

What maintenance do the Rolls batteries (or similar) need? Are they fit and forget?

My current UPS is in a small boiler room about 1m x 1m with a concrete floor and block walls, and not that much flammable stuff in it. Although it is part of the house, it is accessed only from outside. Would this be suitable for "proper" batteries, or should they be in a separate building?

[camillitech]

What maintenance do the Rolls batteries (or similar) need? Are they fit and forget?

My current UPS is in a small boiler room about 1m x 1m with a concrete floor and block walls, and not that much flammable stuff in it. Although it is part of the house, it is accessed only from outside. Would this be suitable for "proper" batteries, or should they be in a separate building?

Your current location seems just fine and I guess if it has a boiler in it's well ventilated and not too cold, purrfect. I've just fitted Rolls batteries to my new 'off grid' build after years of using forklift cells. Not that there's anything wrong with fork lift batteries, as Biff says they're very forgiving and can stand lots of abuse. However I replaced a forklift bank for a mate with Rolls S530's a couple of years ago http://lifeattheendoftheroad.wordpress.com/2012/04/16/bouncing-batteries/ and was severely impressed with them. So much so that I spent £3K on a set for my new house



I've mounted mine on a sturdy wooden frame to keep them warmer and make topping up easier, they are quite thirsty and float at a higher voltage than forklift cells. I religiously check SG's fortnightly and log them, my mates cells require topping up more often than mine as I have these fitted http://www.navitron.org.uk/product_detail.php?proID=808&catID=157



and I think that price is a miss print as mine were half that. Billy has had Rolls cells with hydro caps fitted in his barge and hasn't topped them up in seven years.

Sounds like a great project and great to see someone else doing something because they want to and not because it makes financial sense  

Good luck, Paul

[billt]

Trying to fully integrate the original PV system is silly

 Why ?

Trying to fully integrate the original PV system is silly. If you don't lose FIT entitlement altogether, the system output will be lower with so the FITs will be lower - and the cost will be totally disproportionate.

[camillitech]

the system output will be lower with so the FITs will be lower - and the cost will be totally disproportionate.

How will the system output be lower? the generation meter is after the GTI and before the Mulitplus so the output kWh will be the same. Granted if the energy is not consumed via the AC bus and backfed into the batteries then the efficiency will be lower but then the OP will not be importing at night. Sure it probably makes no economic sense but then that's probably not the goal.

[billt]

That depends how the system is designed. Using a Sunny Island type system the PV output will be throttled when not consumed on site, hence less total generation. A SI system can't be grid connected AFAIK, hence there will be no export payments. Anything done to a FIT system needs to be approved by the relevant bureaucracies, so work done will need to get MCS approval. This will be expensive, which is the main point.

No doubt there are ways of doing it that don't involve changing the grid connected system, hence FITs won't be affected. I would expect that they will also be expensive to implement, just to avoid running a generator for a couple of days.

The OP wanted advice on implementing a super UPS system, without modifying the existing grid tied system. Billi then went on about using all the PV generation, by integrating the current PV system with the UPS system and then adding more PV. I'm just pointing out, along with Biff and Martin, that that isn't a sensible route.

I've got nothing against complicated, and even expensive, gadgets and systems, but to recommend an even more complex and expensive (and imaginary) system doesn't seem terribly good advice.

[martin]

This does rather bring to mind the (now said to be untrue) story of how the Americans spent gazillions on building a "space pen" that could write in zero gravity (I remember when you could buy them, so it wasn't that much of a fib), the Russians scratched their heads for a bit when faced with the same problem, then used pencils...........

[camillitech]

I don't think it's a sensible route either and I've lost count of the number of times that I've said "a battery system 'on grid' is neither cost effective or green". I just didn't see how the generation would be less, having an 'off grid' head and having my meters on the outputs of both Sunny and Windy Boy's. My system is configured not to 'throttle' anything but of course it's not G83 compliant 

Cheers, Paul

[Tinbum]

The Sunny Island is G59/2 approved.

[billt]

I sit corrected.

However, for a backup system, that requires the addition of a G59 relay. So an over the top, expensive, system needs an extra costly component.

http://www.windandsun.co.uk/media/296773/SI60H-80H-G5921-Declaration.pdf

[RIT]

I sit corrected.

However, for a backup system, that requires the addition of a G59 relay. So an over the top, expensive, system needs an extra costly component.

http://www.windandsun.co.uk/media/296773/SI60H-80H-G5921-Declaration.pdf

The current G59 rating seems currently probamatic as SMA does not seem to have a switch in their product range and it you look at windandsun's web site its clear that there is not one currently available. My guess is no manufactor of a automatic transfer switch device has bothered to get the correct UK approval. After all with the FITs system in place there is a limited market for such a device.

[Tinbum]

SMA used to make automatic transfer switches for the sunny backups but no longer do so. The Backup was basically the same as the Island, at that time, but with different software.

[billi]

Here it is for the Victron

Grid Connected Battery Back-up

With earth switching compliant with G59/2 the Victron Quattro and MultiPlus inverter/charges allow you to store excess generation from grid connected PV & wind systems during the day for use at night. As a bonus you will also have backup power should the grid go down.

See Victron G59 statement

http://www.windandsun.co.uk/media/289711/Victron_G59_statement_of_fact.pdf



I say it again , instead of buying   a Victron 3000 watt Multiplus and Batteries , just for the occasional  power failure ,  i would use it everyday and night instead ,  with that  , one can utilise    upto 100 % of homegrown PV   and the extra costs for better batteries  will be covert by avoiding the immesun and Co devices , and the  gain of  avoided imported units   ( even if only  1500 kWh per year at an guesstimated average  price of 20 p per kWh ,  that makes 3000 GBP  in 10 years )

A 15 kWh  Battery that lives more than 10 years   should be under 1500 GBP

Billi

Billi

[al_uk]

Thank you all for the debate! Lots of food for thought, and I'm going to do some more research before coming back.

On a slight tangent, If I want to add more PV, then am I right in saying that I have the following options?

1. Call my DNO (SSE) to find out whether I can go beyond my existing 3.68kW install. If so, then standard MCS grid tied install of another approx 4kW.
2. If DNO says no, or wants to charge £££ to find out, then next best option (as per Nowty) is DIY. So, 2nd hand panels, into a GTI, then into a mini grid provided by a Multiplus/Sunny Island but synced with the main grid. Then to use the downstream power locally. Any excess power will be throttled back by the Multiplus. 

Am I correct in thinking that the Multiplus can be connected to the grid as a UPS (via 16A plug and socket) and G83/G59 does not apply. Therefore I need no notification to the DNO and no electrician EIC as long as the power is not exported back out to the AC1 input. However the moment I reconfigure the software to export back out to the AC1 input then G83/G59 applies?

I am confident I can use almost all the power locally from the diy "offgrid" system all year round.

Thanks again for all the comments.