Off Grid PV Systems

[DBA Forum (B) - Christopher Morton]

Just wondering if anyone has experience with full off grid PV systems (with generator backup obviously)? I am looking at a large PV system 4-5kW for a barge to run a main 230v ring during peak hours and then batteries to run systems during the hours of darkness. I am also considering a couple of 1kW mobile wind turbines for winter as an additional source for day and night.

Has anyone done this before or is the more traditional route of a small battery bank and generator the accepted norm? I'd be interested in opinions and experiences to help with our decision making process.

Many thanks.

Kip

[DBA Forum (B) - Nigel Seaman]

Christopher,

Go to the KnowledgeBase section of this website. Look under the top00ic of Electrical.
Chris Roy's Solar Calculation Spreadsheet is particularly useful.
Many people have installed PV on their barges, in fact it is a regular Forum topic of discussion.

I am in the planning stage and have found it frustrating that the key players in the market will not offer any assistance whatsoever with regard to the integration of a PV system with an existing Battery banks / Inverter / Genny system.

Regards,

[DBA Forum (B) - Christopher Morton]

Dear Nigel,

Many thanks. The downloadable handbook looks very useful. I have been researching for some time but haven't yet found anyone who lives truly off grid on the majority solar with a 'normal' level of electrical consumption. I have found off grid packages for sale but they are normally around the £15-20k mark and I am unsure whether they would be suitable for barges (space, access etc).

I have some friends in the renewables trade and they are, as you say, not keen on getting involved. I guess for them it's just TFD with too many unknowns. I will keep looking as with the lack of moorings in the UK I think self sufficiency for water, power and sewage treatment are going to open up areas where traditionally no one would consider mooring for any length of time.

Thanks for the pointers and best of luck with your system too!

Kip

[DBA Forum (B) - Nigel Seaman]

Hi Kip,

I'm glad to be of help.
During my cruises around the Netherlands I have come across a number of converted old and replica barges with off-grid installations. These were mainly German owned. I was in Enkhuizen a month ago and such a barge moored next to us. I asked them if they could show me their system but they unfortunately didn't speak English and my German is fairly non-existent.

I am wondering if any members have recorded the layout of their PV system in wiring diagram format......now that would be useful indeed!
Any takers?

Cheers,

[DBA Forum (B) - Colin Stone]

Kip,

Chris Grant, MV ESME, has an off grid 240v system. I recall 2.5kwp system - 10 250w panels.

A search on the Forum will find his posts with lots of detail, and also all the other aspects of self sufficiency.
I guess the trade steers away cos they are only interested in charging lots for MCS? schemes.

Colin Stone
KEI

Sent via BlackBerry® BIS

[DBA Forum (B) - Christopher Morton]

Dear Nigel,

I think it would be an incredible resource if people could provide keep system diagrams of sewage systems, PV, electrical and so on with comments about what worked and what didn't. There is so much I would do differently from my first boat, although to be honest we inherited a lot of the infrastructure so I am dealing with someone else's poor design. It has been a harsh task master but useful in the long run.

I will keep hassling my friends in the renewables trade and anything useful I will pass on for consideration to the technical section.

Best regards

Kip

[DBA Forum (B) - Christopher Morton]

Dear Colin,

Many thanks indeed. I will hunt him down (in the nicest possible way obviously) and see what his posts reveal.

Best regards

Kip

[DBA Forum (B) - Daniel Boekel]

This has some great reading:
http://www.otherpower.com/

Google for 'off the grid solar' for lots of results.

SMA is a big manufacturer, 'problem' with most barges is they mostly use 24volts, where al lot of bigger off grid solutions are 48volts.
For such a heavy system I'd say go 48 volts.
look for the 'sunny island' systems by SMA, they can be combined with big solar inverters and / or micro-inverters (of most brands also)

I recently bought a used, tested, gel-battery from a fork-lift company with a remaining capacity of 700 AH / 48v so about 30 kWh for just 1200 euro's (1400 kg so most you get back when recycling in 10 to 20 years time)



2014-09-16 12:46 GMT+02:00 DBA Forum (B) - Christopher Morton <dbabarges-pvYRptiajiAdnm+***@public.gmane.org>:


Just wondering if anyone has experience with full off grid PV systems (with generator backup obviously)? I am looking at a large PV system 4-5kW for a barge to run a main 230v ring during peak hours and then batteries to run systems during the hours of darkness. I am also considering a couple of 1kW mobile wind turbines for winter as an additional source for day and night.



Has anyone done this before or is the more traditional route of a small battery bank and generator the accepted norm? I'd be interested in opinions and experiences to help with our decision making process.



Many thanks.



Kip

[DBA Forum (B) - Christopher Morton]

HI Daniel,

Yes I certainly agree with you ref the 48v system. It also means greater efficiency for conversion back to 230v so is a winner all round. The only minor snag is that you would have to have separate conversion to 12/24 for pumps and lighting on board as there is very little available for 48v, but that said, I guess it's a pretty small price to pay.

That sounds like a great deal on the forklift battery. I guess if you can spec a system and then pick up the elements individually you must be able to make big savings when compared to 'packaged systems'. I think going the domestic route is the way to go as everything is geared to providing 230v. Food for thought though.

Regards

Kip

[DBA Forum (B) - Chris Grant]

Kip

Yes, I have installed an AC solar off grid system on our barge Esme for
over a year now. It all works well but there are a few things to
consider which I'm still perfecting. Have a look at
http://www.mvesme.co.uk/the-barge/solar-electric-system which describes
the basic system. I'll make a list of the changes I've made since then
and update the page. The main one is you will need the latest Victron
Quattro or Multi in order to run their downloadable 'assistants', the
main one being the hub2 v3 assistant to prevent export of excess power.
http://www.victronenergy.com/blog/2014/07/29/self-consumption-hub-2-v3-assistant-a-major-update/

They are still working on this to get it right but it does work.

I'll also add here that you may not need anything like 4-5kW as the
problem off grid is knowing what to do with the excess on sunny days and
preventing big surges of power and overcharging of batteries when the
power has no-where to go. See
http://www.victronenergy.com/upload/documents/Whitepaper-Self-Consumption-and-Grid-independence-with-the-Victron-Energy-Storage-Hub-EN.pdf

page 5 for details

More later, Chris

Dear Colin Many thanks indeed. I will hunt him down (in the nicest possible way obviously) and see what his posts reveal.

[DBA Forum (B) - Kevin Wade]

I have 500w of 36v house type panels with an MPPT into 1180ah of traction batteries. We are not in the slightest energy "responcible" and out bigget draw is a full size domestic 230v fridge freezer.

Even this time of year we can get 2-3 days without running the engine or generator. I suspect with another 500w we could get this in the winter too.

Do a search on my blog in the sig for solar. Mine is a very simple system and it works.

[DBA Forum (B) - Christopher Morton]

Dear Chris,

Interesting stuff and very useful thanks. I guess the excess power on very sunny days is a serious consideration and was looking at the Solamiser or similar to divert excess solar generated electricity to an immersion heater but even so I guess there would still need to be a resistive somewhere which can cope with the excess.

Given a clean slate and a new project what would you do differently?

Kip

[DBA Forum (B) - Christopher Morton]

Thanks Kevin. Looks like a nice simple system but I think I would have increased energy needs as I am looking at an onboard sewage system with an aerator and a biomass cooker/CH boiler. Nice system though and obviously works well.

Kip

[DBA Forum (B) - Chris Grant]

Kip, the trouble with the solamiser and other such addons is that they generally monitor current export and divert in order to retain only a couple of watts export sending the rest to a load. In an off grid installation there is no grid to monitor and if you are connected to the grid you must prevent all export as it is generally illegal and dangerous, if the port is switched off or trips you will end up powering the port or electrocuting a repair man who thinks they have isolated the port. I have a special licence with SMA to re-configure the Sunny Boy in 'off-grid' mode which renders it outside local country settings and regulations. Hence the need for the Victron hub2v3 assistant which prevent all export and only connects the grid or gen if things are getting bad re state of battery cha
rge or demand outstrips availability or solar and inverting. The good thing about Victron assist is that it can take care of short high demands and smooth out usage. In other words you could have a
fairly crude dump to water heater which may even use some battery to top up solar for short periods until water is heated and then solar will recharge the borrowed power.

The Sunny boy power is cut back by monitoring the mains Hz while the Victron is set up to increase the Hz to 52Hz when the battery voltage rises above a preset level (about 29V) and or the stage of charge is 100% which is then seen by the Sunny boy solar inverter which cuts back it's output to about 100W. This is a standard format for Inverter communication and the occasional increase of 2Hz is not an issue unless you have old fashioned freqency driven clocks. However, you can;t be on grid when this happens as it will cause a depahes with the 50Hz grid and sync erros with the inverters. The Sunny boy sees the Victron as the grid and syncs itself with it.

Where are you based and what is your ship size? When we get back to Brugge I will have more time to write up my system and ideas including a clean slate design. Sadly I'm stuck with two perfectly good Victron Multi 3000s but outdated firmware which is too old to run the latest hub2 v3 and I can;t really justify replacing them with a Quattro 5kva. I have a friend though who has the new Quattro 5kva with a similar Sunny boy system and we will be installing this all with hub2 v3 during the winter so will be able to test it thoroughly and let you know the results. Chris Grant

Dear Chris, Interesting stuff and very useful thanks. I guess the excess power on very sunny days is a serious consideration and was
looking at the Solamiser or similar to divert excess solar generated electricity to an immersion heater but even so I guess there would
still need to be a resistive somewhere which can cope with the excess.
Given a clean slate and a new project what would you do differently? Kip

[DBA Forum (B) - Christopher Morton]

Looks like the Victron Hub 2v3 is the heart of this system. I guess the difficulty being that we want to have our cake and eat it by operating in island mode but with the option of taking genny power or shore AC should it be needed but without the export option.

I currently live on a widebeam near St Neots but we have our eye on a barge (24m) in Holland which is an empty shell. I am going through the planning and financing at the moment and having seen off grid kits at around the £15-20k mark I thought it best to ask those who have already done it, especially given the very niche requirements. I have the option to start from scratch and build all the systems to compliment each other (pellet fired oven/CH/hot water, aerobic sewage treatment plant, traction batteries, RO unit etc). My ideal end result would be to end up with a self sufficient unit (apart from the odd diesel fill up and pump out of the sewage plant once every 6-12 months or so) as it opens up far more options in terms of moorings for us.

Glad I have asked the question and many thanks for all the detailed feedback. More work yet to do and would be really interested to chat further about your friend's Quattro system and how that works out. I doubt we'll be purchasing before Christmas this year so I have time to look at all the options.

Regards

Kip