Longtime lurker going offgrid

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Re: Longtime lurker going offgrid

Postby davidg » Wed Feb 03, 2016 2:04 pm

offgridCBR wrote:If I was to go with a cheap/ok auto-start genset for battery charging what would you recommend?


Budget 5k to 6k for a "cheaper" generator that will last, approx 8kVA, 3 cyl 1500rpm properly silenced and weatherproof, anything cheaper will let you down when you need it most or will burnout .

offgridCBR wrote:- Looking at using bottled gas (or fixed tank..?) for cooking and for instantaneous boosting of an evacuated tube SHW system at this stage.

stick with bottles, you can own them yourself for approx $300ea, simply have several of them.

offgridCBR wrote:This is very likely to go up with the new house and associated amenities.

expect it to triple. Pumps etc take power to drive..


offgridCBR wrote:Would a worm farm system work here?

yes.

offgridCBR wrote: (I will definitely check out the biolytix system - thanks Kurt!).

can't they there gone, either "onZite" or "AA worm farms" now appear to be the 2 major choices.

offgridCBR wrote:I had the same concern with power usage of an aerated system... :?

be concerned very concerned.

offgridCBR wrote:What BMS would work well with the Winston batteries and quoted system?

depends on what you are prepared to spend.

if you are definitely going SMA then consider one of the ones that "talk to the inverter" although they are very limited.

Me I would Selectronic myself , but I'm biased foor several reasons, however I do have systems that run LiPo's on Selectronic. Variable frequency power management control can cause issues, not always however if your unlucky enough to be one of the installation where frequency is an issue it will take enormous patience to maybe resolve the problem and can be very frustrating.

offgridCBR wrote:I was also hoping to be able to do the occasional welding in the shed... what inverter rating would be required to support that?

The 8.0h will do it, but don't have much else on at the time the true rating of the 8.0H is really only a 6kW continuous. My SP-Pro SPMC-482AU 7.5kW does welding etc with ease even with the running, the surge factor is pretty decent 18kW's

offgridCBR wrote:Also definitely upgrading the standard insulation, current standard is:
R 4.0 ceiling insulation batts
R 2.0 wall insulation batts + 7mm plywood bracing and cladding (looking at weathertex)
Heavy Duty roof sarking & wall wrap
R 1.5 under floor insulation


R4.0 is a joke, try going at least R8+ for the ceilings, in other words try and at least double the insulation values across the entire exterior of the building minimum. At that height above sea level you would nuts not to.
--
Our new build is R10.0+ in the ceiling, R7.0+ for the exteriors walls, R2.5 in every internal wall, sitting on a thermally broken slab.


offgridCBR wrote:It rarely snows and is usually quite light if it does where the property is located.

Snow equals no power being produced at all, like wise fog etc.

offgridCBR wrote:Davidg, why would the altitude dictate the price of the system? And why do you envisage that it would be under specified/designed, outside of the number of panels and inverter rating?

If it was my system I'd double the number is panels. Cold has an impact on all types cells regardless, just less so on LiPo's, ie they will not deliver quite the amount of theoretical power that would be otherwise available at 15C to 35C above 35C is bad, below particularly subzero chemical reactions slow down a lot making less energy available to be used at any instant and overall. They will tolerant it better than PB but ultimately heat and cold has an impact on their long term life and particularly high heat.
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Re: Longtime lurker going offgrid

Postby Gordon-Loomberah » Wed Feb 03, 2016 2:15 pm

offgridCBR wrote:I was also hoping to be able to do the occasional welding in the shed... what inverter rating would be required to support that?



I used to do quite a bit of welding with a 2.4kW Selectronics, also 3, 4 and 7kW Latronics, and they ALL handled it with no issues, other than occasionally having to allow a bit extra time between long runs with the MIG with the smaller 2 inverters.
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Re: Longtime lurker going offgrid

Postby offgridCBR » Wed Feb 03, 2016 9:14 pm

Gordon-Loomberah wrote: used to do quite a bit of welding with a 2.4kW Selectronics, also 3, 4 and 7kW Latronics, and they ALL handled it with no issues, other than occasionally having to allow a bit extra time between long runs with the MIG with the smaller 2 inverters.


Good to hear that I don't need to upgrade the inverter!

Thanks for the other answers davidg. I won't be dropping 5-6k on a generator anytime soon though....

I will definitely up the insulation though cavity space will be an issue.

The local CRT in Bungendore has the AA Worm Farms, I will drop by and see what they want for one installed.

Didn't realise you could purchase the 45kg bottles, I thought they were on a swap/loan system like bbq bottles.

Currently I am looking at SMA due to the installer favouring them, but I am open to changing them also. He has been the only reasonable quote out of 6 I contacted around Canberra. Most wished to install Lead Acid systems for 36-55k :evil:

Will try and fit a fireplace in also. But still thinking of having a couple of those small efficient Mitsubishi R/Cs installed.

Other than the actual storage spot/insulated room for the gear is there anything else I am missing? and BMS....
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Re: Longtime lurker going offgrid

Postby davidg » Thu Feb 04, 2016 7:24 am

offgridCBR wrote:I won't be dropping 5-6k on a generator anytime soon though....


Anything cheaper at the altitude would be a waste of money. The number of "little" diesel generators around that are dead is amazing. The amount is based on what would allow it to be around long term.

offgridCBR wrote:Currently I am looking at SMA due to the installer favouring them, but I am open to changing them also. He has been the only reasonable quote out of 6 I contacted around Canberra. Most wished to install Lead Acid systems for 36-55k :evil:

I certified for SMA. For off-grid I still prefer Selectronic with PVI ABB inverters, costs more and in my opinion works way better. I'm battery agnostic, I have installed both types of batteries but the price you have been quoted is very cheap, I hope it works out, I'd be wary. As for BMS the setups, the BMS arrangements I have installed can workout up to about $1500.00, there a combination of LVD/HVD, DC high current relay cutoff, dynamic balancing modules, the wiring, etc.

offgridCBR wrote:Will try and fit a fireplace in also. But still thinking of having a couple of those small efficient Mitsubishi R/Cs installed.

Add the extra Solar, make the array ground mount so you can clean them off when required on the roof make them essentially in accessible if you needed to do this.

offgridCBR wrote:Other than the actual storage spot/insulated room for the gear is there anything else I am missing? and BMS....

Did you do or have a proper detailed load profile completed? or ???? based on price. I have to ask. If not then before getting or considering quotes, it's critical it's done with a full proper load profile in detail, rather than a general estimate. One family did one for me, the quotes they had received based on a certain amount of kWh's (24hours) were an average of 8-10kWh's per day short of what they were really going to use overnight (roughly 12hoours). Off-grid is not the same of being on the grid or having the grid available, one needs to ensure you deal with some of the worst rather than only typical, a generator will allow for mostly the average and likely last decades for reasonable "cheap" one.

I installed a system in SA using LiPo's the spec for that was based on 15kWh's overnight (12hours) based on the final load profile worked through with them, it only just meets the demand their using, only 2 years down the track, my quote was approx $10K more than others, I have recently suggested an increase in the number of panels on the system as the Kaco inverter that was installed will allow for double what it has on it now, they have the roof space to do it.

If it had been anything like other quotes it would have been woefully short of delivering the required kWh's they are using as an average now (Other quotes had allowed maybe approx 10-15kWh's per 24hours), took them only a few months to hit 20kWh's average being used overnight or approx per 12 hours, glad I allowed a decent "increased average load factor or growth factor" during the summer holidays for the last 2 years they have had 10 people in the house and it still copes, just. 8-) #just saying.
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Re: Longtime lurker going offgrid

Postby Cherokee Solar » Thu Feb 04, 2016 7:36 am

Hi offgridCBR,

I'm off grid and use less than 5kWh per day and haven't run a generator for years. Everyones advice here about the wind turbine is spot on. Add more panels to your system.

Have you considered burning firewood for your heat source? Firewood can also provide an oven and stove top to cook on as well as heating your hot water - it gets hot. If you have space you can grow a wood lot or harvest your own trees. One medium sized wood heater could easily heat a 150sqm home, although I hope you placed plenty of insulation in the wall cavities and roof space?

I use a flat panel type solar hot water panel and I'm at 700m ASL in VIC and the system runs a bit of water through the panels if it senses that there is a frost, but I have never had a burst pipe due to freezing water anywhere in the entire water system and we just had the coldest winter in 26 years. Evacuated tubes are meant to be better than flat panels but I have a preference for old school technology and it occasionally hails here and I wonder about those evacuated tubes.

I recommend the A&A worm farm systems and the whole thing runs on gravity (as I have sloping block) so uses no energy whatsoever. You can chuck in any organic matter and the worms break it up very quickly. The downside is that they are expensive. I wonder about all of the high tech systems with their pumps and alarms and monitoring circuits and chemicals because basically nature breaks manure down into soil - all of the time - and has done so for a very very long time.
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Re: Longtime lurker going offgrid

Postby bpratt » Sat Feb 06, 2016 9:03 am

offgridCBR wrote:- I will definitely steer away from wind and go with some more panels if I have left over coin. If I was to go with a cheap/ok auto-start genset for battery charging what would you recommend?


For fuel, either diesel or LPG. Petrol goes off quicker than diesel, but a petrol generator converted to LPG would work.

- Can't go with the traditional septic system sadly. Geotech did a Site & Soil Assessment for On-site Effluent Disposal, result was topsoil to 300mm, clay to 600mm then weathered granite from 6-800mm. Report stated surface or subsurface irrigation and an aerated wastewater treatment system. Would a worm farm system work here? (I will definitely check out the biolytix system - thanks Kurt!). I had the same concern with power usage of an aerated system... :?


My worm farm treatment plant came from the guys down at A & A Worm Farms at Hastings in Victoria, wormfarm.com.au
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Re: Longtime lurker going offgrid

Postby Gordon-Loomberah » Sat Feb 06, 2016 9:15 am

bpratt wrote:...a petrol generator converted to LPG would work.


Don't waste money on converting, just get a straight LPG unit, that's what I use here. I use it it charge the LiFePO4 battery via a 25A charger, IMO there is no need for a huge expensive generator capable of running every house load at once.
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Re: Longtime lurker going offgrid

Postby Cherokee Solar » Sat Feb 06, 2016 9:33 am

Gordon-Loomberah wrote:IMO there is no need for a huge expensive generator capable of running every house load at once


I second that - and the smaller units are more readily repairable by local people which means that the maintenance costs will be lower. It may be worthwhile finding out who services such things in your area and then buy a name brand - like a Honda for example - that will make the whole process easier for you. ;)
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Re: Longtime lurker going offgrid

Postby bpratt » Sat Feb 06, 2016 9:34 am

Gordon-Loomberah wrote:
bpratt wrote:...a petrol generator converted to LPG would work.


Don't waste money on converting, just get a straight LPG unit, that's what I use here. I use it it charge the LiFePO4 battery via a 25A charger, IMO there is no need for a huge expensive generator capable of running every house load at once.


Agreed, but I was suggesting if the OP did buy a petrol one, he could get it converted across to LPG.

Personally I have gone the diesel generator route. I got what I thought was a pretty good deal about 7 years ago, and got a 15kw generator.... certainly overkill for a home, but it can run everything. It runs a very low load, and it's also a 1500rpm one too, so it runs quite efficiently.

If I were to buy a new one now, I certainly wouldn't go anywhere near that big, particulary as the plan is to go offgrid eventually, so a smaller generator with a 25A or perhaps even a bit bigger charger would be all that's required.
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Re: Longtime lurker going offgrid

Postby tom rickard » Mon Feb 08, 2016 9:27 am

David mentioned it briefly, but if you are using a Sunny Island get a BMS that talks directly to it. Scroll down on this page: http://www.nothnagel-marine.de/index.ph ... anguage=en To get an idea of what you are looking for.

Basically when A/C coupled the Sunny Island in Lithium mode relies on information from the BMS for it to switch off the slave inverter by changing the A/C frequency very slightly. If you don't have a BMS that can talk to the Sunny Island, you will have to use other methods to ensure your batteries aren't overcharged.

Make sure your installer has done a similar system before (ie: SMA and LiFePo4), and if possible speak to the owners of that system.
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