Solar panels and house batteries

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07 Jan 2013 12:12 #1 by Ewart and Vivian Halford
Ewart and Vivian Halford created the topic: Solar panels and house batteries
Hi all, I would like to hear from those of you who have solar panels and house batteries.
I understand it depends on the appliances people have but with space and weight restrictions conciderd.
To the Peters with 480& 460 amp hours, do you find it is over kill or not?
Those who have less what are your thoughts.
With what you have would you bo it the same again or make changes if you had to do it again.
Cheers

Ewart oka 365
0428911147

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07 Jan 2013 12:18 #2 by Peter_n_Margaret
Peter_n_Margaret replied the topic: Solar panels and house batteries
We have 460Ah of AGM (Fullriver DC series) after we replaced the original 600Ah bank 3 years ago.
Base your battery capacity on your usage with some spare such that typical SOC does not go below 60% on a regular basis (but can go much lower if conditions dictate).

I reckon you can't have too many solar panels.

Cheers, Peter.
OKA196 tinyurl.com/OKA196xtMotorhome
Mob.0428171214

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07 Jan 2013 12:50 - 07 Jan 2013 12:59 #3 by dandjcr
dandjcr replied the topic: Solar panels and house batteries
Ewart, we have 200w of solar and 2 SuperCharge 105AH house batteries (plus a starter battery).

I reckon that's about the minimum but it meets our needs, we don't have any high power electrical needs, (microwave, kettle, aircon etc) requiring a large inverter although a bread maker would be good. We've spread our power needs across gas and solar, and water is heated from the engine.

More solar would always be better as electronic devices multiply but our batteries are kept well charged (our trips are usually in sunny conditions) and nearly all our appliances are 12v (pumps, fans, lights, electronics, HF Radio, chargers etc) or low power AC.

We do run the 3 way fridge on 240v during the day because it's more efficient than 12v (less cable power loss) and solar power is available when not moving.

I wouldn't want to be without solar or gas (you always need several ways of doing everything) but I wouldn't really want more batteries either since they are heavy and we've got enough "heavy" as it is. I might add another 100w of solar so we are less affected by overcast conditions or alternator failure. A bit more gas would be an advantage, 2x 4.5kg bottles (plus a 3kg reserve) is not enough for a 3 week desert crossing and gas refillers are become scarce (only 1 in Port Hedland, where they mine the stuff!).

Plenty of power monitoring is a must so you don't get caught short.

Although we didn't really plan it that way, we've ended up with an acceptable compromise of power requirements and power supplies, proven over 120k km of outback travel.

David and Janet Ribbans - Oka 148
Oka148 profile here.
Visit our technical and travel blogs: here.
Last Edit: 07 Jan 2013 12:59 by dandjcr.

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07 Jan 2013 13:13 #4 by Hank Onthewater
Hank Onthewater replied the topic: Solar panels and house batteries
Hi Ewart
Peter is right you can't have too many solar panels, except for the cost of course.
Before you buy anything, calculate your daily usage ie in amp-hours, and then decide how long you want to stay without starting the engine. Then apply worst case scenario, ie winter, or parked in the shade, and all these things determine the size of your batteries and solar panels.
In addition to that you need approx 10-20% extra capacity for the charging losses, and another 20-40% to take into account the aging of the batteries, that become over time less efficient to hold the charge.
Lastly do not believe the advertising blurbs in regards the wattage of solar panels: they may be correct at the Equator, at noon, with no clouds, and the panels being new. A more realistic figure is somewhere round the claimed wattage minus 20%.

On my boat I have 160 Watt of panels plus wind generator with 5x100 Amp/hr AGM house batteries (Century). With no wind and little sun, this is not enough for me, have to run the aux engine for a few hours every 2-3 days. If I would buy more panels I need a bigger boat as there is no (esthetic) room for these on my current boat.

On the van/trailer I have 3x100 Amp/hr AGM house batteries (Odyssey PC2150) and 240 watts of panels, more than enough as the current fridge is used on gas, when stationary.
I would like to add more solar panels to the van (ie 300 watt), so I can be more self sufficient when parked in the shade. My plan is to add one more battery of the same ilk.

I have somewhere a spreadsheet that calculates requirements for batteries, panels, aux charging, wiring, fuses etc. I can email that if you like.
hank

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07 Jan 2013 14:29 - 07 Jan 2013 14:32 #5 by Len208
Len208 replied the topic: Solar panels and house batteries
Hi Ewart,
Collyn Rivers does a very informative book on solar in motorhomes.I suggest you look at his site or cmca books.Its about $40.Len

www.caravanandmotorhomebooks.com/books/campervan_motorhome.htm
Last Edit: 07 Jan 2013 14:32 by Hal Harvey.

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07 Jan 2013 14:34 #6 by Garry and Chris
Garry and Chris replied the topic: Solar panels and house batteries
We have 540watt of panels and 3 120Ah batteries running a fridge and a 60 liter Freezer. a 7 or 8 days without sun or driving the fridge warms up but the engles keeps frozen

OKA 306

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07 Jan 2013 14:50 #7 by Hal Harvey
Hal Harvey replied the topic: Solar panels and house batteries
Sort of off topic but you could always consider doing what we did too; a methanol-powered fuel cell. Our Efoy 2200 generates seven amps automatically as required, day or night. I think it would run everything for anybody. There are smaller output (cheaper) units available too. We have no solar panels - well we do have one but it's not connected - but there are Efoy users who also incorporate solar panels, which cuts down on the Efoy fuel usage. The noise level when running is about the same as a computer, they're maintenance-free and they're safe to use indoors.

www.eco-camper.com/e-shop/fuel-cells

www.sefca.com.au/page/direct_methanol_fuel_cells.html

www.efoy-comfort.com/benefits

Principal advisor to the Minister for Tourism, Liza Harvey MLA
... OKA 260 ... "I'm not leaving any sooner than I have to!"
www.byles.net/OLDportal/members-vehicles-public/5-oka-260

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07 Jan 2013 14:55 #8 by Ewart and Vivian Halford
Ewart and Vivian Halford replied the topic: Solar panels and house batteries
Thank you all for your thoughts, my initial thought was 2 x 220 amp hour batteries but at 65 kg each I not so sure, 300 amp hour may be a good midrange to aim for.
Len I do have 3 of Collyns books.
Space and weight is my biggest concern. As far as electrical items go we will only take if we have spare power. Like Collyn says keep it simply and pack lightly. Easier said than done. Will have 2 Autofridges, gas bbq and maybe deisel stove and heat exchange hot water system.

Ewart oka 365
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07 Jan 2013 15:19 #9 by Ewart and Vivian Halford
Ewart and Vivian Halford replied the topic: Solar panels and house batteries
Thanks Hank I have Cillyn book and there are few web sight I can use.
Hal have they gotten any cheeper ? Is the fuel still hard to get and what is the chances of a fire?

Ewart oka 365
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07 Jan 2013 15:43 #10 by dandjcr
dandjcr replied the topic: Solar panels and house batteries

Ewart and Vivian Halford wrote: Thank you all for your thoughts, my initial thought was 2 x 220 amp hour batteries but at 65 kg each I not so sure, 300 amp hour may be a good midrange to aim for.

Ewart, several smaller batteries would be my preferred option, they are easier to locate and spread the weight around, they can be used for different applications, and if one fails you've only lost one.

We used SuperCharge Allrounders, which are deep cycle but with starter capacity. They are all the same size so we can swap them around and use them for either function. A big 300AH battery would be good for winching applications though.

David and Janet Ribbans - Oka 148
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Visit our technical and travel blogs: here.

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07 Jan 2013 15:55 - 07 Jan 2013 15:59 #11 by Hal Harvey
Hal Harvey replied the topic: Solar panels and house batteries

Ewart and Vivian Halford wrote: Hal have they gotten any cheaper? Is the fuel still hard to get and what is the chances of a fire?


I don't think they have gotten any cheaper, despite our exchange rate improvements, so it's still an expensive exercise - once. The fuel has always been easy to get, maybe easier now there are more people selling it. I just order it from KK and it turns up a week later. It uses very little fuel and the fuel has a three-year use-by. Much more chance of a fire from a battery or wiring than anything else on a vehicle I think; melted insulation and all that. Efoys are more common on boats than anything I think, and boaties are a fairly pyrophobic lot.

Oh, no weight issue either. The Efoy is about nine kilos and a full fuel container is about nine kilos. I think Ruedi and Susi replaced one of their batteries with an Efoy so no space loss and a fair few kilos saved.

Principal advisor to the Minister for Tourism, Liza Harvey MLA
... OKA 260 ... "I'm not leaving any sooner than I have to!"
www.byles.net/OLDportal/members-vehicles-public/5-oka-260
Last Edit: 07 Jan 2013 15:59 by Hal Harvey.

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07 Jan 2013 19:16 - 07 Jan 2013 19:43 #12 by PeteFox
PeteFox replied the topic: Solar panels and house batteries
Ewart
it seems to me you have two main concerns, i.e space and weight. Lead acid batteries are both big and heavy and to top it off you cannot use more than 50% of their nominal capacity in Amp Hours (AH) on a regular basis for AGM batteries without severely compromising their life expectancy. That is the deeper you discharge a battery the less the number of charge/discharge cycles the battery is good for before it either fails or the capacity is reduced. This 50% nominal capacity really makes a 300AH battery bank only a 150 AH battery bank except for the occasional emergency.

There is a way around this. A couple of years back myself and three other owners of Kimberley Karavans got together and replaced the original 320AH lead acid battery setup with a 180AH lithium battery.
The weight went from 110kg (Lead) down to to 26 kg with lithium, as you can see from the photos the space requirement also went down by quite a bit. The Kimberley is a bit unusual in that it uses 9 x 35AH batteries.

This is the standard Kimberley setup


This is the same Kimberley with a 260AH lithium setup


As you can see 100kg v's 28kg




The reduction in theoretical capacity is not an issue because the safe discharge level of a lithium battery is 90% discharge though I work on 80% with my batteries.
A 320AH AGM has a usable capacity of 150AH @ 50% discharge
A 180AH Lithium battery has a usable capacity of 144 AH @ 80% discharge
In the example above the 260AH lithium is only 57% discharged after 150AH has been used or to put it another way it has 208AH of usable capacity @ 80% discharge.

However (there is always a however)
Lithiums are more expensive per AH but not much more expensive per AH of usable capacity. A set of AGMs cost $1350 and the Lithium was about $1450 when I did my conversion.

You absolutely cannot let lithium batteries get too flat. A single discharge to below 11.5v may be the end of a lithium battery - a low battery cutoff is a must.
Lithium batteries require correct charging and a Battery Management System (BMS) is an absolute must - there is no way out of this. You need a programmable regulator regulator for solar charging (14.6v bulk and 13.7v float) and a battery charger capable of the same settings.

The best news for WA residents is that the Rod Dilkes operates EV Power at Margaret River and is the guru for these batteries. Rod has developed his own BMS and sells these battery packs complete with LV cutoff and BMS

I don't have any connection with EV Power other than one as a happy customer and 2 years later I am still happy.

Pete Fox OKA266 MultiCab
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Last Edit: 07 Jan 2013 19:43 by PeteFox.

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07 Jan 2013 20:18 #13 by PeteFox
PeteFox replied the topic: Solar panels and house batteries
A couple of other photos

This is Rod's BMS in action. The green lights on each cell indicate that the battery in within acceptable voltage range. At this stage the battery is nearly fully charges. the red light on one cell indicates that it is fully charged and is not accepting any current, the other cells are still being charged but at a low rate, probably less than 2 amps. Part of the function of a BMS is to balance the cells.



The second photo is my lithium installation. I have removed the Kimberley battery box entirely and relocated the charger LV control, kill switch and put in a decent distribution bus. There is a perspex cover to all of this that is not in the photo.


Pete Fox OKA266 MultiCab
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07 Jan 2013 21:05 #14 by Peter and Sandra OKA 374
Peter and Sandra OKA 374 replied the topic: Solar panels and house batteries
As Peter says the ongoing development of Lithium brings the weight down and they don't mind deeper discharges. We have 480ah (4x 120AH) of AGM's and 500w (4 x 125w) of solar, can last pretty much indefinately with out moving as long as there is some sun. I don't charge the house batteries from the vehicle at all, just let the solar do it all. We have a 12v 130l Vitrifrigo fridge freezer, use diesel for space heating, hot water and cooking (Webasto diesel cooktop and Thermotop for HWS and space heating. We use a 1,000w 240v electric jug for boiling water and a normal Sunbeam toaster for toast via an 1800w PSW inverter. Any extra solar is used to heat hot water as the calorifier has a 240v element. We also charge all the usual electronic items like laptops, kindles etc.

OKA 374 LT Van, converted to camper/motorhome,
400ah Lithiums, 680w solar, diesel cooking heating and HWS,
Cummins 6BT, Allison 6 speed auto, Nissan transfer.

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08 Jan 2013 09:48 #15 by Ewart and Vivian Halford
Ewart and Vivian Halford replied the topic: Solar panels and house batteries
Well I'm glad I asked the question, it gives me options I hadn't considered, thankyou to all for you information. As I live in Australind I think I iwll have to take a trip to Margret River.

Ewart oka 365
0428911147

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08 Jan 2013 10:18 #16 by Peter and Sandra OKA 374
Peter and Sandra OKA 374 replied the topic: Solar panels and house batteries
One of the best places for solar panels is a mob called Bit Deals on ebay, free delivery, I've bought over a dozen panels from them so far and know plenty of others that have as well. stores.ebay.com.au/Bit-Deals?_rdc=1

OKA 374 LT Van, converted to camper/motorhome,
400ah Lithiums, 680w solar, diesel cooking heating and HWS,
Cummins 6BT, Allison 6 speed auto, Nissan transfer.

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08 Jan 2013 11:30 #17 by Peter_n_Margaret
Peter_n_Margaret replied the topic: Solar panels and house batteries
There are also lightweight panels available in various forms...tend to be somewhat more expensive... saw some mounted on aluminium sheet that weren't too bad...

Cheers, Peter.
OKA196 tinyurl.com/OKA196xtMotorhome
Mob.0428171214

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08 Jan 2013 14:09 #18 by Tony Lee
Tony Lee replied the topic: Solar panels and house batteries
The EFOY fuel cells may not be quite the pay-once system that is touted. My understanding is they do require regular servicing, but at the time I enquired, neither the frequency of the service nor the cost was available.

I guess fuel costs are a known amount, but for those venturing off the bitumen, the costs of freight to remote locations may be a deal-breaker.

One Australian manufacturer of motorhomes was installing fuel cells for a while but I'm not sure if that is still the case, and if not, what the reason was.

Given the problems we have had synchronising our travels with post office mail pickups, I would imagine the only practical way to make sure of fuel availability would be to carry extra fuel and then you have the problems of finding space to carry it, and the weight, and the potential of leaks in the containers.

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08 Jan 2013 14:11 - 08 Jan 2013 14:15 #19 by Tony Lee
Tony Lee replied the topic: Solar panels and house batteries

One of the best places for solar panels is a mob called Bit Deals on ebay, free delivery, I've bought over a dozen panels from them so far and know plenty of others that have as well. stores.ebay.com.au/Bit-Deals?_rdc=1

Hmmmmm!!!!
Would love to know if anyone has succeeded in getting this mob to honour warranty. I had an inverter blow up and apart from one very dismissive reply to a polite request for the warranty claim procedure, have not had a response from them in over six months of trying, plus official complaints to Ebay.

If anyone has been able to find out a phone number, or even a direct email address, I would much appreciate it.
Last Edit: 08 Jan 2013 14:15 by Tony Lee.

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08 Jan 2013 15:19 #20 by Len208
Len208 replied the topic: Solar panels and house batteries
The concern I have always had with efoy is carrying methanol.It burns invisibly,such as you see at motor racing where the mechanics when refuelling catch alight but no flames are visible.Truma were supposed to be producing a similar unit running lpg but it hasnt surfaced yet.Lithium seems to be the answer but too expensive at the moment.

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