Solar panel advice

Ocsid, thank you for your comments.  Yes, one can power a microwave using a lead acid and a large enough inverter but it will have a damaging effect on the battery. I can drill a hole into concrete using a normal drill bit but I’ll not be able to use it again- had I used the correct masonry bit for the job I would have been able to drill lots of holes if needed!  Large draw on a lead acid will warp plates etc and shorten the life of the battery drastically. I found this out to my cost-  I had 2  x 90ah batteries and they were fine for the first 2 years but that was it! I needed new batteries. I could have spent £400 on two new LA batteries which, I now know are damaged under conditions that I would use them or go Lithium and get rid of the worry.

Yes, a 2000w inverter will handle everything I need with the microwave drawing about 70 amps or so. I can’t see the point of buying a bigger inverter if the capacity of a 2k inverter  is well within the zone you ask it to operate. A pure sine wave stops all the fears associated with modified sine wave. 

A Lithium will supply this amperage without damage and it can be recharged quickly again without damage. As for the 25yrs longevity of the Lithium- let’s just agree to disagree. Neither of us can prove or disprove, all I can say is that I have researched this quite heavily as you can imagine and I am more than impressed by the abilities of a Lithium Battery. With 1000s of cycles- and I mean thousands- proved by people who have tested these batteries for months and months, Manufacturers have tested them to destruction and from these tests, real facts emerge. I tend to believe the unbiased evidence produced. I have to say that these Lithium Iron PHOSPHATE batteries are completely different to the batteries found in phones tools etc and they are suffering from the problems that some Lithium Iron batteries have had in the past. You talk about real life situations- that’s why the battery is surrounded by clever electronics- these electronics will shut the battery down if there is a problem therefore protecting it from damage. However, you do accept that there are different Lithium technologies. Life4Po batteries are safe! Inside a caravan untouched and unmoved I can’t see that any abuse will occur. No fumes, no acid, no maintenance,  and 1/2 the weight. - always something the caravanner is aware of

I can’t comment on how you use your batteries or battery but I would suggest that you use it for lights and pumps-? - hardly a stress for even a lead acid. The fact is that a Lithium is more economical to buy if you want the full fat usage of your caravan. It leaves a LA battery on the start line as it breaks the tape at the end of the race! The term’ it’s like wild camping with hook up’ is very true. It’s not just the microwave though, and let’s not get hung up on the microwave , it’s everything else I want to use on board and in the awning. My awning lights for instance light the awning like daylight on the darkest of nights and draw 4 amps. No problem for a Lithium, the toaster vacuum and to a lesser extent the blender  all require high amps- again, no problems with a Lithium. 

We will see if the 20- 25 yrs life span comes true- well, perhaps I, like you will not get that far but I will have had a wonderful time trying these technologies out -  but I am glad to be in a position where I can start to prove the next generation of technology in a practical and real life situation.  My goodness, I wish I was 30 again- the technological future is very exciting.  The price, as in all relatively new technologies will inevitably drop and I think Lithium will become commonplace in years to come- unless another technology comes along which is better and I’m perfectly able to accept that as possible. I will keep the forum informed as to progress. The one thing I can say is by using the microwave, I am using something that I bought anyway!! And why use gas (even if it is from a Safefill) if the sun has filled the battery and to make 4 rounds of toast it uses 8% and no damage to the battery. The 310w panel will charge the battery much faster after a heavy draw- and carry on the good work the 135w has provided over the past 6 years. 

Just as a footnote, A LA battery or batteries, linked up to a decently sized solar panel are perfectly capable of keeping you off grid as many  have found. Lights and pumps take very little power and even our Avtex only uses 30watts. A small inverter of say  150 watts can run one or two appliance which don’t require much power. Horses for courses!! 

I was pondering fitting another battery box in the floor of the MH garage to accommodate a second battery, preparatory to getting an inverter to run the microwave off-grid. However, given your comments on the punishment this would give a LA battery, I think I'll give up on that idea. I'm too long in the tooth to justify shelling out for a Lithium based setup.

Have you seen the EZA system by RoadPro? Cyber? When I started, I had 2 x 90ah batteries and the inverter I have now. I had no idea at the time that repeated heavy discharge of LA batteries is detrimental to them. It can warp the plates etc. They worked fine for Two years and to be fair, they were not of good quality as I later found out. One lives and learns. However, AGM LA batteries are better adapted to the task but are still not the full answer.  Research on the web told me that if I wanted to do what I had set out to do, Lithium was my only real choice. It’s a long term thing but I reckon at £500-£600 a year saved on going EHU - it’ll be money well spent. If I last 3 years the kit will owe me nothing and there’ll still be at least 17 yrs at least of useful service in the kit I have. I’m taking the gamble because I love the thought of living off grid and so does the OH. And as I have said before, it opens up so much more in the way of out of the way sites- something we love. In 2017, because of the non EHU situation with me, we were able to go on holiday with my daughter and SIL, and their 2 boys. (Plenty of power for showers!) We all had a wonderful 15day holiday in fabulous weather - £60! And that was purely because I was non EHU. Just an example of what can be achieved. 

Bit of an eye-watering price tag and at my age, hard to justify. Apart from a quick burst for a microwave, I'd also need prolonged power to recharge the E-bike batteries. I'll need EHU even if only every four days or so.

When we bought our van I asked for a second battery to be fitted, which they did.  The fitted it behind the main battery, continental van battery under a seat.  To get to this battery I had to disconnect the main battery, which left the terminals live. Unscrew four screws so that I could lift the electric control box out of the way remove main battery, drag slave battery out disconnect that. Then do the whole thing in reverse to fit a spare battery.  First time I did it to almost an hour mainly in the dark.  What a palaver.  

I have modified this I have made the rear battery the master battery.  The front slave battery is connected to this with a fused cable Anderson connectors and quick release clamps.  It now takes less than 5 minutes to drop in a battery. If necessary I could take the depleted battery to a pub garage house, where I am sure for a few beer tokens they would recharge it.  In reality the only time the batteries are depleted apart from operator error is when we are off ehu for 5 nights at new year. All other times the solar panel copes well. 

For me at the moment lithium ion batteries are just not cost effective.  But if you are interested I suggest that you  waste /spend a couple of hours looking, on you tube, at some the rigs and equipment that our colonial cousins  use when they go Boondocking (spl!)