MPPT V's PWM regulators

Things 12V and 24V
groper
Posts: 239
Joined: Sun Nov 18, 2012 11:23 am
Location: cairns

Re: MPPT V's PWM regulators

Post by groper » Sat Jun 21, 2014 7:28 am

All good points Dennis.

I doubt many have tried various cheap mppt controllers from ebay or wherever so your on your own for the most part. But your approach is correct. Each should have its own mppt in an ideal world.

The price of all the technology in this industry is falling extremely rapidly . You can buy quality commercial individual mppt controllers known in the industry now as " power optimisers" which are fitted up to individual panels OR smaller groups of panels. See here http://www.solaredge.com/groups/powerbo ... -optimizer these only cost about $75 each now.

To use them effectively, it's really only worthwhile on larger arrays where the operating conditions of the multiple panels could vary significantly such as different incidence angles on the cabin top and different amounts of shading. Hard to justify it on a small system with panels next to each other as most have.

As to the lithium, more solar vendors are starting to supply lithium batteries for house bank purposes. It seemed the EV guys were the only game in town for a while there, but the others are starting to come onboard. The longer you wait the cheaper it will get IMHO, especially once the domestic market becomes involved in lithium banks. This hasn't happened yet, largely due to industry codes of practice which really only detail the use of lead acid batteries in stand alone remote power solutions . ( non grid tie systems) The industry was reluctant to get into lithium batteries due to the bad press lithium polymer batteries had catching fire, and most didn't understand the fact that lifepo4 chemistry is not the same, only simimilrity is it contains lithium and is much safer. They are starting to realise this now, and the industry looks like it's going to accept lifepo4 batteries. This is a big deal, because it then means insurance will then cover systems installed with lithium batteries - previously not so. So pretty soon, the price of lithium batteries should fall as it becomes mainstream.

dennisail
Posts: 61
Joined: Tue Feb 19, 2013 1:42 pm

Re: MPPT V's PWM regulators

Post by dennisail » Sat Jun 21, 2014 2:52 pm

Cheers. Nice link. I will look into them. I really do like the idea of MPPT and when they are something like $30 for each panel I might get a few.

You are probably right with the lithium. I have enough space for probably 1.5kw of solar if I really wanted. But with the 800 I have I may almost be able to cook electrically and possibly even fill dive tanks electrically. A large lithium bank would be required.

I think I will get some used AGM for now and wait a couple of years before we go long term cruising to buy the lithium bank.

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