Sizing my system

[Superstar]

I've been lucky enough to have been given 8x100ah lightly used 3 year old AGM's, so I'd like to design my system around them, I have the possibility of getting some more in the future, but I think they will do with my usage for now, I've worked out my average usage is under 3kWh per day and the average winter sun is 3 hours, so with this I was thinking of a 1.5kw solar array (2 strings of 3x250w poly panels), batteries in 48v, (4x4x12v 100ah AGM's) (my only hesitation with 48v is that these batteries have been used in pairs, so they are of different ages and brands, would I be better off using 24v?) using a Victron 150/60 (but if I go to 24v would I need a bigger charge controller?) I don't know what type of inverter to use yet, I was looking at the Victron ones, but they do sound a little pricey, are there any Chinese ones that are proven to be good? I have grid power available, so if I'm not getting enough charge in winter I have the option of switching to grid power or using a charger for the battery bank. does this system sound ok, or am I missing something really obvious?

[littleharbor]

Have you included links to outside vendors? These would need to be approved by the moderators before they will post up.

[cebury]

And it was the type of apostrophe that didnt pass through. Some do, so don't. I see your initial post cut off there.

[sdold]

Copying from other sources (such as MS Word or Notepad) and pasting into the forum causes these kinds of problems.

[Syberdog]

I typically change the .txt to a .rtf for editing and it hasn't cut me off yet. Probably the font being used- try a different one.

[AzRoute66]

Copying from other sources (such as MS Word or Notepad) and pasting into the forum causes these kinds of problems.

Actually, Notepad is probably one of the best places to copy/paste from. If you have it in MS Word or other editor, copying it into Notepad, saving it as 'txt', then re-opening the .txt file to get your forum-ready 'copy' is probably the safest way I can imagine.

[sdold]

I tried copying and pasting from Word and Notepad and got the same result, truncated at the apostrophe. Maybe something was a little different if you tried it and didn't see the truncating. Strangely, copying and pasting from a forum post didn't cause it.

[AzRoute66]

Well, if it is already in a forum post, it has passed all of the quirky rejection filters already by hook or by crook. Pre-Qualified so to speak. Note that a .txt file opened by Notepad is likely to be quite different than a rich text file opened by Notepad that 'looks' identical. The problem is that there are so many different 'versions' of common characters (such as apostrophe and quote) in the extended ascii character sets.

[Superstar]

I was writing the post from my iPhone, I'd written it three times before I decided to copy the txt before trying to save, but it kept cutting most of the message off, anyway, it's edited now and thanks to everyone for your help on finally getting my first post to eventually work and not get myself in trouble here

[sdold]

This is the same message copied and pasted back into Notepad, and then copied and pasted into the forum, and it's also a single line. If you can read this, it works.

Anyway, to the OP: I'd test those batteries before building a system around them, because "lightly used" might have meant "lightly charged" and they might have lost a lot of their capacity just sitting around. Are you planning two parallel strings of 4 in series for a 48V system?

[Superstar]

I'd test those batteries before building a system around them, because "lightly used" might have meant "lightly charged" and they might have lost a lot of their capacity just sitting around. Are you planning two parallel strings of 4 in series for a 48V system?

Yes two strings of 4, hence my hesitancy in using them in series due to the age difference and brand difference. These batteries were used for diesel fire pumps and were used once a month to start the engine to ensure the motor would start in an emergency situation. so yes lightly used and charged straight back up, and left on a trickle charger at all times, so I think they wold be fine, is there an accurate and cheap method of testing the batteries?

[Superstar]

I think I had more of an audience when I couldn't post