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Planning a new installation

Featured Replies

Question: 
24v system
Biggest amps panels I can get.
Smallest battery bank possible.
Grid tied.

Make sense?

8 minutes ago, The Terrible Triplett said:

Smallest battery bank possible.

Lead acid or LFP?

8 minutes ago, The Terrible Triplett said:

Grid tied.

You mean hybrid, right? Otherwise "batteries" makes no sense :-)

Smallest Victron LFP battery around 60Ah, can charge at 2C, or 120Amps. So largest array size would be 120*26 (nominal) ~= 3kw. Remains best to design safety into it than to rely on a software limiter.

For lead acid my feeling remains at least 200Ah batteries and no more than 2kwp of PV. That leaves you with a 40% (of Ah capacity) recharge rate sans any software limiters, which is a tad above the limit but probably safe enough (with temperature sensors and placed outside the house). Scale as appropriate.

Edited by plonkster

11 minutes ago, plonkster said:

hybrid, right

Damn, yes, my mistake. Hybrid. Jip, I am with you. 2.4kw would be my largest on 225ah lead acid bank. I have a spare controller ... just waiting for panels. ;-)
But data first.

Am interested in Erastus view on 350w panels on a hybrid system with small battery bank on a MPPT.

  • Author

@ Erastus  Have you received permission to be a net producer? In Mossel Bay your are not allowed to be a net producer of electricity so you cannot use the grid as a battery. Also, they seem to be quite strict on the 3.5 kVA maximum size for domestic installations.

  • 2 weeks later...
On ‎2018‎/‎09‎/‎18 at 6:12 AM, Erastus said:

Simple a bigger than normal lawnmower engine from Talisman +/- R3000 a second hand 100amp alternator from scrap yard. a pulley or 2 an you have a nice 5Kwatt generator.

P = I X E   50V X 100A = 5000W

hi there

always loved this idea but where's the 50 v come from

what mods do you do

cheers

1 hour ago, maxomill said:

always loved this idea but where's the 50 v come from

Close voltage to 48V and makes the math easier I assume :-)

For LFP batteries its pretty common to do math using 50V because they spend most of their life above 50V.

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