It isn’t actually that big of a building. It’s just that with a reasonably shallow pitch and the roof ridge pointing North, the entire roof is suitable for panels.
It is actually my Mother’s granny flat. My sister runs a guesthouse from the main buildings:
My mother is off-grid, and my sister uses all the excess power.
I just found an under-construction photo of the tower I built. (It was taken standing on the roof a few years ago now).
That 8x8m platform certainly contributed to the panel real estate.
I forgot the last row of panels on the South of the roof straddling the ridge is also angled North.
All the other panels are E & W, following the pitch of the roof. Initially, the whole roof had frames like that, so I built the tower to get rid of those frames. It looks much better now.
So you have a base, several modules (which means you can decide how much capacity you want), and then you have the BMS/BMU on top, plus a cable set that plugs into those nice connectors.
That’s why they are individual items.
I truly regret not listing the BYD. It is one of the best batteries on the market, it should really go right at the top of my list. It’s just not very popular in SA, and I always assumed it was because of cost.
But with that said: I’ve seen them represented at EVERY solar trade show I’ve attended, so they certainly have a footprint here.
Very neat, I like it, but the cost … 17.5% higher than Pylontech for the same capacity. At 70Amp constant discharge I assume that I will need 3 x 4kwh batteries (104A x 2 = 208A required / 70A per battery = 2.976, rounded up to 3). Or is the 2.976 close enough to maintain warrantee?
I suppose when I add a cabinet for the Pylons, 27U or something similar, that’s an added R6k, so 10%. But still …
That sounds great! Are you able to share it with me here? Is the fix specifically for this issue. ie Incorrectly reporting high discharge and adjusting DCL to zero? Been going backwards and forwards with their support team - seems strange they haven’t suggested this fix.
If there is one thing that can make a solar system become a dead weight, it is the batts.
We assume all is going to go well, I don’t. Always look at what can go wrong and plan for that.
Like:
Inverter has a major problem, weeks offline, get a 48v Axpert to tie one over. All are already in place.
MPPT gives drama, use Eskom.
But the batts … man, that brings everything to a “pletterstop” … unless you get lead acids as a quick fix.
Whoever has the best backup/support … priceless … as stuff will break.
This is 1 of the main reasons I prefer smaller Ah batteries but have a few of them. If one fails the other can still work. That is also 1 of the flaws of the BYD battery. Only 1 BMS/controller connecting your bank.
@Gungets - to answer your question on the continuous discharge of 70A. Here is some emperical evidence of my mom load testing her system… This is a Victron Multiplus II 3000VA, with a BYD LV Flex Lite 5kWh battery.
In South Africa, it is the Flex Lite. Yes 70A is correct. Ie. Not a 1C battery and 2 required for a 5kVA.
You need 1 BMU per battery bank, whether 1 battery or 64.
The items you listed there are not for use with the Flex Lite, they are for the LVS and LVL which are a different - more expensive - Premium stackable (VERY COOL) product.
The Flex Lite can be placed on top of one another up to 4 high using pins supplied with each battery. You can also buy feet for the bottom battery OR instead buy a cabinet from BYD to make it easy to connect all 4 batteries into one bank.
BYD does not allow daisy chaining. Each battery must be connected to the busbar - IMHO, this is the right way. Daisy chaining a la Pylon is dangerous.
Remember to use the black CANbus terminator (pins 5,4) that comes with the Flex lite on the second CAN port of the last battery to terminate and if with Victron use a Blue Victron terminator (pins 7, 8) in the BMS CAN port of the Cerbo GX.
Ps. They are currently sold out in SA, more coming next week. So someone other than us is buying them. We use about a pallet (12 x Flex Lite) every 2 weeks.
Sadly… no. There is currently no way to know if the battery supports it or not. Venus does however use the LOWER of the static voltage and the one the battery sends, so there is still some value in this (especially in that initial not-quite-balanced phase of ownership). Two years ago I was asking them lots of questions – specifically during testing I managed to drop a cell to 2.6V, became very worried, and stopped the test to ask questions, questions I didn’t get answers to – and then other things took over and I didn’t look at it further. That’s how it always goes in this business
Vote Time, if I might be so bold. Green highlight is where the batteries satisfy or exceed the constant discharge requirements of the warrantees. Yellow where they are marginal, red where they don’t. My Scottish heart wants 1. My head another, but I don’t want to sway votes. Need to order latest Monday, and part with a seriously large splodge of wonga, so appreciate your participation.
