Jaco,
I am considering an installation using multiple 5kVA’s.
This may not be installed in one go but I want to cater for the eventual design at the outset.
A 3ph installation that will allow for 4 5kVAs Multis per phase.
I will have a battery bank busbar with 4 DIY battery banks.
(Disregard MPPT inputs for this problem).
An issue that is confounding me at the moment, is how to physically lay out the battery banks, the busbar placement and the multis so that all the DC cabling is equal lengths.
I can use the furthest extremity cable length and this cable length to all multis.
But I feel there must be an optimal layout that will use the least DC cabling.
I also don’t want to use lengthy Cu busbars, which would make the cabling look like the cheaper option.
Have you ever considered this issue?
Hi Phil. Depending on your wall space and hight off the wall I can help you with the layout to minimize cable length. The bigger the wall the more you can play with the units. A long busbar for 12 multi 2’s will be very expensive. Running g cables much cheaper.
If you have a wall with adequate height you can consider 3 rows of 4 units above each other, maybe with shorter bus bars from top to bottom with 2 units to the left and 2 units to the right of the bus bars. In this layout you will use the least cable and a positive and negative busbar of around 1.8m each.
Let me check something before I continue.
Okay I see you are using 4 battery banks. Also 2 left and 2 right of the busbar with symmetrical wires going to the busbar.
If you choose to do it like in the picture Mark posted below, you will need trunking big enough to fold the slag into. In that installation we used a busbar close to the middle of the trunking and looped the slag into a 100x100 trunking. Remember that the DC cables should be symmetrical for each set of 4 per phase, but need not be symmetrical for all three sets/phases. In short if the furthest unit for the Phase 1’s set is 2 meters from the busbar, all four needs a DC cable of 2 meters, but if the furthest unit of the set for phase 3 is only 1 meter, all four needs a cable of 1 meter. In this case it does not matter that phase one has 2 meter cables and phase 3 has 1 meter cables. Each phase is seen as a single parallel set and the symmetrical wires in a parallel setup matters.
@Phil.g00 and @Village_Idiot I need to let you guys know. The biggest distributor in the Southern hemisphere increased their prices on the 5KVA units by R200 per unit on monday and another R200 per unit today.
Importers of other equipment say we will have a shortage of hardware from June.
If you guys are interested in buying, now is the time. I dont see the prices dropping again after an increase. Phill Pm me if you need help procuring the units before your return later the year. Village you are also welcome to talk to me.
A new install for a customer in Sandton with space left for another 2 batteries, Mppt and another inverter. Customer already knows he is going to upgrade in the near future.
2x 5kva Multi’s, 3 x 10/8 Freedom wons and 20 x 555 longis on two Mppt’s. 1 x 250/100 and 1 x 250/85.
Edit: Little sidenote. THis customer contacted me and stated that he wants me to be competitive with a Sunsynk quote he already received from some other installer. I could not be competitive as we recommended a much bigger system, but managed to show him the advantages of Victron and sold him a system of almost double his original quote.
@JacoDeJongh , i hear that Sans is requiring each battery to have it’s own fuse disconnect and then one fuse disconnect for the inverter, when installing more than one battery ??
Morning Tariqe. There is still a lot of controversy around this topic. Preciously it was clear. Any DC supply should have a double pole disconnector and at least the positive must have overload protection. It was simple to interperate and follow. We still stick to that guideline. In the instalation above the freedom won has its own overload protection and can be isolated seperatly. Then each inverter can be isolated on hie own as well. Most batteries lately has got some kind of build in overload protection in the form of a breaker, but sadly only a single pole breaking the positive, resulting in the need to still install a double pole isolator somewhere in the circuit.
Terminology is also important here. Victron terminology is “one battery, many modules”. If you have 4 modules combined into a single bank, that is considered one battery, and 4 modules. By that terminology, and in as much as the battery maker tells you to combine the batteries like that (with the included cables or busbars), a single fuse is sufficient.
As far as I know at least Pylontech uses the same terminology. You can have container-sized batteries, and in that application it very likely has some sort of protection between strings internally, but from an installer’s view: One battery. One fuse.
Brother 2: Upgraded his 45kwh BSL bank to a 135kwh BSL. Had a new roof build over his entertainment area and we fitted 24 more 550watt panels and another RS450/200 MPPT.
This client got screwed all the way. His been sold real crap equipment, installation took over a month and commissioning another 2 months and by the time the installer decided to bail, the Mppt on one inverter were blown and the second install bypassed. We did not want to add to his misery and decided to use whatever were usable to keep costs to a minimum.
We were lucky to get a reference from @jatho for a friend of his in Botswana. Learned a lot about exporting in the process and after a very long time quoting and planning the client accepted our quote. We went over the border, got robbed blind by people who did not want to let us through with tools, but after all the project was completed.
Now interesting enough, there is no Earth leakages / RCD’s in Botswana and its not required. Try convincing a client that its beneficial to him and his family is the easy part, trying to buy one to install is another. They dont stock it, because its not used.
Getting approval to install and feed back into the grid is not easy but it was done. Signing off is another thing. None of our qualifications means anything over there so a local company had to be used for the signoff. They must be on site on the day of commissioning to take the Muni inspectors through everything. All functionality of the system gets tested and verified and all scenarios gets simulated, changovers tested ext ext ext and then the Muni guys will signoff and give approval that the system can be switched on. They are accompanied by a guy that will reprogram the meter to allow for buy and sell before they leave the site.
Client very specific that appliances should remain where they are and that we must install around them.
Nice little 3 phase install with almost 50 panels on the roof. Different sizes to allow for multiple facing parts of the roof.
As a last note. The inspectors asked the client to phone me on the day of commissioning to congratulate us on the standard of work. " They have never inspected an installation like this". To us in SA this is a pretty average installation and not one of my best, but over there, this is top notch.
Last week we had the privilege to help a returning customer (One of our members) to upgrade a totally off-grid system.
We previously upgraded his system in JHB and he was left with 4 Pylontech’s. He decided to move them to this remote site in Sabie Park area. They had an old 24 volt system with a 1500 watt MW inverter, Microcare Mppt, 8 x 115watt panels and a bunch of Royal 1150 batteries. The system did well for what they needed, but the client wanted to upgrade.
I havent seen someone that lives as power efficient as this guy in a very long time. Main house with 2 separate two bedroom cottages as well as n store room with a fridge. We were 6 adults there occupying all three units. In the mornings the batteries would be on 80% plus. 2.8kwh over a 14h period = 200wh constant load.
He now has 4 x Us3000, 3kva Multi 11 and 8 x 550 watt panels to keep him off-grid for a long time to come.
I met a new client on a trip to Natal last month. One of the most heartbreaking stories I have heard in n very long time. Client wants to ensure that his wife will have power no matter what happens to him. He had a few quotes on the table already but with less reliable hardware. With the pricing of victron lately, we managed to offer him a system a little bit bigger than his previous quotes at the same price. Had about 3 days to get everything together and start the install.
He opted for 2x 5kva Multi 2’s, 2 x 5kwh Lithium Battery SA units, and 12 x 550watt panels on the roof. System currently underperforming and we are going back to add more loads to the system to increase efficiency.
Sidenote: Lithium battery SA has recently made the Victron supported list.
Edit: We did this install based on budget and not for the full consumption. After two months of operation we saw that the client has a shortfall of 2kwh during might times and decided to add one 5kwh battery to reduce his night time consumption from the grid.
