My brick-built battery house in the garden is wind- and watertight and ready for the 64 EVE cells, three MultiPlus-II 5000s and three SmartSolar 6000RS units.
I have designed a stainless-steel battery rack on which they can stand stably and safely, and had stainless-steel end plates made to compress eight groups of eight cells each. Four REC IQ2 BMSs and a master unit for monitoring the cells are ready.
Now that it is time for the wiring and fuses, which I wanted to implement using the Lynx system:
In terms of space, and especially thermally, I think Adler EF3 fuses in a Distributor look appealing but risky. I fear the Distributor will get far too hot…
B) Looking at the cabling from the Lynx distributors to three SmartSolars and three MultiPluses, which will be mounted next to one another in a single row, you cannot avoid having two sets of short, medium and long cables from the Lynx. What is Victron’s view on using different cable lengths in a three-phase MultiPlus setup and with three SmartSolars, each charging and discharging the batteries at 100A?
That is why I am connecting the devices according to the Tichelmann principle: each device has a positive cable that is the same length as its negative cable.
Below is the diagram (adapted following some useful feedback). What do you think?
This is the theoretical setup, but the busbars are drawn much longer than the devices connected to them. You’ll end up with differences in cable lengths, and I’m wondering how critical this is.
My second question is whether the Distributor is suitable for use with Adler EF3 fuses, as these produce much more heat than the Mega fuses, which I no longer trust. Fine in the short term, perhaps, but after five years I think the plastic will suffer from this heat build-up.
In addition, there isn’t enough space for all the devices above the battery rack, especially because I’m giving the three MultiPluses a separate rack so that the vibrations aren’t transferred to the single-leaf wall.
With the layout shown in the drawing you made, the current is distributed very unevenly across your busbar, which isn’t right.
Connecting the negative cable from your batteries like that isn’t right either. Those should also be distributed neatly across the busbar. In addition, 140 mm² is too thin when connected this way.
That is precisely why all the cables should be the same length and connected alternately, as in the image I posted.
In principle, fuses should not become hot or warm. If they do, either the connection is not good enough and/or your cables are too thin.
On a 50×10 mm busbar, the resistance is so low that hardly any voltage difference develops, so as far as distribution is concerned, I’m not worried about seven cables within a 40 cm section.
I’m more concerned about the short, medium and long cables running from the busbar to the various devices, which are located at different distances from the busbar/Lynx—unless this 50×10 mm busbar is three metres wide, allowing all the devices to be connected with cables of equal length.
That’s why I’m wondering how the Lynx distributor’s design takes this into account.
EF3 fuses inevitably generate heat when you run 100 A through them; otherwise, they would never blow when the current becomes too high. NH1 fuses generate even more heat, and their advantage is that they have to heat up considerably before they trip, making them more forgiving under peak loads.
Batteries, on the other hand, need to be disconnected extremely quickly in the event of a short circuit—hence the use of Class T fuses.
Unfortunately, I don’t have room for four Lynx devices, and Megafuses seem outdated to me, hence my combination of Class T and NH1 fuses.
And Mr Tichelman has made quite a name for himself in horticulture; you still come across his design very often today.
I’ve adjusted the diagram, but I don’t agree with your comment about the busbar.
Victron supplies an (estimated) 250 mm² busbar, whereas I’m using a 500 mm² pure copper busbar, to which all the cables are connected next to one another over a length of 50 cm (and most likely even within 30 cm).
