These batteries come with 2 Pos and 2 Neg terminals but their manual shows each battery to be individually connected to the busbar. Victron’s Wiring Unlimited guide recommends parallel connecting the terminals with a heavier busbar connection from the Pos of the first battery and Neg of the last battery. Are there charging current issues with either of these methods.?
Both ok for AGM. probably ok for many lithium setups. Busbar may be slightly better.
But better to follow the manufacturer's guide.
The BYD Flex manual shows individual connections to a bus bar in pretty much all the pictures. Unlike Pylontec and other manufacturers that show and provide short links.
And further explains they should be individually fused under some country regulations.
Some manufacturers don't want batteries to be series connected due to bms/protection limits. They do often explicitly state so though, BYD does not. Probably best to follow the pictures in the manual.
So for balanced current share on a bank bank it is better to individually bus bar them anyway.
I have now 8 sets of SOPzS Batteries (each 12 cells, 24V/735Ah) hence I have in total 5840Ah @24V because I have a farm and being 100% Off-the-Grid.
The H01N2-D 70mm² cables where by me made in "mass production" and ALL cables have exactly the same lenght to a Singel 80x10mm Aluminium Busbar because I have a Stihl motor with 12kW (suck around 600A) and currently one MultiPlus-II 24/5000 (but I get 2 more) and the Busbar is the ONLY solution if you have
1) high loads
2) many battery sets (because of physical limitations)
Ok, I have payed for the first 4 sets 8000€ and could have even gotten higher capacity for only 6000€, BUT my current SOPzS cells have a weight of 39kg, while the lesser expensive ones (4350Ah) 240kg each. No way to install such Dinos by hand.
Oh, each battery set has its own Balancer and also its own BMV702 with 500A Shunt.
I wish, Victron would have a Smart Battery Protect with 300-400A, because I discovered, that a 220A is on my main power cable (exclusive 24V DC) not enough, and installing 3 of them at the endpoints in 24m, 36m and 63m is no option because of the voltage drop error.
Have a nice Sunday
A battery protect is unidirectional so would not have been appropriate in your application. As you charge and discharge through one DC path.
You can set the inverters to shut down on SOC or voltage anyway so protect the batteries that way.
