Hi having issues with very hot 35mm2 cable to battery. Had a high voltage warning through shunt, and discovered the mega fuse didn’t blow but the plastic holder was badly melted. Please see plan below, the Vic sbp not installed yet but this is the only way I can think of protecting the battery. Also considering panels in parallel to reduce voltage or mixing. The load is only to a gang plug for charging and the fridge freezer as trialling, a little shocked at voltage issue as wasn’t even full summer sun. Honestly,
nervous and am cutting off panels when sun is out for long period…….help
The way you’ve shown that SBP wired in suggests you expect it to handle current both ways. It doesn’t.
35mm2 cable is too small.
Don’t know that “hybrid” device, but high V warnings must be originating there…
High voltage does not blow a fuse, nor does it make a connection melt. The likely cause of your melting is a loose or improperly made connection that had a high resistance. Is your inverter set properly for lithium battery charging profile. The rating of the fuse must be the same or lower than the rating of the cable. Your fuse is higher than 35mm2 rating so can not protect the cable. If my maths is correct, your 3.2kW panels / 3.5kW inverter should be 150A at 24V, check your smartshunt current readings, so a 65A SBP will be too small and as noted above will not work with bidirectional current flow anyway.
Thanks John for response, ok understand with the SBP, my mistake 35mm2 was as per inverter manual 2 awg however thinking comment on inverter is sound….cheap unit?
Thankyou, the inverter is set up for Lithium, I will change the fuse to 150a, noted just with the patchy sun the negative from the battery to the dc switch and following to the shunt is warm so will check shunt settings
Check all your connections are seated and torqued properly and the crimps are tight. You fuse should be rated at least 25% higher than the maximum current so a 200A would be better and still in spec for 35mm2 cable.
Have a read of Victron’s publication Wiring Unlimited. https://www.victronenergy.com/blog/2019/09/03/wiring-unlimited/
Thank you really appreciate responses