Hello all. I brought a DC to DC charger in preparation for upgrading my lead acid batteries. I hooked it up to the lead acid batteries and it worked perfectly. Hit absorption status and changed the batteries.
My eco worthy battery arrived and I swapped them over.
Then the DC to DC charger started acting weird. It would charge normally then think the van battery was at 7 volts and shut off. This would happen every 2 minutes or so.
So I sent the DC to DC charger back thinking it was busted and brought another.
The same 7 volts drop happened again.
I put a multimeter on the van battery and it definitely doesn’t got down to 7 volts.
So I have a 2009 mercedes sprinter. The alternator is one year out and the battery is maybe 4 years old.
The wiring is 16mm². From the van battery the length is about 1 metre. From the leisure battery it’s about 2 metres.
Those breakers you show are really poor quality, they often have high resistance and cause voltage drop. There are so many posts on here with bad experience. Remove them and replace with fuses. Then you should het the correct voltage.
And looking at them, why do you have 30A breakers on a 30DC to DC, you should have a 40A fuse, never run a fuse or breaker at above 75-80% of its rating. With lithium your DC to DC is probably running at full current and causing the breakers to start opening, which cools them down, they reconnect etc. This would not happen with lead acid because the lead acid would not take as much current for as long. Really rubbish devices.
Not sure what you mean by “Really?”. Have a look around, the reputation of the cheap no name breakers is not good.
Use a reputable brand like Blue Sea rather than no name stuff, but I have made the recommendation above to use fuses. If you go Blue Sea buy from a good dealer not certain on line sites which run the risk of fakes.
