Drop In Lithiums

[CarpeDiem 239]

17 hours ago, Island Time said:

This is a good example of a basic system

I don't think that this is a 'GOOD' example of a basic system.  I think that these kinds of pictures set DIYers up for an immediate fail, there's just so much more to be considered here.  Sure it is an "example" but it isn't good (imo) and that should be called out.

Consideration needs to be given to:

• fusing between battery packs in case of a battery short and understand if you do or do not need to fuse
• issues of connecting drop-ins in parallel - 4 BMS's that do not talk to each other is a recipe for massive current flows
• not fusing the start battery - I know 99% of NZ installations are unfused, but that doesn't make it right
• not having a shunt to measure current to manage the Li charging profile to know when to stop
• not having a way to top off the starter battery

While this diagram is basic, I personally think it's a bit generous to call it "good".

 

[Island Time 991]

5 hours ago, CarpeDiem said:

I don't think that this is a 'GOOD' example of a basic system.  I think that these kinds of pictures set DIYers up for an immediate fail, there's just so much more to be considered here.  Sure it is an "example" but it isn't good (imo) and that should be called out.

Consideration needs to be given to:

• fusing between battery packs in case of a battery short and understand if you do or do not need to fuse
• issues of connecting drop-ins in parallel - 4 BMS's that do not talk to each other is a recipe for massive current flows
• not fusing the start battery - I know 99% of NZ installations are unfused, but that doesn't make it right
• not having a shunt to measure current to manage the Li charging profile to know when to stop
• not having a way to top off the starter battery

While this diagram is basic, I personally think it's a bit generous to call it "good".

 

Fair point. When I posted this I was thinking about an example of Alternator load dump management, not an instruction diagram of how to install a complete system. It is NOT saying any particular LiFePo4 units can do a bank of 4, does not say how to config BMS's, or fuses. But it DOES show a basic way of using your alternator (externally regulated with correct voltages, and hopefully temp sensing) with LiFePo4 batts. Which many web sites say you cant.