Battery - Charge & High Load Question

[swisscraft]

Hi there,

just a theoretical question we discussed today and I wonder if you can bring some clarity: The discussion was about DC vs. AC and Genset etc. etc. At the end following was not clear to us:

A) Assuming you running a high power device (12 V) or put a high load on your inverter (like Waterheater, Washing Machine, Aircon etc.) Using somewhere between 100 - 200A/12V.
B) On the same time you generate the similar amount of Amps (either charger/Alternator or whatever)

So in theory you just use the energy you produce. But is this not putting an enorm stress on the batteries or is there just a "flow trough"? Are there any other drawbacks?

Thanks for any ideas on that!

[Lake-Effect]

Originally Posted by swisscraft

... so in theory you just use the energy you produce. But is this not putting an enorm stress on the batteries or is there just a "flow trough"?

In any electrical system, the sum of the currents flowing into a given point must be equal to the sum of the currents flowing out of that point. Part of Norton's theorem I believe.

So, in the given situation, simplified, let's say we have current being demanded by the load (let's call it L), and we have the current supplied by a generator (G). The current (B) going to the battery bank will be G - L, so if G and L are about equal, there will be little current going to or coming from the battery. So, no stress to the battery.

[Lake-Effect]

oops - Kirchoff's law, not Norton's

[swisscraft]

Thanks guys!

[smac999]

just make sure all the wiring can handle everything. there will be voltage drops across everything when it's all high current.

but yes. if say you have a 200a alternator and you're running the engine. and you're pulling 150a off your inverter, you could still have +50a going to charge your batteries. or if you pulled 200a off the inverter. the battery current is 0 and would just stay at the same state.


get a battery monitor.