Hi All,
We all know how our beloved beasts love to have exactly the right voltage on it's components and to that end a lot of time and effort is spent on getting the wiring, grounding and alternator up to snuff. Recently I have been monitoring my battery levels more closely since I am running my first fridge ever from a secondary battery setup
Very happy with the national luna btw!
In any case, my car has been sitting in the back yard for a couple of weeks after the abenteuer und allrad messe this year and I noticed a few things. First of, my gel batteries (which were free so that's why I "chose" gel) did not get fully recharged even after a 6 hour trip home. My setup is probably not ideal yet (no dc-dc charger, just a relay to isolate). This has probably also resulted in my main battery also not being fully charged.
I used a regulated power supply set to 14.4 volts to top up both the main and secondary batteries and left the system like this after this was done. After a couple of weeks my secondary batteries are at 12.65 volts, which makes sense since not all of them are the same quality (they were secondhand) so the voltage drops to the lowest battery. The only thing connected is a turned off HF set, a turned off inverter and a turned off fridge (which means only the battery monitor is effectively working).
My main battery is of course connected to the car which is just sitting there with the hood open. When I recently checked the voltage again (directly on the battery itself) I measured 12.35 volts which would be around 75% charge, though officially you would need to measure it open circuit.
So, it seems to me that the range rover electronics do use quite a bit of power just when the car is sitting doing nothing. I do have the key in the ignition but it is turned all the way to off. My battery is only 2 years old and is a respected brand but also seems to be a bit tired already. Seeing as the battery needs to cycle deeper than is desirable for a plain lead acid battery I was wondering if our vehicles would be better of with a battery that is more suited for this type of use, ie an AGM for example which you can find in most modern vehicles with that bloody stop/start system.
Any thoughts anyone?
Cheers,
-P
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