MEXICOWANDERER wrote:
...It's worse than relying on a volt meter for state of charge.
Perfect and appropriate analogy for these forums.
That said... I am fortunate to have the ability of relying on a volt meter... but only for camping because I don't have an amp hour meter and don't like to draw electrolyte unless I have to.
1. I know the condition of my bank before I hit the road.
2. My old rig has such little parasitic draw that I can pick a time when little draw has occurred prior to taking a volt reading.
3. I use voltage as a rough gauge. If I note cause for concern, I may whip out the hydrometer or simply start the genny.
After 48 hours without a charge during my last trip, I noted 12.48V with very little draw for hours prior (morning-time after a coastal night with no furnace required) and the negative pulled for a half hour prior.
We were packing up to head home anyway, so this test was just for drill. Had I been staying, this would have told me that I had at least 2 more nights before I needed to fire up the genny or hit the road and put the alternator to work. And that's if I wanted to adhere to the 50% rule of thumb.
