Lately it is becoming 'fashionable' to mount what they call monitors or battery controllers in motorhomes, and I would like to make some reflections on that. I think it is important because I have had several cases of clients with confusion on the subject.
Just looking at the voltage of a battery We do not know if it is good or bad or if we have a lot or little load in it. SEspecially if the voltage that marks the device is below 9 or 10 volts is when we really know that we have very little charge.
If, for example, we take a battery that is nearly sulfated and we charge it to the maximum it may reach us up to 12.5 volts, for example. Confident, we started using it. However, surely that in a very few minutes it will run out and we will run out of power. Although it read 12.5 volts, it had almost no accumulated current and it returned an erroneous data.
The capacity of a battery is the current it has accumulated inside but this is not proportional to the volts that it marks. Only in cases where it is a new battery does it give us a certain indication. For this reason, in automobile electrical workshops, to see how a battery is doing, they do not measure volts with a multimeter. It is likely that you have perhaps seen that in these workshops they use large tweezers that put between the positive and negative with a resistance in between (which heats up).
What really matters to many of us caravanners to know is how many hours we have of current in the batteries for the use that we are giving them, without having to start the engine. In this case there is another type of device that really it does measure how much charge is left in the battery in each case. Depending on the consumption we have at all times, it tells us the hours that we have left of use, with a fairly close approximation. So we can decide if we turn off lights or reduce consumption.
Speaking in the first person I must say that I have this system installed in my caravan and it is very comfortable for me. If, for example, I am watching television, I have a light on and also the heating turbo and 'I have battery for 6 hours' I turn off the lights. In this case, it happened that, after 6 hours of battery life, after turning off the lights, it started telling me that I had 18 hours left. In this way, you manage what you spend to avoid surprises and suddenly run out of battery.
Finally, it should be noted that in these other devices the way of mounting is very important (distances, cable sections, ...) so that it works well or badly. If you are interested I am always at your disposal to answer all questions or doubts. You can leave a comment on this article or, if you prefer, send me an email and I will answer you personally.
Once again, enjoy traveling!
A hug and see you on the road.