Just back from 2 weeks away without EHU. Difficult to check energy usage but it appears that the gas used was about 0.5kg per day.
We have two solar panels and thought the battery was kept well charged. It generally went from 13.8 to about 11.8 on the built in meter. I wasn't too concerned until I checked on this forum and found 11.8 seems to be only 1/3 charged. Can anybody confirm this. I was thinking I needed to keep it above about 8 but this implies I should be keeping it above about 12.
What do others think?
Too much information and no knowledge can be a bad combination.
13.8 is presumably when the panels were charging the battery, otherwise it shouldn't be more than about 12.7V.
11.8 is very low and will cause problems with the battery life. What wattage are your solar panels?
We have 2x65w panels. Since I obviously don't know what the display means any figures I quote are meaningless. I did assume everything was going really well. We lasted 2 weeks with no problem and quite a lot of TV. The radio reception was really or and we used the TV for the digital radio. I would have used this less if I'd thought there was a problem. My question is really:
"How do I know when it is safe to use the TV without running out of power"
On the narrow boat forums, where people depend on battery power far more than we do, 11.8 is reckoned to be the lowest a battery should be allowed to go regularly. If it dropped to 11 regularly you would be reducing the life of the battery drastically.
The answer your question is difficult to calculate but you probably need to watch the voltmeter regularly and see if you can work out a pattern, and try to reduce your usage as much as possible, such as replacing all your bulbs with LEDs.
Using the TV to receive digital radio, for example, is very power hungry/wasteful
I suppose all I need to do is turn off the TV when the reading reaches 11.8
I don't think it went before this in the last two weeks, but I wasn't really looking at this figure; it was a lot higher than 0!
Can I check the value at any time or do I need to turn everything off, as the battery is always charging?
You need to test the battery under load to get an accurate reading.
A battery may show 12.6 to 12.8 which is fully charged. But as soon as you put any load on it then the voltage may drop this is because the battery doesnt have any reserve capacity.
12.8 is flat. EDIT: This should say 11.8 is flat.
I wouldnt run mine down that far. Your pulling too much power compared to what your putting back.
You need more power going in or less going out.
Make sure you charge the battery with a good smart charger.
This is a new caravan. It is working fine. The battery is good. There is no problem whatsoever. If I ignore the reading everything is fine. I just want to know what the reasons mean. I don't need a charger or anything else. Others have said 12.6 is fully charged. You see my problem. I need to know what the gauge is showing.
Quote: Originally posted by Grampian91 on 10/8/2014
You need to test the battery under load to get an accurate reading.
A battery may show 12.6 to 12.8 which is fully charged. But as soon as you put any load on it then the voltage may drop this is because the battery doesnt have any reserve capacity.
12.8 is flat. I wouldnt run mine down that far. Your pulling too much power compared to what your putting back.
You need more power going in or less going out.
Make sure you charge the battery with a good smart charger.
From my narrow boat experience your figure at the start of para 3 (12.8) certainly isn't a flat battery!
A fully charged 12v battery will read around 13.8v off load.
This is why when you bench test communications equipment used in vehicles (trancievers etc) the bench supply is set to a nominal 13.8vdc. This way when you set the maximum transmit power on the bench you know that will be the max when it goes in the vehicle.
Quote: Originally posted by david8858 on 11/8/2014
A fully charged 12v battery will read around 13.8v off load.
This is why when you bench test communications equipment used in vehicles (trancievers etc) the bench supply is set to a nominal 13.8vdc. This way when you set the maximum transmit power on the bench you know that will be the max when it goes in the vehicle.
Surely 13.8v is when the engine is running. My motorhome battery reads about 12.6v when fully charged. I'm going to fit a better digital meter when I get round to it though. You can get little LED digital voltage modules from china on eBay
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Topic: Elddis battery meter
