Leisure Batteries

[arh]

Reading this months MMM I see the article about the battery situation, now, I'm seriously thinking of putting a Truck battery in instead of the one thats in place.Of course it won't go under the passenger seat,(which is a pain anyway as one has to remove the seat to check it). But I was of the impression that the engine battery came into the "equal battery size/age/condition" senario, or am I wrong here?, I have a 80w solar panel and a batterymaster thingy, as well as the electrics that came with the van. The question is "If I put a bigger battery in, will the solar panel cope with it, or will the bigger battery swallow all the watts that the panel puts out, thus robbing the Engine battery of the "left-over juice". On a further note, can I put up another panel and just wire it into the same terminals on the batterymaster thingy, or is it more complicated than that.Will I have to have a serious discussion with Mr.Wickersham?.

[spospe]

An 80 watt solar panel will only produce about 4 to 5 amps peak charge and as is intended this will be directed first of all at the leisure battery.

 

When the leisure battery is fully charged any excess current will go to keep the engine battery topped-up. A bigger leisure battery means that it will take longer for it to fully charge (assuming that you have run it down) and so it will take longer before the engine battery can receive any current. This should not be a problem, as the only use of a battery master type device is to keep the engine battery fully charged during periods of inactivity.

 

Adding another solar panel may be quite easy, but you need to read the installation instructions for your solar regulator to find out how to go about it.

[Clive]

You could always have a serious discussion with me!.

 

Firstly the battery Master will allow a maximum of 1.1 amps to flow from the leisure battery to the starter battery when the leisure battery voltage is at least 0.6 volt above that of the starter battery. It has nothing to do with the number of solar panels you might have. Its intended to ensure that your starter battery always has sufficient charge in it to run the alarm and possibly tracker system you might have plus start the motor. It is unlikely to keep the starter battery FULLY charged but will keep it adequately charged.

 

Your solar panel will be connected via a REGULATOR into the leisure battery wiring system. If you wish to increase your solar "real estate" then you need to ensure that the regulator is capable of handling the increased solar contribution.

 

Doubling the size of your leisure battery bank means it will take twice as long to charge from whatever means you have in mind. It will not overload anything, but one word of warning.

 

Some modern vans intelligent charging systems have a 3 stage charge algorithm. The middle phase will allow the battery voltage to go perhaps as high as 14.4 volts. When the charge current has fallen to quite a low value the charger detects this and reverts to a maintaining voltage around 13.5 - 13.8 volts. If you have a much bigger leisure battery bank than originally intended for the van or if the batteries are old and leaky then it is just possible that the minimum level of charging current (amps) in phase 2 will not fall sufficiently low to allow the charger to get to phase 3 with a reduced voltage. And you will (over time) gently boil off water from your leisure battery.

 

Hope that helps

 

C.

 

 

 

 

[arh]

Thanks to Clive and Spospe for the replies. I will check the paperwork for the regulator to make sure, the van is now 8 years old so I doubt that it will be state of the art electrics, but after saying that it is Italian and very much up to date.Thankyou again.arh.