# Saving my Vehicle Battery - Good idea or bad



## Ken38 (Mar 24, 2009)

I have a tracker and an alarm on my MH and they draw about 40mA as measured with a multimeter.

When I park up the van and forget for too long I can get a discharged vehicle battery and can't start. Bad for me as I have to rig up a charger. Bad for the battery as it does like to be deep cycled.

So my idea is to disconnect the vehicle battery and connect a link, with a fuse, to the leisure battery. If I leave it too long I risk my leisure battery but at least that is not as bad with deep cycling.

I do intend to fit a solar panel sometime but not until the spring.

60Ah of leisure battery charge should last about 60 days at 40 mA. I am not sure what my leisure battery size is. I guess about 120Ah.

So brickbats please.

The fuse is to ensure I don't try to start off the leisure battery. That would be a good "smoke" test!


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## CliveMott (Mar 10, 2008)

This is not an unusual scenario. You need to connect your van to a hookup overnight one every couple of weeks or fit a decent sized solar panel that will still provide meaningfull amps during a dull winters day. Suggest 80 watts min then this will sustain you in the summer.
To make sure that both batteries get charged then its either a battery mate or a simple bridging fuse.

If you park the van in a barn then forget the solar, just make sure that barn has a mmains supply!

More here
http://www.motts.org/BRIDGING FUSE.htm

C.


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## Ken38 (Mar 24, 2009)

My idea is a slight variation. By disconnecting the vehicle battery it should hold high charge for a very, very long time.

If I do fail to charge up the batteries only the leisure battery is getting drawn down. That is better at handling such long and deep discharge.

I still struggle with solar simply because I have to drill a hole in the roof, run a cable inside the van somewhere and glue 8 Kg of solar panel properly onto my roof.

I know many people have trod the path but ....


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## kandsservices (Sep 5, 2010)

Its possible that disconnecting your vehicle battery will send a signal from your tracker if it is monitored and send you a message every time or a phone call from the call centre to say that your battery has been disconnected if its not monitored then you should be fine fitting the link like clive motts one.
Kev


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## BarnacleBob (Oct 31, 2010)

I suggest you fit a battery master as suuplied by Vanbitz. This little device allows the leisure battery bank to trickle charge the starter battery when its voltage drops to a certain level. ( I forget the actual voltage.) Once fitted you can forget about it and you will use the leisure battery power to top up the engine battery automatically.

A battery master is fitted to my vehicle and it works well.

Fitting a solar panel of 80w ouput will keep your leisure battery topped up if your 'home is stored outside.

Bob


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## Ken38 (Mar 24, 2009)

I disconnected a few times the other day to get the battery load when shut down. I didn't get a call. Interesting observation and thanks.

Regarding theft of the vehicle, you need to get in the van to disconnect the battery so it's not a great concern.

Of course when I disconnected the alarm wasn't set so it's still possible it would make the alert call.


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## pippin (Nov 15, 2007)

Disconnecting the engine battery while you do the change-over would mean resetting the radio code.

The ECU might not like it either.


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## Techno100 (May 8, 2010)

If you have your hab battery linked to your cab battery before lifting the positive connection clear of the cab battery's terminal Nothing should be affected. :roll:


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## Ken38 (Mar 24, 2009)

I was surprised but disconnecting the battery for a very short time did not lose the key code or affect anything else.

*But please all remember when disconnecting batteries you disconnect the earthed (frame) terminal first (normally the negative but not always).

*The reason for this is if you touch any metal work there is no short circuit. Once the earth is clear of the battery you can disconnect the non-earth (normally +ve) terminal safely. A dropped spanner across the battery terminal to frame (earth) will cause a major short circuit and may even weld itself into position and get very hot.

You reconnect non-frame first then the frame (earth) terminal.

Sorry about the pedantic use of the words frame, earth, +ve and -ve but it is important to get it correct. :?


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