Battery Disconection and Memory

[porgey]

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Hi. Planning on installing a dual battery system with battery in the cargo area on my 09 JGCL CRD. Haven't decided on battery size yet but it has to power an Engel 38 litre. I can't see anything in the Jeep hand book in regards to safeguards for saving memory when disconnecting the cranking battery terminals ,can anyone offer advice . I am a retired mechanic but not too clued up on computerised diesel powered jeeps . Cheers Porgey Seaford Vic

[chrisk]

Originally Posted by porgey

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Hi. Planning on installing a dual battery system with battery in the cargo area on my 09 JGCL CRD. Haven't decided on battery size yet but it has to power an Engel 38 litre. I can't see anything in the Jeep hand book in regards to safeguards for saving memory when disconnecting the cranking battery terminals ,can anyone offer advice . I am a retired mechanic but not too clued up on computerised diesel powered jeeps . Cheers Porgey Seaford Vic

Porgey,
I also have a late model WH CRD with a second battery installed in the rear. Mine is called a "thumper" & I purchased it from the "home of 12 volt" who are based in Adelaide. Check out their web site or they are always aroung at the caravan shows.
Now, to hopefully answer your question. The best thing to buy is a "readarc" battery isolator ans install it off the starting battery of your car as it descrive in the info that it comes with. It's really easy & I did it myself. I tow a van & have an anderson plug at the rear of the car to charge the van batteries while its connected. The redarc isolates these batteries depending on the charge it senses in the starting battery. If the charge in the staring battery is correct it then passes any excess charge from the alternator through to the the batteries in the van & the thumper in th rear of the car. I run a 38litre engel off the thumper for at least 4 days without the need to run the car, any normal driving will replenish the charge in the rear battery so on a normal trip I don't run into any problems. Hope this helps in some way. By the way I'm only just down the road in Frankston if you want to PM me I can give you more info.

[fester]

Originally Posted by porgey

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Hi. Planning on installing a dual battery system with battery in the cargo area on my 09 JGCL CRD. Haven't decided on battery size yet but it has to power an Engel 38 litre. I can't see anything in the Jeep hand book in regards to safeguards for saving memory when disconnecting the cranking battery terminals ,can anyone offer advice . I am a retired mechanic but not too clued up on computerised diesel powered jeeps . Cheers Porgey Seaford Vic

Most modern vehicles although electronic generally only lose memory in things like the radio. Not sure about things like seat positions etc depending on model specifics but I've seen kits for sale marketed as memory retainers etc that look like jumper leads with a 9 volt battery connection on the end. You know like your smoke alarm battery. Never used one and I can only guess the issue might be to disconnect from the car battery as quick as possible after connecting the 9 volt in case the 12 volt battery starts to damage the 9 volt by duming power in. At any rate if you realy want to save your memory it would be pretty easy to make up a jumper system with a 9 volt battery or just get a set of jumper leads, connect one end of each to the leads on the car side andmake sure you have them contacting the terminals of the battery as you slide the leads off one at a time.Then you can have the jumper leads still connected to the battery and sit it on the ground whilst the other ends are on the vehicle leads. Just make sure they are insulated from the body and the positive can't arc out on anything.