Has anyone done this?

My battery must be 10 years old it is labelled Jaguar but is actually VARTA.

What an amazing battery!

I have just bought a new one AC Delco 730 CCA!-it's a biggie.

I has occurred to me that it might be prudent to change over without losing the power.

Has anyone done this? What is the best way? Just connect them in parallel?

Thanks

 

I used my battery charger, + clamped to the+ cable - to the ground stud in the trunk,while I cleaned the terminals. It kept all the memories going, no windows to reset etc.

Stu

 

Be very careful about connecting a battery charger without a battery. Depending on the electronics in the charger you may get a safe voltage out or you may brew up your electronics.

 

I have not tried this but I did read on a forum that someone in a workshop said he made up a little bit of kit involving a cigar lighter plug and a normal little pp3 9V battery, apparently it was just enough to supply a voltage to keep the memory going, make sure the cigar lighter stays "live" when the keys are not turned on ,
Similar to this
Car Computer Clock Stereo Memory Saver Battery Backup Unit Automotive 12 volt | eBay

and this
Car Memory Battery Saver Radio Code Computer | eBay

search ebay for " Battery memory Saver "

 

Yeah definitely avoid using a battery charger - many have very rough outputs which can peak as high as 20 volts if there is only a low load on them; indeed some can knacker an alternator even when the battery is connected.

You can get little battery (9v) gadgets to plug into the cigar lighter / aux power socket which (provided every thing else is switched off) can supply enough current keep a dormant computer alive long enough to change batteries.

Somewhere I read that there are date codes on batteries so you might be able find out when the old battery was made. Mine's labelled 'Jaguar' too, but whether it's the original or a dealer fitted replacement I don't know.

Are you sure you've got the right new battery 730 CCA sounds a bit low ? The replacement battery for the X350/358 is an 019 which is has a CCA of 800 to 850 amps and a capacity of 90 to 100 Ah (dependent on manufacturer and quality)

 

+1. Connecting a charger without a battery could cause very expensive damage.

 

To clarify, I used a good quality Schumaker battery charger set at 2 amps., but maybe I was lucky, no damage. Would a 2 amp battery tender be safer?

Stu

 

There are lots of variables involved both in the charger and in the car in determining whether damage would occur, but the potential is there for it to happen.

A small nine or 12 v battery (or filtered DC power supply) with a series diode is the safe way to maintain power if it is important to you.

The output of a charger may not be steady DC, and may present voltages unsafe for the car without a battery connected.

 

I concur with WhiteXJR.

Never put a charger onto a battery while its still connected to a car unless the charger manufacturer specifically states that it is designed to work safely that way.

Never leave a car connected to a battery charger without a battery - period / full stop. It looks like you were lucky and got away with it; but a charger still isn't designed to power car electrics, it's designed to charge a battery which ain't the same thing.

Best way to maintain supplies is to rig another 12 volt car battery in parallel with the main one (crock clips to the main leads) remove the old battery install and connect the new one, then disconnect the temporary battery.

The temporary battery doesn't have to very big, but it must be a 12v car battery and it should be reasonably charged (ie show at least say 10.5 volts when measured open circuit). I guess I'd whip the battery out of my Hyundai Getz if I had to do it.

If you use a different type of temporary battery, then as WhiteXJR says, you'd need a blocking diode to prevent the possibility of the old and new (especially the new) car batteries discharging back through the temporary battery, because if it were say a 9v PP3 in series with one or two [no more] AA or AAAs (9 + 1.5 +1.5) the back current might be big enough to make them explode.

 

Correction

My JAGUAR (varta) battery is 90Ah and 680 CCA and the AC delco is 780CCA not

730 CCA as I posted. So the Ac Delco can deliver more amps.

On the JAGUAR battery the date code is on one of the terminals and is 73 with 03 below ie November 2003


Many thanks for all replies.

 

By the way ... I think the 019 number I quoted is a Brit/Euro number and may not apply in Aus (certainly doesn't seem to exist in the US).