My 928 suffers from a battery drain which I have yet to work out. I've broken down a few times as a result if I forget to disconnect the battery. Any idea if this has enough power to start a 928 s4

http://m.ebay.co.uk/itm/231563686515?nav=SEARCH

Apart from being a very nice colour it would also make a useful power source for camping trips

 

I would get a larger one that uses super capacitors as they can discharge energy much quicker which is needed for starters. Like this one.

http://www.ebay.com/itm/NOCO-Genius-...item27fe0140df

The smaller ones will also wear out quicker too as the capacitors inside will have to work a lot harder than a jump start pack that has larger better quality capacitors.

 

In my experience the biggest failure in all this type of starter packs is the cr@p leads and clamps. The leads may be 3/8-1/2" OD, but they generally have very small dia conductors inside them, and while the clamps sometimes looks like copper, they are mostly anodised ally, with little grip or strength. They all need to be tested by trying to start a car with a poor condition battery. Claims of high current capacity should be treated with great scepticism. I made my jumper leads using 70 sq mm welding cable (fine copper wire, heavy, but very flexible), and steel clamps that are difficult to open with one hand.
The first link above says it has a 6Ah battery (6000 milli amp hour=6Ah), and can deliver 200A - maybe for a milli second under special circumstances. Also says for starting small to medium cars - dont think even a 4.5L would fit this description. One look at the cable size on the second unit tells you a lot - why are the starter cables the size they are on a 928 ?
I would need to see a demo before I bought anything like these. Even with my very good heavy cables I could not jump start my car from a full size battery in a 4 cyl car unless it was running and charging.
jp 83 Euro S AT 56k

 

Fix the drain - usually just a matter of being very very methodical, and taking time to measure everything well... this is a better solution than any band aid.

If you need a back-up solution - you'd do better to consider a real battery... an Odyssey PC680 will actually start a 928 (up to 520A& 180CCA). You need to mount, connect, and figure out how to charge it yourself.

For me it solves a different problem (primary battery death due to "natural" causes) - But I suppose it would get you by.

Better to fix the drain though - I'd estimate it would take less time than installing this.

I carried a portable backup system in my other car for about 3 years - charged it every few months. The only time I ever tried to use it - it was dead (totally unable to charge to a useful level) - even though the gauge initially said it was fully charged.

I got exactly 0 uses out of it - total waste of money, time, space and the gas to haul it around for 3 years ... Never again!!

Alan

 

I keep one of these for emergencies.



Bought it on sale at Lowes for $15 bucks. It's small enough to fit in a glove compartment and I even take it along on motorcycle trips.
This does NOT jump start the vehicle. You plug it into the cigarette lighter socket and it charges the battery. The display indicates when the car is ready to start. Usually takes 15 minutes.
If the battery is completely flat, this most likely won't help...especially with a V8.

I keep a real jump pack in my SUV during the winter.
This will start anything and will work great for your camping trips. It has a 12 volt power socket, twin 120 Volt power outlets (500 watts continuous) and a USB charger port. Also has an air compressor and led light. I also use it during short power outages before firing up the generator.
Downside is that it's large and cost about $100.00.

 

I went with this one... small so I can take it with me for cell/tablet recharging and purchased pump for tires too. Add this to a PC1700 from Odyssey and a reduction in power consumption switching to LEDs... not bad...

http://shop.antigravitybatteries.com/micro-start-xp-10/





However... I haven't had to jump start since picking this one up and using it right away- but that's mainly b/c I haven't been driving for, I think, a month or two now due to other issues...

 

Mike,

As Alan says trace the leak and fix it irrespective of anything else. After the car has sat overnight go into the central electrics and see if you can find a comparatively warm relay as a start point for the search- use a temp gun.

Beyond that these devices look quite impressive- whether or not they can support starting a 928 I would reserve judgement on until I tried it but for the price not a bad piece of kit to have in the locker irrespective of what it is actually used for.

Regards

Fred

Regards

Fred