Ring Automotive RPP 210 12V 40ah Power Pack Complete with 300W Inverter

A great product, very versatile. After charging the Ring power pack up for the initial 36 hours, it started my Aston Martin DB7 with a partially discharged battery straight away- even though it has a 5.9 litre engine! It was also used in sub-zero temperatures and the inverter has since been used to trickle charge the Aston's battery to prevent further non-starts. Contrary to other reviews the inverter is silent when in use and keeps going for a long time. Totally recommended.

I'm on my second one of these. The first had to go back after the inverter stopped working. Not too sure why as I've ever only used it with an appliance that draws around 10W. I think the inverter is the weak link in an otherwise good product.

Good points:
Battery seems to last for ever, hardly surprising with 40A at hand, most of the cheap and nasty ones use 12A or 17A batteries which are also probably cheap and nasty.
Inverter, 300W which is fine for a fair amount of small appliances, old style lighting, laptops etc.
Jump Leads, nice and chunky, a bit short which means the power pack probably can't stay on the floor, short leads mean less power loss for jump starting which is exactly what you want. Also there's a switch and cut out which should make it idiot proof.
It's jump started my 5 cylinder diesel with no problem and I hadn't a clue when it was previously charged

Bad points:
Inverter, it generates a modified wave form which is fine for resistive loads such as old style lighting (tungsten/krypton,halogen), also runs laptop power supplies. This will be useless for inductive loads such as fluorescent lights or energy saving lights. It's a simple inverter for simple loads. It powered my laptop and other small loads with no problem for hours on end, but don't expect it to power fluorescent lighting and some motors. If the inverter screams then you've plugged in an inductive load. a good inverter, that handles such loads, will cost several hundred pounds alone.
a/c 500mAH adapter woefully small. Ring recommend 36 hours charge, but at 1/2 an amp maximum and a 40AH battery capacity it doesn't take much working out. 36 hours may be fine if you've just jump started a vehicle, but if the battery has been run down with the inverter, 12v output or lamp then you'll be looking at 4-5 days charge. I suppose there's no chance of over-charging with 500mAH

I don't regret buying this and I would buy one again as there isn't anything else out there. It's fantastic for jump starting and good for small mains voltage loads. I think the best way of charging is via the cigarette socket if you know you'll be on a 3-4 hour journey, unfortunately there's no indication of charge via this method. Don't expect to be able to run mains 230v inductive loads such as fluorescent lighting, I've known cheap 1000W petrol sinewave generators fall over with just two 40W fluorescent tubes, but handle two 500W floodlights - it's all down to the quality of the inverter and this power pack has a bog standard cheap one to keep within budget.

These units are an absolute life saver when you find that you've got a flat battery and can potentially save a fortune in avoiding the costs of getting out the roadside assistance companies or trying to borrow some jumpleads. For this reason it should be an essential item in any car boot space but beware of the cheap ones that have flooded the market recently if you have any car engine above 1.8litres.

I have the Ring 210 40aH power pack (the Ring 135 is only 20aH and only recommended for use on upto 2.5L petrol and 2.0L diesel engines) as you need something with a bit more oomph to crank petrol and diesel engines upto 5litres and 4litres respectively.

Despite what some vendors claim, it will not jumpstart a completely flat battery (the residual voltage has to be higher than 1.5v in it) but you can connect the powerpack to the lighter socket for 15mins to trickle charge the car battery before jumpstarting the vehicle. It is a big heavy unit (18kg!)but thats because of the inbuilt 300W invertor which is useful for camping, and long car journeys to power a laptop etc.

The leads are heavy duty and 1.5m long, but still aren't long enough to reach into my estate's engine bay from a ground position. This is a bit of a pain seeing as it is a hefty weight to lift and hold there, whilst trying to connect the leads. If only they were 2m it would be better.

As mentioned earlier it will jumpstart the bigger diesel and petrol engines that your bogstandard powerpacks won't, so worth paying the extra if your car falls into this category.