Jump Starting from Hybrid Cars

Two nights ago, I though I had nothing better to do than start up the Peugeot 5008 and take it the two miles to the garage to get one of its ABS sensors replaced, before I sell it. Stupid me, I forgot that I should have checked the battery first since it's been sitting on the driveway for 6 weeks or so. So it wouldn't start. I thought it wouldn't be a problem given that I have two other healthy cars sitting on the driveway next to it (our Prius and new Outlander PHEV) that I could jump start it from. Alas, no.

A quick search of the internet shows that due to the small size of the 12V 'starter' battery on hybrid cars, they are not suited to providing the large current that gets sucked up when turning over an engine as well as the risk of upsetting the associated electronics and settings. I recollected (and recorded in a previous post) that I had bought a jump start unit for jumping the Prius after an experience when I'd left interior lights on and it drained the small 12V Prius battery. The unit I bought is shown below:

It consists of a 12V battery big enough to turn over a small engine and is more than capable of starting the Prius' starting system. The positive and negative clamp cables are tethered to it. You can also use it as a pump to blow up flat tyres. We did let the battery go once again after this and this unit was easy-peasy to use and get the Prius up and running. I thought it might just have enough grunt to try and turn over the 1.6L diesel on the Peugeot. However, this time, I'd left it in the shed after clearing the Prius out and hadn't put it on charge so it was flat too. Bah! I was forced to borrow a neighbour's Vauxhall Astra and used my other jump start cables to start it okay. Lesson learned - always keep your charger charged!