Jump Starter Pack - Procedure

[Herbie]

My RX450h takes 15.32A to get it to the READY state, so I would assume that an IS300h would be the same.

[matt8]

11 minutes ago, Herbie said:

My RX450h takes 15.32A to get it to the READY state, so I would assume that an IS300h would be the same.

Thanks Herbie. Simply trying to understand; how was this measured? Was it observed for a split second as someone pressed the power on button? I'd have thought that there is no ongoing power draw once it's in Ready.

[ColinBarber]

11 minutes ago, Herbie said:

My RX450h takes 15.32A to get it to the READY state, so I would assume that an IS300h would be the same.

Was everything turned off? 15A seems high.

I jumped a RX400h once from a Battery charger, that could only supply 8A maximum.

[ColinBarber]

1 hour ago, matt8 said:

Thanks Colin. Makes sense.

Is 2.1Ah alarm battery sufficient when the aux battery is 45Ah?

It won't last long if you used it as a replacement for the aux Battery but would give sufficient current to get it to 'Ready'. The 45Ah is there to allow you to power lights, stereo, heating, power unlock doors etc. for at least some time without being in Ready mode, and to allow the vehicle to stand for two or three weeks and still have enough capacity to 'start' the vehicle.

[Herbie]

4 minutes ago, ColinBarber said:

Was everything turned off? 15A seems high.

That's a good point actually. I can't remember now. I would have had the tailgate open but did I turn off the interior lights?

Tell you what, I'll do the experiment again and make sure everything IS off this time

[Herbie]

8 minutes ago, matt8 said:

Thanks Herbie. Simply trying to understand; how was this measured? Was it observed for a split second as someone pressed the power on button?

Yes it was, but possibly incorrectly now as I think about it. I'll run the test again and post the results.

By the way, a 12V 2.1Ah Battery should (if I remember correctly) provide a maximum of 21A for one minute, depending on type and age - but it's a very long time since I had to think of things like this so don't hold me to that

[Thackeray]

47 minutes ago, ColinBarber said:

Was everything turned off? 15A seems high.

I was wondering the same. I'm not very familiar with what these numbers mean - I haven't given it much thought since school days!. Not trusting myself to remember the formula (V=I/R or something like that?) I looked it up on the internet and found this page that says 15 amps on a 12 volt circuit equals 180 watts. If this is right (please, someone,  correct if it's wrong) this is easier for me to relate to - a bit less than a couple of 100 watt bulbs. That sounds a bit high to start a computer circuit or two. But there must be some sort of relay to open the hybrid Battery circuit - maybe there's a physical electro-mechanical switch to open it. If that's the case a brief supply of 180 watts might be possible.

But it probably takes only seconds to get the hybrid circuit to the ready state, so the 15 amps probably doesn't depend solely on the 12V circuit for very long.

36 minutes ago, Herbie said:

I'll run the test again and post the results.

It'll be interesting to see some more details.

[ColinBarber]

2 hours ago, Thackeray said:

That sounds a bit high to start a computer circuit or two.

There are a lot of ECUs in the vehicle, at least 20 on the 300h which will all consume power with the ignition on. The stereo and nav system, if not turned off, consume power, including its cooling fan. The hybrid system has pumps for brakes etc. Auto headlights could come on if dark.

Best to turn on the ignition, let it settle for 30 seconds, make sure everything is turned off that you are able to turn off, and then try to go into 'Ready' mode - even that will consume power as you have to press the brake pedal which will put on the brake lights - luckily LED otherwise that would be 40 w on its own.