Dead Battery

Nodding_Donkey

Ahh good, can you explain the following then (a quote from one of your links)

"If the sending alternator's regulator gets a wee bit confused"

that seems to imply that electronic circuits have somehow developed feelings.

Skynet anyone?

EdGasket

Certainly. It was trying to explain in simple terms for non-technical people such as yourself, that if you suddenly change the load on a regulated voltage/current device, such as when connecting a flat battery, which in turn is supplied by a high inductance device(the alternator windings), you momentarily get huge voltage spikes which the voltage regulator is unable to regulate in the first few milliseconds. It is these spikes that take out your voltage regulator and/or car electrical systems.

[Deleted User]

Richard53 wrote: »

Sealey's recommendation is that the power pack is safe to use with modern electronics, IF you follow their 'updated' method, which is to connect the booster for 5-10 minutes to the dead car *with the ignition off* to get a bit of charge into the dead battery, then disconnect and start as normal. Trying to start the car with the booster connected was NOT safe, according to Sealey.

I'm sorry but, their advice is nonsense.

The battery in the jump starter pack, in no different to the battery bolted into the car.

TrickyWicky

EdGasket wrote: »

Yes, I have an electronics degree and am a chartered electrical engineer. How about you?

So you have an electronics degree but for a trade you're and electrical engineer not an electronic engineer? Those are usually two very different fields suggesting you're still not being straight with us.

TrickyWicky

Richard53 wrote: »

My mistake - I was conflating starting with a booster pack and jump starting and didn't make myself clear. Sealey's recommendation is that the power pack is safe to use with modern electronics, IF you follow their 'updated' method, which is to connect the booster for 5-10 minutes to the dead car *with the ignition off* to get a bit of charge into the dead battery, then disconnect and start as normal. Trying to start the car with the booster connected was NOT safe, according to Sealey.

Whoa.. so hang on, one minute sealey say it's not safe, then they don't but when you're caught out on the hop (like Ed Gasket) you have another explanation for the whole thing?

Come on, get real please people.

As for the 5-10 minutes thing, the probability of that is that the battery in the pack simply cannot supply enough current to start a car (Have you ever taken one of these things apart? - the battery is nothing like a car battery). Attempting to jump start it directly from a booster pack can work on cars with low charge but not completely flat which is when you connect them up for a few minutes to boost them. From my POV there is confusion between you and sealey as to who means what and who understands who is talking about what.

There is probably more risk to the battery pack itself due to the high amount of current you'll be trying to draw from it hitting the starter motor too quickly.

Richard53 wrote: »

As I have stated above, I would use a booster pack on my own car, or a jump start, or whatever it took to get me going. What happened was that an RAC man attending a vehicle on our site said (in the hearing of one of our bosses) that we shouldn't be using it. The boss put the use of the booster on hold (for customer vehicles) and asked me to contact Sealey for clarification. That was Sealey's reply, and it was in writing from their Product Development Manager or some such, not a Saturday boy. The bosses took advice from their legal people and we were banned from using it on customers' cars. Now we just give the number of a local garage, or advise contacting the RAC/AA. It's all to do with liability issues, and very little to do with the technology.

You're changing your story again! It's been unsafe then safe, unsafe and now it's avoided purely for legal implications because an RAC man said not to use a booter pack (which most of them carry themselves anyway). You know the key to holding up your side of an arguement? Pick one or two points and defend them to the end. Don't keep rearranging your story all the time to try and make it stick because it doesn't work.

EdGasket

TrickyWicky wrote: »

So you have an electronics degree but for a trade you're and electrical engineer not an electronic engineer? Those are usually two very different fields suggesting you're still not being straight with us.

I don't know what you are trying not very successfully to prove but the I.E.E. happens to be the relevant professional body for professional Electronic Engineers hence I am a M.I.E.E.

If you want to ignore my advice then fine but there's no need make me out as some kind of fraud. I have no hidden agenda as you seem to imply.

I have posted links to relevant articles and experiences showing that jump-starting is not safe even when done in the so called 'correct' way. You can appear to get away with it but damage to components can manifest itself weeks later in some cases after jump starting.

TrickyWicky

Ed, yes I did doubt you and lets face it this is the internet. As far you're concerned I could be a professor!

The first article you posted just didn't back up your side of the arguement and you should know that. The fact that you then had to take to google to dig up some dirt makes it look worse.

Some cars might coincidentally go screwy when being jump started. They could be friday cars or have other faults, shorts, corroded circuits etc. There is no definitive cause unless you take the ECU to bits and start diagnostics on the components.

What I can say however is that I drive (or rather I used to drive) a very fragile french car that was known for having fragile electronics and despite shorting the battery while it was running and watching sparks fly everywhere, it was fine. I've jump started very expensive cars and each one has been fine.

You yourself as an electrical engineer should know what happens when you get polaritys confused and lets face it, there are plenty of idiots out there who will blame the car rather than themselves.

[Deleted User]

Once the engine is running, there should be little or no current flowing through the jump leads, as the current from the alternator would pretty much balance the current in the battery.

EdGasket

Bedsit_Bob wrote: »

Once the engine is running, there should be little or no current flowing through the jump leads, as the current from the alternator would pretty much balance the current in the battery.

Oh boy I think I'll give up!

Rover_Driver

Bedsit_Bob wrote: »

I'm sorry but, their advice is nonsense.

The battery in the jump starter pack, in no different to the battery bolted into the car.

Their advice is not quite nonsense. If you leave a charged battery connected to a discharged battery, current will flow to it and you will eventually end up with two partly charged batteries.


If left for 5 - 10 minutes, it may be long enough for the discharged battery to start the engine.


If not, and you have to jump start the engine, in that time there will be at least some power transferred to the battery which could help to prevent a spike as it may not be such a sudden surge.