Car wont unlock

[N2STY]

Can you recommend a good 12v booster pack?

I have found gooloo to be very good especially 3000 and 4000 there a bit over kill but I use them in the workshop as well they do do smaller ones

 

[Lovemyev]

Can you recommend a good 12v booster pack?

You can pay as little or as much as you like for a booster pack really TBH.
If you only intend to boost an EV then one of the smaller capacity units will be fine.
If you have a ICE car in the family and you want the facility to be able it, then go for a better capacity.
Like with EV’s normal the prices increase as the battery size of the booster pack increases ?.
It will depend on your budget really ?.
I opted for the Halo Bolt Air unit because it has way more battery capacity than you are every likely to need, but it has a built in air compressor as well.
Had it about 3 years now and it has been used a lot to help out family and other people who have been caught out with a flat 12 volt battery.
It’s surprising when you offer your help somebody and you pull out a booster pack.
“You are going to use THAT small thing, to try and start my car - no way” !.
The the look on their face when their car starts is priceless !.
Of course, they intend to go out and to buy one now !.
I would never be without one TBH.
It’s just stored under the drivers seat.
If I need it in an emergency for my car, I can use the emergency key to open the drivers door, then flip the handle on the back door.
A bit harder to get to in the boot !.

 

[Wobbly]

Thanks guys, as you probably guessed I'm new to this situation so still learning!


It looks like the booster packs vary in amp output.
What do you suggest as a minimum requirement for a EV?

 

[N2STY]

Thanks guys, as you probably guessed I'm new to this situation so still learning!


It looks like the booster packs vary in amp output.
What do you suggest as a minimum requirement for a EV?

It's not so much for minimum requirement some of the cheap low powered ones are just rubbish if your budget can be round £100 then this is great Deal: GOOLOO GT3000 https://amzn.eu/d/alXGc1B
One of the easiest to use and read display has 24 months stand by time

 

[Lovemyev]

It's not so much for minimum requirement some of the cheap low powered ones are just rubbish if your budget can be round £100 then this is great Deal: GOOLOO GT3000 https://amzn.eu/d/alXGc1B
One of the easiest to use and read display has 24 months stand by time

Agreed - Buy cheap, buy twice .

 

[pshotton]

What I don't understand is how my car can be completely disabled by a flat 12v battery when the main battery is full. Surely there could be some sort of tapping off the main pack to supply 12v,then we wouldn't need the 12v battery.

 

[N2STY]

What I don't understand is how my car can be completely disabled by a flat 12v battery when the main battery is full. Surely there could be some sort of tapping off the main pack to supply 12v,then we wouldn't need the 12v battery.

For safety the high voltage battery is disabled so the 12v is there to supply car it also supplies the solenoid contacts to the high voltage battery so no 12v no high voltage battery available

 

[pshotton]

I understand that's the way it is but it still doesn't make sense. I can get a 12v supply off my household mains. It seems trivial to have a connection that can feed a 12v power supply while keeping the main supply disconnected. Why have an unnecessary point of failure.

 

[Gadget Geek]

It's almost as if the accessory battery needs an accessory battery for emergency starts.

 

[N2STY]

I understand that's the way it is but it still doesn't make sense. I can get a 12v supply off my household mains. It seems trivial to have a connection that can feed a 12v power supply while keeping the main supply disconnected. Why have an unnecessary point of failure.

Because the 12 volt supply has to be completely independent from the high voltage system
To run the DC to DC converter to get 12v would have to be constantly switched on to the high voltage to work that's just a waste of energy

 

[Kithmo]

Isn't the Gen 2 supposed to keep the 12v topped up when the car's off as long as the HV is above a certain level of charge ?

 

[pshotton]

Because the 12 volt supply has to be completely independent from the high voltage system
To run the DC to DC converter to get 12v would have to be constantly switched on to the high voltage to work that's just a waste of energy

That's just not so. A battery is a battery. I'm not asking for the whole HV system to be on, I'm just saying why can't there be a connection from before the main breaker to a DC/DC convertor supplying 12v? Why waste money on a separate battery when the car already has a bloody great big one.

 

[N2STY]

That's just not so. A battery is a battery. I'm not asking for the whole HV system to be on, I'm just saying why can't there be a connection from before the main breaker to a DC/DC convertor supplying 12v? Why waste money on a separate battery when the car already has a bloody great big one.

Because the 12 volt can't charge without the DC to DC converter switched on which runs off the high voltage battery you can't connect 400v to the 12v without DC to DC and you can't just use a bit of the 400v battery as the cells would be unbalance

 

[pshotton]

But y

Because the 12 volt can't charge without the DC to DC converter switched on which runs off the high voltage battery you can't connect 400v to the 12v without DC to DC and you can't just use a bit of the 400v battery as the cells would be unbalance

You can run DC-DC off 400v (the car already does this), and it only has to be switched on when you want it. You don't need a 12v battery. You just need the converter off the battery bus BEFORE the main switch, not after it, separately switched. It's simple, saves the cost/weight/failure of the 12v battery. Give me a sensible reason why this can't be done.

 

[N2STY]

You can run DC-DC off 400v (the car already does this), and it only has to be switched on when you want it. You don't need a 12v battery.

So when the high voltage battery is switched off without a 12v battery how will the alarm work or unlock doors or even use the app? And how would you switch the high volt battery on with out 12v solenoid to move the contacts?

Why Do Electric Cars Have a 12v Battery? – Top Charger

A 12v battery is the most efficient way to power low voltage electrical systems like the ECU, alarm and 4G modem. The main battery is also isolated for safety.

topcharger.co.uk

 

[bryer]

Driving it won't make any difference to charging the battery leave in ready or charging the HV will be fine but if duff battery it's just a sticking plaster

Thought the regen charged the 12V when it was low as a complement to the HV?

 

[N2STY]

Thought the regen charged the 12V when it was low as a complement to the HV?

The regen only does one voltage and that's for HV Only the only thing that charges the 12v battery is DC to DC converter
The only time it charges is ready mode or if HV battery is being charged or when you use app for like remote heating
Here is a example

Just before I left work I used remote heating just after 0100 then drived home got there at 0200 put car on smart charge untill I used remote heating just before 2100 then left for work at 2100

 

[pshotton]

So when the high voltage battery is switched off without a 12v battery how will the alarm work or unlock doors or even use the app? And how would you switch the high volt battery on with out 12v solenoid to move the contacts?

Why Do Electric Cars Have a 12v Battery? – Top Charger

A 12v battery is the most efficient way to power low voltage electrical systems like the ECU, alarm and 4G modem. The main battery is also isolated for safety.

topcharger.co.uk

Ever heard of a mechanical switch? And given modern dc-dc converters draw practically no current when there's no load, why not power alarm, doors etc all the time. I'm still not hearing any good argument for why we need a 12v battery.

 

[N2STY]

Ever heard of a mechanical switch? And given modern dc-dc converters draw practically no current when there's no load, why not power alarm, doors etc all the time. I'm still not hearing any good argument for why we need a 12v battery.

Mechanical switch just isn't practical we have manual DC switches at work and they are lethal you have to be really fast not to pull an arc
Ok a another scenario you're driving along and you run your battery out to zero with out the 12v battery you will have no brake assistance no handbrake no lights including hazards no power steering not exactly failsafe is it but that old 12v battery would have been charging up till that point so you can safely stop put your hazards on I don't think there is one EV out there without a auxiliary battery

 

[pollenface]

I'm still not hearing any good argument for why we need a 12v battery.

I get the same question a lot from my peers. Best answer I can give is that's just how the manufacturer designed it.

We might see EV's in the future without an Aux 12v battery.