12v battery and Noco booster

[OriginalBigAl]

Has anyone had to use this booster or any other in anger and did it work as expected? We all think we know the theory of how to use them on a EV but does that match the actuality. Scenario, you get back to the car and its dead, you had the foresight to buy said item, so dismantle the key ring gain access to car , lift bonnet and connect your Noco, car comes to life, what next? Presumably the BMS has shut down 12v charging because the main battery is low, by putting it into ready mode will this then start to recharge the 12v? and all is good , but you need to find a nearby charger. If not when you exit the car the ready mode disengages leaving the electrical power needs from the 12v or Noco . You disconnect the Noco and the 12v still has not enough humpf to power the car and it shuts down. So do you re-connect and leave it for a while or try driving to the nearest charger with it still connected. You will need enough 12v power to get the chargers to work. These boosters are mainly designed for ICE cars to give cranking charge to start the engine then the alternator will take over , so I,m guessing it will give a charge to the 12v battery but you might have to sit there for a while before disconnecting , I do not know, over to the experts and members who have more knowledge on tis subject.

 

[Lovemyev]

I decided to purchase and carry a 12 volt booster pack, when going full EV back in 2019.
I did this after reading about people getting stranded due to flat 12 volt batteries.
I have carried the pack in two EV’s now and covered about 30,000 miles.
It has never been used on our car(s) but has been used on a number of other ICE cars with flat batteries !.
When your battery voltage falls to low, in will not enable the car to boot into ready mode.
The 12 volt battery is only receiving a charge when the car is in ready mode or on charge.
Connecting a jumper pack raises the voltage enough for the car to reach ready mode.
As soon as this is achieved, the traction battery ( via the inverter ) is providing a similar charge of around 14 volts, as seen by an alternator providing charge on a ICE car.
Not in standby mode though, only in ready mode is the 12 volt being charged.
At this point the jumper pack should be able to be removed.
Depending how low the 12 battery really is, it maybe a good idea, just to leave the car sit in ready mode for a while, before setting off.
If the traction battery has sufficient range to get you home, then off you go.
If you are only travelling a short distance, then you may need to boost the battery again as it has not had enough time to fully recover.
Personally I would not leave the booster pack attached to the 12 volt battery while driving !.

 

[OriginalBigAl]

I decided to purchase and carry a 12 volt booster pack, when going full EV back in 2019.
I did this after reading about people getting stranded due to flat 12 volt batteries.
I have carried the pack in two EV’s now and covered about 30,000 miles.
It has never been used on our car(s) but has been used on a number of other ICE cars with flat batteries !.
When your battery voltage falls to low, in will not enable the car to boot into ready mode.
The 12 volt battery is only receiving a charge when the car is in ready mode or on charge.
Connecting a jumper pack raises the voltage enough for the car to reach ready mode.
As soon as this is achieved, the traction battery ( via the inverter ) is providing a similar charge of around 14 volts, as seen by an alternator providing charge on a ICE car.
Not in standby mode though, only in ready mode is the 12 volt being charged.
At this point the jumper pack should be able to be removed.
Depending how low the 12 battery really is, it maybe a good idea, just to leave the car sit in ready mode for a while, before setting off.
If the traction battery has sufficient range to get you home, then off you go.
If you are only travelling a short distance, then you may need to boost the battery again as it has not had enough time to fully recover.
Personally I would not leave the booster pack attached to the 12 volt battery while driving !.

Thank you for a full reply. The one point I have is that if you are on your own as soon as you open the door to disconnect the booster then ready mode and the 14v supply will stop and if you have not left it long enough, disconnecting the booster will leave the weakened battery to try to keep the car active . If the booster acts as a trickle charger then there could be quite a long period of waiting for it to give the 12v enough power to run things independently. It would of course be much easier if there were two people, one just to sit in the drivers seat. I,ve asked this question because I think many people will see the booster as being an instant solution, which in certain conditions it could be, but conversely could be problematic and not work in a pre-conceived manner. If the traction battery is low ,will BMS let it charge the 12v battery when its put into ready mode.? Again thanks.

 

[Lovemyev]

Thank you for a full reply. The one point I have is that if you are on your own as soon as you open the door to disconnect the booster then ready mode and the 14v supply will stop and if you have not left it long enough, disconnecting the booster will leave the weakened battery to try to keep the car active . If the booster acts as a trickle charger then there could be quite a long period of waiting for it to give the 12v enough power to run things independently. It would of course be much easier if there were two people, one just to sit in the drivers seat. I,ve asked this question because I think many people will see the booster as being an instant solution, which in certain conditions it could be, but conversely could be problematic and not work in a pre-conceived manner. If the traction battery is low ,will BMS let it charge the 12v battery when its put into ready mode.? Again thanks.

The booster pack is not acting like a slow conventional trickle charger as such, it just would take ages to raise the power.
It is intended to give an instant rapid boost to the depleted 12 volt battery, lifting it high enough so that when you press the start button, it is then is able to boot the car into the ready mode.
As soon as this is activated, the 12 volt battery is receiving the maximum charge rate from the HV traction battery, sending over 14 volts to the battery.
If the car is just left sitting a while in this ready condition, it will keep providing a charge to the 12 volt battery.
Even if the traction battery is fairly low, it still has the ability to charge the 12 volt battery.
If your traction battery is extremely low, then placing the car on charge ASAP is a must.
Then the 12 volt system will be receiving a lengthy charge while the traction battery is charging.
If the 12 volt battery has been allowed to become extremely depleted, or has failed internally, it is likely to be unrecoverable even after a charge and will require replacement regardless.
Booster packs are great to get you out of a tight spot, if you battery has become a little low on charge, but of course they do have there limitations on what they can rescue.
In all of the many years I have been driving ICE vehicles, I never thought it necessary to carry a booster pack.
Jump leads sometimes.
But when going full BEV it became a must have item for us anyway.

 

[PeteC]

Has anyone had to use this booster or any other in anger and did it work as expected? We all think we know the theory of how to use them on a EV but does that match the actuality. Scenario, you get back to the car and its dead, you had the foresight to buy said item, so dismantle the key ring gain access to car , lift bonnet and connect your Noco, car comes to life, what next? Presumably the BMS has shut down 12v charging because the main battery is low, by putting it into ready mode will this then start to recharge the 12v? and all is good , but you need to find a nearby charger. If not when you exit the car the ready mode disengages leaving the electrical power needs from the 12v or Noco . You disconnect the Noco and the 12v still has not enough humpf to power the car and it shuts down. So do you re-connect and leave it for a while or try driving to the nearest charger with it still connected. You will need enough 12v power to get the chargers to work. These boosters are mainly designed for ICE cars to give cranking charge to start the engine then the alternator will take over , so I,m guessing it will give a charge to the 12v battery but you might have to sit there for a while before disconnecting , I do not know, over to the experts and members who have more knowledge on tis subject.

I had to use a booster last week. The 12v battery had died for some (unknown) reason so I bought a booster pack. I did just as you describe to attach the booster and the car very quickly came to life. I set it in ready mode and then got back out to remove the booster and close the bonnet, then got back in the car and stayed in it for a while with the car in ready mode to give the 12v battery a bit of charge. I can't remember if I had to put the car back into ready mode after getting out to shut the bonnet, but I guess I did. Whatever, I had no problems keeping the car alive and have had no problems with the 12v battery since then. My main battery was somewhere in the mid 60% SoC when this happened.

 

[OriginalBigAl]

Cheers guys , just one addition . If you are worried that exiting the car turns off ready mode, then do not touch the drivers door , but get out of the passenger door (swearing at MG for the shelf) disconnect, close bonnet, then get back in the same way. Ready mode stays active. Well thats worked out well, I,ll start looking for one of these boosters with a bit more confidence.

 

[Lovemyev]

I am able to leave the car via the drivers door while still in ready mode.
It will give out a warning on the dash and a bong, informing you of the fact that the car is still booted, but it will let you escape .

 

[Kithmo]

My 8 year old BAKT 12v jumper pack gave up the ghost last week, mainly because I forgot to charge it for over 2 years, so I bought one of these off amazon, it comes with a neat carry bag which fits nicely in the MG4 glove box so I don't have to clamber over the back to gain access to the boot if I ever need to use it.
Amazon product ASIN B0BVQKZNV2

 

[PeteC]

My 8 year old BAKT 12v jumper pack gave up the ghost last week, mainly because I forgot to charge it for over 2 years, so I bought one of these off amazon, it comes with a neat carry bag which fits nicely in the MG4 glove box so I don't have to clamber over the back to gain access to the boot if I ever need to use it.
Amazon product ASIN B0BVQKZNV2

That's the one I bought when my 12V battery died. I keep mine in the armrest storage where it also fits nicely.

 

[Rolfe]

How often do you charge it? The thing about these things is, I feel that If I'm caught short because I let the battery run down, that's on me, but I should be able to charge it again like I can charge the battery of my spare phone when I forget all about it for ages. Something that's going to brick permanently if I don't keep topping it up is not really suited to a device intended to be stored and forgotten about till needed.

 

[PeteC]

How often do you charge it? The thing about these things is, I feel that If I'm caught short because I let the battery run down, that's on me, but I should be able to charge it again like I can charge the battery of my spare phone when I forget all about it for ages. Something that's going to brick permanently if I don't keep topping it up is not really suited to a device intended to be stored and forgotten about till needed.

I only bought it last week so no need to charge it yet. It's got a display that shows the state of charge (99% at the moment) so it's easy to check how it is. The hardest part will be remembering to take a look!

 

[Rolfe]

That's exactly what I mean. I leave my spare camera visible near the charging socket in the kitchen to try to remind me to charge it now and again, but it's not the end of the world if I forget. These things are going to be hidden away in the car and forgotten, like I forget my type 2 cable is under the bonnet until I suddenly realise I need it.

 

[johnb80]

My 8 year old BAKT 12v jumper pack gave up the ghost last week, mainly because I forgot to charge it for over 2 years, so I bought one of these off amazon, it comes with a neat carry bag which fits nicely in the MG4 glove box so I don't have to clamber over the back to gain access to the boot if I ever need to use it.
Amazon product ASIN B0BVQKZNV2

Be very careful with this item, I bought one following recommendation to use with my i3. A short time after buying it, 2 days !!! I had cause to use it. The i3 has a 20 amp/hour AGM battery for the 12v so it doesnt have massive loads on the 12v. Feeling smug I connected the booster pack, my 12v came alive and then it shut down againb, 2 further attempts rendered the GREPRO unit flat. I got my old Sealey booster pack brought to me, clipped it on and all was good. I placed the GREPRO unit on charge as per the instructions and after a very short time it was swelling up, very hot and bending the whole case. I stopped the charge and placed it outdoors in a tin.
I returned it to Amazon and purchased a NOCO unit which seems to work fin.
If you are charging the GREPRO unit, dont leave it unattended, charge it on a non combustabke surface, at the first sign of trouble, switch it off.. I am absolutely convinced if I hadnt stopped the charge I would have had a house fire.

 

[Rip Van]

How often do you charge it? The thing about these things is, I feel that If I'm caught short because I let the battery run down, that's on me, but I should be able to charge it again like I can charge the battery of my spare phone when I forget all about it for ages. Something that's going to brick permanently if I don't keep topping it up is not really suited to a device intended to be stored and forgotten about till needed.

Ordered mine 20th May 23. I took it out to check it before we went away on 27th September, still at 95%. We'll see what happens when we get back 8th October. We were away for a similar period end of May/start of June but the car fired up nae probs.

 

[Kithmo]

Be very careful with this item, I bought one following recommendation to use with my i3. A short time after buying it, 2 days !!! I had cause to use it. The i3 has a 20 amp/hour AGM battery for the 12v so it doesnt have massive loads on the 12v. Feeling smug I connected the booster pack, my 12v came alive and then it shut down againb, 2 further attempts rendered the GREPRO unit flat. I got my old Sealey booster pack brought to me, clipped it on and all was good. I placed the GREPRO unit on charge as per the instructions and after a very short time it was swelling up, very hot and bending the whole case. I stopped the charge and placed it outdoors in a tin.
I returned it to Amazon and purchased a NOCO unit which seems to work fin.
If you are charging the GREPRO unit, dont leave it unattended, charge it on a non combustabke surface, at the first sign of trouble, switch it off.. I am absolutely convinced if I hadnt stopped the charge I would have had a house fire.

Thanks for the heads up, I haven't charged it yet as it's showing 99% on the display but I'll certainly keep an eye on it when I do.
I bought this particular one after reading a good review on the Auto Trader website.
I noticed that the input on it (to charge it) is only 5v and the output is only 11.5v, which is just about enough to activate the HV battery relays, but I can't see it starting an ICE vehicle with 11.5v.
I think it would be easy to overload it when your vehicle has booted up, my old one said in the instructions to disconnect it as soon as the car has started to prevent this.

 

[PeteC]

Be very careful with this item, I bought one following recommendation to use with my i3. A short time after buying it, 2 days !!! I had cause to use it. The i3 has a 20 amp/hour AGM battery for the 12v so it doesnt have massive loads on the 12v. Feeling smug I connected the booster pack, my 12v came alive and then it shut down againb, 2 further attempts rendered the GREPRO unit flat. I got my old Sealey booster pack brought to me, clipped it on and all was good. I placed the GREPRO unit on charge as per the instructions and after a very short time it was swelling up, very hot and bending the whole case. I stopped the charge and placed it outdoors in a tin.
I returned it to Amazon and purchased a NOCO unit which seems to work fin.
If you are charging the GREPRO unit, dont leave it unattended, charge it on a non combustabke surface, at the first sign of trouble, switch it off.. I am absolutely convinced if I hadnt stopped the charge I would have had a house fire.

Thanks again for this warning. I'll be keeping an eye on mine. I've never left phones etc plugged in overnight since I had one swell up in a similar manner. Mind you, I do leave the car plugged in overnight!

 

[johnb80]

Thanks again for this warning. I'll be keeping an eye on mine. I've never left phones etc plugged in overnight since I had one swell up in a similar manner. Mind you, I do leave the car plugged in overnight!

I have 2 EV's and 2 home batteries that are always charging unattended overnight BUT they all have decent BMS systems and protections in place

 

[KevW]

Has anyone had to use this booster or any other in anger and did it work as expected? We all think we know the theory of how to use them on a EV but does that match the actuality. Scenario, you get back to the car and its dead, you had the foresight to buy said item, so dismantle the key ring gain access to car , lift bonnet and connect your Noco, car comes to life, what next? Presumably the BMS has shut down 12v charging because the main battery is low, by putting it into ready mode will this then start to recharge the 12v? and all is good , but you need to find a nearby charger. If not when you exit the car the ready mode disengages leaving the electrical power needs from the 12v or Noco . You disconnect the Noco and the 12v still has not enough humpf to power the car and it shuts down. So do you re-connect and leave it for a while or try driving to the nearest charger with it still connected. You will need enough 12v power to get the chargers to work. These boosters are mainly designed for ICE cars to give cranking charge to start the engine then the alternator will take over , so I,m guessing it will give a charge to the 12v battery but you might have to sit there for a while before disconnecting , I do not know, over to the experts and members who have more knowledge on tis subject.

It's more likely the HV hasn't been able to charge the LV battery due to condition, connection etc. If the LV fails it can't connect the HV system so by using a booster you are technically throwing a big switch. Once you have achieved that the HV will then recharge the LV.

 

[Pontyboy]

I am totally baffled how a brand new modern EV can constantly have such an issue.
It's amazing owners of brand new cars have to carry an emergency starter pack.
Why on earth can't this issue be resolved by MG.
I have enjoyed my ownership but now feeling the car may be unreliable am seriously looking to change for a recharge by a different manufacturer. Sad situation.

 

[rusty715]

Has anyone had to use this booster or any other in anger and did it work as expected? We all think we know the theory of how to use them on a EV but does that match the actuality. Scenario, you get back to the car and its dead, you had the foresight to buy said item, so dismantle the key ring gain access to car , lift bonnet and connect your Noco, car comes to life, what next? Presumably the BMS has shut down 12v charging because the main battery is low, by putting it into ready mode will this then start to recharge the 12v? and all is good , but you need to find a nearby charger. If not when you exit the car the ready mode disengages leaving the electrical power needs from the 12v or Noco . You disconnect the Noco and the 12v still has not enough humpf to power the car and it shuts down. So do you re-connect and leave it for a while or try driving to the nearest charger with it still connected. You will need enough 12v power to get the chargers to work. These boosters are mainly designed for ICE cars to give cranking charge to start the engine then the alternator will take over , so I,m guessing it will give a charge to the 12v battery but you might have to sit there for a while before disconnecting , I do not know, over to the experts and members who have more knowledge on tis subject.

I am led to believe it's a software fault in that when the battery is full the charging from 400v stops the monitoring so as the battery drains it is not topped up even if 400v is 100%
It seems many faults with the software someone every day has some problems.
I brought a battery pack as I had to be jump-started 3 times, after which MG fitted a new battery and EC unit, no problems since so have not tested the booster pack