Dead 12v battery again

[kort]

I’m not sure how NOCO is NOT compatible with lion battereys - at the end of the day it provides 12V DC - and the noco is _NOT_ a charger - it’s a booster that provides 12V power to the 12V bus - it’s _NOT_ charging the 12V LiON battery - it provides power to the 12V bus for 1-2 minutes and then you disconnect it and the car takes over charging the 12V battery - you don’t leave the NOCO connect to “charge” the LiON 12V battery

the _ONLY_ reason a 12V power source would _NOT_ be compatible with a 12V battery was if it continues to force power down the throat of a LiON 12V battery after it was full....that’s not the case here.

12V DC power is 12V DC power - regardless of power source.

I understand the NOCO may not be a good source to charge a LiON battery - but please explain to me why it’s not a good 12V power source to power the Taycan to wake it up?

now leaving the NOCO connected to the 12V bus while the Taycan is also charging the 12V bus and the NOCO is providing power to the 12V bus and all that going around - I could also see connecting the NOCO directly to a LiON battery might not be the best for LiON battery - but again that’s not what we are doing here - and the LiON battery in the porsche has it’s own power regulator on the battery leads…

someone’s going to have to explain to me in the context of the Taycan how the NOCO booster (not charger) is “bad” for the LiON battery that it’s not directly connected to while it spends 30-90 seconds powering the Taycan’s 12V bus so that the car can wake up and take over from a 12V death situation - and no you don’t get to quote bland CYA vauge statements about the NOCO not being compatibilty for LiON batteries that were written for ICE vehicles who’s power bus architecture and connections is completely different than the Taycan.

I look forward to being educated.

read the user guide and tell me how you interpret it.
I have no dog in this fight, someone suggested this as a solution and I visited their site and read this and the way I read it is that the noco is incompatible. maybe I am missing something.

https://no.co/media/nocodownloads/format/g/b/gb40_v3_userguide_01.11.2019_web_1.pdf

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[daveo4EV]

yeah I’ve used it twice it works fine - I’m not sure how it’s “incompatible“ - there are only two connection points - and it provide 12V DC - and it’s not connected “TO” the LiON battery - it’s connected to the 12V power bus for the vehicle...

it provides 12V power - the fact that there is a 12V LiON battery on the 12V power bus is irrelivant…but I’m not an EE - that‘s why i asked

but I’m not sure how providing “power” is “incompatible”.

 

[chrisk]

Based on the manual of a similar (but not Noco) booster my understanding was that there is a risk of fire/explosion for the booster. The booster itself uses an Li battery which is sensitive to overcurrent.
Given that the Taycan's 12v battery is not totally drained (but rather disconnected from the car), the moment the car comes back to life, it can start backfeeding power to the booster and the booster might blow. This is not a concern when jumping an ICE car because if you jump it it means its battery is totally drained so it is unlikely it will backfeed any power back to the booster.
Most modern booster are supposed to have overcurrent protection, but I am not sure how well that works.

 

[NC_Taycan]

Daveo4ev and chrisk are both correct. To jump start Taycan you need 12V. Or 12.6V. Or 13.4V. From Lead Acid. From Li-Ion. From your wife's car. Doesn't matter. Once the car is awake and re-energizes the safety relay on the Taycan's 12V battery AND wakes up the HV battery and DC-DC converter to charge said 12V battery, then you are potentially in for trouble if the voltage on your jump start solution, whatever that might be, doesn't match the 12V system voltage on the Taycan. Current will flow in or out, and if that happens at a high enough rate into a Li-Ion jump start battery, you might have a problem. The kind of problem that requires fire extinguisher chemicals you don't have in your garage. A good (read more expensive) jump starter will have electronics protecting it's storage battery from this, and a jump starter with a lead acid battery doesn't give two fu#ks about a differential like this. If you disconnect your not-overcurrent-protected Li-Ion-based jump starter solution as soon as the car wakes up, you are probably OK (you are minimizing but not eliminating your risk). Use a cheap 12V lead acid battery and jumper cables and you have zero risk.

 

[daveo4EV]

@NC_Taycan I appreciate the detailed response - this is what I thought it was - the risk is NOT incompatibility but rather back feed of dissimilar voltages into the “booster” battery - potentially damaging the booster and in extreme cases causing exothermic reactions in the booster - I also believe/agree leaving the booster connected to the Taycan beyond it’s use of ”waking the vehicle up” is also probably ill-advised...

however NOCO “claims” to have overcurrent protection - and I believe if disconnected promptly after the Taycan has woken up there is risk but minimal risk as the vehicle will be in the early stages of waking up and not everything will be happening at once.

I’m fairly certain leaving the NOCO connected to the jumper posts for extended durations is ill-advised - but as a simple “booster” the risk is probalby minimal - and the risk is not to the Taycan, but rather the booster.

 

[NC_Taycan]

One point of clarification. If in fact your 12V battery is low enough that the safety relay has disengaged, you will need to leave the booster connected until the HV battery wakes up. You will hear a soft thunk from the HV battery relays shortly after you start to hear vehicle systems come to life. If you disconnect too early, the car will just die again right away, but you can just try again.

 

[chrisk]

however NOCO “claims” to have overcurrent protection - and I believe if disconnected promptly after the Taycan has woken up there is risk but minimal risk as the vehicle will be in the early stages of waking up and not everything will be happening at once.

My booster which is similar to NOCO has overcurrent protection but it is not clear to me if protects the direction when the booster sends power to the car or the other way around too. I agree with you that disconnecting the booster immediately after the car wakes up is a good idea.

 

[Scandinavian]

This stuff is complicated. Leaves my head spinning. I don't think Porsche is going to recommend a Noco or any other booster other than there own equipment. The only thing that seems to apply is that people have reported a Noco type booster can successfully wakeup the car.

Porsche talks about CC/CV or pure CV characteristic charges. So who makes those and what are they?

CTEK are the most known and also very good. If you look closely at this charger for lithium batteries, you can see it is the same as Porsche has put their logo on. Buy from CTEK and avoid Porsche tax!
https://www.ctek.com/uk/products/car/lithium-xs-uk.

They also sell a more powerful unit for workshops etc.
https://www.ctek.com/uk/products/car/pro25s-uk

 

[Freakzilla9]

Well ctek is indeed perfect as I’m attaching good to know app which states only recommended lifepo4 should be used

also I have bought the nocoboost gb40 which is kept only for jumping purpose as @daveo4EV and would not be spending more just for something which even hasn’t happened to me (12v dead battery)
So I will follow dave suggestion and as soon as it hv starts up I disconnect it

Ihave also asked noco support and attached their reply

 

[Scandinavian]

Well ctek is indeed perfect as I’m attaching good to know app which states only recommended lifepo4 should be used

also I have bought the nocoboost gb40 which is kept only for jumping purpose as @daveo4EV and would not be spending more just for something which even hasn’t happened to me (12v dead battery)

If you look at the CTEK site and download the manual for the charger, it describes how it will handle a Li battery that has been protected against under voltage. Maybe this function in the CTEK chargers makes a separate booster battery unneccesary. I am not an EE so perhaps others can comment.
Sounds good though and CTEK are a well known company with great chargers and maintainers. The fact that Porsche has branded it as well as a lot of other car manufacturers is Comforting.

 

[NC_Taycan]

That's interesting. I'm not familiar with this unit but if it can supply enough current to allow the system electronics to re-start, that will open the under voltage protection cut-out relay. If it us opening the UVP via some other method, that would be concerning - except for the indication that Porsche is branding this same unit as their own...

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