12v lead acid battery replacement with LiOin - Bimmerfest - BMW Forums



Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > BMW i > BMW i3 I01 (2014 - Current)

BMW i3 I01 (2014 - Current)
The BMW i3 and BMW i8 are the first two cars launch under BMW's new sub brand BMW i. The i3 is an all carbon fiber, all electric vehicle meant for urban mobility.

Reply
 
Thread Tools Display Modes
  #1  
Old 03-13-2019, 08:24 AM
Joc Joc is offline
Registered User
 
Join Date: Mar 2019
Posts: 1
Mein Auto:
12v lead acid battery replacement with LiOin

Hi All
Hello from Wales, it's raining again

I am new to EV's and have just got a 2016 I3 with a 60AH battery with no REX
The range is a bit of a problem
I am thinking of replacing the 12v lead acid battery with something lighter
at rest, the car draws about 0.003A and the maximum load I can put on it is about 4A
with all light on etc. Which seems small.

Do you think I have made a mistake?
Can I remove the 12v battery and reconnect the same battery, i.e. will it give me error messages
If I fit a new lead-acid battery will I have to register it with CCU what will have if I don't

do you think I will get problem fitting a LiOin battery
John
Reply With Quote
Sponsored Links
Advertisement
 
  #2  
Old 03-13-2019, 11:30 AM
jadnashuanh jadnashuanh is offline
Officially Welcomed to the 'Fest
Location: NH
 
Join Date: Jun 2011
Posts: 2,050
Mein Auto: 535ix-drive GT; i3 BEV
The charging curves for a LiOn battery versus any type of lead acid one is quite different. The life of the LiON battery and potential safety IS a problem, IMHO. The computer in the i3 is capable of handling either a wet cell or AGM type lead acid battery. I do not remember LiON being an option. I don't think it will last, and you might blow it up since you'd be trying to charge it to a higher voltage than a lead acid one would allow.
__________________
Jim DeBruycker
Reply With Quote
  #3  
Old 03-15-2019, 06:48 AM
frogy's Avatar
frogy frogy is offline
Officially Welcomed to the 'Fest
Location: MO. USA
 
Join Date: Nov 2017
Posts: 216
Mein Auto: 02 325CI, 15 535xi GT
This is sooo true. I do not have #s in front of me but this is reason for so many thermal runnaways you see on UTube. There are many diff chemistries for Lithium-Cobalt being the most dangerous (Bowing elect fires) but all Lith will take as much charge as you want to give them even though they have a very limited high/low charge rate without damage. If charger is not designed for Lith do not install one.
Reply With Quote
Sponsored Links
Advertisement
 
  #4  
Old 03-15-2019, 06:50 AM
frogy's Avatar
frogy frogy is offline
Officially Welcomed to the 'Fest
Location: MO. USA
 
Join Date: Nov 2017
Posts: 216
Mein Auto: 02 325CI, 15 535xi GT
Another note-Lith do not like to be completely discharged, this can brick a Lith
Reply With Quote
  #5  
Old 06-05-2019, 01:13 AM
sipabit sipabit is offline
Registered User
Location: Bay Area
 
Join Date: Mar 2018
Posts: 56
Mein Auto: 2016 BMW i3 REX
Yes, it would be a big mistake to replace the lead acid battery with a lithium. The lead acid needs to be charged full all the time which is what the car is designed to do. You wouldn't want that for a lithium of that size. Lithiums can be overcharged w/o a battery management system. You'd have to address a lot of the way the battery is managed. Even if you were able to do that there's really no benefit of having a lithium accessory battery over a lead acid. Remember that when replacing the battery, BMW needs to register it. So unless you have access to registering it with the car w/o BMW knowing, you wouldn't be able to do it anyway.
__________________
A fanatic of all things electric. Ridables like electric ice chests and stand up scooters I adore. Drones like DJI, I root for. I'm a fan of both, but nothing beats my love for my 2016 i3 Rex with Deka World. Shhh, don't tell my wife.
Reply With Quote
  #6  
Old 01-23-2020, 02:03 PM
Antigravity Batteries Antigravity Batteries is offline
'Fest Sponsor
 
Join Date: Jan 2020
Posts: 38
Mein Auto:
Well, I wouldn't say it will be a big mistake. Actually, it will be smarter to make the switch to Lithium-ion! Given that whatever brand you go offers battery management system (BMS) with their Lithium-ion battery!

Lithium has so many advantages over lead-acid! Such as longer life, lead-acid batteries are rated at 800 to 1000 cycles, whereas lithium is estimated at around 2000 to 2500 cycles! That means an automotive lithium battery will last from 8 to 10 years!!

Also, Lithium is two times more powerful than lead-acid, so where a lead-acid 60ah battery will give you like 800 cranking amps, lithium will provide you with 1600 CA!!!

Not to mention a 60 ah lead-acid battery will be least 45 pounds, whereas lithium will be 18 pounds only!!
Reply With Quote
  #7  
Old 01-23-2020, 10:22 PM
God-Follower's Avatar
God-Follower God-Follower is offline
Achtung! Hochspannung!
Location: Pacific Northwest
 
Join Date: Oct 2014
Posts: 1,359
Mein Auto: 2018 i3, F10 535d
Quote:
Originally Posted by Antigravity Batteries View Post
Well, I wouldn't say it will be a big mistake. Actually, it will be smarter to make the switch to Lithium-ion! Given that whatever brand you go offers battery management system (BMS) with their Lithium-ion battery!

Lithium has so many advantages over lead-acid! Such as longer life, lead-acid batteries are rated at 800 to 1000 cycles, whereas lithium is estimated at around 2000 to 2500 cycles! That means an automotive lithium battery will last from 8 to 10 years!!

Also, Lithium is two times more powerful than lead-acid, so where a lead-acid 60ah battery will give you like 800 cranking amps, lithium will provide you with 1600 CA!!!

Not to mention a 60 ah lead-acid battery will be least 45 pounds, whereas lithium will be 18 pounds only!!
The problem is it would need more than just a BMS; it would likely need it's own DC/DC converter to reduce the 14V output charging voltage of the i3 down to ~13.2V. Since the i3 runs at 14.2-14.9V depending on temperature, load, and measured battery SOC I can't see any other way of making a Lithium battery work as a drop-in.

Now that we added a DC/DC converter, we will likely have additional parasitic load; draining the battery while the car is parked.

With some clever computing you could add a bypass circuit to bypass the DC/DC when the vehicle voltage drops below 14V and eliminate that parasitic draw, but you would have to account for the inrush current the Lithium would pull as soon as the vehicle awoke and began charging again; the contractors for your bypass circuit would have a short lapse of time between bypass and DC/DC active. Would this be too much of an instantaneous load for the vehicles DC/DC to handle on a regular basis? Because that is a near $10k dealer visit oops...

I agree it would be a beneficial upgrade to the car since the 12V AGMs have proven so unreliable, but want to set realistic expectations for those thinking of a retrofit.
__________________

Last edited by God-Follower; 01-23-2020 at 10:24 PM.
Reply With Quote
  #8  
Old 02-17-2020, 06:41 PM
Antigravity Batteries Antigravity Batteries is offline
'Fest Sponsor
 
Join Date: Jan 2020
Posts: 38
Mein Auto:
Quote:
Originally Posted by God-Follower View Post
The problem is it would need more than just a BMS; it would likely need it's own DC/DC converter to reduce the 14V output charging voltage of the i3 down to ~13.2V. Since the i3 runs at 14.2-14.9V depending on temperature, load, and measured battery SOC I can't see any other way of making a Lithium battery work as a drop-in.

Now that we added a DC/DC converter, we will likely have additional parasitic load; draining the battery while the car is parked.

With some clever computing you could add a bypass circuit to bypass the DC/DC when the vehicle voltage drops below 14V and eliminate that parasitic draw, but you would have to account for the inrush current the Lithium would pull as soon as the vehicle awoke and began charging again; the contractors for your bypass circuit would have a short lapse of time between bypass and DC/DC active. Would this be too much of an instantaneous load for the vehicles DC/DC to handle on a regular basis? Because that is a near $10k dealer visit oops...

I agree it would be a beneficial upgrade to the car since the 12V AGMs have proven so unreliable, but want to set realistic expectations for those thinking of a retrofit.
Without wanting to sound like a jerk I have to point out there is quite a bit of mis-information on this post. I noted someone above talked about Thermal Runaway, I noted someone talked about explosion, and another stating Lithium is damaged by over-discharge. And last I will reply to your statement about charging. While all these potential issues are somewhat accurate when applied to OLDER and DIFFERENT Lithium Chemistries and technologies, they are not relevant to what we are offering as Automotive Starter Batteries.

As mentioned we have a full BMS Battery Management system that protects the battery from over-charge and over discharge. This protects the battery from getting into an extreme over-discharge or overcharge conditions. Additionally we are using the Lithium Chemistry called Lithium-Iron Phosphate, which is the most stable format of the many different Lithium Chemistries and operate in the same voltage and current ranges as a Lead/Acid Battery. IN fact it is a direct replacement for Lead Acid. I can go on about this but want to keep this relatively short.

Now in regards to God Follower, I think you are not understanding how a Lithium Battery Charges. The Lead/Acid Battery that is used in the i3 is a standard format 12v Battery normally called an ETX18 though I think the ETX20 also works in there. This is a standard Motorcycle/Powersports Battery made by DEKA and is rebranded by BMW. It is used in larger Touring bikes like the Harleys and some BMW bikes. It is a Motorcycle/Powersports battery plain and simple, and charges as any of these do. But the fact is they are not lasting so long in an i3... but the fact is the same version of the Lithium Battery chargers exactly the same as the Lead acid would. There is no need for any additional charger or any conversion because the i3 is Charging the Lead/Acid the same way it would charger the Lithium REPLACEMENT. We sell a similar battery into the Harley community alot. OUr version is called the ATX20.. but we have a built-in Jump starting feature so I'm not sure that would be compatible with the electric Car set up being our low-voltage cut off on the BMS is a little higher. But we have another model that does not have that feature. I will do some research on it.
Reply With Quote
  #9  
Old 02-17-2020, 07:49 PM
God-Follower's Avatar
God-Follower God-Follower is offline
Achtung! Hochspannung!
Location: Pacific Northwest
 
Join Date: Oct 2014
Posts: 1,359
Mein Auto: 2018 i3, F10 535d
Quote:
Originally Posted by Antigravity Batteries View Post
Quote:
Originally Posted by God-Follower View Post
The problem is it would need more than just a BMS; it would likely need it's own DC/DC converter to reduce the 14V output charging voltage of the i3 down to ~13.2V. Since the i3 runs at 14.2-14.9V depending on temperature, load, and measured battery SOC I can't see any other way of making a Lithium battery work as a drop-in.

Now that we added a DC/DC converter, we will likely have additional parasitic load; draining the battery while the car is parked.

With some clever computing you could add a bypass circuit to bypass the DC/DC when the vehicle voltage drops below 14V and eliminate that parasitic draw, but you would have to account for the inrush current the Lithium would pull as soon as the vehicle awoke and began charging again; the contractors for your bypass circuit would have a short lapse of time between bypass and DC/DC active. Would this be too much of an instantaneous load for the vehicles DC/DC to handle on a regular basis? Because that is a near $10k dealer visit oops...

I agree it would be a beneficial upgrade to the car since the 12V AGMs have proven so unreliable, but want to set realistic expectations for those thinking of a retrofit.
Without wanting to sound like a jerk I have to point out there is quite a bit of mis-information on this post. I noted someone above talked about Thermal Runaway, I noted someone talked about explosion, and another stating Lithium is damaged by over-discharge. And last I will reply to your statement about charging. While all these potential issues are somewhat accurate when applied to OLDER and DIFFERENT Lithium Chemistries and technologies, they are not relevant to what we are offering as Automotive Starter Batteries.

As mentioned we have a full BMS Battery Management system that protects the battery from over-charge and over discharge. This protects the battery from getting into an extreme over-discharge or overcharge conditions. Additionally we are using the Lithium Chemistry called Lithium-Iron Phosphate, which is the most stable format of the many different Lithium Chemistries and operate in the same voltage and current ranges as a Lead/Acid Battery. IN fact it is a direct replacement for Lead Acid. I can go on about this but want to keep this relatively short.

Now in regards to God Follower, I think you are not understanding how a Lithium Battery Charges. The Lead/Acid Battery that is used in the i3 is a standard format 12v Battery normally called an ETX18 though I think the ETX20 also works in there. This is a standard Motorcycle/Powersports Battery made by DEKA and is rebranded by BMW. It is used in larger Touring bikes like the Harleys and some BMW bikes. It is a Motorcycle/Powersports battery plain and simple, and charges as any of these do. But the fact is they are not lasting so long in an i3... but the fact is the same version of the Lithium Battery chargers exactly the same as the Lead acid would. There is no need for any additional charger or any conversion because the i3 is Charging the Lead/Acid the same way it would charger the Lithium REPLACEMENT. We sell a similar battery into the Harley community alot. OUr version is called the ATX20.. but we have a built-in Jump starting feature so I'm not sure that would be compatible with the electric Car set up being our low-voltage cut off on the BMS is a little higher. But we have another model that does not have that feature. I will do some research on it.
Always happy to engage in friendly discussion, and I would be thrilled if you guys had a drop in replacement unit for the i3.

I also agree that the 12V battery in the i3 is not a special built unit, but something in the i3 is causing them to fail prematurely. Whether it is increased parasitic draw, overcharging during operation, or some other facet I do not know

Correct me if I am wrong, but the 100% charged cell voltage for LiFePO4 batteries is 3.65V. 3.65Vx4 cells=14.6V for a 100% charged 12V replacement unit.

My concern is that the i3 often runs at 14.9V in colder weather to "wake up" a cold 12V SLA/AGM battery and get it to accept a charge again. If your BMS has a way to handle that over-voltage, then it shouldn't be a problem; just want to make sure all the facts about how the i3 charging system works are on the table before someone commits to installing one and ends up with potential issues.

I can speak from personal experience as to the behavior of the car, as I have a voltage gage installed in both the rear of my car(part of my amp setup) and in the 12V outlet up front.

P. S. I own a couple of your portable jump start units. Top notch gear!
__________________
Reply With Quote
Reply

See More Related BMW Stories

Tags
12 volt battery


Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > BMW i > BMW i3 I01 (2014 - Current)
Today's Posts Search
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On



Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
X3 E83 Battery Replacement Register/Coding Mystery USMC4USA X3 E83 (2004 - 2010) 10 02-27-2018 10:47 AM
E46 Replacement Battery Info Here Weaselboy Do-It-Yourself H.Q. 106 12-29-2014 02:38 PM
Battery replacement NickD 3 Series & 4 Series 9 09-08-2003 01:16 PM
Safety notice I just received at work. Hunter Do-It-Yourself H.Q. 0 11-19-2002 07:52 AM


All times are GMT -7. The time now is 05:31 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
© 2001- VerticalScope Inc. All rights reserved.