E90 330i 升級LiFePO4 鐵鋰電池用後感，一個字，勁。。。

yeukfung · 發表於 20-7-2018 16:23:07

Hi all,
小弟近日先發現呢個GROUP，原來好多寶馬朋友在這來，我渣左部車E90 330 一年多了，最近升級左LiFePO4 鐵鋰電池 (已試左成2000公里，好認真的試左...)

我响discuss 度開左支thread, 有興趣可以參考下...
https://www.discuss.com.hk/viewthread.php?tid=27577606

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1) 啟動好快鬼快, 唔識點形容
2）低扭好實淨，由1000 轉上3000轉，再上5000 - 6000 全部都好快，反應好左好多，相信同佢低內阻有關...

深入D既數據資料，我有以下幾個但用英文寫會快D...：

LFP電池base voltage: 12.8V, lead acid 12.0V
14.4V constant voltage can charge the LFP to 100%, but with the alternator output, it will only keep the voltage at 14.05V, which means 90% of battery capacity can be maintained.

For the LFP I used, it's 60AH, so, only around 55AH is inside the battery.

- CCA Testing within this 1000km, it's varies from 1150 to 1200 CCA, it does not rise or drop much, more or less keep stable in this 1000KM journey, while comparing to 90AH AGM, it was around 900CCA to 930CCA

- Internal resistance testing, it's varies from 2.35mOhm to 2.5mOhm , while comparing to AGM, it is around 3.0mOhm to 3.2mOhm

- voltage drop during cold start, the MIN voltage recorded is 11.8V - 11.9V , while i didn't record the AGM, but for 60AH battery, it's very strong

- alternator output test for cold start, I use inpa to monitor the generator AMP from cold start to warm up, there is two case:
1) your battery is full - the max AMP generated from alternator is around 100Amp for around 20 seconds, and eventually drop to 20Amp within 1 minutes, and the charge of battery reach 14.05V
2) your battery is NOT full - the max AMP generated from alternator is 170Amp for over 1-2 minutes, and start to drop when battery voltage reaches 13.8V and then eventually goes down to 14.05V after 2 minutes, and then back to 20Amp.

- temperature test, i don't have equipment, just use hand to test several area, I can say... does not feel any heat/warm on the battery, just normal and usual

drawback to my car with IBS:
- IBS is now partially working, as it no longer able to detect battery capacity when it's in sleep mode, it can still read the battery terminal voltage.

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用後感：

- 有兩次因為玩CODING無插叉機，用左可能10% 電，著車時發現點解個轉數响800RPM成分幾兩分鐘，唔太正常，CHECK完發現BMW佢會MON住個電池電壓，唔夠13.8V時佢會FULL LOAD咁樣差粒電, 成180A... (雖然我極之反對，但始終人地係打南磨，唔係叉機), 跟住慢慢上番14.05V 就正常番）若果粒電好乾的話，真係好容易整死個打南磨..

- 買番來時一定要叉足電, 我買番來時有13.17V, 好似好正常，跟住我用8A既叉機去叉，叉左成4個半鐘CC先慢慢行CV, 所以有成32AH叉左入去, 若果呢32AH 係個打南磨叉既話，真係會整傷部車。。。 (我唔知家陣出邊賣既電池會唔會咁，但呢一樣野大家注意下會安全D）

- 一下重腳的 DME(KL87 點火果邊的VOLTAGE) VOLTAGE DROP 就明顯唔同，之前我AGM 90AH 電壓空轉踏上3000RPM 時， 90AH會跌到13.0V左右, 但家陣果個大部份都係去到13.4V，加速上都好明顯...

所以，若果真係要升級，值得的(當然要考慮價錢，香港果間感覺安全D，但小弟這個平民貪平去左淘寶搵左間台灣研發既品牌,都有齊認証)，因為LFP供電真係好穩定（若果你係玩電腦的，Lead acid = 7200 HARDDISK, AGM = 15000 SCSI Disk, LFP = SSD)，當然可以考慮用超級電容做穩壓，但因為佢會慢慢DISCHARGE，所以我無考慮(之前部POLO試過，對突然加速的確有明顯較果)

升級前，確保部車無漏電先，因為粒電池唔係下下滿的話，會好傷個打南磨...

yeukfung · 發表於 4-8-2018 01:27:42

Meco 發表於 22-7-2018 22:13
鐵鋰電，全名磷酸鋰鐵電，其中一類鋰電池，電池同時擁有鈷鋰、鎳鋰和錳鋰的主要優點，電壓是3.2 V、終止充 ...

hi 師兄，

謝謝你的意見，我不是在推銷，我祗係一位普通愛DIY的人，但不時會睇好多唔同既方案去整好部車，就好似師兄改左個好靚的標板落你部車度，我亦都有將個M3 CLUSTER 放落部E90 度。。

至於LFP 電池，我研究左個CHARGING PROFILE好耐，最近有一D發現，但祗限E-Series, 小弟完全唔熟F-Series...

有幾個 concept 先定清楚，相信你都知道的：
1) BMW charging profile will never want to charge the battery up to 100%, it's defined target is 90% full, which allows a sudden current to enter the battery without over-charging it. it apply to both AGM or normal Lead Acid battery, and it try to stable the voltage around 14.1V at battery terminal
2) AGM battery is more sensitive to overcharge... so far what i monitor with INPA, it's max output to generator is 14.8V when my battery is partially full(messing around with INPA over half hour without connecting to charger)
3) BMW has 2 types of power management system, with IBS is Advanced Power Management System, without IBS is Basic Power management
4) IBS has 2 main function, a) to monitor the battery terminal voltage and report to DME then it know how to adjust the alternator output to regulate the voltage of entire car, and b) monitor the State of Charge(SoC) when the car is in sleep mode, it wakes up for several milli seconds every 2 hr and check the terminal voltage value to check the SoC of the battery, once it drops below 30% SoC, it will command the DME/CAS to disconnect the battery supply and preserve the battery for next startup of the car, this is to avoid electrical drain causing the car cannot start next time...

so, with basic facts above, i start to see if LFP is good fit to E90 car equpied with IBS, or say, safe to use as a replacement ( now i have been using it over 5000km, and so far it works really fine, strong cold start, will monitor how the spark plug burns later next week when i have more free time)....

a) first thing i need to check is the charging pattern on LFP comparing to Lead Acid, which found that Lithium based battery charging pattern is far simpler than Lead Acid based, no floating charge or trickle charging tricks..., just CC and CV is pretty enough to charge up a battery.
if LFP battery terminal voltage reaches at 14.05-14.1V, the battery is already 90-95% of charges, which is around 13.4V when float charge is gone (tested after 20hour of car sitting overnight, that indicate the battery is at 90% SoC)...

b) IBS is no longer able to detect SoC of the new LFP battery, which is expected, as the base voltage is far different to Lead Acid, and now I even removed my IBS and replaced with normal brown ground cable...

c) truly agree with you that it's SUPER expensive in hong kong... while depends on your confident, I found one taiwan branded LFP with all the safety certificates... with just RMB1350... so with this budget... i personally cannot resist myself not to take the risk and try it...

d) and just after the replacement, the car is different... it pulls much stronger in 3000 to 5000rpm, which i don't even believe the feeling myself... so far i have attempted to log so many data during the transition on charging current across first 1000km... and so far i see it accept higher current in charging, which indicate faster to reach 14.0V after cold start, but for explaining why it feel better.. i have no clue at the moment... if you have some guidelines or method that can help to see the different, please share the idea with me...

yeukfung · 發表於 4-8-2018 17:46:38

本帖最後由 yeukfung 於 4-8-2018 17:50 編輯

Meco 發表於 4-8-2018 14:53
首先AGM電池軟件數據存於IBS微處理器上，去計算幾時充電及停止充電，如果用駁上非AGM電池， IBS 察覺電壓 ...

Hi c-hing,

thanks for your reply, regarding the charging pattern, the pattern is totally the same for AGM or LFP after the car start, just AGM accept more current within first minute..

Screen Shot 2018-08-04 at 5.40.45 PM.png

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yeukfung · 發表於 5-8-2018 23:43:17

Meco 發表於 5-8-2018 14:03
到尾我都不建議轉磷酸鋰鐵電在用緊的BMW上，除非BMW指定要用磷酸鋰鐵電。磷酸鋰鐵電與鋰電都有高放電功率， ...

Hi C-hing,

Thanks for your time and effort to discuss the battery and charging info regarding BMW, it's pretty amazing and appreciate your valuable time

for all those material you have discussed in this thread..., actually, i have already read before i attempt to work on this project...

i would be more conviced that BMW is actually using phosphate-based lithium-ion as the cell voltage match with BMW spec:

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5-8-2018 23:06 上傳

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5-8-2018 23:06 上傳

I don't guess why most of the factory don't using it, what i know so far is german gov has some direction on car, which need to be 1M electric car running on the road by 2020...
https://abcnews.go.com/Business/ ... 20/story?id=8364933

For this LFP upgrade attempt is sure an unofficial way, instead of purely and blindly trust the LFP company that it's perfectly fit nor afraid not to use BMW approved battery, i do this attempt for interest and see how things go...

and that's why i try and even create a custom applicatoin to log out so many real data and do comparison and see if any strange pattern occurs, if yes, so that i will fall back to normal AGM battery...

so far it's been over 6000km in 2 months and everything running good...

I do this with several mindset which you may not agree but that's the case in my car, at least...:
1) when i rev up from idle to 4000rpm when car is parked, the voltage reading in INPA will drops to some point, with weak battery, it may reach 12.0V for about 0.5second, that indicate there is moment which alternator cannot cope up with the rate of change (some other say for performance consideration, the DME will even momentary disable the alternator to have max boost of the performance), i have no way to verify the software logic, but at least I aware the symptom on voltage drop when the car rev up quickly.

2) base on this, there is really several milli seconds is purely counting on the battery to provide spark, for a higher base voltage 13.2V comparing to 12.0V, it does have real different

3) i ohm checked the ignition coil, each of the primary coil ohm is around 0.5Ohm, with 12V battery, it will be 24A, and with with 13.2V battery, it will be 26.4Amp
for the power different which will be 12V * 24A = 288W while 13.2 * 26.4 = 348.48W, from pure calculation, it is large in my eyes (although it just few sparks, but u asking me if there is any different)

4) it's really cheap, just RMB1350, even cheaper than AGM, why don't take a try for fun?

5) AH usage is 90%, and u can see a very recent video, with same size of AH to same load, LFP far outperform with SLA and AGM... as they are in different chemical structure, for the AH value printed on the label, it's just base on 1C current test. (of coz, u may say there is no use for the battery, but please think of it this way, what if you alternator die, every mile is actually counting on battery, that will see the different, for normal 30Amp draw, the LFP can handle over 1 hr, while with 90AH AGM, which maybe only able to handle max 1 hr...)
https://www.youtube.com/watch?v=YNc4lm6FbI8&feature=youtu.be

6) why would people prefer AGM over normal flooded Lead acid? to me, coz it's just an upgrade... and i just want to see if it's possible to upgrade...

7) with the market price of my e90 330i 2005, it's already lower than 30,000 hkd, which i have nothing to lose in case of disaster happens. so it become a pure testing toys for me. Personally i enjoy working with engine, so will try to see how to make it runs better.

8) those overcharing/undercharing logic board isn't new stuff, the one I got also has it, and I tested with overcharing to 16V before installation.. so far it's fine..

and you see in my e90post, i even want to adjust the DME charging parameter to fit with it... (i am currently learning how to hack, but it's real difficult...)

at the time of release of this car, LFP does not even exists...

i am coming from computing background, which you can think of ssd is becoming popular 2014, and most macbook before 2010 is only comes with normal harddisk, while it still safe to upgrade as long as you know their interface matches ...

same for the LFP, as it's becoming popular in recent days, which lead to me see if it's possible to switch over... safely according to my personal views and findings :-)

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E90 330i 升級LiFePO4 鐵鋰電池 用後感，一個字，勁。。。

E90 330i 升級LiFePO4 鐵鋰電池用後感，一個字，勁。。。