Apparently there is a way to charge a dead battery without using the BMB's!
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Is it possible to get information on the level One Battery Recovery ? I want payed this information . I am in France ...
dhrivnak
Active Member
Am I correct the small VDS screen remains dark even with a charged 12v battery? If so sorry but you are beyond my knowledge. If the VDS works I can likely help a little.
Look at the post down the page titled
Safely trickle charge a bricked pack in/out of car - solution
With one of those boards you could read the voltages and charge each brick. It should be a must buy for every roadster owners toolbox. There are a lot of hobby chargers for lithium that could charge a 9s to a variable voltage. Tesla only charge cells to 80-85% so you need to dial a lithium charger back. But you could get all the readings you would get from the screen albeit manually with a pencil and paper.
Safely trickle charge a bricked pack in/out of car - solution
With one of those boards you could read the voltages and charge each brick. It should be a must buy for every roadster owners toolbox. There are a lot of hobby chargers for lithium that could charge a 9s to a variable voltage. Tesla only charge cells to 80-85% so you need to dial a lithium charger back. But you could get all the readings you would get from the screen albeit manually with a pencil and paper.
0V, it is connected between the negative terminal of the pack and the output cable. You would need to also connect to the positive side by removing a BMB board to get a voltage reading.
One dead brick will only lower the total pack voltage by 4V, but the voltage can vary over 50V between a full and empty charge, so you need to be able to read all of the bricks to determine the actual pack status.
One dead brick will only lower the total pack voltage by 4V, but the voltage can vary over 50V between a full and empty charge, so you need to be able to read all of the bricks to determine the actual pack status.
Full pack voltage, but you shouldn't rely on the voltage measurement as the only metric for pack health. As [URL='https://teslamotorsclub.com/tmc/members/mlauto.22448/']MLAUTO[/URL] pointed out, a dead brick can hide within the full pack voltage, and the resistive cells in that brick can drain the rest of the battery. Effectively making the battery useless until removed or replaced.
The best way to get an idea of the pack health is to get voltage measurements of each brick over some delta time. Every time you pull a log file, the tarball that the Roadster zips up for you contains a file with all the brick voltages—third column in ahr.log. Copy the values into your preferred spreadsheet editor and divide each value of the column by the factor 8192 to get each brick's measured voltage. The brick numbers are in the first column in zero based format and the bricks ordering scheme is outlined here.
I'm confused, or maybe it's the car... Looking at the ahr.log file, it appears that my brick #9 is the odd one in my pack:
brick soc v
0 888013 33168
1 888013 33168
2 888013 33168
3 888013 33168
4 888013 33168
5 888013 33168
6 888013 33168
7 888013 33168
8 888013 33168
9 863311 33008
10 875901 33088
11 882135 33128
12 888013 33168
13 888013 33168
14 888013 33168
15 888013 33167
16 888013 33168
<snip>
The rest look the same as the last few; 888013 SOC, 33167 or 33168 voltage
Yet, the overall log (as reported by VMSParser.exe) claims it's brick #14.
05/03/2018 05:00:24 | 1525348824 | DAY | odo = 47279.7 range soc = 80%, brick ave 141.947Ah, brick min 139.382Ah, min Ah brick 14, CAC 139.68 Ah
But there are lots of bricks that look just like #14. Why is it identified as the min?
Long ago (4/12/2017), VMSParser reported it was brick #9. Did the ahr.log just not get updated in the past year?
Which is right?
The log file shows voltages and your range is within the .02V balancing range. The Ah log is capacity which isn't determined by a specific voltage reading. Your brick #9 could be the brick with the greatest Ah capacity, as it will take more Ah of charge to get it up to full voltage, and will have more Ah to give up before it reaches empty. You really need to look at the voltages when the cells are empty, as the first one to hit the min voltage is your weak one.
Ah, ok. That makes sense, though it's a bit of a puzzle why brick #9 would go from being the worst to the best in a year. Looking back in the logs, #9 is called out as worst most of the time, but I nearly always grab the logs when the pack is full (standard charge). {shrug}
Interesting tool... A good use is that one can determine a pack's balance without putting the car in diagnostic / debug mode, or for watching the same over time (I grab the logs every month).
Interesting tool... A good use is that one can determine a pack's balance without putting the car in diagnostic / debug mode, or for watching the same over time (I grab the logs every month).
I just watch the voltages thru the service menu after a charge and again when the battery is getting low. A brick that has the high voltage after a charge and the lowest after a full use is going to be the worst one. If the brick numbers always vary, then you don't have a problem. I don't see how the Ah rating of every brick can be acurately calculated if is not allowed to be fully cycled. The cycle is limited by other bricks, so only the weakest one should be right.
