Peter's idea of using his digital slaves in a simple analogue mode got me thinking on how I could improve my system. It has a number of weaknesses that I should address.
1. Unable to detect a faulty slave board or easily test and confirm they are functioning correctly. Peter has put led's that give an indication of what they are doing, but 8 of my cells are tucked under the rear seat where the fuel tank was located.
2. My current method of shutting down the controller in a under voltage or over voltage (think regen, full pack and starting from the top of a hill, all of which I can achieve. ) is possibly not safe.
So, solution to the first problem. Peters idea of sending the low voltage warning cascading through all boards provides a method of testing the functioning of the system. I can easily implement this with my controller as a automatic test when the ignition is switched on or the battery charger is connected. If the test fails, then no go. All that is left was to figure out how to test the high voltage cut-off signal. It occurred to me that I can reprogram the slaves so that they signal both a high or low voltage warning on the same output. If we get a warning while charging then it is a high voltage fault and we can implement charger control. If we get a warning while driving, then just determine weather or not regen is active and take appropriate action.
The second problem has to do with the fact that I was feeding the idle and brake signals into my module and then sending them on to the controller. I never did like this approach and actually did not implement it on the car. Just had the low voltage warning only. My new approach will be to instead shut down the controller by turning off the IGN (or KSI as most controllers label it) terminal. This will be much safer because as long as the idle switch is closed the controller will not activate, no matter what throttle signal it recieves and stepping on the brakes overrides the idle switch and throttle signal. That is why it is better to keep them connected directly to the controller but monitor their status instead.
Greg
EV managment module
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Proposed module updates
Greg Fordyce
Daewoo Matiz
http://www.evalbum.com/4191
Daewoo Matiz
http://www.evalbum.com/4191
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Change of plan
If you have seen some other of my recent posts, I am planning on removing this module from my Fiat. But I am not killing it off. My original idea was to use this as a rpm limiter for my Volvo which has a series wound DC motor. This type of motor can rev to self destruction if not under load. Another feature was to control the vacuum pump for my brake servo. At the moment it is connected to my stop light circuit, so is running more than it needs to. My proposal is to have a timer circuit so that it only runs the pump for a few seconds at a time. I have written the code for both these functions, shown on the first page of this thread, but the rpm function is not yet tested. A project for the summer I think.
Greg Fordyce
Daewoo Matiz
http://www.evalbum.com/4191
Daewoo Matiz
http://www.evalbum.com/4191
More BMS Options
There is a new off-the-shelf Lithium BMS with a centralized architecture, with individual cell monitoring, high cell charge cutoff, low cell warning, temperature monitoiring. It also has a nice small display, and is fully configurable. Current monitor and data logging option too, so a complete package.
Info is here:
convertthefuture -dot- com
There is also a manual available:
go to the shop, then look for page 2, users manual
that should answer most questions.
Price is about US $950 for a 48 cell BMS with display.
Info is here:
convertthefuture -dot- com
There is also a manual available:
go to the shop, then look for page 2, users manual
that should answer most questions.
Price is about US $950 for a 48 cell BMS with display.
- retepsnikrep
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Re: More BMS Options
hardym wrote:There is a new off-the-shelf Lithium BMS with a centralized architecture, with individual cell monitoring, high cell charge cutoff, low cell warning, temperature monitoiring. It also has a nice small display, and is fully configurable. Current monitor and data logging option too, so a complete package.
Info is here:
convertthefuture -dot- com
There is also a manual available:
go to the shop, then look for page 2, users manual
that should answer most questions.
Price is about US $950 for a 48 cell BMS with display.
I don't have the technical skill to build Peter's magic system, so I'm very interested in buying off the shelf from Mark. Email is on it's way.
Tim Crumpton
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Re: More BMS Options
timpootle wrote:I don't have the technical skill to build Peter's magic system, so I'm very interested in buying off the shelf from Mark. Email is on it's way.
That's probably not right Tim.
Can you solder?
Can you follow instructions?
Do you understand the principles?
If yes, then you can do it with care and guidance.
Regards Peter
Two MK1 Honda Insight's. One running 20ah A123 Lithium pack. One 8ah BetterBattery Nimh pack.
One HCH1 Civic Hybrid running 60ah A123 Lithium pack.
Two MK1 Honda Insight's. One running 20ah A123 Lithium pack. One 8ah BetterBattery Nimh pack.
One HCH1 Civic Hybrid running 60ah A123 Lithium pack.
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Tim,
Peter's system isn't hard to put together and most of the hard development work has been done, but if you want an off the shelf solution, 2 come to mind.
1 - Cedric's cell protectors on the Agni website. The new version works on all lithium chemistries, you might have to adjust the voltage settings for your particular cells though.
2 - An Australian system, it's been getting good reports from users. http://www.evworks.com.au/index.php?category=6 You would have to check the terminal spacing to see if they will work for your cells.
BTW Peter, what's the status on the multi-slave pcb?
Peter's system isn't hard to put together and most of the hard development work has been done, but if you want an off the shelf solution, 2 come to mind.
1 - Cedric's cell protectors on the Agni website. The new version works on all lithium chemistries, you might have to adjust the voltage settings for your particular cells though.
2 - An Australian system, it's been getting good reports from users. http://www.evworks.com.au/index.php?category=6 You would have to check the terminal spacing to see if they will work for your cells.
BTW Peter, what's the status on the multi-slave pcb?
Greg Fordyce
Daewoo Matiz
http://www.evalbum.com/4191
Daewoo Matiz
http://www.evalbum.com/4191
- retepsnikrep
- Posts: 1387
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