Planing CanView and BMS+ conversion with lithium

Exactly.
The bluetooth device never freeze.

My computer is connected exactly like canview on the odb plug. So no freezing problem. It give the highest and lowest cell voltage and the signal quality (because there is noise on the bms side). This pc log all the 70 cell voltage twice each second. And also all sort of data from prius can: amperage, igbt temp, motor temp...

Bluetooth is perfect. Self connecting when pc is powered, high isolation, low cost. I can even read cell voltage in my home, say 10 meters from my car.


I also had pc problem when using a usb-oscilloscope. This notebook being self powered. If the pc is on the rear seat then I have freezing problem. If this pc is on the perspex over the lithium cells it is ok !!!
With or without some opto isolator between pc and oscilloscope on usb line. All wires shielded with just the last 1-2cm unshielded.
I think it is the differential voltage between the cells and the car body.
I suppose that floating is a kind word. It must be high and brief variations. The culprit must be the boost-converter.
And add also inductive problem. One time I saw negative voltage on a data bus where only opto are connected.
Last summer, I done a quick test with a metal screen. This don't solve. But didn't connect this screen to the "car ground" and the bms inside this screen was still connected to the cells.

 

planitiare

if iyou use 70 cells and the startoff voltage is OK and do not go below ~210 then you keep the litium pack connected

so wy do i need to use the canview anymore
yes to automated the contactors but in this case i can manually switch the pack on and off
still use the bms+ for the SOC faking and sometimes use the canview just to see whats happening.
that way if the canview breaks down i dont have to wait weeks and pay like 10-25% of the total add pack build cost for a new canview etc etc.

 

You only need canview in order to send 210v end-voltage to bms+.
This is not indispensable if you will not deplete the cells more then say 66-75%.
If 210v not send it will be 200v so average cell voltage will be 2,85v. That's average. The lowest will be...

Sending this message to bms+ can be done by a pc connected on can bus (may be scanguage can do this too). Like canview my pc do this when I touch the screen. I also use "orig mode" when the trip is long.

Canview give you temperature, amperage, Ah, volts ... interesting but not indispensable.

 

yes it snot that i dont want canview i stil use it and need it but want to be dependable on that one part to do all.
so you use your pc to send message to the bms+ instead of the canview?

210 wil be 3volts.. is that not to low? i think i would go for 215-217

problem with the CBM boards ( cheap nice person bleeding boards ) is they stop at 3,6 and the small chargers that i want to use 35 of ( 1 for 2 cells ) stop at 3,7 hahaha so thats a problem.
guess i have to measure the total voltage and have a main relay to shutoff the main 230 volts. ac to the chargers.

 

Actually Norms latest BMSplus version 2 or "BMS2" does not need a Canview. The voltage can be set via dip switches on the PCB. It only has three relays which are now built into the BMS2. Incidentally it also does not need a touch screen. Designed so you only need to use a ScangaugeII. Only US$449.

 

i now that
and when i pay a liitle over 2000 euro then 449 is almost in the 10-25% range

 

i think i am going to use cell-log 8s or 8m to monitor the cell voltages and trip a relay to stop charging and or have a warming tone when voltages drops below a set point

not a lot i need 8 or 9 of these

 

planitaire
can you tell me/us what amps/kw your pulling ( from the canview screen? ) during EV mode and BMS+ high SOC ( ICE OFF ) when driving at 80kmph?
and how long can you keep that up ( of course ICE warm etc )
and di you also look at the packv screen what the diff was betwteen the oem cells? when going down to 210volts?

 

Several month ago i made a test drive with nimh and A123 cells.
In this graph the speed is between 75 and 95 kph because the road was not flat. Average 85 kph.

All data come from prius can bus.



In red is MG2 mecanical power (computed from torque and rpm)
In green electrical power coming out from HV battery
In yellow engine losts when spining at 990 rpm. These would have been saved in "out of gas " mode. Average 1.66 kW.
Outside temp was 25°C.
MG2 temp 33°C.

Average voltage was 225v, maximum amperage 70A average between 40 and 55A.

So probably, at 80 kph you will need 10.5 kW. Add 1.7 kW for engine.
Total 12.2 kW => 54A

If you use 80% of 20Ah:
18 minutes 24km

 

nimh and a123? you also used oem battery packs?
what was the total kwh of the packs?

 

Yes nimh is still connected. So if there is a serious problem on lithium side you can drive with just nimh. Just open the contactor.
If the problem become permanent unplug bms+.

nimh energy is 1,3 kWh 40% usable and about 39kg
A123 Lithium energy is 4,55kWh maximum 90% usable and about 41kg...
So total is 5,85kWh.

But I can only use 125Wh of nimh (10%). Bms+ threshold is 210v but after driving, if you wait several minutes voltage goes up, for exemple 220v. Nimh is not then depleted. That's not what I want. I keep nimh only in case of a major problem.
In order to use more energy comming from nimh you would decrease bms+ thresold. But this would also decrease lithium cell voltage. Not good for there life. Not good too for nimh life. But possible.
Unlike enginer kit, nimh stay cold, and his dod is very small. May be this will increase nimh life.


I am not sure Prius need 12.2 kW at 80 kph. During summer, may be it is smaller, say 11kW.
Lopezjm2001, do you have this power, on a flat road, no wind, no rain (but you have 150 kg more inside your Prius) ?

 

My Enginer kits only supply about 15amps each at best, they are trickle chargers. They are really just range extenders. So at any time my DC Converters can supply about 30 amps. So A123 20AH pack is rated 3C continuous according to Xueming = 60amps. So in the worst scenario case my PHEV kits can supply about 90amps continuous. A lot depends on the terrain and gradient of the road. I do not have flat roads where I live. The load keeps changing according to road gradient. A lot depends on where you drive. The flat roads of Holland are ideal.
The 20ah A123 lithium pack does the heavy lifting when needed for high load such as when starting. The two Enginer kits do most of the work. I started with one Enginer Kit which was the start of my learning curve. If you have one you know what I am talking about.

 

I have been busy rearranging the architecture of my 3 PHEV kits. I moved one Enginer 4KWH battery pack and two 48V chargers into the tyrewell. I made up a stainless steel tray for the two RFE battery packs to sit in inside the tyrewell. Moved my two DC Converters inside my Enginer box. Moved my 20AH A123 lithium pack on top of my Enginer box. Freed up my back seats. Will post photos tomorrow. I used two pieces of 500mm long of unistrut to bring the Enginer box about 40mm higher. It makes it easier to remove and install Enginer box as I no longer need to access nuts underneath my Prius. Two polystyrene pads between battery packs and bottom of Enginer box.

 

wow 150kg and you use the 2 kits and the a123
love to see those pics.

best planitaire i was thinking you used the OEM add packs and the A123 i understand you still have the oem pack

i just read a topic here where the prius run out of gas 2 x and limped to the gas station in EV.. now 2011-2012 the oem battery is dead and replaced.... dont now what low SOC and voltages the prius alows in that situation but it deadly for the HV battery i guess.,.

so lets keep the nimh battery in a happy SOC

i am opting for 72 cells just to have a liitle more and looking ar your info the inrush current wil be not that high.
wunder what wil happen if i use the OEM relays with the 3e relay with the resistor on it.. wil that prevent a big inrush? or level it of a bit....

did you do a capacity test of your batterys when you got them and now after months of driving did or are you going to do that again. just to see if they still hold up?

edit

thinking about getting these
http://dx.com/1-3-lcd-lipo-life-liio-battery-voltage-monitor-led-buzzer-102947
and like with the cell-logs connect a relay to it ( use the led or buzzer voltage/driver to switch a small relay ) to disconnect the charger ( my zivan got a external input for a closed -charger on- and open -charger off- control ) and keep the buzzer when a cell gets to low during driving.

 

Using 70 cells x 3.3v = 231v = NiMH SoC = 70% (good choice).

Using 72 cells x 3.3v = 237.6v = NiMH SoC = 73.5%

These SoC values are based on NiMH battery internal voltage.

A long term NiMH SOC of 73.5% could be a problem. The Prius normally keeps the NiMH SoC between 60% and 70%. The NiMH may not be too happy with a SoC of 73.5%.

 

Third relay and 22ohms resistor are designed for charging some capacitor in the hsd convertor.
You can have a huge amperage (very low resistance and maximum delta V) but not a lot of energy.

When // nimh and lithium, there is not a high delta V. But you have more energy until the amperage become enough low.

For exemple, a graph from a test, when coupling 70 A123 with 244v and nimh 226v (Nimh can have a lower voltage and some nimh battery have a less internal resistance then mine)



Delta V was 18v. Maximum amperage was near 30A. About 12 secondes over 10A.

If You add 2 lithium cells, 18v become 25v. So inrush amperage would be probably more then 41A.

If you have a nimh voltage near 210v and/or if cells are hotter amperage will increase too.

As you can see, with 70 cells voltage stabilizes near 235v. With two cells more you will be over 240v.

I don't do a capacity test. First test were in summer and now temperatures are lower.
I don't leave lithium cells in my car. But nimh stay cold. His internal resistance is higher.

 

3,5 % more is not that lot or do you think it is?
a realy low SOC/voltage wil really damage the oem i guess. 70 or 73 will not! "?"?

3,3 is nom. but when charged and connected they are more like 3,4/3,5 right? so thats 238/245 volts

if the soc gets to high the bms+ will just like with a normal prius bleed of energy using the ICE right? or not...
and the nihm is cooled..

only thing i can think of is that the nihm is not liking the high rushes of amps into it from the lituim pack.. but then again this only happens when first connected and when driving and braking a lot you do put in a lot more amps in the nimh oem battery and during driving a lot more then connecting your litium pack one's for every trip.

so.... do i see something wrong here?

yhea already expected that got something to do with the invertor. but not sure so asked
41amps.. the nimh can handle 100a.. or more so is that really a wurry?\

and wy do not test AH. now after to long! this is the perfect way to see if these cells hold up.. or if its trowing money away..

when coltage stabilize at 235 and with 2 cells more at 240 then are you not doing the same as with the enginer kits that dc- dc to 240/242 volts.??
so wy would that be OK and this not?

 

I don't know what bms+ does when voltage is over 240v during some time.
Without lithium bms+ can quickly engage engine in compression mode, somewhere between 240 and 245v.

Please ask Norman for this.

In the graph before this append only during 2-3 seconds. I never had compression mode in this situation.

Try 72 A123 cells and tell us


About inrush current, note that it can be increased when
-delta V increase: nimh low and lithium high. For example 210-245v
-not all prius nimh are equals. Mine has a highter internal resistance.
-hot nimh have less internal resistance. For example when connecting lithium in a car all windows closed outside in summer, during a sunny day. Lithium have also less internal resistance but the most important is nimh.

So keep some security factor.

 

yes i wil blowup my oem pack and tell you

whats your Ohm ? mine now is 0,02 per cell and its ~cold outside 5-7 celsius or so
and 21 or 26 at canview for total pack.

when i am driving in ev and high soc ( by bms+ ) the ice wil stay of above 46kmph ( ev mode auto. disingage ) so i dont wurry about a higher voltage and charging the oem pack because all energy wil go to drive the car not the oem pack charge.
even standing stil its used 250 watts with al the ecu's on board.

what do the cells measure without the tabs? i wil also get those without the tabs its cheaper ;-)
but they are smaller... the site only got size with the tabs on them...

 

Tell us and take pictures

The nimh ecu say between 0,021 and 0,024 ohms each. Total 0,304.
When batt temp was 17°C.

I done some test and found 0,5 ohms at 8°C.

A123 cells dimensions without tabs : 160x227 mm. Thickness 7,3 mm.
Weight 482gr.