SwedeSpeed - Volvo Performance Forum banner

61 - 69 of 69 Posts

·
Registered
Joined
·
2,167 Posts
Discussion Starter · #61 ·
So I decided to do some testing of my own ... my DRL are still in operation knowing that the CEM PWM the voltage to be a constant 13v at the bulb I figured my voltmeter would also see 13v and I could see if the CEM also PWM the voltage when the switch is in the "Manual" On postion (last position on switch). I found something rather odd I was getting full system voltage at the lights in both DRL and Manual on position does that seem odd to anyone else?
First, you won't be able to measure an 80hz 90% PWM signal with a normal DMM, maybe a high end fluke with trueRMS but anything under $400 won't show the correct value. Most of the time, the signal is at full system voltage, with short intervals of 0v (that's what PWM is), inexpensive DMM will average 8 or so consecutive ADC readings which will be very close to full battery voltage.

Second, was the engine running? When the engine is off, the PWM is disabled (presumably, as the input voltage would be lower). This is actually how I figured out what was going on, the BOW3 would work with the engine off but not while it was running - the opposite of what would happen if there was no regulation.
 

·
Registered
Joined
·
2,167 Posts
Discussion Starter · #63 ·
I have a fluke 88 V update rate is something like 245 milliseconds, and yes the vehicle was running and the meter was fluctuating around 14 v
With the PWM signal we have, the period is ~12.5ms with an off time between 0.6-1.0 ms. I'm not surprised it didn't register. What's it show on AC volts?
 

·
Registered
Joined
·
34 Posts
Didn't actually think to check that seeing as it wasn't my main concern. Ill see if I can't hook up the scope tomorrow during lunch and get a readable signal, I'm curious to see if the PWM is still there with the switch in the on position.
 

·
Registered
Joined
·
2,167 Posts
Discussion Starter · #65 ·
Didn't actually think to check that seeing as it wasn't my main concern. Ill see if I can't hook up the scope tomorrow during lunch and get a readable signal, I'm curious to see if the PWM is still there with the switch in the on position.
It's kind of tricky to get a good measurement on, as it's the voltage across the filament with the lights on and the design of the H11 socket makes probing difficult. I started with alligator clips but soon found out the mini variety aren't rated at 4A (after they melted). I ended up cutting up an old HID harness for the male/female superseal connectors on 12AWG, and made a voltage/current piggyback that the scope can clip to with the bulb installed normally.
 

·
Registered
Joined
·
34 Posts
Well luckily the harness that came with my HID kit runs from the OEM connector to the ballast but is the same connector as for the bulb so it's basically a bulb connector extension so testing is a breeze. I would like to propose a question, if the DRL disable does stop the PWM how is it doing so with a software update is the just running 100% duty cycle and always commanding on? Couldn't that potential overload the transistors? Just a theory...
 

·
Registered
Joined
·
2,167 Posts
Discussion Starter · #67 ·
if the DRL disable does stop the PWM how is it doing so with a software update is the just running 100% duty cycle and always commanding on? Couldn't that potential overload the transistors? Just a theory...
Yes, that is exactly what it is doing via software - turns off the voltage feedback loop and set 100% duty cycle.

However, this has a result of *reducing* the power dissipated in the CEM transistors - they are PMOS, so very very low R_ds on and nearly infinite R_ds off. Only time this type of transistor dissipates (significant) heat is when switching off-on or on-off, when it is in the transition (aka resistive) region. This is called switching loss: http://www.allaboutcircuits.com/technical-articles/switching-losses-effects-on-semiconductors/ anyway no worries about 100% duty cycle, it's not like a welder or whatever.
 

·
Registered
Joined
·
4 Posts
Still confused...had the dealer flash my computer this past Saturday with 30679690. Installed my Kensun HID kit Sunday afternoon, with the same results. 35w slim ballast with H11 bulb, flickering then out with BOW warning; 55W slim ballast with same H11 bulb, no start with BOW warning; Older 55w ballast with same H11 bulb, slight flickering increasing to rapid flickering and rapid clicking in ballast unit.

Not sure where to go from here.
 

·
Registered
Joined
·
2,167 Posts
Discussion Starter · #69 ·
Still confused...had the dealer flash my computer this past Saturday with 30679690. Installed my Kensun HID kit Sunday afternoon, with the same results. 35w slim ballast with H11 bulb, flickering then out with BOW warning; 55W slim ballast with same H11 bulb, no start with BOW warning; Older 55w ballast with same H11 bulb, slight flickering increasing to rapid flickering and rapid clicking in ballast unit.

Not sure where to go from here.
We know now that DRL Disable alone is NOT a safe alternative to the KBOWE. So that is the only viable method of doing a retrofit using the OEM/stock wiring. Sorry for the confusion.

Please take KBOWE technical discussions here: http://forums.swedespeed.com/showth...ID-Data-If-you-have-installed-a-kit-read-this

We are working on a commercial/group buy for KBOWE here: http://forums.swedespeed.com/showth...nts-a-Volvo-P1-specific-WMM-safe-HID-Retrofit
 
61 - 69 of 69 Posts
Top