Do you know what your FANS are doing ???

[Roland Stone]

During a battery charging cycle, has any OBSERVANT OWNER noticed/monitored when and at what stage their cooling fans switch off(?). – e.g. when (elapsed time)/after instruments indicate: 

battery 100%/0 amps/time to charge remaining: 0 hrs/min, charging indicator light green……….
and charging cord module “charge” light off   >>>>>>>

Wondering if there’s ANY consistency in fan shut-off occurence from one Empulse to another ?  Most owners I've personally asked don't have a clue which is why I'm posing the question to a wider audience here.

[00049 (AKA SopFu)]

Mine is all over the place. Usually they turn off by the time it gets to 100%. In the winter, the fan cycles while it's charging - probably on 80% and off 20% when ambient temp is below 50* F. My guess is there is a preset temperature that turns the fan on. If the charger drops below that temp, they turn off. My firmware is over a year old, so Brammo may have also changed that setting over time, too.

[Roland Stone]

00049 (AKA SopFu):

Your response is exactly WHY I wrote up the post, but it's going to take a few more replies to find out if others are experiencing erratic fan behavior.  Problem is, even as often as the cooling fans come into play with every charging event, and even as noisy as they are, I suspect most owners don't pay much attention to them and probably care less, - assuming if they're not on fire they must be working right.

[frodus]

Mine only comes on when the charger amps are maxed out,  near the first part of charging. It goes away when it gets to the CV phase of charging and amps drop.

Mine really only goes on when it gets warm.... Which naturally happens when current is higher, and thus power is higher.


I think its set for two events. One when ambient temp is above a certain point... And another when the. Charger is pushing full power. If ambient is low and the charger hit CV and amps are dropping, I think the fans stop.

[Roland Stone]

Only 2 replies (other than mine) out of 88 viewson the subject.  What does that say................?

Here's what Brammo Service says:

"Yes, your Empulse has two charger fans that run at the same time. They move air across the bottom of the chargers baseplate.

The fans turns ON at 45°C (as measured by the Eltek charger measurement at the baseplate reported via the BMS CANbus).

Fans turn OFF at 40°C (as the baseplate cools down).

The Eltek charger’s baseplate is where the temp is measured which you cannot touch."

Although there are variations and without getting into detail, for the most part my fans switch on about 15 minutes after the charger is plugged in and only switch off around 1 hour 25 minutes after the battery SoC is 100% and zero amps are indicated on the LED.  At that end point, the charging cord module can be heard to disconnect from incoming voltage, -all indicator lights off.  My observations aren't scientific, but not being able to "touch" the base plate to measure temperature leaves few options understanding what's going on with the fans.  Without being able to measure the temperature at the untouchable base plate removes any possibility verifying correct fan operational temperature.  Also interesting that of the little owner feedback offered, the fans seem to be doing their own thing which bugs the hell out of me, and answers from engineering are not forthcoming.  Can only surmise it's another proprietary bit of information not intended for publication and prevents owners reporting possible fan operational anomalies.  Maybe it will take the fans torching off someday to finally get some answers.

[Shinysideup]

Roland, Roland... your bike's not on fire... ride!

[kingcharles]

My fans also used to stay on for hours after charging (seemingly) stopped at 100% but since recently the stop immediately!

So it changed for some reason. It may have to do with a cell balance algorithm still running in the background?

I also noticed that when charging gets interrupted for some reason (at a level 2 public charge station) that the fans also keep spinning forever.

I have decided to build a workaround. I plan to hook up a big 140mm case fan to the 12V system which hopefully avoid the charger fans to turn on.
I plan to make this removable such that I can use it only at home.

[frodus]

As an EE (and EV Parts reseller, and having built my own EM), I observe that the fans are working exactly how they're supposed to. They're there to cool the charger when it starts going above a set temperature. Nothing more, nothing less. Under different environmental temperatures, the on/off times are going to be different because its not time based, its temperature based.

The charger seems to ramp current up slowly (good idea for lithium) until full charger power. At some point, the temperature of the base plate gets too warm, fan turns on. It stays on until after the current drops. The fans continue until the base plate is below the set temperature.

From what you've explained, your bike is doing just what its supposed to, and there's nothing out of the ordinary, nor any proprietary information missing. That's just how chargers work, along with just about every other type of power electronics out there,

[Roland Stone]

Thanks for that, frodus, but if you get back to this post, - does it seem reasonable that it would take over an hour for the baseplate temperature to drop below 104 degrees F after the batteries are fully charged?  When the "time to charge" has been reached and all indications the battery is charged, from that point the charging cord/module is only pulling 0.03 amps which is likely what the fans are reqiring.  It just seems with no apparent charging taking place the baseplate would reach that fan switch-off temperature sometime sooner? 

It's not a big deal and I'm at least relieved knowing approximately when (time wise) I can expect my fans to shut down.  My only conclusion would be that baseplate must be getting cooking hot during charging for it to take close to an hour and a half to cool off below 104 F after all apparent charging has ceased.  Maybe if the cooling fan operation relating to battery charging explanation were available to owners, there wouldnn't be as much conjecture from need-to-know freaks like me.

[frodus]

Back to this post? Was I not on topic the entire time?   

Yes it does make make sense. Most power electronics have an active cooling system that will turn on at a certain temperature, and off at another (as explained before).... but there is also some hysteresis, which keeps the fan from turning on/off/on/off/on all the time right around that setpoint. I just don't have time to explain every detail about power electronics, cooling, thermal resistance, CFM, power loss, PID loops etc.

Basically you have a delay so that if the temperature is at that edge of turning off, it'll wait a little bit then turn off. That delay could be 5 minutes, it could be 30 minutes or hither, whatever Brammo's engineers settled on. The baseplate could be only 2 degrees above the setpoint, but it'll be on and will stay on for that hysteresis time. It doesn't mean anything is "cooking hot". If it was getting cooking hot, the charger would shut down. The fans overshoot to ensure that everything stays nice and cool.

And BTW, another tidbit to help settle your concerns: I know for a fact that the Sevcon controller and the Eltek charger both have an internal shutdown temperature. That means if some temperature gets too high, they'll shutdown and fault. They won't reset until either a power cycle, or until the temperature drops under that shutdown temperature. Its independent of the rest of the controls on the bike.

[kingcharles]

Hi Frodus, from the behaviour that I have noticed it seems to me that that fans are not controlled directly by the charger but by another element in the bike.

In some situations the fans will NOT shut down. Especially when a public L2 acts funny.
So whatever controls the fans needs optimization.
Also it would be nice if there would be some sort of speed control on the fans rather than full blast or off.
These fans are a possibility for Brammo to improve on.
I hope that a future firmware update will address this.
Thanks.

[Shinysideup]

I am NOT and EE. (Work in medicine). But it seems possible to me that part of the reason the fans could stay on is that the charger's base plate (aluminum) may be also picking up heat from the battery pack itself, which is a fairly large thermal mass and heats and cools much more slowly than the charger. On the other hand, my theory could be totally ignorant. In that case, just see my previous post about going for a ride!

[frodus]

You're right, apologies. The fans aren't controlled by the charger directly. I was trying to simplify a little as a "charger system". I'll rephrase. The Charger control system (Includes Charger, Fans, VCU, L2, etc) has (at the very least) a temp set-point and some hysteresis.

The charger is part of a larger system. It does not have built-in fans, those are Brammo-added parts. Brammo has a heat-sink and fans blowing across and they're controlled by the VCU of the bike. The VCU reads the temperature of the base-plate and turns on/off the fan accordingly. They obviously added in some hysteresis to keep the fans from going on/off/on/off at temperatures right near the setpoints.

I guess I'd be much more worried if the fans NEVER came on, rather than them being on when you wouldn't normally expect them to.

[Roland Stone]

frodus, - glad you're still here then........  Appreciate your attempt educating me.  Your "hysteresis" explanation  helps in understanding why, even were I able measuring the temperature at the base plate, the cooling fans might run beyond any specific programed temperature cutoff.  However since I can't measure the temperature, I see why it might seem to the layman the fans are "doing their own thing".  I can also see where getting into explaining the more technical of the electronics to the uninitiated can be a "sticky wicket". 

That said, - some elementary similar explanation of fan function and operation available in the Owners Manual or other would quiet the possibility of any owner concern when puzzling the fan operation on his/her new bikes.   

[MaxTemplar]

My fans are activated as soon as I connect the charger even if the air temperature and the engine temperature is between 7 and 10 ° C and the bike is stopped for several hours, then is cold.
--Today I saw that the fan starts only after several minutes that it is charging, if it is stopped for some time and the temperature is low, the fan will not start when I plug in the charger--

Fans stop at 100% charge or just unplug the charger even if it is past 1 hour from the beginning of the charge and is 80%.