Cleaned hv blower and battery. Battery temp now hotter

I removed hv battery blower for cleaning. blew out lint/dust/dirt with compressor keeping blower blades stationery (spinning blower with compressed air can burn it out). Then with prius half dissembled I decided to remove hv battery for cleaning (additional 6 hours).

Tested blower with a variable voltage bench power supply found that it puts out a couple of pounds of thrust at 12.6 volts and pulling 5.25 amps..Blower is labled 12vdc and clearly markes + and - terminals. Turning voltage down to about 3.75 volts pulling about 1 amp blower sounds about the same rpm's as its first prius selected cooling speed and blowing a nice amount of air (no more thrust).

Removed hv battery, removed battery cover, blew between battery modules with compressed air didn't see much if any dust..
Checked battery terminal nuts without torkwrench.. but applying about 3.5 pounds of (tightening) tork to all battery terminals about 12 of them turned 1/16 revolution all other terminal nuts were solid and didn't move at all.

Installed battery cover, installed battery. connected everything. Prius wouldn't ready because I didn't have service plug in the lock position (my first time removing and reinstalling service plug). drove car 5 or 6 miles with rear interrier pannels off to make sure everything was ok. Then reassembled entire rear of vechicle..

Drove prius about 20 miles only to see an increase of hv battery temperature.. Battery temp before cleaning with heavy regen and battery assist was 107 degrees (outside temp 73 degrees) now 116 degrees batt temp.

Dissembled rear of car the next day to check everything. I decided to jumper blowermotor directly to battery and discovered slight air leak between input air duct and output duct.. and discovered engineered leaks designed by toyota (3 cammel humps in base plate where battery cover attaches are engineered leaks only observable under high speed blower operation) .

I Moved battery carrier catch plate more toward passenger side and duct leak went away...I had previous reinstalled battery carrier catch plate more toward drivers side. The battery carrier catch plate is a thin sheet metal plate that clips to the hv battery vent tube and mounts between input and output ducts. With its bolts loose the carrier catch plate can move +or- 3/16 inch. Latter tear downs for increased battery temp indicate battery carrier catch plate hasn't much effect on battery cooling ?

Anyway reassembled everything I still feel hv battery temperature is higher than before.
I then found scanguage command to manually control hv battery blower..This alone should be discussed in a new thread.

Also of special mention; regen battery current used to peak at 92 amps. After tighting 12 of 56 battery connections regen peaks slightly over 100 amps, my scanguage displays erraticly after 99.9 amps. I see 97 amps with moderately hard braking as compared to before I would see 92 amps regen..

I don't believe this additional peak regen current is causing the higher battery temperatures i'm observing.
All the under torqued battery terminal nuts were on the driverside end of the battery module string.
Could this driverside end be subject to higher temperature deviations eventually loosening battery terminal nuts?

Another special note is the toyota hv battery service documentation shows all battery terminal nuts are not reuseable. And all high current carring connections it says to use new nuts..

I used the same nuts to reconnect orange high voltage high current cables to the hv battery...
I speculate now ; Are new nuts cleaner than old nuts.? are new nuts using self locking threads..?
Anybody used new nuts for the hv battery connections? are new nuts available at the dealer (I dought it) ?

Another notation; The gen I prius had tsb on hv battery bus replacement and + battery terminal sealant applicaton. I read the document for doing this it states wash all parts in boric acid mixture to eliminate corosion.. And wash hands thoughly before reassembly.. could I have inadvertantly contaminated by battery system terminal nuts with corosive electrolite acid leading to eventual connection failure ? (no battery leakage seen).

I dissembled and reassembled the rear interier of my prius (blower side only) about 4 or 5 times now (takes me only 1 hour per cycle including analysis).

I would recomend blowermotor cleaning but not to clean hv battery..
My blower had about 1/8 inch junk between fan blades my prius has 56000 miles 95% driven with windows up.

I believe I have affected air flow within the battery case somehow..
I will nodought be taking battery cover off in the near future to see what gives.

Also of special notation there is a green tape seal over the battery ecu lid that was cut on my system prior to my entry.
(I purchased the car from the dealer with only 8 miles on vechicle and nobody has ever touched my prius).

Also there is a missing nut on the lower right which holds battery assembly to battery base plate...I've seen about 3 pictures of gen II batteries on the internet now, all have the same missing nut.

Also I believe the engineered air leaks in the battery cover are so the driver can smell the batterys over heating which I've experienced in rentals and my own while decenting mountains...Running airconditioning on high with headlights and using brake mode seems to keep hv battery from overcharging and smelling while coasting down steep mountains..

I am keeping my hv batt cool with manual scanguage control.. whats bizzare is the more I cool the battery the harder the prius works the battery..

I've seen this bizare effect last summer when I put a foam pipe between passenger side air-conditioner vent and battery intake vent enabling cold air to be piped to the hv battery.. This also resulted in the prius working the battery harder. After hours of city driving battery got hot anyway due to the higher demand prius system placed on the hv battery.

It seems the intake thermister located about 4 inches from air intake duct above battery module 3 ? determins how hard to work/stress the hv battery...

Also I wouldn't recommend putting the hv blower in high speed modes without first cleaning junk/debris from blower. Because cloged blower could blow junk into battery cooling channels..

The first 3 speeds the prius automaticly selected are very slow compared to manual speeds 5 and 6.
I would guess the prius selected third speed to be under 1200 rpm but speed 5 & 6 8000-10000 rpm guess-timating would blow dirt and junk into battery box..

Also manual selection of blower speed with scanguage, I believe changes/interfeers with the prius selected speeds 1 & 2 to be much slower than normal...But I cannot prove this yet...
Many times I've seen system speeds 1 & 2 to be slower than manual selected scanguage speed number one..!!

I'm attaching a thermal evaluation none on the gen I hv battery that seem applicable for those with special hv battery interests.

As always please excuse spelling errors..

 

yes the rubber flap swings freely. But only on sg speed 1 not on prius speeds 1 or 2.

In fact there is a two by three inch hole in the bottom of the exhaust vent that exhausts onto the aux 12 volt battery. I cannot feel any air flow when I put my fingers into this hidden exhaust opening on prius blower speeds 1 and 2. I only feel air flow with scanguage speed 1 and above.
Could someone with virgin prius hv batt check for airflow in the hidden exhaust vent hole? The cargo carrier has to be removed for access.
Hv battery temp should be 105 for system speed .
The hv battery cools nicely while on the highway but not good while stopped.
If fact just after hiway drive exhaust duct is hot from doing its job. Duct is not even warm while stationary.

 

Britprius. teckstream/sgII blower speed 1 is slow but faster than prius system speeds 1 and 2.
My 12 volt battery is the toyota prius battery and not optima. I did intall the 12 battery myself but as I recall it fit snugly in the
battery pan.. and the exhaust ducts are screwed in place.. I'm reasonably certain all is installed correctly and that exhaust duct
has at least one inch clearance between battery. I will have to double check this clearance as your explanation seem likely.

EDtheFox. I can't be certain if the blower motor is brushless or brush type. A two wire brushless dc motor has transistors
and hall magnetic sensors to fire stator coils at the approriate time for armature rotation...Spinning a 2 wire brushless
motor that has internal transistorized stator coil control will damage its transistors especially if the blower gets spun
backwards which happens when cleaning with compressed air... Unsure if its brushless it's best not to spin it while cleaning..

I couldn't see what kind of bearing seal if any exists.. The squirel cage blower has a recessed bottom where the motor
was attached. Several write-ups suggest the motor speed control is using PWM (pulse width modulation) suggests also that
the hv blower motor would be brushless. I dont think It would be efficient to control a conventional comutator dc type motor
with PWM. And for longevity I would hope toyota choose brushless blower motor for this critical application.

I tore down prius again this week removing battery cover again, this time for a detailed inspection of air seals..
Prior to removing battery cover I devised an air pressure measurement test using a cessna aircraft altimeter..

The aircraft altimeter is completely sealed unit with a threaded hole in the back of it that senses air pressure.
I was able to attach hose between altimeter and battery case by removing one of the three nylon posts located on the top of hv battery
cover.
I measured about 60foot decrease in altitude (.06 inch mecury back pressure) with blower connected directly to 12 volt battery..
Compareing this to .77 inch of water (.056 inch mercury) specified in the lab tests done on gen-I battery (from My orignal attachment)).

Special note here; gen-I battery is cooled by blower sucking air through 38 batteries. @9.9 volts .056 inch hg
gen_II battery is cooled by blower blowing air through 28 batteries @12.9volts .060 inch hg (mine)

I don't have factory specifications for genII battery air flow/pressure.

prius gen 1 blower specifications
speed temp on temp off volts amps power scfm press drop
low 95.9 91.4 3.52 1.3250 15.90 15.9 .095h20 = .00477hg (Start/stop/amps/pwr good for genII)
med 106.7 104 6.5 2.7 17.55 32.6 .350h20 = .02571hg
high 122 118.4 9.9 4.9875 49.38 48.4 .770h20 = .05658hg

I believe genI and genII blower motors are identical because my genII blower showed the same currents at the voltages shown above.
I don't know if the squriel cage assemblies/cfm are the same for genI and genII.

My airflow inspection of the seal in the battery box didn't show anything obviously wrong.

The seal consists of about 1/4 inch by 1/4 inch single side adheasive foam strip thats stuck to the top part of the battery
cover and seals across the outside battery tops just above battery terminals. The same continous foam strip seals
against the top of the battery end clamps (sandwitch end brackets).

My final area of concern is the battery carrier catch plate that clips to hv battery vent tube and case between intake and exhaust
ducts. The prius service manual says this catch plate is to be installed prior to installing battery cover (not that obvious because
one would think the catch plate is part of the cover NOT).

This battery catch plate is very thin metal with four large nuts welded into it. Overtorqueing the associated large bolts
bends the battery catch plate. Mine didn't bend till about the fourth time torking and untorking/repositioning it
(actually bent untorking it).


This battery catch plate has two single sided adheasive foam strips one at each vertical end that are critical and not very obvious
how they seal.
I straighted MY catch plate perfectly (has structural creases for strength but still flimsy considering the large bolts
that attach it). I studied how the two foam strips on this battery catch plate seal for no less than 30 minutes before I figure
it out I THINK?

oK reassembled battery case, tested back pressure now I have even less pressure (failure?) .057hg was .06hg.
I did blow between battery modules with compressed air again, before assembly (maybe blew out more dust nothing obvious).

Test drove prius the battery seems slightly cooler even though I have less backpressure (more air leakage?).

Conclusion; There are many places where the air can leak (bypass battery cooling channels) within the battery assemply.
many of which will seal as fine particles of dirt/dust plugs the smaller gaps between battery module terminals.


Note; With 1 of the three nylon posts removed from the battery case top I can feel (with my cheek) a good amount of warm air
flowing from the hole with the slowest blower speed but nothing measurable with altimeter back pressure test.

Special Note;Hv battery always cools best when car is traveling 40mph and above. I'm begining to think the blower is continously
variable using PWM and possibly runs high speed concealed just below road noise (stealth mode).

The faster you drive the more road noise and easier to conceal High battery temperature/cooling noise?
I've pondered this stealth high speed blower theory for years but more so now! (nonconfirmed stealth mode)

Also of importance: the battery is more efficent at 105-110 degrees. Its temperature is a vital feedback component to its
charge/discharge closed loop system.
I've seen several pc posts "Why is my battery charging its allready at 7 green bars" ; System trying to heat up hv battery
to highest efficency ??
Switch blower to high speed (with sgII) system doubles the load on battery instantly.. put foam pipe between passenger air conditioner vent
and battery intake vent; system doubles the load on batterys instantly.. iNTAKE THERMISTER CONTROLS LOAD REGARDLESS OF EXISTING BATTERY TEMP.
IE; battery temp 116 degrees blower switched to high; instant 20 amp battery assist while allready going 50mph (provided 7 green bars soc).
IE; battery temp 116 degrees blower switched to high; regen jumps from 50 amps to 90 amps
IE; battery temp 116 degrees blower switched to high; charge current limit and discharge limit instantly goes to default (105, 125 amps).
Prius closed loop/feedback system will determine and manage bettery temp regardless.

This week I'm exploring 07e321cf 056116cf 3808 000100010000 (scan-guage-programming) I believe this is showing battery module balancing.
Readings 00EF indicate module pair (14) E is to high (F) followed by 00E0 = discharge the pair with possibly .350 amp. reading toggles
between read voltage EF and discharge it (E0, E1, E2, E3) E8 = no ballancing nessary..next DC = pair 13 high toggles between
DA and D3 , D3 is less load than D0, Next cell pair to balance cA THEN BA THEN AA counts backward...

NOT full CONFIRMED. I've measured my battery modules twice now all center modules exactly the same to two decimal
places ie 8.01 end modules can be .01-.02 higher or lower depending on air flow.. amazingly equal voltages...

I will post any significant progress in the future..Its been 5 days since doing the above and the battery is slightly cooler..