107 MPG (2.2L per 100km)

hi all.

im still on the second tank fillup since getting my plug in up and running.
was getting good numbers this tank averaging 2.3L / 100km.

tonight when i got home from work, and i checked the consumption screen, i was somewhat shocked to see 2.2L / 100km ! that's 106.9MPG US (over 647KM and just over 1/3 of the tank) 3 pips have disappeared from full.



to say im happy is the greatest understatement i have ever made

conditions have been all city, between 50 and 70kmh, some small hills (as is evidenced by the regen)
temperatures here are in the mid 20's (c) to low 30's. daily commute is 38km round trip to work and back.

i don't think it can get better than this (MPG wise) so i thought i would post this washed out phone picture now. i was planning to do this at the fill up point in about 3 more weeks.

the first bar on the MFD at the 30 minute mark shows where i started a cold engine and left work.
so you can see the entire commute (one way, work to home). the car had been parked in the lot at work for 9 hrs before i left. im using about 3.5kwh per day from the wall.

i am kind of curious as to what MPG / L/100km other plug in users are seeing ?

Jason.

 

i actually brought the car a few months ago, with the kit already installed, but the batteries were toast.
so i embarked on a mission to restore the plug in system, using better quality batteries and BMS / charger.

these kits (or a better version of them) are still available.
search for mdtech phev kit. the system i have installed in my car started life as a 4kwh enginer plug in kit.
the mdtech ones are supposedly much better than the original enginer ones, though i have no personal experience with them.

i got the replacement parts to fix my system from ev-power in western australia.

depending on where abouts you are located, you are welcome to look at my car (im in western sydney)
though you won't be able to see as much as is in my thread on the rebuild and the video there too.

the related thread is here.... Enginer PHEV kit Rebuilt with quality components and new batteries | PriusChat

Jason.

 

yeah, i think i will be able to get 6 weeks of commuting to work and back and other neighborhood trips before i have to fill up again.

im now at 750km on this tank and still averaging 2.2L / 100km.
still 2 pips above half showing on the fuel gauge too

most days i consume about 3.7kwh from the wall and i have about 25% remaining on the SOC meter (for the plug in system) so allowing for some losses due to efficiency of chargers etc, i assume im using about 3kwh per day give or take.
my charger is a 2.5kw, 25A unit, so i can fully charge in around 3.5 hrs.

my economy has improved markedly since i learned some of the secrets of the G2 Prius....
like how it seems counter intuitive to wait until the engine cuts out before driving off from a cold start...
if i wait till it cuts, and the coolant temp is around 48c, i get WAY better economy in the first 5 minute segment, than if i just drive off straight after starting up.

add to that im not in a big a rush to get anyplace anymore at my age, im slowing down (my young hoon days are LONG past ), so im happy to sit a few km under the limit and just use warp stealth mode more often.

jason.

 

my mistake, the charger is rated at 1.5kw... 25A.

even at 1.5KW charge, it's still less than 1C charge rate. the cells i have can handle 1C rates on charge.
and 2C continuous discharge, with peaks of around 6C on the discharge.

in my system, i have about 1C max discharge rate and roughly 0.3C charge rate.
because the cells are arranged in a 2P16S string, i have 80ah per cell group, so at 25A charge rate, it takes about 3.5hrs for a full charge. as i am well within the limits set by the cell manufacturer, i should have a nice long life from them.

the cells have a 36 month warranty, and are rated to 2000 cycles to 80% and 3000 cycles to 70%.
most days im around 70% when i recharge, so in theory, i should see somewhere around 10 years from this pack.
that's longer than i think i will own this car...

Jason

 

thanks.

the system has been flawless so far.
i have over 120 cycles on the pack now. the BMS and cell modules have been perfectly accurate too.
the BMS i used was purchased from EV power in western Australia and is the one here..

Battery Control Unit for 4-20 cell (12-60V) systems - EV Power BMS Control Units - Battery Management

cell modules were also purchased from the same vendor here.
CM60

charger was again from ev power and can be found here.
TCCH-16C-25A 48V - Chargers T Series 1.5kW PFC LiFePO4 - Chargers

the small items like wiring and other bits and pieces were purchased through a local electronics retailer.

one thing i would do a little differently if i were doing this now.
when i ordered the BMS system, i wasn't exactly sure how we would interface it with the existing DC-DC converter.
i had (wrongly) assumed that the easiest way would be to have the BMS cut the main pack from the DC-DC on the input side. so i ordered the BMS with a ginormous relay (about as big as a clenched fist).

as it turned out, it was far simpler to use a very small micro relay to switch the 2 pin wire on the DC-DC.
and leave the DC-DC connected full time to the pack. with the system off there is always some load on the pack, but it's so marginal that you could leave it connected for years and not notice the drain.

with this knowledge, i would have asked Rod at EV-Power to make the BMS slightly differently, and saved myself a bunch of time and money.

i have only had the LVC trip 2 times on me. once when i had the tunes blasting and didn't notice the red light (or hear the alarm beeping) and once when testing to make sure that it would do as it was supposed to.

on both those occasions, the pack took about 4.8kwh to charge back up. so allowing for losses in charging efficiency, this seems about right. of note is that these cells are rated at 40AH, but many claim that they get closer to 44-45AH before LVC.

i don't regret doing this for one second. if i could have afforded to i would have liked to install 90AH cells instead of the 40AH ones, but at the time i couldn't and the truth is that the 40AH / 4Kwh gets me to and from work with around 30% soc remaining most days.

hope this info is somewhat helpful.
Jason.

 

The cell modules are needed for correct operation of the BMS. Without them, the BMS has no way to know if one cell goes high or low.

Also. Yes they only bleed off 800ma each, but by the time they would start to turn on, then charger has ramped back the current as the pack would be nearing full.

So the 800ma each is more than sufficient.
800ma x 16 would be 12.8A total if all of them were turned on.

Without the cell modules, the BMS would only be able to see pack voltage. And not cell protection.

Jason.