Yes, no posts for a long time. Why's that? Because everything JUST WORKS!
We're just at 10K miles and there's really nothing to report. I plug it in 2 or 3 nights per week and just drive it. Our poor Prius now only gets used once, maybe twice a month when we need a longer trip.
It did just fine in all the snow last winter. The heat doesn't bother it. It's carted back 600 lbs. of pavers and potting soil from the home center a couple times no problem.
Basically "No trouble at all" makes for a boring blog. Sorry'bout that ;-)
OK, actually there is one thing. A 'known issue' with one of the sensor boards causes the airbag warning light to come on. It will still work, but it's irritating.
I'm trying to get the dealer to actually have the part(s) I need in hand before I go down there since it takes 4 hours to charge before I can come back and I don't want to do that twice. Whaa whaaa, first world problems...
Sunday, August 3, 2014
Saturday, June 14, 2014
2014's are here! and $Cheap$
[Edit: Mar.2015: End of year deals on 2014's have pushed after tax credit prices in some markets below $10K. Buying a used one could be stupid with these prices for New]
There was no 2013 iMiev in the US since 2012 stock was still getting sold off.
However the 2014's have just shown up at our local dealer and they've done some NICE things!
They now all have 50% faster charging cords that they come with so you don't have to pay to have it upgraded somewhere else like I did. They all have high speed CHAdeMo charge ports and both front seats have heaters. Everything else pretty much just worked so they didn't mess with it. Smart!
-AND- they dropped the price.
Basically you can get the upgraded vehicle for around $15.5K after tax considerations.
Sure I paid more like $14K but that was 'special incentives' for things that had been sitting on the lot for a year.
Anyway. Great stuff, highly recommended. Mine is running great here on it's first anniversary.
There was no 2013 iMiev in the US since 2012 stock was still getting sold off.
However the 2014's have just shown up at our local dealer and they've done some NICE things!
They now all have 50% faster charging cords that they come with so you don't have to pay to have it upgraded somewhere else like I did. They all have high speed CHAdeMo charge ports and both front seats have heaters. Everything else pretty much just worked so they didn't mess with it. Smart!
-AND- they dropped the price.
Basically you can get the upgraded vehicle for around $15.5K after tax considerations.
Sure I paid more like $14K but that was 'special incentives' for things that had been sitting on the lot for a year.
Anyway. Great stuff, highly recommended. Mine is running great here on it's first anniversary.
Wednesday, November 27, 2013
Kickstart me!
Update! It supposedly shipped on Wed.
We'll see. Hopefully here in time for the EV club meeting.
This looked interesting so I jumped in during the initial campaign.
EMW Juicebox on Kickstarter
Where else are you gonna get a 15KW capable Level2 EVSE for $99?
OK so the J1772 cord and connector are $130 extra. Still not too bad.
The premium version with Time-Of-Use control looks nice but it wasn't
worth the extra $100 for my uses.
Edit: 08/21/13
Guess I'm in line to get one. The 'production' versions are starting
to ship out. Even got a picture:
We'll see. Hopefully here in time for the EV club meeting.
This looked interesting so I jumped in during the initial campaign.
EMW Juicebox on Kickstarter
Where else are you gonna get a 15KW capable Level2 EVSE for $99?
OK so the J1772 cord and connector are $130 extra. Still not too bad.
The premium version with Time-Of-Use control looks nice but it wasn't
worth the extra $100 for my uses.
Edit: 08/21/13
Guess I'm in line to get one. The 'production' versions are starting
to ship out. Even got a picture:
Monday, August 12, 2013
ASalt and Battery: Long
Or, talking your battery wisdom with a grain of salt:
There is a LOT of information out there about the care and feeding of Lithium Battery packs. Much of it has some grain of truth contained within. How do you separate all of that out into a 'Best Practices' to maximize battery life and performance for your particular use pattern with your particular MiEV in your climate. It's a deep subject, so put on those hip waders.
There are at least four major types of batteries that are referred to a 'Lithium' and several chemistry/materials/build-process variations within each of those. So, if someone starts talking about what "All Lithium Batteries Do" you can start ignoring them now. Each type/sub-type is optimized for particular tasks, cost and service life. Lithium Traction Batteries (for car use) are sufficiently similar that some generalizations can be made. Almost any 'rule' applied absolutely will either damage the battery life or the usability of the product. This is a game of weighed tradeoffs.
First, remain calm. The Yuasa/Mitsubishi engineers seem to have done a pretty darn good job of constraining the operation of this LiMn based battery pack in useful, well thought out ways. For the most part you really can let the system operate itself, which, coming from the old DIY days where you had to watch everything all the time is an enormous relief. There are of course exceptional circumstances that generate exceptional exceptions.
What do we know? Some of it's really good stuff:
The MiEV system seems to do a good job of preventing overcharge (arguably one of the top killers of this battery type) both by having a per-cell tracking system and by limiting the maximum voltage per cell to a number well below (3.96V?) the Max charged spec for these cells (around 4.1v +/- temp.correction)
Granted that leaves roughly 4-6% of the potential usable energy storage untapped, but that's probably a VERY good tradeoff for overall battery life.
It also appears to do a good job of limiting the maximum discharge. I don't know the exact numbers, but it appears that the system hits 'Turtle Mode' where it begins to limit the available maximum current at somewhere around 15-20% charge and cuts it off entirely around 5% below that. Actually I suspect it limits current so that the lowest cell doesn't go below their selected 'Min' Voltage number as that's generally the best way to prevent cell damage.
All of the above requires that the pack stay in good balance. As a long serial string of batteries goes up and down the charge discharge cycle(s) together, each cell will act very slightly differently than the others. Cells that are warmer toward the middle of the pack or colder toward the edges, cells with slightly different variations within the manufacturing tolerances, maybe variations in the battery monitoring boards themselves, all can conspire to cause a particular cell to drift off from the average over time. Since the MaxV/cell the MinV/cell and the maximum current that can be drawn from the string are all limited by whichever cell has drifted off the most in a given measure, it's obviously very important that they behave as much alike as possible.
As the first cells reach full charge during the charging cycle, the battery board signals the charger to cut back on the charge current. The battery boards start to bypass current from the highest cells burning off the excess current with an onboard (per cell) resistor to keep the maximum voltage on that cell under control. This is called top balancing. It keeps doing this until all the cells have reached the correct voltage or a timeout occurs, which appears to be about an hour. Over time and a number of cycles this allows all the cells to reach the same charge state, and tends to keep them there.
Lets look at that for a moment. People who have seen and reported about the on-battery-board per-cell resistors make me doubt that they can dissipate any more than 5W and probably less. At somewhere around 4V/cell that translates into roughly one amp. We know the balance time is limited to around one hour. Therefore the maximum variation between cells that can be corrected by the balancing system is around 1Ah. Since the nominal capacity of each cell is around 50Ah the balancing system can handle variations of around 2% per charge cycle. I'm sure that's plenty enough to handle the day-to-day variation, but is probably woefully inadequate for people who are 'saving' their batteries by never (or only very rarely) reaching full charge. Granted that doing a full charge a couple times a day could reduce battery life by some amount, especially if it's allowed to sit (or run) at high temperatures on a regular basis.
How do we know for sure? We don't really. My personal guesses cause me to make sure I reach full charge/full balancing cycle about once every couple weeks. I might back off that a bit if I was living in the Arizona summer and the car was going to sit out in the sun for hours after reaching full charge. [ie: I only do the full balance thing when the car is relatively cool] Since cell-to-cell variations tend to increase as the cells age, generally speaking I'd be inclined to balance more often as the car gets older.
We also know the getting the pack down to two 'bars' on the full-O-meter occasionally allows the battery management system (BMS) to reset/revise some of it's capacity assumptions. So letting it get down there once a month or so (depending on usage patterns) is probably a good idea.
Q: Doesn't restricting the depth of cycling improve the cycle-life of the pack?
A: Sure it does. Say you keep it between 6 bars on the low end and 13 on the high end. Wow, you might get 5000(!) cycles out of it. Of course you're only getting about 30 miles/charge, but still, 30x5000? that is 150,000 miles. Pretty good eh?
Imagine some other slob who charges all the way almost every time and runs it down to 2-3 bars... What a sap, maybe only gets *half* as many cycles out of his pack. Huh, that's 60-65 miles/charge and 2500 cycles. Darn, that sucker only got 150K miles out of it... ;-)
Now granted maybe the more careful user would be getting even more cycles out of it or the other even less, at this point we just don't know. The numbers are semi-informed speculation. The slob definately had the easier time of it though and got to drive a bunch further per charge.
Accelleration kills batteries. Kills'em dead! ...or maybe not.
Again the Mitsu engineers have made some pretty good tradeoffs. It appears those cells can probably stand short term surges up to 10C (about 500 amps) without much problem. They seem to have crafted the acceleration profile so it doesn't surge much beyond the 150A (3C) maximum continuous limit. How do we know it limits to 150A? We don't exactly, but that Amp-meter on the dash appears reasonably linear (especially in the plus direction) and if you have been in an EV that has a motor current meter, you'd be pretty sure this is battery amps that's shown.
Granted keeping it pegged at 150A (Max on that 'power' instrument's scale) for long periods probably isn't good for it, especially if it's unusually hot or unusually cold (below freezing) or the charge state is low (below 4 bars) but accelerating briefly near the top of that meter probably isn't causing much harm. I try not to do that every time, or keep it above 100A for any extended period. Besides it DOES seem to kill the range!
So what do we know again?
Don't go pegging the power meter for extended periods, especially if v.hot, v.cold or v.low.
Don't let the batteries sit at full charge if it's real hot or for extended periods of time (I show 6-8 bars if I'm gonna leave it for a week, might go lower if I was going to leave for longer and I don't charge to full if it's over 100F)
Don't run it hard if it's extra cold out (wwwweeell below 30F)
Don't run it down below 2 bars on a regular basis.
Don't be topping it off all the way several times a day if you can avoid it.
Do let it go through a full cycle occasionally. Twice a month? Once a month? Something like that.
...it's not all that hard...
There is a LOT of information out there about the care and feeding of Lithium Battery packs. Much of it has some grain of truth contained within. How do you separate all of that out into a 'Best Practices' to maximize battery life and performance for your particular use pattern with your particular MiEV in your climate. It's a deep subject, so put on those hip waders.
There are at least four major types of batteries that are referred to a 'Lithium' and several chemistry/materials/build-process variations within each of those. So, if someone starts talking about what "All Lithium Batteries Do" you can start ignoring them now. Each type/sub-type is optimized for particular tasks, cost and service life. Lithium Traction Batteries (for car use) are sufficiently similar that some generalizations can be made. Almost any 'rule' applied absolutely will either damage the battery life or the usability of the product. This is a game of weighed tradeoffs.
First, remain calm. The Yuasa/Mitsubishi engineers seem to have done a pretty darn good job of constraining the operation of this LiMn based battery pack in useful, well thought out ways. For the most part you really can let the system operate itself, which, coming from the old DIY days where you had to watch everything all the time is an enormous relief. There are of course exceptional circumstances that generate exceptional exceptions.
What do we know? Some of it's really good stuff:
The MiEV system seems to do a good job of preventing overcharge (arguably one of the top killers of this battery type) both by having a per-cell tracking system and by limiting the maximum voltage per cell to a number well below (3.96V?) the Max charged spec for these cells (around 4.1v +/- temp.correction)
Granted that leaves roughly 4-6% of the potential usable energy storage untapped, but that's probably a VERY good tradeoff for overall battery life.
It also appears to do a good job of limiting the maximum discharge. I don't know the exact numbers, but it appears that the system hits 'Turtle Mode' where it begins to limit the available maximum current at somewhere around 15-20% charge and cuts it off entirely around 5% below that. Actually I suspect it limits current so that the lowest cell doesn't go below their selected 'Min' Voltage number as that's generally the best way to prevent cell damage.
All of the above requires that the pack stay in good balance. As a long serial string of batteries goes up and down the charge discharge cycle(s) together, each cell will act very slightly differently than the others. Cells that are warmer toward the middle of the pack or colder toward the edges, cells with slightly different variations within the manufacturing tolerances, maybe variations in the battery monitoring boards themselves, all can conspire to cause a particular cell to drift off from the average over time. Since the MaxV/cell the MinV/cell and the maximum current that can be drawn from the string are all limited by whichever cell has drifted off the most in a given measure, it's obviously very important that they behave as much alike as possible.
As the first cells reach full charge during the charging cycle, the battery board signals the charger to cut back on the charge current. The battery boards start to bypass current from the highest cells burning off the excess current with an onboard (per cell) resistor to keep the maximum voltage on that cell under control. This is called top balancing. It keeps doing this until all the cells have reached the correct voltage or a timeout occurs, which appears to be about an hour. Over time and a number of cycles this allows all the cells to reach the same charge state, and tends to keep them there.
Lets look at that for a moment. People who have seen and reported about the on-battery-board per-cell resistors make me doubt that they can dissipate any more than 5W and probably less. At somewhere around 4V/cell that translates into roughly one amp. We know the balance time is limited to around one hour. Therefore the maximum variation between cells that can be corrected by the balancing system is around 1Ah. Since the nominal capacity of each cell is around 50Ah the balancing system can handle variations of around 2% per charge cycle. I'm sure that's plenty enough to handle the day-to-day variation, but is probably woefully inadequate for people who are 'saving' their batteries by never (or only very rarely) reaching full charge. Granted that doing a full charge a couple times a day could reduce battery life by some amount, especially if it's allowed to sit (or run) at high temperatures on a regular basis.
How do we know for sure? We don't really. My personal guesses cause me to make sure I reach full charge/full balancing cycle about once every couple weeks. I might back off that a bit if I was living in the Arizona summer and the car was going to sit out in the sun for hours after reaching full charge. [ie: I only do the full balance thing when the car is relatively cool] Since cell-to-cell variations tend to increase as the cells age, generally speaking I'd be inclined to balance more often as the car gets older.
We also know the getting the pack down to two 'bars' on the full-O-meter occasionally allows the battery management system (BMS) to reset/revise some of it's capacity assumptions. So letting it get down there once a month or so (depending on usage patterns) is probably a good idea.
Q: Doesn't restricting the depth of cycling improve the cycle-life of the pack?
A: Sure it does. Say you keep it between 6 bars on the low end and 13 on the high end. Wow, you might get 5000(!) cycles out of it. Of course you're only getting about 30 miles/charge, but still, 30x5000? that is 150,000 miles. Pretty good eh?
Imagine some other slob who charges all the way almost every time and runs it down to 2-3 bars... What a sap, maybe only gets *half* as many cycles out of his pack. Huh, that's 60-65 miles/charge and 2500 cycles. Darn, that sucker only got 150K miles out of it... ;-)
Now granted maybe the more careful user would be getting even more cycles out of it or the other even less, at this point we just don't know. The numbers are semi-informed speculation. The slob definately had the easier time of it though and got to drive a bunch further per charge.
Accelleration kills batteries. Kills'em dead! ...or maybe not.
Again the Mitsu engineers have made some pretty good tradeoffs. It appears those cells can probably stand short term surges up to 10C (about 500 amps) without much problem. They seem to have crafted the acceleration profile so it doesn't surge much beyond the 150A (3C) maximum continuous limit. How do we know it limits to 150A? We don't exactly, but that Amp-meter on the dash appears reasonably linear (especially in the plus direction) and if you have been in an EV that has a motor current meter, you'd be pretty sure this is battery amps that's shown.
Granted keeping it pegged at 150A (Max on that 'power' instrument's scale) for long periods probably isn't good for it, especially if it's unusually hot or unusually cold (below freezing) or the charge state is low (below 4 bars) but accelerating briefly near the top of that meter probably isn't causing much harm. I try not to do that every time, or keep it above 100A for any extended period. Besides it DOES seem to kill the range!
So what do we know again?
Don't go pegging the power meter for extended periods, especially if v.hot, v.cold or v.low.
Don't let the batteries sit at full charge if it's real hot or for extended periods of time (I show 6-8 bars if I'm gonna leave it for a week, might go lower if I was going to leave for longer and I don't charge to full if it's over 100F)
Don't run it hard if it's extra cold out (wwwweeell below 30F)
Don't run it down below 2 bars on a regular basis.
Don't be topping it off all the way several times a day if you can avoid it.
Do let it go through a full cycle occasionally. Twice a month? Once a month? Something like that.
...it's not all that hard...
Monday, August 5, 2013
Going Coastal
We had to go over to the coast to do some work on a house. Being a crazy person I'm like "Lets take the electric car!" Between PlugShare (PlugShare totally rocks!) and google maps we got it all verified that it was at least possible...and off we went (after a full charge of course)
We needed to get to Yachats and while that's 'only' 75 miles away, there is the coastal mountain range in-between, so we planned a little stop on the way (sometimes known as 'dinner') so we wouldn't have to drive slow.
The Newport OR. AV charging station is in a city lot about a block east of the main downtown traffic light at Hurbert & 101. Our 15 min. of sun for the day.
Like most of the AV chargers we met, this one took SEVERAL tries before it would charge. The indicator lights on this one showed 'car connected' before we plugged in. No 'master reset' was required though.
We ate an the Newport Steak & Seafood place about 7 blocks south. Best $8 steak dinner ever.
NOT a fancy place, though clean enough.
It took '12 bars' to travel the 45+ miles there and then two hours charge during dinner got us more than enough to make it the 25 miles to Yachats. We actually did our charging at a house, (using a 'Y' cable that allows 240V charging from a pair of 120V outlets. Yes, it's possible...) but here below is the car at the Yachats Commons charging station. (which actually WORKED! Of course it was the one we didn't really need...)
This farmers market happens Sundays just over from the charging station in Yachats.
You could do worse for a pass-time...
After a good overnight charge we headed down 25 miles to Florence where the Three Rivers Casino has an AV charging station. On this one we had to call to get it reset out of a persistent Error state.
However, once charging we got to relax with free drinks at the casino. In fact they give you $10 of 'free play' there for first-timers and we left with $15 more than we came in with. Casinos aren't my thing, but we had a pretty good time.
By doing the trip as a loop we got to check out several more charge locations. The excitement never stops.
Then there was the 45 miles to Veneta. we used 12 bars on this part of the trip. We needed about another two hours charge to make it the 40 miles home. There's not a lot to do in Veneta. Some fast food resturants... Fortunately the charging station (1.5 blocks south of the main intersection on Territorial Hiway) came with a cute attendant. [OK, not really. it was reset city here again as it would stop charge after 5 min. intermittently]
Q: How come there's all the boring pictures of the car sitting at another boring charging station?
A: Well, because sitting at a charging station is boring. We're trying to illustrate that fact. If you're going to use your EV for actual travel, get one with LOTS of range or a quick charging port. This isn't that car. Just my $0.02
...now if it had about another 8 miles of range, so we could consistently 'make it' using the shorter route from Corvallis to Yachats then it would be a different story. Turning an 80 min. trip into a 240 min. trip isn't viable most times. Plus, it's not like driving the Prius is exactly a hardship... ;-)
[Edits: 2014] AeroVironment (the AV on the chargers above) is out of it's federal/state grant period and they're now 'charging' $7.50 per charge. That would have added $30 to the cost of our little trip and there's no way I would have done it like that. $0.10/mi+ on top of the other time and cost issues makes it less than viable. Granted, if you're doing it every day then their $20 monthly subscription makes good sense. Of course that doesn't cover the BLink and SEMA charge 'networks'... It would sure be nice if a single 'network' subscription would work all over. I'm guessing that's not going to happen anytime soon. In some areas you need to be a member of four different networks to get consistent charging everywhere.]
We needed to get to Yachats and while that's 'only' 75 miles away, there is the coastal mountain range in-between, so we planned a little stop on the way (sometimes known as 'dinner') so we wouldn't have to drive slow.
Like most of the AV chargers we met, this one took SEVERAL tries before it would charge. The indicator lights on this one showed 'car connected' before we plugged in. No 'master reset' was required though.
We ate an the Newport Steak & Seafood place about 7 blocks south. Best $8 steak dinner ever.
NOT a fancy place, though clean enough.
It took '12 bars' to travel the 45+ miles there and then two hours charge during dinner got us more than enough to make it the 25 miles to Yachats. We actually did our charging at a house, (using a 'Y' cable that allows 240V charging from a pair of 120V outlets. Yes, it's possible...) but here below is the car at the Yachats Commons charging station. (which actually WORKED! Of course it was the one we didn't really need...)
You could do worse for a pass-time...
We would love to show you lots of pretty pictures of the coast. However it's the Oregon Coast! so fog and occasional showers ruled. ...at least until we started to leave then of course it was fabulous!
After a good overnight charge we headed down 25 miles to Florence where the Three Rivers Casino has an AV charging station. On this one we had to call to get it reset out of a persistent Error state.However, once charging we got to relax with free drinks at the casino. In fact they give you $10 of 'free play' there for first-timers and we left with $15 more than we came in with. Casinos aren't my thing, but we had a pretty good time.
By doing the trip as a loop we got to check out several more charge locations. The excitement never stops.
Then there was the 45 miles to Veneta. we used 12 bars on this part of the trip. We needed about another two hours charge to make it the 40 miles home. There's not a lot to do in Veneta. Some fast food resturants... Fortunately the charging station (1.5 blocks south of the main intersection on Territorial Hiway) came with a cute attendant. [OK, not really. it was reset city here again as it would stop charge after 5 min. intermittently]
Q: How come there's all the boring pictures of the car sitting at another boring charging station?
A: Well, because sitting at a charging station is boring. We're trying to illustrate that fact. If you're going to use your EV for actual travel, get one with LOTS of range or a quick charging port. This isn't that car. Just my $0.02
...now if it had about another 8 miles of range, so we could consistently 'make it' using the shorter route from Corvallis to Yachats then it would be a different story. Turning an 80 min. trip into a 240 min. trip isn't viable most times. Plus, it's not like driving the Prius is exactly a hardship... ;-)
[Edits: 2014] AeroVironment (the AV on the chargers above) is out of it's federal/state grant period and they're now 'charging' $7.50 per charge. That would have added $30 to the cost of our little trip and there's no way I would have done it like that. $0.10/mi+ on top of the other time and cost issues makes it less than viable. Granted, if you're doing it every day then their $20 monthly subscription makes good sense. Of course that doesn't cover the BLink and SEMA charge 'networks'... It would sure be nice if a single 'network' subscription would work all over. I'm guessing that's not going to happen anytime soon. In some areas you need to be a member of four different networks to get consistent charging everywhere.]
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