Re: batteries & hypermiling
- View SourceMark,
my 97 coming off the charger.
156V nominal pack will be at about 160V+
econ 65 amps
normal 115 amps
power 195 amps (if the batteries are capable, which they won't be for long)
driving on a level surface the amp draw at a steady speed is amazingly close to the speed in mph.
Hypermiling the Force will not make as big a difference as it can in the insight as the vehicle is already much more efficient but you can certainly maximize it if you drive that way most of the time. Stay in econ and a lot of coasting.
I would put in a light lithium pack before lead if doing a full swap. A 70 AH CALB 52 cell pack would handle most conservative driving. Find a higher C rate cell and smaller would work. The way I use my car most of the time I could likely operate it on 40 AH CALB's but would like a bit higher capacity for a more conservative drain, when climbing hills and freeway travel. And better long term value.
Tough decision. Don't have your salted road issue
What happened to the Insight?
--- In firstname.lastname@example.org, "m_sev@..." <m_sev@...> wrote:
> Thank you all for the input. I can see that it is between gel and lithium, with their relative pricetag and performance.
> For me it is partly a question of how long the car holds up with salty NE roads and what I expect to be modest usage from someone versed in getting 70mpg from an original Honda insight and biking.
> Can anyone comment on typical current draw (144 or 156v) vs speed when using a 'hypermiling' driving style? Delicate driving makes a huge difference in the Insight, and I would think it also would in an EV.
> ---------- Original Message ----------
> From: Tom Hudson <tdhudson@...>
> To: email@example.com
> Subject: Re: [solectria_ev] AGM batteries
> Date: Tue, 28 Feb 2012 10:05:26 -0600
> Great analysis, Don.
> I have to confirm the comments on AGMs -- I have a set of Interstate AGMs that went into
> my E-10 about 4 years ago and they're already pretty much done. And we don't use that
> truck very hard -- usually pretty short trips. I have to wonder if there is something
> about the two strings of batteries in there (originally it had three strings of smaller
> lead-acids) that just isn't a good thing in general, because no matter what batteries we
> put in the truck, they do not last very long. At any rate, it's massively disappointing.
> At some point I need to replace the truck batteries, but have to really think about what
> to do because they run two motors on the thing and the current loads on a single string
> would be too much -- I wonder if it would make sense to split the system into two separate
> strings, with one per motor. The biggest complication would be charging, I think. Of
> course, a BMS might address everything, if each battery is charged individually -- I have
> a set of the PowerCheq equalizers on there, but I don't think they really helped that much.
> On 2/28/2012 2:20 AM, theoldcars@... wrote:
> > One of the better AGM batteries for EV loads is the Odyssey. A Universal
> > Battery would be an inferior EV battery and would become a disappointing
> > experiment. One that keeps getting revisited because of the low initial cost.
> > Your right there is not much data published by battery manufacturers that
> > would apply to EV use. Its not because they don't know, its because lead and
> > most other batteries do not hold up well to EV type loads. If they did
> > these same manufacturers would be very proud of that information and you would
> > have no problem finding it.
> > However there is a larger problem with all AGM batteries. They are a great
> > challenge to keep in balance and because of this if used in series they
> > have a very high failure rate.
> > All this has been proven out all ready by the OEMs, Solectria and by many
> > EV drivers.
> > Solectria picked the Gel battery because they stay in balance so well they
> > don't require a BMS only a slight over charge. As it turned out even with
> > the a very high end BMS the OEMs never could reach the rated cycle life of
> > AGM batteries.
> > As far as lead batteries the best way to go in the Solectria is the Gel.
> > Solectria did their research well if there would have been a better option
> > at the time they would have used a different battery.
> > Well that was a long time ago and now there are better options. The lead
> > chemistry has not had any major improvements. What has happened though is the
> > price of lead acid batteries has gone up substantially. Six years ago
> > there was no good options or ones that made economic sense. Lead always has
> > been a marginal battery for EV use and in fact made the cost of running an EV
> > more expensive then an ICE. The only exception has been maybe the Solectria
> > if driven under the best conditions in a lower mile use. There are a
> > hundred good reasons why we need to stop using oil but its also wise not to
> > waste your money.
> > If you factor in the real amp hour rating of a lead battery under EV type
> > loads it usually half its capacity or less. In a one hundred Ah lead
> > battery capacity is usually a 5 amp load for 20 hours. Some manufacturers in the
> > past have even use a 100 hour load of 1 amp. There are two problems here
> > for EV drivers. One is you only really have maybe 40 Ah and this is when
> > their new. The other is taking the manufacturers rated cycle life and expecting
> > to get the same results with EV loads. If a low cost AGM battery
> > manufacturer claims 600 cycles you most likely would be lucky to reach two or three
> > hundred cycles before they require replacement. Some have done far less then
> > two hundred cycles.
> > So if your looking around at replacement options and relative value. You
> > need to factor in what your results really are in an EV, and how long the
> > dollars spent most likely will last. Also the limitations of using the lead
> > chemistry.
> > For long term use with lead you should not discharge less then 50 percent
> > on a daily basis. When new if you figure a 40 Ah 100% discharge at EV
> > loads. 50% would be 20 Ah or about a 20 mile round trip. Hills, high speeds,
> > carrying more weight then the driver or the worst high speeds on hills your
> > results will be far less range before hitting a 50% SOC. Also as the pack
> > ages your no longer going to have 40 Ah to draw on. The 40 Ah amount is when
> > new so this will drop as the cycle life is used up. So there will be a point
> > where trips over ten miles one way start to degrade the pack at an
> > accelerated rate.
> > While writing this I thought I would give it another try to find some data
> > on the Deka 8G27 _http://www.mkbattery.com/images/8G27-DEKA.pdf_
> > (http://www.mkbattery.com/images/8G27-DEKA.pdf) Here you can see the cycle life on
> > the Deka 8G27 is 600 cycles at 80% DOD and this is with a two hour rate.
> > They don't provide the load but what ever it is they are allowing two hours
> > so its not an EV type load. I would guess the load is around 20 amps. So
> > unless you only drive 20 miles an hour or less and don't carry any passengers
> > or take on hills you might drive for two hours with 32 miles of range and
> > this would be with 80% DOD and by Deka give you a 600 cycle life.
> > Here is another link from Deka with basic information on Gel and AGM
> > batteries
> > _http://www.dekabatteries.com/assets/base/0139.pdf_
> > (http://www.dekabatteries.com/assets/base/0139.pdf)
> > I believe a pack of 13 Deka 8G27 is going to run around 2600 and for long
> > life a 50% DOD is recommended by Deka. If you manage to reach 20,000 miles
> > your cost per mile is 13 cents.
> > Compare this to the CALB which is what the group buy is on.
> > A 60 Ah cell from CALB which capacity is really 66Ah is sold by dealers as
> > low as 1.25 per Ah or 75 dollars a cell. If you use 52 cells your cost for
> > a pack would be 3900 dollars.
> > Cycle life on the CALB with 80% DOD is 2000 cycles however this is with an
> > 18 amp load see link.
> > _http://www.calibpower.com/ProductDetails.aspx?p=2&id=2_
> > <http://www.calibpower.com/ProductDetails.aspx?p=2&id=2_>
> > (http://www.calibpower.com/ProductDetails.aspx?p=2&id=2
> > <http://www.calibpower.com/ProductDetails.aspx?p=2&id=2>)
> > Like any battery if you stay out of the lower half of the SOC it will last
> > a lot longer. Another big factor is if you reduce your load and losing
> > weight does just that. With losing 500 pounds your range would go up with and
> > your load would be less. So your 30 Ah capacity at 50% DOD with LifePo4 is
> > going to take you a lot farther then 30 Ah lead pack which in a hour would
> > be getting closer to 100% DOD
> > I have not found much data showing cycle life on CALB with EV type loads.
> > However here they are showing a 100 Ah cell cycled at 30 amps to 0% SOC for
> > 500 cycles and it still had over 100 Ah of capacity.
> > _http://jackrickard.blogspot.com/2010/06/life-in-lifepo4-cycle-life-and.html_
> > (http://jackrickard.blogspot.com/2010/06/life-in-lifepo4-cycle-life-and.html)
> > Once you have driven a LifePo4 EV you will never want to go back to lead.
> > Don
> > In a message dated 2/27/2012 5:43:00 P.M. Pacific Standard Time,
> > m_sev@... <mailto:m_sev%40juno.com> writes:
> > I've been looking around at battery replacement options, and am
> > considering AGMs. Has anyone used 'Universal Battery' products vs MK/Deka to comment
> > on relative value? Specifically UB12750 vs MK 8A24.
> > I don't find much in the way of specs to describe the differences, so
> > aside from faith and price, don't have much to go on.
> > Thanks,
> > Mark
> > [Non-text portions of this message have been removed]
> Thomas Hudson
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