The 120 amps the system can generate is of concern. I did get 7 or so years out
of the original OEM battery. Maybe a hybrid system of two smaller batteries.
One lithium and one lead. In parallel. Maybe they would allow the best
qualities of each to shine. I have some small 16ah batteries that m
-Original Message-
From: EV On Behalf Of Lee Hart via EV
Sent: Thursday, 22 April 2021 6:46 am
To: George Tyler via EV
Cc: Lee Hart
Subject: Re: [EVDL] From my nissan leaf .com: Why the Leaf 12v system
undercharges the 12v battery.
George Tyler via EV wrote:
> An alternator is very
The Lexus also uses a smart-key, which is relatively high draw. Combine
this with a already worn and near end-of-life 12v battery, and it can
easily die in a week. In fact, the infrequent use is really hard on the
12v and is deep-cycling it which causes sulfation which further reduces
it's capac
Glenn Brooks via EV wrote:
Up until last year, my daughter had an older Lexus SUV hybrid... the
car stayed parked for weeks sometimes. When parked for a week, the
battery pack and the lead acid battery always went dead from some
mysterious, undetectable current draw.
Automakers usually size the
Willie via EV wrote:
Here is a relevant anecdote:
My 2013 Tesla S ran through 12v lead batteries at the rate of about one
every 12 months. That was of no great concern to me while the batteries
were under warranty. However, after the first three, that part of the
warranty expired and I boug
George Tyler via EV wrote:
An alternator is very different to a Dc-Dc converter in this respect. Modern
high frequency DC-DC conv. Have very small inductors storing very little
energy. An Alternator has a HUGE inductor storing a lot of energy, and this
is not on the output but in the control sid
Peri Hartman via EV wrote:
So, how can one explain the difference in drain ? How much telematics is
necessary while the car is parked and unused, it just seems horribly
excessive. But these designers aren't stupid, there must be a reasonable
explanation.
My impression is that automakers don't
seattle.org/ >>
-- Original Message --
From: "Lee Hart via EV"
To: "Peri Hartman via EV"
Cc: "Lee Hart"
Sent: 21-Apr-21 9:19:46 AM
Subject: Re: [EVDL] From my nissan leaf .com: Why the Leaf 12v system
undercharges the 12v battery.
Peri Hartman via E
Peri Hartman via EV wrote:
Add this to the puzzle.
My 2011 leaf is just shy of 10 years old. I'm still using the original
LA battery. The only thing I can think of that may be different for me
is that I never agreed to use nissan's carwings, which is some sort of
telematics... But, I'm bother
quot;Willie"
Sent: 21-Apr-21 3:41:01 AM
Subject: Re: [EVDL] From my nissan leaf .com: Why the Leaf 12v system
undercharges the 12v battery.
On 4/20/21 8:52 PM, Lee Hart via EV wrote:
I agree with -Phil-. I think lithium is the wrong choice for the 12v battery. It's
expensive,
On 4/20/21 8:52 PM, Lee Hart via EV wrote:
I agree with -Phil-. I think lithium is the wrong choice for the 12v
battery. It's expensive, offers no advantages, and "cures" a problem
that doesn't exist.
Here is a relevant anecdote:
My 2013 Tesla S ran through 12v lead batteries at the rat
! You
won't get much overshoot from the DC-Dc converter.
-Original Message-
From: EV On Behalf Of Lee Hart via EV
Sent: Wednesday, 21 April 2021 5:32 pm
To: Robert Bruninga via EV
Cc: Lee Hart
Subject: Re: [EVDL] From my nissan leaf .com: Why the Leaf 12v system
undercharges the 12v ba
x.com; Electric Vehicle Discussion List
Cc: Glenn Brooks
Subject: Re: [EVDL] From my nissan leaf .com: Why the Leaf 12v system
undercharges the 12v battery.
Hmm, Phil’s comment about battery drain is very interesting. Up until last
year, My daughter had an older Lexus SUV hybrid . She worked i
Robert Bruninga via EV wrote:
what is the "load dump" problem?
In automotive parlance, the dreaded "load dump" occurs when the
alternator (or DC/DC) is charging at a high rate, and something causes a
sudden drop in load current. It could be a loose or corroded battery
cable, or a cracked or
Load dump is when an inductive load in the vehicle is switched off, or in
some cases, regenerates power back into the 12v bus. There are tons of
inductive loads in modern vehicles that can cause this. Many are damped
with freewheeling diodes, but not all. The 12v lead-acid battery acts like
a bi
ation
> >> for
> >> a lead acid may be way off. How about a supercap "battery", much less
> >> critical. Seeing that we don't notice the leaf battery losing capacity
> >> until
> >> it's dead, maybe we don't actually need much capa
It appears that Lawrence has already made up his mind, so in a few years'
time we can ask him how that Leaf 12v lithium retrofit worked out.
In the meantime, other folks here now have good, useful information and
advice from two knowledgeable and experienced engineers and EV builders, Lee
and
what is the "load dump" problem?
Bob
On Tue, Apr 20, 2021 at 11:04 PM (-Phil-) via EV wrote:
>
> I have definitely seen failures of the DC-DC (PCS) in Tesla Model 3's from
> people installing aftermarket Lithiums. The load dump problem is real! I
> have one sitting here that I did an autopsy o
t;> critical. Seeing that we don't notice the leaf battery losing capacity
>> until
>> it's dead, maybe we don't actually need much capacity?
>> GWT
>>
>> -----Original Message-
>> From: EV On Behalf Of Lee Hart via EV
>> Sent: Wed
until
> it's dead, maybe we don't actually need much capacity?
> GWT
>
> -Original Message-
> From: EV On Behalf Of Lee Hart via EV
> Sent: Wednesday, 21 April 2021 2:14 pm
> To: Lawrence Rhodes via EV
> Cc: Lee Hart
> Subject: Re: [EVDL] From my niss
I won’t jump into a technical argument about the suitability of one battery
type over another for a particular application, but it never hurts to think
about the environment when making decisions. I’ve several several years working
with communities poisoned by emissions from battery processing f
we don't notice the leaf battery losing capacity until
it's dead, maybe we don't actually need much capacity?
GWT
-Original Message-
From: EV On Behalf Of Lee Hart via EV
Sent: Wednesday, 21 April 2021 2:14 pm
To: Lawrence Rhodes via EV
Cc: Lee Hart
Subject: Re: [EVDL] From my
I have definitely seen failures of the DC-DC (PCS) in Tesla Model 3's from
people installing aftermarket Lithiums. The load dump problem is real! I
have one sitting here that I did an autopsy of. (Blown FETs on the primary
side, that then took out the HV feed into the PCS)
A PCS failure in the
Lawrence Rhodes via EV wrote:
https://mynissanleaf.com/viewtopic.php?t=22752 According to these guys a lead
battery is not what a Leaf needs. Seems a lithium of some sort would do great.
Another site said the DC/DC converter can put out as much as 120amps. The
brakes and other systems that run
My Valence 40ah battery which cost 100 dollars used after being recycled from a
medical cart was always in balance...however it was $1,200 MSRP new. so you get
what you pay for. I may try to find another of those as the 40 ah more closely
matches the Leaf lead capacity. Lawrence
On Tuesda
Lawrence Rhodes via EV wrote:
I live in San Francisco so freezing isn't an issue. It seems your findings
differ from the Leaf forum.
Keep in mind that opinions are not facts. You can get any answer you
want online.
Do you have a Leaf? Measure the 12v battery voltage yourself.
I have a 2013
I have 2 weeks of voltage and current datalogs taken at 1 second
intervals. The absorption phase seems adequate if you drive it enough. If
you aren't driving far or often, add a tender. Mine had the integrated
solar panel, but didn't work because it was parked inside. I sold the Leaf
in 2014 an
I live in San Francisco so freezing isn't an issue. It seems your findings
differ from the Leaf forum. They seem to think the lead battery is constantly
undercharged so lithium would fair better since the battey's BMS will balance
the battery constantly resulting in longer life even at 80% SOC.
I owned a 2011 Leaf and my tests showed that it did a proper 3-stage
temperature-compensated charge.
The reason the 12v battery doesn't last as long as many would expect is the
rather high quiescent loads from the Telematics system. This is the same
problem in many EVs today.
I think I've discus
https://mynissanleaf.com/viewtopic.php?t=22752 According to these guys a lead
battery is not what a Leaf needs. Seems a lithium of some sort would do great.
Another site said the DC/DC converter can put out as much as 120amps. The
brakes and other systems that run on the 12v system might need a
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