How long is too long?

[Peter VanDerWal]

Too long is usually measured in months, not hours.

You're fine.

>
> So, if allowing a partially discharged battery to sit too long is damaging
> because the battery builds up sulfate on it's plates, how long is too
> long?
>
> For example, I'm using sixteen 8 volt flooded batteries. My new commute
> has my driving 6 gentle miles one way, (resting voltage of about 137v)
> parking for 12 hours, then returning home, over a route that is 6-9 gentle
> miles depending on which way I choose to drive for 12-15 miles round trip.
> I plug in immediately upon returning to home in the evening.
>
> Is 12 hours too long? Am I risking permenant sulfation?
>
> On my last pack, I was driving 15, harder discharging miles one way, but I
> was charging up immediately upon arrival at my destination, and then
> charging immediately upon returning home.
> ________________________________
>
> Rich A.
> Maryland
> http://www.austinev.org/evalbum/371.html
> http://patriotfuel.blogspot.com/
>
>
>
>
> _________________________________________________________________
> Stay in touch when you're away with Windows Live Messenger.
> http://www.windowslive.com/messenger/overview.html?ocid=TXT_TAGLM_WL_Refresh_messenger_052008
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Richard Acuti]

So, if allowing a partially discharged battery to sit too long is damaging because the battery builds up sulfate on it's plates, how long is too long?

For example, I'm using sixteen 8 volt flooded batteries. My new commute has my driving 6 gentle miles one way, (resting voltage of about 137v) parking for 12 hours, then returning home, over a route that is 6-9 gentle miles depending on which way I choose to drive for 12-15 miles round trip. I plug in immediately upon returning to home in the evening.

Is 12 hours too long? Am I risking permenant sulfation?

On my last pack, I was driving 15, harder discharging miles one way, but I was charging up immediately upon arrival at my destination, and then charging immediately upon returning home.
________________________________

Rich A.
Maryland
http://www.austinev.org/evalbum/371.html
http://patriotfuel.blogspot.com/




_________________________________________________________________
Stay in touch when you're away with Windows Live Messenger.
http://www.windowslive.com/messenger/overview.html?ocid=TXT_TAGLM_WL_Refresh_messenger_052008

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Roland Wiench]

If you are discharge down to 50% DOD it is advise to charge it as soon as
possible.  If down to 30% DOD you can wait 12 hours or to the next day.

If I am only to 10 to 20% DOD, and still at that level for days, I will
normally charge every 4 days at that rate.

You can charge every time you want, no matter what the DOD is.  My method
for charging if I only use 5 ah out of the battery then charge at 5 amp. If
you use 10 ah, then 10 amps  or 20 ah, then 20 amps and etc.

Remember at this low usage of ah, you are normally in the finish charging
cycle, so do not apply the normal maximum charge your battery charger can
attain.

Anytime I charge the battery with only 5 to 20 ah use, I only charge it to
the maximum voltage then shut down the charger.  For my 6 volt batteries
that when the battery gets to 7.4 volt.  This may between 95 to 98% SOC.

About once a week, I may applied a finish charge to bring them up to 100% if
I have any battery more than 0.02 volts out of balance otherwise I will
applied the finish charge about once a month after I water them and do a
equalization charge of 7.78 volts per 6 volt battery.

Roland


----- Original Message -----
From: "Richard Acuti" <dmc650@...>
To: <ev@...>
Sent: Tuesday, May 13, 2008 8:33 AM
Subject: [EVDL] How long is too long?

>
> So, if allowing a partially discharged battery to sit too long is damaging
> because the battery builds up sulfate on it's plates, how long is too
> long?
>
> For example, I'm using sixteen 8 volt flooded batteries. My new commute
> has my driving 6 gentle miles one way, (resting voltage of about 137v)
> parking for 12 hours, then returning home, over a route that is 6-9 gentle
> miles depending on which way I choose to drive for 12-15 miles round trip.
> I plug in immediately upon returning to home in the evening.
>
> Is 12 hours too long? Am I risking permenant sulfation?
>
> On my last pack, I was driving 15, harder discharging miles one way, but I
> was charging up immediately upon arrival at my destination, and then
> charging immediately upon returning home.
> ________________________________
>
> Rich A.
> Maryland
> http://www.austinev.org/evalbum/371.html
> http://patriotfuel.blogspot.com/
>
>
>
>
> _________________________________________________________________
> Stay in touch when you're away with Windows Live Messenger.
> http://www.windowslive.com/messenger/overview.html?ocid=TXT_TAGLM_WL_Refresh_messenger_052008
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Bill Dube]

Sulfation is kind of like plaque on your teeth. If you remove it just
as it is forming, it doesn't harden and become very difficult, if not
impossible, to remove.

As the sulfation ages, it "hardens" and becomes increasingly
difficult to remove. Thus, letting lead-acid batteries sit, partially
discharged, is unwise.

Removing aged hardened sulfation requires some serious voltage and
current during the finish charge. You basically have to "hammer" it
off. Doing so is tough on the grids and the paste itself. Folks claim
success with the pulse type de-sulfators, and I suspect that they
work to a degree, but why not simply charge the batteries up every
couple of months and avoid the problem?

Bill Dube'
At 10:33 AM 5/13/2008, you wrote:

>So, if allowing a partially discharged battery to sit too long is
>damaging because the battery builds up sulfate on it's plates, how
>long is too long?
>
>For example, I'm using sixteen 8 volt flooded batteries. My new
>commute has my driving 6 gentle miles one way, (resting voltage of
>about 137v) parking for 12 hours, then returning home, over a route
>that is 6-9 gentle miles depending on which way I choose to drive
>for 12-15 miles round trip. I plug in immediately upon returning to
>home in the evening.
>
>Is 12 hours too long? Am I risking permenant sulfation?
>
>On my last pack, I was driving 15, harder discharging miles one way,
>but I was charging up immediately upon arrival at my destination,
>and then charging immediately upon returning home.
>________________________________
>
>Rich A.
>Maryland
>http://www.austinev.org/evalbum/371.html
>http://patriotfuel.blogspot.com/
>
>
>
>
>_________________________________________________________________
>Stay in touch when you're away with Windows Live Messenger.
>http://www.windowslive.com/messenger/overview.html?ocid=TXT_TAGLM_WL_Refresh_messenger_052008
>
>_______________________________________________
>For subscription options, see
>http://lists.sjsu.edu/mailman/listinfo/ev

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Roger Stockton]

Richard Acuti wrote:

> So, if allowing a partially discharged battery to sit too
> long is damaging because the battery builds up sulfate on
> it's plates, how long is too long?

The deeper discharged the battery is, the sooner you should recharge it.

> For example, I'm using sixteen 8 volt flooded batteries. My
> new commute has my driving 6 gentle miles one way, (resting
> voltage of about 137v) parking for 12 hours, then returning
> home, over a route that is 6-9 gentle miles depending on
> which way I choose to drive for 12-15 miles round trip. I
> plug in immediately upon returning to home in the evening.

I wouldn't think that 6mi from a roughly 13kWh pack should represent much DOD at all; I'm going to WAG it at perhaps 10-15%DOD.  I think that not only is it safe to hold off charging until after the return trip, but that you might even get better life this way than if you charged fully at each end.

While the battery company charts predict exponentially longer cycle life as DOD decreases, the wear and tear on the batteries due to fully charging after each very shallow discharge could greatly reduce the actual cycle life.

Cheers,

Roger.

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Peter VanDerWal]

It probably would keep ift from sulfating, but the constant charging while
sitting for several months will likely boil off a significant quantity of
electrolyte.
If you cook off enough you'll expose the plates which is probably worse
than simple sulfation.

>      Well, here's a dumb question:
>      I understand that using a photovoltaic array on your car's roof
> wouldn't provide enough power to charge a traction pack in reasonable
> time, but could it provide enough of a "trickle" charge while parked
> to prevent this sulfation and extend the battery's life? If not, can
> someone explain why not?
>
> On Tue, May 13, 2008 at 8:48 AM, Bill Dube <billdube@...>
> wrote:
>> Sulfation is kind of like plaque on your teeth. If you remove it just
>> as it is forming, it doesn't harden and become very difficult, if not
>> impossible, to remove.
>>
>> As the sulfation ages, it "hardens" and becomes increasingly
>> difficult to remove. Thus, letting lead-acid batteries sit, partially
>> discharged, is unwise.
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Andrew Kane-2]

     Well, here's a dumb question:
     I understand that using a photovoltaic array on your car's roof
wouldn't provide enough power to charge a traction pack in reasonable
time, but could it provide enough of a "trickle" charge while parked
to prevent this sulfation and extend the battery's life? If not, can
someone explain why not?

On Tue, May 13, 2008 at 8:48 AM, Bill Dube <billdube@...> wrote:
> Sulfation is kind of like plaque on your teeth. If you remove it just
> as it is forming, it doesn't harden and become very difficult, if not
> impossible, to remove.
>
> As the sulfation ages, it "hardens" and becomes increasingly
> difficult to remove. Thus, letting lead-acid batteries sit, partially
> discharged, is unwise.

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Zeke Yewdall]

For vehicle that are parked for month at a time without being used, yes.  I
have little tiny PV's (2 to 10 watts) on several of my ICE vehicles that
don't get used frequently and might go two or three months without being
started.

Z

On Wed, May 14, 2008 at 9:56 PM, Andrew Kane <googoleyes@...> wrote:

>     Well, here's a dumb question:
>     I understand that using a photovoltaic array on your car's roof
> wouldn't provide enough power to charge a traction pack in reasonable
> time, but could it provide enough of a "trickle" charge while parked
> to prevent this sulfation and extend the battery's life? If not, can
> someone explain why not?
>
> On Tue, May 13, 2008 at 8:48 AM, Bill Dube <billdube@...>
> wrote:
> > Sulfation is kind of like plaque on your teeth. If you remove it just
> > as it is forming, it doesn't harden and become very difficult, if not
> > impossible, to remove.
> >
> > As the sulfation ages, it "hardens" and becomes increasingly
> > difficult to remove. Thus, letting lead-acid batteries sit, partially
> > discharged, is unwise.
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Andrew Kane-2]

     Hi Zeke, do you mean that yes, the PV arrays are preventing
sulfation in your case, or that you are receiving a significant charge
on the traction pack from them when sitting for months at a time?

On Wed, May 14, 2008 at 9:04 PM, Zeke Yewdall <zyewdall@...> wrote:
> For vehicle that are parked for month at a time without being used, yes.  I
> have little tiny PV's (2 to 10 watts) on several of my ICE vehicles that
> don't get used frequently and might go two or three months without being
> started.

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Zeke Yewdall]

Well.... ICE's don't have traction packs... and my EV is one of the
batteryless types... (and no coupler between the motor and transmission
either...    just a pile of unassembled parts so far... a different ice
issue... :)  but on the ICE's the PV's are preventing sulfation (or just
dead batteries) by preventing the starter batteries from slowly going dead
due to self discharge (or phantom loads) over several months.

On Wed, May 14, 2008 at 10:24 PM, Andrew Kane <googoleyes@...> wrote:

>     Hi Zeke, do you mean that yes, the PV arrays are preventing
> sulfation in your case, or that you are receiving a significant charge
> on the traction pack from them when sitting for months at a time?
>
> On Wed, May 14, 2008 at 9:04 PM, Zeke Yewdall <zyewdall@...> wrote:
> > For vehicle that are parked for month at a time without being used, yes.
>  I
> > have little tiny PV's (2 to 10 watts) on several of my ICE vehicles that
> > don't get used frequently and might go two or three months without being
> > started.
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Andrew Kane-2]

     Cool- thanks for the clarification.

     P.S. I got all excited when I read


>... and my EV is one of the
> batteryless types...

Until I got to
>   just a pile of unassembled parts so far...

     Sorry I misunderstood your original post, in which you clearly
indicated you were talking about ICE vehicles. My bad!

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[lyle]

Some military vehicles and generators used to use a photovoltaic array that went to dc-dc trickle charger for flooded batteries and they did require weekly to monthly maintenance to ensure the electrolyte did not boil off.  But now, most military units are gravitating to gel cell so they disconnect the photocells.  This is primarily due to the cheap dc-dc chargers were found to be draining the gel cell batts (at night).


--- On Wed, 5/14/08, Peter VanDerWal <evdl@...> wrote:

> From: Peter VanDerWal <evdl@...>
> Subject: Re: [EVDL] How long is too long?
> To: "Electric Vehicle Discussion List" <ev@...>
> Date: Wednesday, May 14, 2008, 5:56 PM
> It probably would keep ift from sulfating, but the constant
> charging while
> sitting for several months will likely boil off a
> significant quantity of
> electrolyte.
> If you cook off enough you'll expose the plates which
> is probably worse
> than simple sulfation.
>
> >      Well, here's a dumb question:
> >      I understand that using a photovoltaic array on
> your car's roof
> > wouldn't provide enough power to charge a traction
> pack in reasonable
> > time, but could it provide enough of a
> "trickle" charge while parked
> > to prevent this sulfation and extend the battery's
> life? If not, can
> > someone explain why not?
> >
> > On Tue, May 13, 2008 at 8:48 AM, Bill Dube
> <billdube@...>
> > wrote:
> >> Sulfation is kind of like plaque on your teeth. If
> you remove it just
> >> as it is forming, it doesn't harden and become
> very difficult, if not
> >> impossible, to remove.
> >>
> >> As the sulfation ages, it "hardens" and
> becomes increasingly
> >> difficult to remove. Thus, letting lead-acid
> batteries sit, partially
> >> discharged, is unwise.
> >
> > _______________________________________________
> > For subscription options, see
> > http://lists.sjsu.edu/mailman/listinfo/ev
> >
>
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev

     

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[joe-22]

Actually, I have acouple of these also, and I've found that even with two of
them in parallel, they won't boil off the electrolyte on anything larger
than a small lawn equipment battery. But they DO keep a battery from
discharging, as well or better than a wall-wart maint. charger does.

Joseph H. Strubhar

Web: www.gremcoinc.com

E-mail: joe@...

----- Original Message -----
From: "Peter VanDerWal" <evdl@...>
To: "Electric Vehicle Discussion List" <ev@...>
Sent: Wednesday, May 14, 2008 2:56 PM
Subject: Re: [EVDL] How long is too long?

> It probably would keep ift from sulfating, but the constant charging while
> sitting for several months will likely boil off a significant quantity of
> electrolyte.
> If you cook off enough you'll expose the plates which is probably worse
> than simple sulfation.
>
>>      Well, here's a dumb question:
>>      I understand that using a photovoltaic array on your car's roof
>> wouldn't provide enough power to charge a traction pack in reasonable
>> time, but could it provide enough of a "trickle" charge while parked
>> to prevent this sulfation and extend the battery's life? If not, can
>> someone explain why not?
>>
>> On Tue, May 13, 2008 at 8:48 AM, Bill Dube <billdube@...>
>> wrote:
>>> Sulfation is kind of like plaque on your teeth. If you remove it just
>>> as it is forming, it doesn't harden and become very difficult, if not
>>> impossible, to remove.
>>>
>>> As the sulfation ages, it "hardens" and becomes increasingly
>>> difficult to remove. Thus, letting lead-acid batteries sit, partially
>>> discharged, is unwise.
>>
>> _______________________________________________
>> For subscription options, see
>> http://lists.sjsu.edu/mailman/listinfo/ev
>>
>
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>
>
> --
> No virus found in this incoming message.
> Checked by AVG.
> Version: 7.5.524 / Virus Database: 269.23.16/1432 - Release Date:
> 5/14/2008 7:49 AM
>
>

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Zeke Yewdall]

Of course you should use a charge controller to prevent this... but that
increases the cost for a decent three stage one with absorb and float stages
to reduce electrolyte usage, and that doesn't have a parasitic load at
night.

Z

On Wed, May 14, 2008 at 3:56 PM, Peter VanDerWal <evdl@...> wrote:

> It probably would keep ift from sulfating, but the constant charging while
> sitting for several months will likely boil off a significant quantity of
> electrolyte.
> If you cook off enough you'll expose the plates which is probably worse
> than simple sulfation.
>
> >      Well, here's a dumb question:
> >      I understand that using a photovoltaic array on your car's roof
> > wouldn't provide enough power to charge a traction pack in reasonable
> > time, but could it provide enough of a "trickle" charge while parked
> > to prevent this sulfation and extend the battery's life? If not, can
> > someone explain why not?
> >
> > On Tue, May 13, 2008 at 8:48 AM, Bill Dube <billdube@...>
> > wrote:
> >> Sulfation is kind of like plaque on your teeth. If you remove it just
> >> as it is forming, it doesn't harden and become very difficult, if not
> >> impossible, to remove.
> >>
> >> As the sulfation ages, it "hardens" and becomes increasingly
> >> difficult to remove. Thus, letting lead-acid batteries sit, partially
> >> discharged, is unwise.
> >
> > _______________________________________________
> > For subscription options, see
> > http://lists.sjsu.edu/mailman/listinfo/ev
> >
>
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Roland Wiench]

A trickle charge is about 7.01 volts per 6 volt battery.  This keeps a low
simmer on the battery and is normally use at the end of charge for a certain
amount of time after the finishing charge cycle.

It is best to applied not more the 6.78 volts per 6 volt battery.  This is
call the maintaining charge.  I got my battery maintainer from a battery
shop a long time ago, before it was in common use.  I think some stores may
carry them now.

I install one on my 73 ICE that was in storage since 73.  I use a maintainer
on a 12V DIE HARD Marine battery.  I could still crank, crank, crank it over
in 2005 when I sold it.

Roland

> >      Well, here's a dumb question:
> >      I understand that using a photovoltaic array on your car's roof
> > wouldn't provide enough power to charge a traction pack in reasonable
> > time, but could it provide enough of a "trickle" charge while parked
> > to prevent this sulfation and extend the battery's life? If not, can
> > someone explain why not?
> >
> > On Tue, May 13, 2008 at 8:48 AM, Bill Dube <billdube@...>
> > wrote:
> >> Sulfation is kind of like plaque on your teeth. If you remove it just
> >> as it is forming, it doesn't harden and become very difficult, if not
> >> impossible, to remove.
> >>
> >> As the sulfation ages, it "hardens" and becomes increasingly
> >> difficult to remove. Thus, letting lead-acid batteries sit, partially
> >> discharged, is unwise.
> >
> > _______________________________________________
> > For subscription options, see
> > http://lists.sjsu.edu/mailman/listinfo/ev
> >
>
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[Lee Hart]

Andrew Kane wrote:
>      Well, here's a dumb question:
>      I understand that using a photovoltaic array on your car's roof
> wouldn't provide enough power to charge a traction pack in reasonable
> time, but could it provide enough of a "trickle" charge while parked
> to prevent this sulfation and extend the battery's life? If not, can
> someone explain why not?

Yes; that it could do. A typical lead-acid battery will self-discharge
in about a year (though it varies dramatically with temperature and type
of battery). A relatively small solar panel (about the same size as the
top of the battery) can keep up with the self discharge rate, and so
keep it fully charged.

Most cars have lots of parasitic loads that draw current all the time.
The newer the car, the worse this problem has become. They have so many
computers and other always-on electronics that it's now common for a new
car on the dealer's lot to drain its battery in less than a month. It
takes a much larger panel to compensate for this -- a square foot or
more per battery.

EVs have lots of batteries, but may or may not have any large parasitic
loads on them. If your DC/DC converter is left on all the time, it may
draw enough current to discharge the pack in a few months. Or, you may
have instrumentation like an E-meter that draws enough current to matter.

Your solar panel can easily keep just the batteries charged; but it may
not be able to keep up with the parasitic loads.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in    --    Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

[EVDL Administrator]

On 14 May 2008 at 20:56, Andrew Kane wrote:

> I understand that using a photovoltaic array on your car's roof
> wouldn't provide enough power to charge a traction pack in reasonable
> time, but could it provide enough of a "trickle" charge while parked
> to prevent this sulfation and extend the battery's life?

I'm not an engineer or electrochemist, but everything I've read suggests
that it's a good idea to start charging a battery as soon as possible after
it's been discharged.  

However, some batteries, notably Hawkers, need or at least want an initial
high current charge.  That's not in the cards with this scheme.  Unless you
were to charge up an ultracap and hit the battery with a BIG initial (but
short) zap.  Hmmmmm.  Somebody tell me I'm wrong.

David Roden - Akron, Ohio, USA
EVDL Administrator

= = = = = = = = = = = = = = = = = = = = = = = = = = = = =
EVDL Information: http://www.evdl.org/help/
= = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Note: mail sent to "evpost" or "etpost" addresses will not
reach me.  To send a private message, please obtain my
email address from the webpage http://www.evdl.org/help/ .
= = = = = = = = = = = = = = = = = = = = = = = = = = = = =


_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev