Charging: how frequently, if daily distance is very short?

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Charging: how frequently, if daily distance is very short?

Darin -@- ForkenSwift.com
Hi all -

[Had a look in the library & archive, but didn't find the answer I'm looking for.  Sorry if it's been dealt with before (a list with this much history, I'm pretty sure it HAS ...)]

Background: We were lucky enough to pick up a used set of batteries for the ForkenSwift last Hallowe'en that I figure have roughly half the capacity of new.  Score!  Driven conservatively in warm weather, they're delivering 30 km (~20 mi.) comfortably.  I've gone as far as 43 km on a charge, but that was pushing things (just to see what was possible).  To me, 30 km is fanatastic; so I want to be as nice as possible and preserve them as best I can.

Question: How often should the car be put on the charger (48 volt Delta-Q QuiQ smart 3-stage) if it is only driven a fraction of its usable range in a typical day?

Examples: Sometimes the car may go 6-8 km (~4-5 mi.) after a fresh charge, then not be used again for the better part of a week.  Other times it may be used, say 6-8 km a day on 3 or 4 consecutive days.

I know batteries will suffer sulfation if left sitting partially discharged.  Maybe I'm mistaken, but I also understand it may be hard on them to subject them to a full charge cycle when they've only been lightly discharged.

Is there a rule of thumb for when I should plug in?  Is "partial charging" ever recommended?

thanks for any advice-
Darin

http://www.ForkenSwift.com
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Re: Charging: how frequently, if daily distance is very short?

Lee Hart
Darin at- forkenswift.com wrote:
> How often should the car be put on the charger (48 volt Delta-Q
> QuiQ smart 3-stage) if it is only driven a fraction of its usable
> range in a typical day?

With your flooded batteries, I'd aim to recharge them when they are
about half discharged, or if you expect it to sit for more than a week.
--
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

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Re: Charging: how frequently, if daily distance is very short?

Roland Wiench
In reply to this post by Darin -@- ForkenSwift.com
Here is how I been charging my batteries for the last 8 years and still
going.  If I remove 3 AH then I charge at 3 amps until I put in 3.03 AH or
about 10 percent more in than I take out for about a hour before I leave the
next day. If I remove 10 AH and then will charge 7 amps for about a hour
that same day and then again 3 amps for a hour before I leave and etc.

Charging at 10 AH or less, the batteries will reach 100 SOC, but will not
reach the normal maximum charge voltage.  It takes at least 15 amp charge to
get them to 7.5 volts per 6 volt battery.  So at least once a weak after I
finish charge, I turn up the current to get them to 7.5 volts for only about
5 minutes.

I find if I full charge the batteries the day before, the voltage will float
down to 6.4 volts and if I leave just after I charge the batteries, the
battery voltage will be at 6.9 volts.

This difference if AH usage for the first mile is 3.1 AH at 6.4 volts and
2.8 AH at 6.9 volts.

Roland




----- Original Message -----
From: "Darin at- forkenswift.com" <[hidden email]>
To: <[hidden email]>
Sent: Sunday, June 07, 2009 7:07 PM
Subject: [EVDL] Charging: how frequently, if daily distance is very short?


>
> Hi all -
>
> [Had a look in the library & archive, but didn't find the answer I'm
> looking
> for.  Sorry if it's been dealt with before (a list with this much history,
> I'm pretty sure it HAS ...)]
>
> Background: We were lucky enough to pick up a used set of batteries for
> the
> ForkenSwift last Hallowe'en that I figure have roughly half the capacity
> of
> new.  Score!  Driven conservatively in warm weather, they're delivering 30
> km (~20 mi.) comfortably.  I've gone as far as 43 km on a charge, but that
> was pushing things (just to see what was possible).  To me, 30 km is
> fanatastic; so I want to be as nice as possible and preserve them as best
> I
> can.
>
> Question: How often should the car be put on the charger (48 volt Delta-Q
> QuiQ smart 3-stage) if it is only driven a fraction of its usable range in
> a
> typical day?
>
> Examples: Sometimes the car may go 6-8 km (~4-5 mi.) after a fresh charge,
> then not be used again for the better part of a week.  Other times it may
> be
> used, say 6-8 km a day on 3 or 4 consecutive days.
>
> I know batteries will suffer sulfation if left sitting partially
> discharged.
> Maybe I'm mistaken, but I also understand it may be hard on them to
> subject
> them to a full charge cycle when they've only been lightly discharged.
>
> Is there a rule of thumb for when I should plug in?  Is "partial charging"
> ever recommended?
>
> thanks for any advice-
> Darin
>
> http://www.ForkenSwift.com
> --
> View this message in context:
> http://www.nabble.com/Charging%3A-how-frequently%2C-if-daily-distance-is-very-short--tp23917318p23917318.html
> Sent from the Electric Vehicle Discussion List mailing list archive at
> Nabble.com.
>
> _______________________________________________
> General EVDL support: http://evdl.org/help/
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>
>

_______________________________________________
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Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
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Re: Charging: how frequently, if daily distance is very short?

Darin -@- ForkenSwift.com
Roland: my charger is fully automatic (smart charger, dumb EV owner?!) so I won't be able to fine tune things the way you can.  Though it does seem to make sense to plan charging so it is finished just before you're ready to use the vehicle, and the batteries are at their perky best.

And I really ought to get a hydrometer (a *better* hydrometer I should say - the first one I got was junk) so I can get a better picture of just what kinds of distances are getting the batteries to what S.O.C. so I can follow Lee's advice of topping up when the car gets to about 50%.

thank you for the info, guys.

Darin

http://www.forkenswift.com
48 volt / 400 amp beer budget Geo Metro