FWIW:

I monitor the use of the batteries with my PIC-based amp-hour meter.
Before I installed my solar panel, I could go for about 3 days before
the batteries got to 50%. The AH meter in fact flashes a red led to make
it obvious when the remaining capacity goes below 50%.  But if I
happened to be away from charging capability for longer, I know that I
can go lower without killing the battery.

L'd love to use traction batteries, but they are too big for the space I
have.

Now that I have the solar panel (13 amps in full sun - 70 amp-hours
typically will go into the battery on a good day if the battery is low),
I rarely go below 20%.


--=20
Larry Bradley =20
Orleans (Ottawa) Canada=20

On Mon, 2014-02-10 at 16:17 +0000, Jim Higgins KB3PU wrote:

> Yes, mostly.  But that wasn't the point.  The point was that shallower de=
pth=20
> of discharge results in much longer life.  That is true regardless of bat=
tery=20
> design.  What you're reminding me of is that golf car batteries are desig=
ned=20
> to last much longer when run to 90% DoD than an automotive battery is.  A=
nd=20
> I'll mention that fork lift batteries will last much longer than golf car=
=20
> battteries when run to 90% DoD.  But neither were the point being discuss=
ed=20
> at the time.  All last much much longer if not discharged so deeply.
>=20
> JimH
>=20
>=20
>=20
> Received from Richard R. Pope at 02/10/2014 07:15 UTC:
>=20
> >Jim,
> >      Golf cart batteries are designed to be discharged as much as 90% o=
f=20
> > their rated capacity. That is why they are called deep discharge batter=
ies.=20
> > It is automotive batteries that are not designed to be deeply discharge=
d. A=20
> > golf cart battery is designed to deliver a relatively steady voltage fo=
r a=20
> > long period of time. An automotive battery is designed to deliver a lot=
 of=20
> > current for a short period of time and then to be quickly recharged. If=
 you=20
> > try to deep discharge an automotive battery you will ruin it in short=20
> > order. A golf cart battery is recharged over a long time period. If you=
 try=20
> > to quick charge it, it will over heat and the plates will buckle and th=
en=20
> > they will short out. Neither battery type should be left in a discharge=
d=20
> > state for a long period of time as the plates will become sulfated and =
then=20
> > it becomes almost impossible to recharge the battery.
> >Thanks,
> >rich!
>=20
>=20
>=20
>=20
> >On 2/8/2014 8:17 PM, Jim Higgins KB3PU wrote:
> > > Received from Peter Johansson at 02/09/2014 01:09 UTC:
> > >
> > >> On Sat, Feb 8, 2014 at 3:13 PM, Larry Bradley <larry.bradley@ncf.ca>=
 wrote:
> > >>
> > >>> ability to handle deep discharge (80%)
> > >> Just because you can discharge 80% doesn't mean you should make a
> > >> habit of it.  The best way to prolong the life of your batteries is =
to
> > >> avoid draining them beyond 50%.
> > >
> > > YES!  and especially true of thin plate batteries like golf car batts=
..
> > >
> > > JimH
>=20
>=20
--=20
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