On 2/8/2014 11:16 AM, Jim Higgins KB3PU wrote:
> Hi Bob,
>
> Greetings from one old OTLISTer to another.  ;-)
>
> Yes, it applies to all healthy lead acid batteries.  (More on the "health=
y"
> aspect below.)  Basically pulse charging is "snake oil" when it is touted=
 as
> better than standard manufacturer recommended charging methods.... someth=
ing
> no one here has done  There is no advantage to the battery from deliverin=
g
> current in short higher voltage pulses except (addressing the healthy asp=
ect
> now) when the goal is to "desulfate" a seriously and chronically undercha=
rged
> battery that is so heavily sulfated that it won't accept a charge by stan=
dard
> methods.  If it will accept a charge, then standard methods of recharge a=
re
> always better.  And recovery of such unhealthy batteries only recovers a
> battery that is of no lasting value in any situation requiring even a
> moderate level of reliability.  It needs to be replaced immediately anyho=
w,
> so I don't even recommend pulse charging in that case.  Such recovered
> batteries are technically recharged, but are essentially end of life junk=
 due
> to the effect of the prior heavy sulfation.  It can result in evolution o=
f
> hydrogen in SLA designs. which leads to loss of water from the electrolyt=
e
> due to hydrogen venting.  SLA designs depend on preventing the evolution =
of
> hydrogen so that water never needs to be added.
>
> Pulse charging increases IR and I^2R losses and in the case of older
> batteries suffering from normal (or abnormal) levels of plate corrosion f=
or
> their age, it can stress partially corroded internal components to the po=
int
> of premature failure.
>
> There's really nothing involving benefit to the battery to recommend puls=
e
> charging.
>
>
>
>
>
> Stepping outside my 35 years of experience with lead-acid batteries from =
this
> point onward...
>
> In the sailboat situation, it seems to me that if the very long leads to =
the
> aux battery cause such a loss of voltage that recharge must be unduly
> extended, or source voltage raised at the expense of another battery
> connected closer to the charging source, the better solution is isolation=
 of
> the two batteries from each other during charging... something that will =
need
> to be done with pulse charging anyhow.... or separate charging systems - =
two
> alternators.
>
> The OPs idea of an "old timey" on-off regulator on the nearby battery whi=
le
> (I assume) the farther battery remains directly connected to the alternat=
or,
> seems like a reasonable solution.  Or maybe a second alternator for the a=
ux
> battery if one can be installed.
>
> JimH
>
>
> Received from Bob Blick at 02/08/2014 04:54 UTC:
>
>> Hi Jim,
>>
>> Does this apply to SLA and AGM as well as flooded lead acid?
>>
>> Friendly regards, Bob
>>
>> On Fri, Feb 7, 2014, at 07:48 PM, Jim Higgins KB3PU wrote:
>>
>>> I will say that my comments re: Pulse Charging come from 35 years as a
>>> Process Engineer in the lead-acid battery industry where I wrote materi=
al
>>> specs and designed processes for battery manufacturing as well as had
>>> plenty of hands-on experience.  The same company also manufactured
>> chargers and
>>> UPS systems.  And its research labs did extensive investigation into pu=
lse
>>> charging.  The short story is that it has no advantage over constant
>>> potential or modified constant potential charging and it has several
>>> disadvantage in terms of greatly increased IR and I^2R losses as well a=
s
>>> possible detrimental effects on the battery depending on the nature of
>>> the
>>> battery system and its load.  The latter probably isn't a factor in thi=
s
>>> case, but it is very much a factor in UPS systems.
>
I see that nobody got it.

The issue is that the long wires drop the voltage. At the last stage of=20
charging, the voltage cannot reach the proper peak to top off the=20
battery. Pulse charging allows me to top off the battery; without it,=20
the battery is never fully charged.

In case of solar charging of batteries, we have a diode then a cap so=20
that we can handle the constant variation due to clouds temporarily=20
blocking the sun. The solution is still the same; we deliver a pulse=20
when it is high enough to deliver the top-off charge. There is no hokum=20
here. this works.

Test it yourself.

--Bob A

--=20

The only place success comes before work is in the dictionary.

VINCE LOMBARDI

--=20
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