On 2/8/2014 5:30 PM, RussellMc wrote:
> I wrote most of this yesterday & didn't send it.
> Could be shorter :-) - but hopefully covers the point.
>
>
>> Bob said:
>>
>>
>>> no, the purpose of the capacitor is to capture the PEAK voltage which i=
s
>>> being lost due to wiring losses, The capacitor is allowed to charge to =
a
>>> peak, then the mosfet switch is engaged to apply a pulse of energy at
>>> the peak voltage.
>> Jim said:
>> I'm not picturing it, but I won't burden you by asking for more info.
>>
>> 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 materia=
l
>> 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 pulse
>> charging.  The short story is that it has no advantage over constant
>> potential or modified constant potential charging
>> ...
>>
> __________
>
> Lets see if I can provide some sort of a "bridge" between these two
> understandings.
> Bob mentioned a situation that I have heard mentioned elsewhere as being
> one where they had used pulse charging to advantage.
> This is in solar powered systems where insolation (sunshine) levels are l=
ow
>   - and equally applies where battery capacity is large relative to the
> available PV panel wattage.
>
> For much  of its charging range a lead acid battery can be charged at
> whatever current level is available. Charging in the first and longest pa=
rt
> of the charging cycle may be at any current available up to some specifie=
d
> maximum. Once a certain maximum voltage is reached the battery is charged
> at constant voltage with current decreasing under control of the battery
> chemistry. The battery may be floated at this specified constant voltage
> indefinitely except for the special actions mentioned below. Actual float
> voltage depends on the type of lead acid battery (flooded, AGM, gel, ... =
),
> sometimes construction style (eg Gates spiral wound differ from the norm)
> and, very importantly whether the battery is long term floated in standby
> mode, or deep or semi-deep discharged. So far all these could (probably) =
be
> handled by a low and variable charging source such as solar may provide.
>
> Then there is boost / equalisation mode. The battery is run at a higher C=
V
> mode for a limited period and caused to take additional charge for a
> limited period. The ability to implement this high voltage charging is
> vital to the long term life of the battery. An excessively limited solar
> source may not have the combination of energy transfer rate and voltage
> needed to implement this mode.
> With a low enough energy source relative to "leakage" current the battery
> may not even properly enter the float mode.
> Battery University say: "The switch from Stage 1 to 2 occurs seamlessly a=
nd
> happens when the battery reaches the set voltage limit. The current begin=
s
> to drop as the battery starts to saturate, and full charge is reached whe=
n
> the current decreases to the three percent level of the rated current. A
> battery with high leakage may never attain this low saturation current, a=
nd
> a plateau timer takes over to initialize the charge termination."
>
> In addition to leakage compensation, Bob notes the effect of long wiring
> runs. The effect of this is obviously complex due to interaction between
> source voltage, circuit resistance, battery state of charge and changes i=
n
> the voltage drop which occur when the battery responds to lower voltage.
> What Bob is reporting is that having a cycled source of higher voltage
> allows charging when a high resistance continuous source does not. This i=
s
> outside Jim's area of charging scenarios and Bob's experiences here are
> complementary rather than opposed.
>
>
>
>       Russell
>
>
>              Battery University - charging lead acid batteries:
>
> http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery
>
>
>            Sealed lead acid battery charging basics
>             http://www.powerstream.com/SLA.htm
>
>            SLA fast charging
>             http://www.powerstream.com/SLA-fast-charge.htm
Gee Russell, you certainly know your way around the English=20
language.Exactly correct!

--Bob A

--=20

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

VINCE LOMBARDI

--=20
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