[AT] Solar battery charger setup

[Bill Bruer]

Thanks, Spencer and Ivan.  I will assume the instructions about the 
regulator are a lawyerism and hook the thing up as-is.

Bill

On 1/18/2016 6:28 PM, Ivan wrote:
> Bill , I'll take a stab at it as best as I can remember .  1.5 watt =
> .125 amp   if you take 1.5 divided by 12.5 volts nominal  wattage
> (watts  divided by volts )   and that is max rating .   Meaning that the
> sun has to be shining straight down at the panel  which it wont most of
> the time . Solar panels have to be angled to match the suns angle for
> max charge if is shining directly on it and constantly change d to match
> the path of the sun across the sky . To get that max charge it has to be
> continiuosly angled to match the suns path across the sky ,otherwise its
> getting less than max output .  Actually the panel will produce a higher
> voltage than that because for it to charge a battery the charging
> voltage has to be up around 14.5 . Truth is your 12 volt battery should
> actuall read about 13.2 or so to be fully charge .
> Another factor is resistance in the wire which can really cut output
> especially if the wire size is too small or extended to reach outside if
> the tractor is in the shed .
>    Where you are located affectsthe output too .  DOwn close to the
> equator the angle is less pronounced ,but the system still haas to be
> able to follow the sun for max output .
>    Very simple to demonstrate this to make it easier to understand . Hook
> the charger up to any 12 volt battery with a multimeter ( digital ) to
> be sensitive enough . Now point the panel toward the sun and move it
> left and right and watch the meter voltage . It will jump all over and
> with a slightly weak battery it will show up even better .
>    Myself I have two solar systems running one for lighting in the house
> (and thats led nightlights only ) the other is on the roof of my camper
> . A 80 watt system to charge the house battery , which it doesnt do very
> well .
> For a weak battery with even a small slow internal loss a panel that
> small will never over charge it . If you want I can send a link for a
> web site that explains it much better , the guy runs his whole house on
> solar and seems to have a very good handle on it .   Ivan
>
> O1/17/2016 5:55 PM, Bill Bruer wrote:
>> I recently picked up one of these 1.5 watt solar battery chargers on sale at
>> Harbor
>> Freight for $14.99 -
>> http://www.harborfreight.com/15-watt-solar-battery-charger-68692.html
>>
>> The manual says it needs an external voltage regualtor to prevent
>> overcharging.  There's no indicaction of that requirement on the packaging.
>> What's the best (cheap) way to set this thing up so that it can be left
>> on a battery for indefinite periods?  Harbor Freight has a 100 watt
>> regulator -
>> http://www.harborfreight.com/7-amp-solar-charge-regulator-96728.html
>> that will also allow you to power a tool but costs $25.99.  Kind of defeats
>> the
>> sale price on the charger.
>>
>> My main use will be to keep the battery hot on my IH 686 tractor with a
>> D312 engine.  However, I would like to mount the panel and regulator on a
>> light
>> frame that can be moved to any piece of equipment where it may be
>> needed.
>>
>> Bill Bruer
>> Murfreesboro, TN
>>
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