[AT] Solar battery charger setup

[ATIS]

My voltage readings were when I hooked the solar panel directly up to my digital multi meter. I did some reading a few minutes ago and it seemed indicate that the resistance within the battery would keep the operating voltage at 12 to 14 regardless of the panels capabilities. This would indicate you don't ever have to worry about  over-voltage conditions.   And you sure don't have to worry about boiling your battery with these little things.

Maybe someone with more electronic knowledge than I could provide a little more insight in helping us keep our antique tractor batteries charged.


Spencer Yost

> On Jan 18, 2016, at 8:25 PM, Bill Bruer <bill_bru at bellsouth.net> wrote:
> 
> 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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