Date: Mon, 22 Dec 2014 09:45:15 -0800
Reply-To: Rocket J Squirrel <camping.elliott@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Rocket J Squirrel <camping.elliott@GMAIL.COM>
Subject: Re: Solar collector
In-Reply-To: <BAY405-EAS281C745389A800448C3D5B4A0560@phx.gbl>
Content-Type: text/plain; charset=windows-1252; format=flowed
To add a bit of detail to what Dennis Haynes wrote:
"Now let's say you want to run that 600 watt microwave. Again for losses
add 10%, (yes this is a bit exaggerated but possible) you need 660
watts. If you only have 10.5 volts the inverter will need 62.86 A/H."
As he says, "Now if you want to run this off a battery for any length
[of time ...]."
Do note the "H" in "A/H" -- that's "hours." If you run the 600 watt
microwave for an hour, then you would want to think of that as 660 watts
(to be conservative, as he describes), and doing the numbers that comes
to 62.86 A/H, as he shows. Likewise, if you run the microwave for 6
minutes -- a tenth of an hour -- that's more like 6.3 A/H.
It takes a lot of energy to heat things. Electricity is a fine source
for it if you have it in abundance. Size your battery accordingly.
--
Jack "Rocket j Squirrel" Elliott
1984 Westfalia, auto trans,
Bend, Ore.
On 12/21/2014 07:05 PM, Dennis Haynes wrote:
> 12 volts X 1 amp would be 12 watts.
> 10 volts at 1 amp is 10 watts. So doing some algebra if you need 12 watts
> and only have 10 volts you need 1.2 amps.
>
> So you have 2-13 watt bulbs. 26 watts. There will be losses both in the
> inverter and the ballast for those lamps. Let's figure we can get 90%
> between the two.
> So to get 26 watts figure we really need 28.6 watts. 28.6/10.5=2.74 A/H.
> Now let's say you want to run that 600 watt microwave. Again for losses add
> 10%, (yes this is a bit exaggerated but possible) you need 660 watts. If you
> only have 10.5 volts the inverter will need 62.86 A/H.
> Now if you want to run this off a battery for any length the battery bank
> should be sized so that the draw is about 20-25% of the rated capacity (4-5
> hour). So you should be looking at a 240 A/H battery bank for this job.
>
> Dennis
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> Dennis Jowell
> Sent: Sunday, December 21, 2014 10:50 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: Solar collector
>
> I have 2-F13T5CW fluorescent bulbs above the gallery area. They are listed
> at 13watts per bulb.
> I understand about the loses in the inverter. But confused with the below.
> "There are some loses in the inverter and as the battery discharges the
> inverter will try to run all the way down to 10.5 volts so that is why I use
> the 1 to 10 instead of 12 volts. "
> What does it mean " use 1 to 10 instead of 12 volts?
>
> Dennis
>
> Dennis Jowell
> Scotch Hollow Farm
> West Newbury, Vermont
>
>
>> On Dec 20, 2014, at 6:08 PM, Dennis Haynes <d23haynes57@hotmail.com>
> wrote:
>>
>> What size are those lights? The inverter draw will be proportional to
>> the load placed on it. Figure 1 Amp/Hour for every ten watts. Watts =
>> volts X amps. There are some loses in the inverter and as the battery
>> discharges the inverter will try to run all the way down to 10.5 volts
>> so that is why I use the 1 to 10 instead of 12 volts.
>>
>> Dennis
>>
>>
>> -----Original Message-----
>> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On
>> Behalf Of Dennis Jowell
>> Sent: Saturday, December 20, 2014 2:59 PM
>> To: vanagon@GERRY.VANAGON.COM
>> Subject: Re: Solar collector
>>
>> Thanks Dennis for the info. I only use the inverter to run the 2
>> lights over the sink when their is no shore power available. Does this
>> still put that much load on the alternator?
>>
>> Dennis
>>
>> Dennis Jowell
>> Scotch Hollow Farm
>> West Newbury, Vermont
>>
>>
>>>> On Dec 20, 2014, at 9:52 AM, Dennis Haynes <d23haynes57@hotmail.com>
>>> wrote:
>>>
>>> From the factory the Westy did not come with a dual battery set up.
>>> What was there was a relay controlled from the alternator
>>> exciter/indicator light circuit wired so that the refrigerator would
>>> work on DC power when the alternator was actually charging. Many have
>>> used that set up to charge an auxiliary battery and for the most part
>>> it somewhat works. The GoWesty instructions may be assuming you are
>>> adding the 2nd battery and solar system at the same time so the
>>> recommendation for the kit. You should be able to connect the solar
>>> panel system to your house battery leaving everything else as is.
>>>
>>> Since you have that 800 watt inverter keep in mind that at full load
>>> you are looking at some 80 amp/hour draw. While running the
>>> alternator will try to be the source and with a relay inter-connect
>>> the chassis battery will also get involved. All the wiring and the
>>> relay needs to be able to support this load. I would suggest #6 or #4
>>> and a 100 amp relay. Yes all the way to the alternator.
>>>
>>> Dennis
>>>
>>>
>>> -----Original Message-----
>>> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On
>>> Behalf Of Dennis Jowell
>>> Sent: Saturday, December 20, 2014 9:03 AM
>>> To: vanagon@GERRY.VANAGON.COM
>>> Subject: Solar collector
>>>
>>> I just received my GOWESTY solar kit to add power to my auxiliary
>>> battery and read the instruction install sheet. The recommended
>>> install procedure is to purchase the GOWESTY auxiliary battery kit.
>>> My 1988 Westy came with the factory auxiliary battery hookup already
>>> installed. My question is do I really need the GOWESTY add on or use
>>> the factory kit on board already. I've been using the 2nd battery for
>>> years. I have a battery charger, 800 watt inverter, and my truck
>>> fridge running off the 2nd battery with no problems but I would also
>>> like to add my stereo to the 2nd battery next. Does anyone have any
>> experience with the solar kit. Any help would be appreciated.
>>>
>>> Dennis
>>>
>>> Dennis Jowell
>>> Scotch Hollow Farm
>>> West Newbury, Vermont
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