Date:         Fri, 29 May 2015 09:42:32 -0500
Reply-To:     Tom Hargrave <thargrav@HIWAAY.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Tom Hargrave <thargrav@HIWAAY.NET>
Subject:      Re: Solar panel question
Comments: To: Jon VO <jondvo@GMAIL.COM>
In-Reply-To:  <55686BFF.9020404@gmail.com>
Content-Type: text/plain; charset="UTF-8"

Jon,

You are technically correct but both are equal if you are reaching a full charge because both systems taper off to a float voltage at full charge.

Also MPPT only justifies it's higher cost if you never fully charge your batteries and your solar panels can produce a voltage significantly higher than your battery voltage, for example if your batteries are 12V and your wired-in-series solar panels are 36 volts. This will almost never be the case with a Vanagon 12V system.

Thanks, Tom Hargrave
www.kegkits.com
www.stir-plate.com
www.towercooler.com
www.grow-sun.com
www.raspberryproject.com
http://goo.gl/niRzVw

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On Behalf Of Jon VO
Sent: Friday, May 29, 2015 8:39 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Solar panel question

John,
The different panels will have a somewhat different I to V curve, and thus the maximum power point for each may be a bit different. Depending on the MPPT controller, this may mean a reduction in power transfer efficiency, but should still charge the battery. Some MPPT controllers generate a particular I to V curve for the attached panels, by sampling over time and various light conditions. Still better than a straight PWM approach.
Jon


On 5/28/2015 8:08 PM, J B wrote:
> The initial test run seemed to work great and pulled in over 10amps 
> during peak sunshine
-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2015.0.5941 / Virus Database: 4347/9851 - Release Date: 05/23/15