Apollo T-80 Alert [RE-wrenches]

[Herb Flynn]

Mick,
	
	The Apollo Solar T80 is designed to take advantage of the MPPT concept 
which requires a higher input voltage than the battery.   The MPPT 
charge controller is based on a DC to DC converter which provides most 
of the advantage since the input voltage can be much higher than the 
output voltage thus reducing the current and saving loss and cost in the 
wiring.   We state in our user manual that the T80 requires about 10% of 
voltage headroom to achieve the published increase in energy harvest 
from the PV array.
   We are taking your suggestion and making our documentation clearer on 
this subject.   If a battery is close to full charge and therefore at 
its highest voltage and if the PV array is wired for a PWM charge 
controller, and if there is any significant voltage loss in the home run 
from the array, and if the array is hot, the voltage headroom may be 
less than the 10% required.

Herb Flynn, Technical Support Manager
Apollo Solar
(203)790-6400
Herb.Flynn at Apollo-Solar.net



Mick Abraham wrote:
> 
> Hi, Wrenches~
> 
> The Apollo T-80 requires PV strings with more than 36 cells for every 12 
> 
> volts of battery. I learned this while replacing a Trace C-40 control on 
> 
> a 24 volt battery with "classic" array wiring (72 cells in each PV 
> string). (The array is 20 feet in the air and there were no funds to pay 
> 
> for an array re-configuration.) 
> 
> The Apollo unit would not work in this situation, and it took awhile to 
> figure out why. I finally installed a Xantrex XW-MPPT controller, and it 
> 
> does work. Apollo's instruction book calls for at least 32 volts peak 
> power in order to charge a 24 volt battery. In additional  testing at my 
> 
> own la-bor-a-tree, however, an array providing 35 to 38 volts peak power 
> 
> (in the cool morning) still couldn't drive normal operation with a 24 
> volt battery. The "35 to 38" volt number came off the XW controller 
> display, which again tested fine after the T-80 balked.
> 
> I have suggested to Apollo that the spec in their instruction book may 
> need revision, and I've also asked for better disclosure of this 
> characteristic on all Apollo sales information. Weeks later, I'm still 
> waiting for a response. Apollo did upgrade the hardware on this early 
> vintage controller at no charge and they updated the firmware, but then 
> they stopped answering my emails.
> 
> The T-80 may be a fine controller, but it is unsuitable for retrofit 
> unless the array can be rewired with higher voltage strings. Apollo 
> seems to find this unimportant; one of their techs even said that all 
> MPPT type controllers have the same issue. 
> 
> Let's see: Outback, Blue Sky, BZ Products, and now Morningstar MPPT and 
> Phocos...all have peak tracking type controllers which can directly 
> replace a C-40 without changing the array...isn't that right? Apollo 
> needs to disclose this factor more fully, and ignore emails from a 
> concerned installer less fully.
> 
> Mick Abraham, Proprietor
> www.abrahamsolar.com
> 
> P.S. If any of you would like to buy this demo controller, send me an 
> offer off list. I don't have the carton and the left side knockout has 
> been hammered out, but other than that it's in mint condition with a 
> blank warranty card.


- - - -
Hosted by Home Power magazine

To send a message: RE-wrenches at topica.com

Archive of previous messages: http://lists.topica.com/lists/RE-wrenches/read

List rules & how to change your email address: www.mrsharkey.com/wrenches/etiquette.php

Check out participant bios: www.mrsharkey.com/wrenches/

Moderator: michael.welch at homepower.com
--^----------------------------------------------------------------
This email was sent to: michael.welch at re-wrenches.org

EASY UNSUBSCRIBE click here: http://topica.com/u/?bz8Qcs.bz9JC9.bWljaGFl
Or send an email to: RE-wrenches-unsubscribe at topica.com

For Topica's complete suite of email marketing solutions visit:
http://www.topica.com/?p=TEXFOOTER
--^----------------------------------------------------------------