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Charge Controllers and Clippers => The "Classic" charge controller => Classic FAQs => Topic started by: Retep on January 14, 2015, 06:54:25 PM

Title: How many amps can a classic 150 take from the panels?
Post by: Retep on January 14, 2015, 06:54:25 PM
A thread reply I read seemed to say that the classic 150 would just not take in the extra amps.
12 volt system in a bus, locked in to 12 volts.  6 golf cart batteries. Classic 150 lite, Trimetric, 6 Hanwha 305T panels VMP=37.7, IMP=8.32 installing all asap.  The hope is that the couple of extra (got them cheap) panels will help keep the batteries charged on lesser days, and minimize or eliminate an older lone woman from having to climb the roof and tilt.  Also, can the charger be set to limit or re-route amperage over the batteries' boiling point? My guess for that based on what I've read is 75 amps.  The standby position is to have the extra 2 panels on a switch or relay to add to the system when solar is limited.  Thank you for helping a newbie who is trying to help a friend.
Title: Re: How many amps can a classic 150 take from the panels?
Post by: Westbranch on January 14, 2015, 07:17:05 PM
Well the answer to the title is ~ 96 amps at 12v as shown in the top line of the first graph in this link

http://www.midnitesolar.com/images/classicFrontPage/graphs.php...

but I'm not sure of the statement in the body of your post...??

perhaps rephrase your question?

ADD: please tell us more, like  specs for those batteries and Classic settings and panel configuration.   If you haven't used the array sizing tool here it is

http://www.midnitesolar.com/sizingTool/displaySizing.php

Title: Re: How many amps can a classic 150 take from the panels?
Post by: dgd on January 15, 2015, 11:34:43 PM
It should not be necessary to switch out any panels because the Classic and Kid will only take the current they need for battery charging.
You cannot 'push' more current through the controller than its maximum ratings/

dgd
Title: Re: How many amps can a classic 150 take from the panels?
Post by: boB on January 17, 2015, 12:46:39 AM

The amps that the Classic can "take" from the solar panels is limited by the battery output current and not the PV input current.

The PV panel input current will always be less than the output current into the batteries.  This is because the input
voltage TO the Classic is always somewhat higher than the battery output voltage.  It is a "power" thing which
involves both current and voltage.

boB
Title: Re: How many amps can a classic 150 take from the panels?
Post by: Retep on January 17, 2015, 08:36:07 PM
Thank you for helping
  So, if I understand this correctly, if I have too much solar power going into the Classic 150, it will not fry the controller, just not allow that extra energy. Yes? Baffling to me.   The reason I want this is that the bus will most often, but not always, be in less than optimal orientation, and the more extra power that can be diverted to her electric water heater, the less likely the genset will need to run.  Now my question (I hope) is how to keep it from boiling the 3 pairs of 6v golf cart battery at 12v-  call it 600 amp hours total.  Is there a way to limit the output charge to the batteries?  She is locked in to 12v by the bus systems.  Thank you for any help or suggestions you can give me.
Title: Re: How many amps can a classic 150 take from the panels?
Post by: Vic on January 17, 2015, 09:29:01 PM
Retep,

YES,  there is an output current limit value,  in output Amps,  that can be set in the Limits menu,  IIRC.   The Classic does a very good job of limiting the output current (into the batteries)  based on that setting.

Good Luck,    Vic
Title: Re: How many amps can a classic 150 take from the panels?
Post by: Retep on January 18, 2015, 10:37:31 AM
Groovy groovy groovy.  Thank you.  Now does anyone know of a more elegant way to divert excess power to her 110v water heater than just putting a timer on it so it turns on around 1:pm after the batteries are hopefully replenished (time to be adjusted manually based on the Trimetric readings)?  Is there any way to divert excess power (over what the batteries can absorb) during battery recover time in the morning?  Thank you Thank you Thank you.
Title: Re: How many amps can a classic 150 take from the panels?
Post by: zoneblue on January 19, 2015, 12:24:46 AM
Try under "oppurtunity load" or "waste not" eg:

https://www.google.com/search?q=current+time+Arlington%2C+WA&ie=utf-8&oe=utf-8#q=site:midniteforum.com++%22opportunity+load%22+%22waste+not%22