Author Topic: LVD operated by Classic Aux port  (Read 145 times)

ct

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LVD operated by Classic Aux port
« on: April 25, 2017, 07:23:49 PM »
I was directed to this forum by the good folks at Midnite Tech Support for ideas/opinions on a project.

Long story short, I need to implement a low-voltage disconnect between a 24V battery bank and a 1000W inverter that lacks programmable LVD setpoints.  I hoped to use an Aux port on the Classic 150 to control the disconnect.

Samlex sells a device -- the BG-60 (Battery Guard - 60 Amps) -- for this purpose, but its native setpoints won't work for my battery.  It is possible to remotely operate the device by grounding control pin 4, but apparently the Aux port on the Classic is active high, so I thought of using the Aux port to drive a small relay (Fuji HH52P) to ground the BG-60's control pin.

The Tech Support people said a lot of people were trying to do the same thing, so I thought I would ask if anyone here knew of previous attempts and/or had any advice or direction to offer.

Thanks for your consideration!

ClassicCrazy

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Re: LVD operated by Classic Aux port
« Reply #1 on: April 26, 2017, 01:42:09 AM »
What low voltage do you want it to disconnect at ?

That device gives you options between 19v and 24v for low voltage disconnect .

Isn't another option to use a contactor iinstead of the Samlex device  controlled by the AUX ?

Larry
system one
Classic 150 , 20 Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie

ct

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Re: LVD operated by Classic Aux port
« Reply #2 on: April 26, 2017, 05:24:05 PM »

Thanks for the reply, Larry! 

Part of the reason for wanting to use the Classic's logic is that I am told it is temperature compensated via a remote sensor actually mounted on a battery.  I don't know if the BG-60's setpoints are temp compensated or not -- I suspect not -- but in either case, there is no way to attach a remote sensor to it, so I am not sure how valid its compensation would be.

If you know of a suitable contactor for this purpose, please let me know.  The ones I have seen so far draw too much power to be operated by the Classic's Aux terminals, which I have been told are limited to 12VDC and ~200mA.  I wonder whether the Aux terminal can be set to operate active low instead of active high?  Maybe I'll give Kyle another call...

All that said, I know very little about the Classic, so please let me know if there are other options or tricks to get this done.

-Chetan

ClassicCrazy

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Re: LVD operated by Classic Aux port
« Reply #3 on: April 26, 2017, 11:22:29 PM »
Read through this for info on solid state relays - lots of info on there about good ones and mistakes to avoid .

http://midniteftp.com/forum/index.php?topic=3595.0

The contacts on Classic will operate a SSR .
If you have a Whizbang then you will be limited to using AUX 1 since the Whizbang uses AUX 2 .
Aux 1 is probably fine for what you want to do  on off and it has Low Battery disconnect setting .

I haven't used SSR or contactors enough to give good recommendations .
Lots of good info on Crydom site about SSR
http://www.crydom.com/en/tech/faqs.shtml

You can look up specs on contactors on this page
http://www.gigavac.com/catalog/power-products

Larry
system one
Classic 150 , 20 Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie