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hawkbaitfpv asked

75/10 Power Cycling ON and OFF

Hey Everyone.


I just finished setting up a budget Solar setup on my Subaru Outback wilderness, Im running a BogueRV Bifacial 100w panel on my roof rack, ERYY 25Ah LiFePo battery and the 75/10 to handle the charging and the load monitoring. The system is currently connected via a 12v plug to my Euhomy 45qt cooler that draws 40-65w at 12v.

I had the system configured and up and running for a few hours after the install but in the evening when the charge voltage from the solar panel dropped the Euhomy 45qt cooler started power cycling, on for a few seconds then back off again, the bluetooth victron app shows the same, power on the load on and off. I've tested the always on, batterylife and user defined profiles (on between 12v and 14.6v ) for the load output and nothing seems to change the status. It does appear to have charged the LiFePo battery from 81% to 100% based on the built in display on the battery pack but its difficult to determine based on voltage alone what the status of the battery is.

I purchased this configuration because it was meant to give me the ability to run the cooler overnight without needing to run the car to charge the battery but it seems that the system is either not able to handle the 60w of startup power from he cooler on the load terminals or theres some configuration Im missing. Currently I have the battery settings set to the default LiFePo chemistry and the load output is set to always on but its still dropping out and coming back on a loop, without any load on the output Im not seeing any power cycling so Im assuming it has something to do with the load on the system but I dont have nay way to diagnose with an alternate 60w DC Load.

Just curious if anyone has had similar issues, or if theres anything thats works for other peope in a similar situation.


Thanks in advance.

MPPT SmartSolarblue power panel
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Alexandra avatar image Alexandra ♦ commented ·

@hawkbaitfpv

It is probably more than 60W start up especially of it has a compressor in it.

It could be volt drop under load (so maybe undersized wiring or high resistance connections) or just the way it starts up the draw is high.

Does it start and run directly off the battery?

Of it does, consider using the load terminals to switch something else to connect the load to the battery.

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hawkbaitfpv avatar image hawkbaitfpv Alexandra ♦ commented ·

It starts up at 60W on my inline meter and settles down to 40-45w on running. although that meter is only running at 10hz so it might be missing a large current demand spike.

As for the voltage drop it looks like it takes the battery voltage from 13.6 to 13.4 then the battery settles back up to 13.5 or 13.6. Im running 10 gauge cable from the solar panel on the roof for 100W and 10 gauge cable over a total run of about 18 inches for the battery, the cooler is wired with 12 gauge cable over 3ft from the load output to the cooler.

The part that's got me is it started up and ran the compressor for about 3 hours cooling down from 70F to 34F without issue when the PV was providing voltage then when the solar power was over for the day it started freaking out. The cooler runs fine on the battery by itself but Id really like to be able to view the incoming and outgoing current.


At this point I'm considering ordering a larger 75/15 just to see if there is some outrush current issue overloading the 10 amps at 12v although i cant imagine a cooler thats rated for 60W peak drawing more than 2x that on startup. Maybe a capacitor on the compressor motor might help to smooth out that current draw, just to give it the power it needs on startup so it doesnt kill my solar charge controller.

I have a second 25Ah battery coming in next week to add to the system but Id like to sort out the charge controller first before installing a second battery in the setup.


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Alexandra avatar image Alexandra ♦ hawkbaitfpv commented ·

Yeah they do (up to 5 times as much). Depends on the compressor start up system. Some almost start in a dead short condition. 60w at 13v is nearly 5A.

Since I am not familiar with the model fridge you have I cant comment there. A short test to eliminate the charge controller as part if the issue, is to connect direct to the battery and check it that way at the voltage you were previously recording.

The battery voltage where was that measurement taken from? The battery or the charge controller side? Is the fuse ok in the mppt?

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pwfarnell avatar image pwfarnell hawkbaitfpv commented ·

@hawkbaitfpv I have 45W fridge and catch peaks of many hundreds of W at start up, the peak power is not the inrush start up power. As a suggestion, connect the fridge direct to the battery not the load output of the MPPT and see if it works from that.

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