GoalZero 1000 and 12v auto charger observations

[Dave-n-Janet]

I've recently gotten a GZ 1000 and the GZ 12v Auto charger. Similarly to pteck I want to just use the GZ for 120v appliances. I have wired a 12v socket to the 12v bus in the AS, then plugged the GZ Auto charger into this socket with the charger on the 5 amp setting.

However, a couple of surprises:
First, even though the GZ had been fully charged using the 120v wall adapter, when I plugged the GZ into the 12v socket it pulled 62 watts for about 10 minutes and drew my house batteries (210ah of 6v golf cart batteries) down 2%. I was surprised the fully charged GZ drew this much. Maybe temperature differential between house (where wall charger was used) and AS, just don't know.

Second, even though I ran this test at 6:30am, apparently the solar controller was providing just enough voltage to overcome the low voltage cutoff on the auto charger to essentially charge off the house batteries, or perhaps the fully charged house batteries are over the low voltage cutoff.

My intent was to just leave the Yeti plugged into the 12v auto charger so when the solar controller was outputting power to charge the house batteries then the Yeti would also be charged. However, it appears that either fully charged house batteries or minimal solar power enables the draining of the house batteries. This means I will need to manage charging the Yeti, only plugging in when the solar panels are producing at least 5 amps.

Pteck's setup is a bit different in that he has hooked up his GZ to an independently controlled output of his solar controller. I'm providing this feedback to anyone who may be thinking of hooking up a GZ1000 to their 12v bus.

Dave

[pteck]

Didn't see this thread until now. Glad you got the Goal Zero!

Since this is referencing the other thread, I'll put the link here - http://www.airforums.com/forums/f37/...um-196422.html

Your feedback is probably useful for others in the linked thread too.

Since the Goal Zero Yeti 12V Car Charger has a automatic charge relay programmed to switch at 12.8V, there is a definitely possibility that a tippity topped off lead acid battery, or with a bit of boost from solar charging, will just be at that threshold causing the behavior you're seeing.

It's not necessarily a bad thing. Just that the "system" has a preference/priority to top off the GZ Lithium bank first.

Because of this, I have my lithium bank on a timer that won't charge until 10AM such that this allows the house 12V lead acid bank to charge first.

Usually the GZ will charge within hours, then it shuts it's charger down as it's full. By mid day, or surely at the end of the day, all banks are fully charged and ready for evening without support of the sun.

As I mentioned in the other thread, it's important to have enough solar generation that it can sufficiently charge both banks because if there's a shortfall, it'll be on the house bank if not manually managed. Yet with the capacity that's installed, even if not full, there's reserve for days.

Interesting note is that all the external automatic charge relays sold, also switch at 12.8V. Very typical thing for multiple banks.