LV6548 Battery Charging

[Skypower]

I’m actually too close to the OCV limit but survived anyway. Only after an entire winter did I learn about the cold panel voltage increase. Luckily, extreme cold+sunlight doesn’t happen here at the same time. That and the panels are always loaded even if the batteries top out, somethings going to use the power.

 

[Ozark]

Further on this...
It's been overcast today but clearing slightly I'm getting 180v at 1a more or less on 5 panels
Still no output to the batteries. The charging light is flashing but no output.
Something new, the inverter shows 52v battery but the Batt test software shows just under 50v at the battery ...
I'll next try transcribing my setup parameters and perhaps you folks could give them a look.

 

[Skypower]

Depending on the overcast darkness, it can make a ton of difference. Full sun and direct aim you should see 5+ amps, flat 4+ this time of year. If not something else is up.

 

[Ozark]

After refreshing the PC battery program correctly, duh, I show 52.7v.
At the batt terminals using a handheld VOM and as well on the 6548 display all agree.

BUT the LEDs on my cheap EG4 Lifepower4 indicate less than 25% charge (1 of 4 LEDs) and low power alarm condition red LED

52.7v shows around 70% charge on internet charts

Is 52.7v low voltage status?

I am really confused, any suggestions would be very much appreciated (trying to leave for the granddaughter's wedding and I'd love to take the trailer...

 

[Skypower]

The inverter is usually only +- .1 of actual. 2 volts is a lot of difference. I’ve never seen a bms report that much difference.The Check both ends with a meter. Bad connection or something in between. You need 2/0 cables minimum between your inverter and batteries if it’s close, 5’ or less.

 

[Ozark]

Reading the BMS using the software I get just the same reading as the inverter: 52.7v
The problem is the idiot lights on the front of the batteries showing 25% power plus low voltage condition doesn't jibe.

 

[Skypower]

State of charge using voltage on Lifepo4 is a rough estimate. If you are showing Zero amps on the app for a few minutes 52.7 volts is roughly 50%. So if you happen to just be putting in just enough to cancel the inverter’s operating draw you would see zero amps. Most batteries take a couple of trips to full charge to set the baseline for 100% full state of charge. Once the batteries have been acclimated, the state of charge in the app will be pretty good.
48volts is empty and 44 is shutdown. I have only once gone to 50 volts and normally only gets to 52.5 on the bottom. Can you charge with a generator or grid. Even a Honda 2000 should be able to charge 30 amps (setting max grid current!) at the battery. Two or three hours you’re done.

 

[Ozark]

LOL, now you've opened a whole nother can of worms...
We're going mobile for a while, selling the house, boondocking etc. I spent 30 minutes mountaineering in the 30 foot U-store-it room this morning trying to find the 48v charger. That's kind of my conundrum, we're packed and I thought ready to roll.

Thanks for the help, it's been very overcast the last couple of days. I'm gonna wing it and see how it goes now that I know the batteries are actually getting juice.

 

[Skypower]

All you need is an extension cord, lop off the socket end and wire it to the grid taps. You will need “clean” electricity. Unusually only an inverter type will do. Doesn’t have to be a Honda. Remember to set the maximum utility charge current(program 11) to not exceed the generator’s continuous watts rating not the surge rating(what’s usually the selling point). If you pull a load from the inverter while you are charging, this is added to the generator load! Say you want to charge to 56 volts and you want to charge at 30 amps so 56x30= 1,680 amps and puts it at what a healthy Honda 2000 can do. Don’t plan on making a cup of coffee at the same time unless you reduce the utility charge to 2 amps first or unplug the inverter and plug the maker right to the generator(probably best). Even a fridge coming on may trip the generator. A bigger cable and a 30 amp plug would work at some camp grounds but you always need to remember that pass through load and adjust the charge if needed. A good auxiliary 48 volt lithium charger will avoid that problem problem of pass through load tho, and may be a better solution for you.
Just giving you options and understanding management.

 

[Ozark]

I didn't realise when I started that the utility draw was adjustable on the 6548.

How I set the trailer up at this point is the solar, 6548 and batteries simply have a 20 and RV 30a outlet. Going down the road the bats can charge and of course when parked.

The trailer has the typical 30a plug, I just plug the trailer plug into the charge/verter. The idea was to change as little of the original wiring as possible so most of the solar stuff could be removed when selling except the roof mounts and PV cable.

2 flooded 100a 12v "house" batteries that run the lights and fridge charge from that 30a plug circuit . That plug also runs the 120v outlets, the A/c and Microwave. That part is all factory. It was working good off the solar until that cloudy day and the idiot LEDs freaked me out.

You suggestion is good. We are taking the Honda and have various adapters. I'd like to get that 30a RV plug to power both the house and the Inverter if required. Gotta have something to do on the road.

 

[Skypower]

Thar you go! Just a bit of energy management. I suggest you put in a breaker box between the inverter and grid. And rig up a transfer switch/interlock to keep it safe and simple if you haven’t already.

 

[Ozark]

Further to this little saga...
Attached a cord to the AC input to top off the solar connected batteries. Plugged it into a 20A circuit.
Immediately tripped the GFCI on the house outlet.

I suppose this has to do with the infamous bonding screw controversy around the 6548.

What is the solution?

 

[Skypower]

How many amps were you trying to charge at?

 

[Skypower]

It could be a very sensitive gfci. And it could be a problem or that bonding screw.

 

[Ozark]

I set the limit at 10A on a 20a circuit. Nothing much else was on it.

What is the downside to "unbonding" the inverter?

I'd guess you want the grounding conductor and neutral to be bonded while running from batteries but not when running from a/c where the inverter is acting like a subpanel.

Unless the charge/verter is supposed to sense the difference and switch automatically. That would be nice.

 

[Skypower]

Un plug. Make sure your line and neutral are correct at both ends and cord. Change to usb or ubs mode. Then turn the inverter off. Plug in to the outlet. Does the house breaker trip when inverter is off? Try to start the inverter. Does it trip? Does the inverter fault?
Disclaimer; I’m not there, can’t see anything, test anything and not an electrician. Be careful.

 

[Skypower]

I set the limit at 10A on a 20a circuit. Nothing much else was on it.

What is the downside to "unbonding" the inverter?

I'd guess you want the grounding conductor and neutral to be bonded while running from batteries but not when running from a/c where the inverter is acting like a subpanel.

Unless the charge/verter is supposed to sense the difference and switch automatically. That would be nice.

It could be the bonding screw but I’d like to see if it is something else first. I don’t like opening it up unless it’s necessary. Hopefully others can shed some light. My bonding screws are removed but mine is not an RV.