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EG4 6500 with 48V Lifepower off grid cabling

Robkh

Robkh

New Member
Joined
Jun 8, 2022
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Location
Phoenix, AZ
Set up EG4 6500 inverter on a cart with 48V Lifepower battery to use for powering my RV off grid. I had wired a 30A RV style plug for direct AC input - when I called Signature Solar, tech recommended I not directly wire the plug to the AC in on the inverter and instead put an intervening breaker box. That is not something I see others have done. I don’t have enough PV to push the minimum 90V that the EG4 6500 requires so I need to plug in to charge the Lifepower battery. Any thoughts on the breaker box?

I also have a 48V battery charger but Signature Solar recommends not keeping the charger connected to the battery and taking off the connections by undoing the lugs after each charge. Any comments about why I can’t leave the charger connected?


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Robkh said:
Set up EG4 6500 inverter on a cart with 48V Lifepower battery to use for powering my RV off grid. I had wired a 30A RV style plug for direct AC input - when I called Signature Solar, tech recommended I not directly wire the plug to the AC in on the inverter and instead put an intervening breaker box. That is not something I see others have done. I don’t have enough PV to push the minimum 90V that the EG4 6500 requires so I need to plug in to charge the Lifepower battery. Any thoughts on the breaker box?
Click to expand...

If you're using a NEMA plug rated at 30a, then the connected-cord circuit beyond that point needs to be spec'd out at 30a holding (based on the upstream circuit's 30a holding), so that if you draw higher than 30a then the input cord between the plug and the EG4 input doesn't meltdown (since we know that the upstream breaker should protect the entire circuit).

Although, a breaker could be nice to have a disconnect means there, so you don't have to unplug the cord when you want to break from the input. Or you can go turn off the upstream breaker supplying the NEMA 30a receptacle when you want disconnect.


Robkh said:
I also have a 48V battery charger but Signature Solar recommends not keeping the charger connected to the battery and taking off the connections by undoing the lugs after each charge. Any comments about why I can’t leave the charger connected?
Click to expand...

I'm not sure why SS would say that, maybe they can answer to that?

As long as the float is not set too high for the battery type, then what's the problem? And as long as the charger doesn't discharge on the battery while AC input power is not being applied to it...
 
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Thank you, Sorcerer…I used a very good 30 A RV cord, cut it in half and use it with a surge protector when plugged into 30 A outlets at RV parks. Signature Solar say they don’t recommend directly wiring a plug to the AC input on the inverter.

Regarding the second issue, if the DC battery charger is off and not plugged in, why can’t the cables stay connected to the LifePower battery? I use the DC charger when I visit my in laws who don’t have a 30 A outlet and using a 15 A to 30 A adapter trips their 15 A circuit breakers.
 
Robkh said:
Regarding the second issue, if the DC battery charger is off and not plugged in, why can’t the cables stay connected to the LifePower battery? I use the DC charger when I visit my in laws who don’t have a 30 A outlet and using a 15 A to 30 A adapter trips their 15 A circuit breakers.
Click to expand...

Theoretically this is correct. But maybe a cheap charger could or would be possible to allow backflow current (waste) so when the AC input is unplugged and charger is off, an amp-clamp test meter could show a reverse amperage drain on the battery (one would have to check if this could happen on their brand/model of charger).

Back in the old days, I had seen some chargers that could discharge a battery when the battery leads were left on and charger turned off.

However, if this did happen or was confirmed to happen on your charger (using an amp-clamp tester to confirm), one could always just install a suitable relay hard-wired into one of the battery leads to break the connection whenever AC power is not present.
 
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I will check for discharge - the charger I use is a AIMS Power CON120AC3648VDC AC Converter & Battery Smart Charger
 
I use a 2 space Square D Homeline 70 amp for my AC out and I could get another for the single AC line in as I do not wire the setup directly to the grid - I only plug in to charge the Lifepower battery.

i want to leave my AIMS DC 48V charger connected to the 48V Lifepower battery so could I place a Nader 2 pole DC circuit breaker 60V 200A between the AIMS charger and the Lifepower?
 
Robkh said:
I use a 2 space Square D Homeline 70 amp for my AC out and I could get another for the single AC line in as I do not wire the setup directly to the grid - I only plug in to charge the Lifepower battery.

i want to leave my AIMS DC 48V charger connected to the 48V Lifepower battery so could I place a Nader 2 pole DC circuit breaker 60V 200A between the AIMS charger and the Lifepower?
Click to expand...

How many amps is the AIMS, 18a? Why would you put a 200a breaker there? Breaker size is always to protect the cable, and you would need a huge cable for a 200a. Unless the 200a breaker is to go between the battery and the inverter DC input, that would make more sense, but the AIMS charger should have a much smaller breaker (based on the size of the cable to be protected).

Also, on your AC input, so am I understanding you are going to use the EG4 internal battery charger, as well as the AIMS charger as an external charger? If you use the EG4 charger, you may need to go turn down the max charging amps down to under 30a load on the AC input...
 
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I agree - the AIMS charges at 18A. As Signature Solar recommended the charger be disconnected from making contact with the EG4 battery after each charge, I wanted to know if any sort of DC circuit breaker would work.

As for using an AC outlet to charge the EG4 Lifepower, I kept tripping my home AC outlet circuit. I changed the max charging amperage down but it keeps reverting to the default of 50A. That is why I bought the AIMS charger.
 
Robkh said:
I agree - the AIMS charges at 18A. As Signature Solar recommended the charger be disconnected from making contact with the EG4 battery after each charge, I wanted to know if any sort of DC circuit breaker would work.
Click to expand...

Yeah again, so any sort of a breaker could work as a simple disconnect, but to also be there to protect from an overcurrent situation could be a mighty bonus, and no extra cost. Might as well size it proper for the cable being used, since your there anyways hehe...


Robkh said:
As for using an AC outlet to charge the EG4 Lifepower, I kept tripping my home AC outlet circuit. I changed the max charging amperage down but it keeps reverting to the default of 50A. That is why I bought the AIMS charger.
Click to expand...

Is the setting getting saved right? Check the manual and make sure you're setting it in a way that it should save right or something. Should be able to set it, where it will not revert. Maybe you have to turn the inverter off, and set it while off for the setting to stick or something. Could ping SS and ask if they know why it keeps reverting on you?
 
Robkh said:
I agree - the AIMS charges at 18A. As Signature Solar recommended the charger be disconnected from making contact with the EG4 battery after each charge, I wanted to know if any sort of DC circuit breaker would work.

As for using an AC outlet to charge the EG4 Lifepower, I kept tripping my home AC outlet circuit. I changed the max charging amperage down but it keeps reverting to the default of 50A. That is why I bought the AIMS charger.
Click to expand...
The reason they would have advised to disconnect is to make sure that you don't charge/discharge at the same time. Additionally you don't want to run the risk of ever creating a loop in your system.

One of the reasons behind not wiring directly to the inverter from a plug is that you have no protection if anything goes wrong. We see systems come back with blown boards nearly every day from people that mistakenly fed A/C into the unit out of a wall outlet that was being supplied A/C by the inverter.
 
BenFromSignatureSolar said:
The reason they would have advised to disconnect is to make sure that you don't charge/discharge at the same time. Additionally you don't want to run the risk of ever creating a loop in your system.
Click to expand...

There's nothing wrong with standalone charger charging while you are using inverter loads. The battery is just a buffer in the middle, the standalone charger may sometimes just act like a power supply, with the battery supplying any load or charging as it needs to based on the demand/voltage on the DC circuit bus. The battery would never be charging or discharging at the same time ever, no matter if inverter is drawing, or standalone charger attempting to fill the deficit or actually charge on the battery. MPPT charger does this all day long (charges on the DC circuit while inverter is drawing off the DC circuit)...

Or perhaps I'm not understanding what you are attempting to articulate there.
 
Thanks…I am not charging when I am using inverter load. I charge when I am RV sites with 30 A outlets or when visiting relatives with only 15 A outlets. I use the inverter when boondocking, ie when off the grid with no external power supply - like at a Walmart parking lot or a park with no electricit.

I just didn’t want to keep taking the cables from the AIMS charger off the battery all the time. I happen to have a spare Nader DC circuit breaker which I had bought for solar (but I don’t have enough roof on my RV for a large enough solar array) - so I could put the DC breaker between the AIMS charger and the EG4 LifePower battery.

Thank you all for your advice which has helped a lot.
 
Thanks to all for advice. Project finished with covers over breakers to prevent accidental shut off. i put a breaker panel between AC in to AC input on the EG4 inverter and a DC breaker between the AIMS battery charger and the batter.
it works fine.
 

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BenFromSignatureSolar said:
The reason they would have advised to disconnect is to make sure that you don't charge/discharge at the same time. Additionally you don't want to run the risk of ever creating a loop in your system.

One of the reasons behind not wiring directly to the inverter from a plug is that you have no protection if anything goes wrong. We see systems come back with blown boards nearly every day from people that mistakenly fed A/C into the unit out of a wall outlet that was being supplied A/C by the inverter.
Click to expand...
Can you expand? Do you mean you don’t want to charge (the battery) and discharge the battery at the same time? Meaning battery is discharging to power the inverter?

or do you mean the battery discharging (leaking) back into the charger when it’s not charging?
 
I believe Ben was saying they are seeing people wire the plug into the AC Output, then plug it into the already shore powered wall socket. This will be bad and is the same as backfeeding a generator into a home wall outlet with a suicide cord.

@BenFromSignatureSolar please clarify if my interpretation of you post is correct.
 
PreppenWolf said:
I believe Ben was saying they are seeing people wire the plug into the AC Output, then plug it into the already shore powered wall socket. This will be bad and is the same as backfeeding a generator into a home wall outlet with a suicide cord.

@BenFromSignatureSolar please clarify if my interpretation of you post is correct.
Click to expand...
The op said he was told NOT to keep a battery charger hooked up to the battery when not charging. Ben said it’s to prevent charging battery) and discharging (battery) at the same time.

ben does touch on “backfeeding” or a loop but that was a second issue within the post.

I think anyway.
 
Given he gave my post the thumbs up, I'm assuming my interpretation was correct.

I understand why someone would want to do what the OP asked, it makes the unit portable and requires less cable routing/management. The problem is you now have a power generating source with a male connector. Bad juju.
 
Yes. Sorry i wasn't in a place I had time to comment. You nailed it pretty much right in the head. If you have power coming in from the charger and loads being powered the bms isn't going to play nice. Even if the AC input is not being powered by the inverter. If the inverter is supplying power to the charger while it's charging batteries that are connected to the inverter you're going to have real big problems.
 
BenFromSignatureSolar said:
Yes. Sorry i wasn't in a place I had time to comment. You nailed it pretty much right in the head. If you have power coming in from the charger and loads being powered the bms isn't going to play nice. Even if the AC input is not being powered by the inverter. If the inverter is supplying power to the charger while it's charging batteries that are connected to the inverter you're going to have real big problems.
Click to expand...
so what happens if your “charging” the battery from your charge comtroller, and powering loads? (Just about every solar system).

is the bms not going to play nice? That doesn’t make sense. The battery doesn’t know what’s charging it.

im having a hard time with all this. On one hand use an inverter/charger to charge, and “pass through” power to loads. But even an inverter ‘charger will be inverting when solar charging.

wait….. are you still talkin about the inverter itself powering the battery charger to charge the batteries?


I think the op is asking why can’t he keep the battery charger connected when he’s not charging.

so if your batteries are unable to power loads through an inverter when charging then are we expected to turn off all loads when charging? What would be the point of a solar system?
 
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