EG4 48V - 18a Charger Charge Two EG4 48V batteries at once?

[JD McGyver]

I am making a solar-capable portable battery backup solution using two EG4 Lifepower 48v batteries. I have purchased the batteries and the EG4 3kw Off-Grid inverter. Also the 18A charger. This is to roll around the house for portable AC and power my home workstation or fridge/freezer during grid down. Plan on using a 4 wheel "furniture" dolly 18x30 as the platform from Harbor Freight. I have seen a youtube video for County Living Experience where he charges each battery in his stack/server cabinet individually with a small generator. I believe that was to top balance each one to even out some variations.

Since I only have 2 batteries, can I use the 18A charger to charge both at once from the 110V grid or a generator? Or do I need to disconnect and charge individually?

Also. With anyone using the 3kw EG4 inverter, I THINK I understand that I will need a minimum of 120V solar input to even start using the charging ability of the inverter. Speaking to Signature solar, they said 160 was recommended for less sunny days. Does that mean that on very cloudy days I will get nothing if the solar input does not equar at least 120v from solar? I currently only have three 100V panels and would prefer not to have three or four rather large 40x80 panels as part of a "portable" solution should I move this solution anywhere other than my home.

Also confusing is that I read/heard that these batteries should be limited to 18A charging. How does the inverter have 80A charging ability when the external chargers are limited to 18A. I see from the forum that the 25A chargers or not currently available on the Signature website and that some folks have had some issues with those.

Any expertise would be appreciated!

 

[Jack Rabbit Off Grid]

don’t quote me but I think the batteries can handle 100amps input ea. Also you can use the charger on as many batteries you wire in parallel. I use the same charger on a rack of six when the sun can’t keep up.

 

[robby]

Yes it can charge two at once but I know on my 27Amp Charger it does not recommend doing more than 4 at once.
IMHO if you can do one at a time it is better if it is possible. That will charge one battery in about 5 hours versus both taking 10 Hours and the charger can get a cool down break in between. If it's a Grid Down and No PV situation then yes you need to charge both at once.

 

[Lilikoi_Heavy_Industries]

Not sure why you bought a separate battery charger. Your inverter has a battery charger.

And yes you need to make a string of panels that generates over 120V before anything will turn on with that MPPT--typically not an issue, you just put enough panels into a string to make enough volts (you need to get this right, overvolting an MPPT will kill it).

 

[JD McGyver]

Two reasons for the separate battery charger. First, I can separate the batteries/banks and charge each independently. Second is that if my PV is not connected, I might be charging from a generator and would prefer not to put generator power through the inverter

 

[Funion]

I have the exact same setup. All is installed just didn’t have time for final hookup and inspection. Will report back. I do also have a question on panel voltage. I have two strings 300V. Is that going to be sufficient to start charging on cloudy days?

 

[Funion]

Also, the inverter will only draw 18A from solar. The 80A rating is how much the inverter can receive and send to the payers bank and the loads. I was confused on that also and confirmed with signature Solar.