Portable power station requirements to charge 2 52 volt batteries at 4 amp

[opimax]

Hi, I want to charge 2 52 volt batteries with 2 4 amp charger using a portable power station. .i understand it will need to expandable with additional batteries for the for the station to fully charge the bike batteries. My concern is not tripping the a protection circuit with 2 chargers plugged in. Whatare the requirements in watts per plug to do this?

my plan is to charge the power station , put it in my van and top off bike batteries while traveling. It should be pass through charging from the 12volt plug (cigarette lighter) to get ant additional amps available before depleting the power station and add accessory batteries as needed and funds allow. I am not interested in solar but won’t mind the option but not wanting to pay extra for it. It may also charge a battery while riding unattended.

tia

 

[PCeBiker]

Check your chargers to see how many amps or Watts they draw from the outlet.

My 48volt 3 amp chargers just happen to draw 3 amps maximum from the outlet. (so about 50% wasted as heat.)

That will give you a pretty good idea of how many amps your power station needs to provide.

You can possibly invest in a high power inverter that could charge both batteries and your power station at the same time.
You'll need to wire it directly to your battery though and have your vehicle running to power it. The 12v plug (cigarette lighter) wouldn't cut it.

You can reduce the amount of battery storage that you would need if you use your vehicle as a power source.

 

[PCeBiker]

Keep in mind that a 3000 Watt inverter draws upwards of 250 Amps from your battery and alternator at 12 volts.

A 1000 Watt inverter is probably enough to charge your two batteries and your power station at the same time, and it's cheaper.
80-90 amps from your vehicle is a more reasonable expectation.


A sinewave inverter makes cleaner AC voltage that is safe to power sensitive electronics like a computer and TV, but it isn't quite as efficient and costs more.

 

[PCeBiker]

It should be pass through charging from the 12volt plug (cigarette lighter) to get ant additional amps available ,..

If you get an inverter that has enough power to operate both your chargers, you won't need the portable power station.
If your travel time is the same as your battery charge time, then your batteries will be charged when you get there.

The only issue I see with this approach is that pulling 80+ amps from your van would be a strain on the alternator and battery.


Coincidentally, my old car had an OEM alternator that only put out 79 amps.
I was considering installing a high power stereo, but then I'd have to buy a 200 amp alternator from the Power Bastards.

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Maybe a new alternator is cheaper than a power bank?
But there is the price of gas to run it though.

 

[opimax]

i have a small inverter but I want/need a power station . It will used at home during power outages and short term use rather than unraveling power cords at home. I think based on the chargers that have labeling the same number of amps listed in at 120 volts s about the same number of amp output at the 52 volts so about 1/2 efficient seems correct. This seems i would need 2 outlets with sine-wave output of 4 amps each and maybe a little more to be safe and not stress the equipment. This equates to how many watts? So far I haven’t seen them listed by amps only watts, how does this convert?

 

[opimax]

Found a chart , 5amps = 600 watts times 2 = 1200 watt unit. Anybody have any strong recommendations for brand and or model?
some units use lifepo and some units use lithium either better than the other? 25 lbs limit also

 

[m@Robertson]

If you are buying a power station, it almost certainly already has an inverter built in. The AC plugs you plug into a power station are going to an inverter inside the power station. Your power station specs will tell you how many amps you can put out. Two 4a chargers are going to want 4 amps each, so you need to be able to deliver 8a of 120VAC. 8a should not be a challenge unless you are looking at small units, which you should not given that you want to power two ebikes.

I do what you want to do, albeit with just one bicycle and charger. The power station I am using is a Bluetti AC200P and I replenish it with three 200w solar panels set up in series. The 200P has 2000wh of LIFEPO4 storage so thats a lot, plus that battery chemistry is good for 3000 cycles not 800 like your typical Li-NMC like you have in your ebike batteries. Amazon tells me I bought mine in 2021 and its still going strong. In fact, they have a Lightning Deal on it right now selling it for like $700 less than I paid for mine:

Amazon.com

Here it is in action in 2022 at the Grand Canyon, where I kept my bike charged up for daily rides for for a week. I'm about to do it again on a camping trip next month. Note that I have the bike plugged into my charger, which is plugged directly into the AC power plug on the power station.

 

[m@Robertson]

i have a small inverter but I want/need a power station . It will used at home during power outages and short term use rather than unraveling power cords at home. I think based on the chargers that have labeling the same number of amps listed in at 120 volts s about the same number of amp output at the 52 volts so about 1/2 efficient seems correct. This seems i would need 2 outlets with sine-wave output of 4 amps each and maybe a little more to be safe and not stress the equipment. This equates to how many watts? So far I haven’t seen them listed by amps only watts, how does this convert?

You calculate watts as volts x amps. So a 52v battery has peak voltage of 58.8v at a 100% state of charge. However, as a charger approaches its target voltage (58.8v) it will taper off its current output so it slowly just touches the peak voltage while putting power into the battery at a very low rate, so you can't just multiply 58.8v x 4a to come up with a peak need of 235.2 watts. Your charger will start tapering its output at (and I am making this number up) 58v, so your true peak will be along the lines of 232w. Not much difference, I know. I just bring it up for the sake of being complete. And of course the inverter itself has some overhead as @PCeBiker has noted.

The spec sheet on your power station will tell you how many watts and amps each plug, and all the plugs, on the unit support. The answer varies per unit. My AC200P can handle 2000w, and the bank of 6 AC plugs can take a total across all of them of 15a.

Unless you are going to be building your system from components and wiring it up all by yourself (to include say a battery, inverter and MPPT controller) for the solar input), these are things you don't really have to worry about as its all built into the power station. You read the spec sheet and buy big enough to do the job you want.

 

[PCeBiker]

i have a small inverter but I want/need a power station .

A larger inverter can really help the power station while you're driving.
Find out what the cigarette lighter amp output is.

You don't want to trickle charge your power station.
You want to help out as much as you can.

It takes roughly 1 HP to generate 1000 Watts.
Your van should easily be able to spare a HP.

 

[m@Robertson]

Yeah if you try and trickle charge a power station, the battery is so large it'll take forever to just make a dent in the thing. Car charging is about the slowest way to bring a power station back up. It'll take hours to do it that way and you'll burn a bunch of $5/gallon gasoline doing it.. My portable unit shown above has a 12v input and thats what its for, but the voltage/.amperage that comes in from just one solar panel - never mind three of them - dwarfs that input.

BUT if you are driving a few hours from camp site to camp site, for sure you want that thing plugged into the car.

 

[opimax]

Thanks everyone. Bought a Bluetti AC 70, waiting for delivery