Portable Power for Charging Batteries

robgallo · Sep 19, 2021

I need some math done.

Need to charge 3 MVP2 batteries on the go at least twice each.

Will this 240Wh charger do the trick or do I need something bigger?

Jackery Portable Power Station Explorer 240, 240Wh Backup Lithium Battery, 110V/200W Pure Sine Wave AC Outlet, Solar Generator (Solar Panel Not Included) for Outdoors Camping Travel Hunting Emergency. https://www.amazon.ca/dp/B07D29QNMJ...t_i_K38PMKZPNQG9DMM23KPG?_encoding=UTF8&psc=1

Chrislaf · Sep 19, 2021

Not sure about the Jackery products, but I have used Goal Zero products and they are excellent. I have one of their power banks and some solar panels that are over 6 years old and are still working like like the day I bought them.

As far as the math involved about charging the batteries twice each, can’t help you there. Maybe someone else will chime in.

Chris

Kilrah · Sep 19, 2021

MP2 batteries are 60Wh. 6 charges = 360Wh, minus some because the battery isn't completely empty, plus some because efficiency so both more or less cancel out.

robgallo · Sep 19, 2021

Kilrah said:
MP2 batteries are 60Wh. 6 charges = 360Wh, minus some because the battery isn't completely empty, plus some because efficiency so both more or less cancel out.

Sounds like 240wh isn’t enough then. Thanx.

Not A Speck Of Cereal · Sep 19, 2021

I've used Goal Zero for years and they work great, but I have been hearing the Jackery name more and more and it seems to work. You can get wH per dollar with them, sometimes with less features, but it still seems to hold up quality wise.

Now that you know that you need more than 240wH, there's a couple of other things I would mention:

If this is just for day trips only, no biggie: get more than 360wH and you'll be set. But if you also use this on multi-day road trips, it won't hurt to get something even bigger, like their Explorer 500wH, because you may end up charging more than Mavic batteries.
I see that the battery you linked to has an input. That means that even without solar panels, you can have probably something plugged into the cigarette lighter to at least trickle top-off the big battery as you're driving around. That might add one Mavic battery to the total you can do per day.
If your road trips mean hitting a motel each night, you'll be able to top off the battery daily. But if you do camping without power, you might consider solar panels. I just want to say: get enough panels that total at least 150% of what your input takes, because solar panels rarely give you 100% of what they're rated. For instance, the battery I have that will take 100w, I plug in 160w worth of panels--this means that the battery with more often actually be taking in 100w rather than something lower (which means it takes more hours to fill up the battery).

Chris

eEridani · Sep 19, 2021

In general, you want to consider a 50% loss as a minimum safety factor. A charger is maybe 80% efficient, and that's a huge maybe. An inverter will be lucky to get 75% efficiency. A sine charger worse than a haversine charger unless you pay the big bucks. And then there is charge efficiency losses in the battery: you can put in 60Whr, but the battery only accepts 50Whr (why the battery heats up during charge).

Buy a large 12v LiFePo 50Ah (600Whr) or 100Ah (1200Whr) battery, and use the DJI DC charger to max out efficiency.

kshaw · Sep 20, 2021

I use the same Jackery to charge my Tello drone batteries and it works great. Battery drain on the Jackery seems to be the same whether using AC or not. I carry a 100 watt folding solar panel and it can recharge the Jackery in just a few hours. (faster than the 12v chargers that came with the Jackery). I do not believe that you can use the Jackery while it is being charged, though. I haven't tried it yet to charge my MA2 batteries. I mostly bought the Jackery for camping to blow up air matress and power my portable XM radio but found that I use it for a lot of other things. Here is a table I started on power inputs and outputs for the Jackery. Note that the Jackery 240 is actually a 292 wh device:

Jackery Power Inputs and Outputs

Input 292wh:

12v from Car	36w
AC Charger	60w
Solar Panel—All Power	45w
Solar Panel--Anker

Important: Inputs must be removed before plugging in devices for use or charging.

Output:

Air Mattress from AC
Dremel from AC
Ipad from USB	9w
IPhone from USB	6w
IPod from USB
Mavic Air 2 from AC
Mavic Air 2 from 12v
Refrigerator from 12v
Refrigerator from AC
Samsung Tablet from USB	8w
Tello recharging from AC
XM Radio from 12v	12w
XM Radio from AC	12w

eEridani · Sep 20, 2021

The Jackery 240Whr specification is from a calculated maximum of 242Whrs (14.4vx16.8Ahr). It will actually deliver less than that because of normal expected voltage drop during discharge.

And, you really don't want to discharge a battery to zero. 80-20 is the normal long life cycle - use 80% of capacity for your calculations, which yields only 192Whr of useful charge. I'd go with the 500WHr model as a minimum (400WHr usable). I'd also only use the DJI DC charger off the battery - the AC charger is not as efficient; and when living on batteries, efficiency is king.

kshaw · Sep 20, 2021

eEridani said:
The Jackery 240Whr specification is from a calculated maximum of 242Whrs (14.4vx16.8Ahr). It will actually deliver less than that because of normal expected voltage drop during discharge.

And, you really don't want to discharge a battery to zero. 80-20 is the normal long life cycle - use 80% of capacity for your calculations, which yields only 192Whr of useful charge. I'd go with the 500WHr model as a minimum (400WHr usable). I'd also only use the DJI DC charger off the battery - the AC charger is not as efficient; and when living on batteries, efficiency is king.

Well, this one shows 290wh 400 Watt Peak Output Explorer 290 Wh Portable Power Station That is the one I got. I believe that this is the same unit labeled as Jakery 240 and certainly looks the same and is the same size. Anyway, it will suit my camping requirements perfectly although two AC outlets would be nice. .

eEridani · Sep 20, 2021

kshaw said:
Well, this one shows 290wh 400 Watt Peak Output Explorer 290 Wh Portable Power Station That is the one I got. I believe that this is the same unit labeled as Jakery 240 and certainly looks the same and is the same size. Anyway, it will suit my camping requirements perfectly although two AC outlets would be nice. .

You got to love specs ... your HF version has only a 200W continuous power spec (read the fine print).

ps: not intending to impugn your unit. Just trying to ensure we are all talking the same thing. On the Jackery website, the 240Whr unit is only $199, quite a bit less than the HF model, too.

kshaw · Sep 20, 2021

eEridani said:
You got to love specs ... your HF version has only a 200W continuous power spec (read the fine print).

View attachment 135097

ps: not intending to impugn your unit. Just trying to ensure we are all talking the same thing. On the Jackery website, the 240Whr unit is only $199, quite a bit less than the HF model, too.

There is a difference between battery watt hours and maximum running watts. Max running watts is the maximum watts that be used continuously after an initial surge which may happen with any kind of motor (maybe a blender, air mattress pump, or refrigerator). The surge can go up to 400 watts on this unit. The Jackery can shut down if this limit is exceeded.

MAvic_South_Oz · Sep 20, 2021

eEridani said:
Buy a large 12v LiFePo 50Ah (600Whr) or 100Ah (1200Whr) battery, and use the DJI DC charger to max out efficiency.

This would be the best way to go if the OP will have a vehicle handy* and easy access to that for recharging.
*Vehicle access just to transport and have the battery handy on site.

But, the MP2 charger MIGHT have issues charging with 12v battery at the usual ~ 12.7v full resting charge.

My M1P charger needs higher voltage (13.05v), or it goes into like a duty cycle type of on / off, and I never could get a charge done that way.
If using the car battery plug, same deal, unless the car is running and the alternator is pushing the usual high 13v to 14v into the system.

In the end I ordered a voltage step convertor for the 4WD to recharge drone batteries at camp when I'm touring.
A few simple plugs and decent wiring to suit the length required, and this works very efficiently.

This post (#10) in one of the many car charging threads has the setup shown, worth reading the thread from the start as the OP was having the typical problem of enough voltage.
(In case it comes up . . . no, it's not because the car outlets were not on due to ignition off when stopped, it is related to low voltage overall.)

Charging Batteries in Car?

Anyone else having problems charging ANY DJI batteries in the car? They don't want to charge unless the engine is RUNNING. Tried multiple car chargers, over 2 cars, one with a brand new car battery. Even tried a 12v/120v power inverter. Tried Mavic Air Batteries and now my new Mavic Pro 2. No...

mavicpilots.com

eEridani · Sep 20, 2021

kshaw said:
There is a difference between battery watt hours and maximum running watts. Max running watts is the maximum watts that be used continuously after an initial surge which may happen with any kind of motor (maybe a blender, air mattress pump, or refrigerator). The surge can go up to 400 watts on this unit. The Jackery can shut down if this limit is exceeded.

I hardly ever speak peak power on anything. The figure is pretty much meaningless until you know the duration it will sustain such a load and if the power factor matters; the old VA vs RMS Watts issue. Plus, inrush can happen with anything AC or DC, even DC chargers or computers, so it's still good to know there is some overhead available.

The Jackery 500Whr unit likely meet the needs of the OP. 400Whr usable capacity, so with other efficiency losses easily provides 300Whr of actual drone battery charge.

eEridani · Sep 20, 2021

MAvic_South_Oz said:
This would be the best way to go if the OP will have a vehicle handy* and easy access to that for recharging.
*Vehicle access just to transport and have the battery handy on site.

But, the MP2 charger MIGHT have issues charging with 12v battery at the usual ~ 12.7v full resting charge.

My M1P charger needs higher voltage (13.05v), or it goes into like a duty cycle type of on / off, and I never could get a charge done that way.
If using the car battery plug, same deal, unless the car is running and the alternator is pushing the usual high 13v to 14v into the system.

In the end I ordered a voltage step convertor for the 4WD to recharge drone batteries at camp when I'm touring.
A few simple plugs and decent wiring to suit the length required, and this works very efficiently.

This post (#10) in one of the many car charging threads has the setup shown, worth reading the thread from the start as the OP was having the typical problem of enough voltage.
(In case it comes up . . . no, it's not because the car outlets were not on due to ignition off when stopped, it is related to low voltage overall.)

Charging Batteries in Car?

Anyone else having problems charging ANY DJI batteries in the car? They don't want to charge unless the engine is RUNNING. Tried multiple car chargers, over 2 cars, one with a brand new car battery. Even tried a 12v/120v power inverter. Tried Mavic Air Batteries and now my new Mavic Pro 2. No...

mavicpilots.com

It seems lame the DJI car charger wimps out below 12.6v. I'll need to test mine, see if it is typical. I've used mine to recharge batteries, but it was enroute. It begs the question is the Jackery products maintain adequate voltage as they discharge.

One of these may be in my future:

https://www.amazon.com/Converter-Automatic-12V-Waterproof-Transformer/dp/B07WFMG11F

MAvic_South_Oz · Sep 20, 2021

eEridani said:
It seems lame the DJI car charger wimps out below 12.6v. I'll need to test mine, see if it is typical. I've used mine to recharge batteries, but it was enroute. It begs the question is the Jackery products maintain adequate voltage as they discharge.

One of these may be in my future:

https://www.amazon.com/Converter-Automatic-12V-Waterproof-Transformer/dp/B07WFMG11F

I'd suspect the Jackery would not run the 12v car charger from that plug.
It has the invertor through which can allow use of the normal mains charger, but boy that will suck the battery very fast, not sure what efficiency the OP would get.

Not sure about all DJI 12v chargers when using a resting 12v battery, some might manage fine.
My Spark charger will charge 3 batteries simultaneously on a resting 12v battery or outlet.
Pretty sure Mini chargers would be fine, not sure about Air / Air2.

I really like the 12v chargers, they are faster than mains power !

That Amazon step convertor you posted a link for is both step up and down, haven't really seen that as I found the plain 12v to 13.8v step up one when I needed it, and went with that.
I found this one which can do the job fine, basically the specs for the one I purchased.
Can't see a price as this one is not available here.

Amazon.com: DC/DC 9V-13V to 13.8V Voltage Regulator,12V to 13.8V15A,step-up module,DCMWX boost converter,waterproof power adapt : Electronics

www.amazon.com

eEridani · Sep 21, 2021

MAvic_South_Oz said:
I'd suspect the Jackery would not run the 12v car charger from that plug.
It has the invertor through which can allow use of the normal mains charger, but boy that will suck the battery very fast, not sure what efficiency the OP would get.

Not sure about all DJI 12v chargers when using a resting 12v battery, some might manage fine.
My Spark charger will charge 3 batteries simultaneously on a resting 12v battery or outlet.
Pretty sure Mini chargers would be fine, not sure about Air / Air2.

I really like the 12v chargers, they are faster than mains power !

That Amazon step convertor you posted a link for is both step up and down, haven't really seen that as I found the plain 12v to 13.8v step up one when I needed it, and went with that.
I found this one which can do the job fine, basically the specs for the one I purchased.
Can't see a price as this one is not available here.

Amazon.com: DC/DC 9V-13V to 13.8V Voltage Regulator,12V to 13.8V15A,step-up module,DCMWX boost converter,waterproof power adapt : Electronics

Amazon.com: DC/DC 9V-13V to 13.8V Voltage Regulator,12V to 13.8V15A,step-up module,DCMWX boost converter,waterproof power adapt : Electronics

www.amazon.com

Have you ever had that boost converter running on the car when the car battery is charging at 14.8v? Seems it would have issues ... and why I pointed to the buck-boost. It'll handle all those situations from 14.8V down to 9V - and still provide 13.8v out.

MAvic_South_Oz · Sep 21, 2021

eEridani said:
Have you ever had that boost converter running on the car when the car battery is charging at 14.8v? Seems it would have issues ... and why I pointed to the buck-boost. It'll handle all those situations from 14.8V down to 9V - and still provide 13.8v out.

Never an issue to have batts charging, with or without the step up convertor.
I do usually use it out of habit whether parked or driving.

I think the charger does what it needs to with its output.

By all means, for that little extra self assurance, the one you posted is not overly expensive, probably no different to the plain step up one, or maybe just a small bit extra, which is likely negligible.