Router Battery Backup

SubtleBeast said:
Nope. That's a three-prong. UK-style I think.
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Decided to buy one, have R 500 rand credit with onedayonly so effectively R 3000 and If I don't like it should be able to sell in a few months for a small loss to some camping enthusiast
 
L-Dog said:
Decided to buy one, have R 500 rand credit with onedayonly so effectively R 3000 and If I don't like it should be able to sell in a few months for a small loss to some camping enthusiast
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Nice. Please come back and let us know how it performs.
 
Dylan_G said:
Right but that's just how *long* it will run for.

In the case of the Ellies Cube Mini... it doesn't output enough current for your use case. It only does 1A per 12V port: https://www.e-systems.co.za/System/FabSheets/0FSLLMINI_Cube_Mini.pdf

View attachment 1337564

As someone mentioned above, your routers *probably* won't pull 1A/1.5A all the time but I mean, do you really wanna take that chance and buy a device that falls short on your actual requirements?
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perfect this helps

what device will work ?
 
x7razor said:
Hi they use a 4s2p pack a total of 8 x 18650 cells BMS is on the main board. Connector and wire you can get at communica electronics or just re-use the old plug and wire :)

You should be able to get the pre assembled packs but from what i saw these shrink-wrapped packs if opened up there is no name on the cells or capacity on them and some use these fake Chinese Rakieta cells branded as 12 000mAh but they are more or less 500-700mAh if tested LOL.

I would rather buy my own cells Samsung, Sony, LG and assemble them myself at least then you know what you have bought.
Click to expand...
This is helpful, thanks. I've found these Samsung cells on Takealot, which should do the job: https://www.takealot.com/samsung-30q-18650-3000mah-4-pack/PLID69527691

But please check if my logic is correct, and help me to make sense of this.

The Ultralan 60W micro-UPS is advertised as having a 17.6AH battery. The datasheet specifies that it consists of 8 X 2200mAh cells. So far it adds up.

My first question
Each cell is supposed to be 3.7V. You've determined that a 4s2p configuration is used. That would add up to 14.8V (4 x 3.7V in series) and 4400mAh (2 x 2200mAh in parallel), not true? If so, why is this micro-UPS advertised as having a capacity of 17.6AH? That would only be true if all the cells were connected in parallel, which it is not, according to you.

Second question
If 4 x 3.7V makes for 14.8V, how do my UPS get to 16.8V, which is what is displays when it first starts to discharge? Am I right to say that it charges to a higher peak voltage (something like 4.2V per cell?) and that 3.7 is a nominal voltage?

Edit: Third question
If I replace the stock battery with my own pack consisting of 8 x 3000mAh cells in 4s2p, that would result in the same voltage (14.8V nominal, 16.8V peak, if above assumption is correct) and a capacity of 6000mAh, which is ±36% higher capacity. Would the BMS be able to take this extra capacity into account in a smart manner and still report battery level accurately, and charge it full etc? Or should I expect the UPS to be confused about what is going on?

Thanks for explaining to someone who only started thinking about this yesterday!
 
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Viva said:
This is helpful, thanks. I've found these Samsung cells on Takealot, which should do the job: https://www.takealot.com/samsung-30q-18650-3000mah-4-pack/PLID69527691

But please check if my logic is correct, and help me to make sense of this.

The Ultralan 60W micro-UPS is advertised as having a 17.6AH battery. The datasheet specifies that it consists of 8 X 2200mAh cells. So far it adds up.

My first question:
Each cell is supposed to be 3.7V. You've determined that a 4s2p configuration is used. That would add up to 14.8V (4 x 3.7V in series) and 4400mAh (2 x 2200mAh in parallel), not true? If so, why is this micro-UPS advertised as having a capacity of 17.6AH? That would only be true if all the cells were connected in parallel, which it is not, according to you.

Second question:
If 4 x 3.7V makes for 14.8V, how do my UPS get to 16.8V, which is what is displays when it first starts to discharge? Am I right to say that it charges to a higher peak voltage (something like 4.2V per cell?) and that 3.7 is a nominal voltage?

Thanks for explaining to someone who only started thinking about this yesterday!
Click to expand...
8 x 2200mAh = 17.6Ah.
 
Viva said:
Only when 8 cells are connected in parallel, from what I understand. When connected in a 4s2p configuration, the resulting capacity would be 4400mAh.
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Series: add voltage
Parallel: add capacity.

3.7V x 8 = 29.6V 2200mAh = 65.12Wh
2200mAh x 8 = 3.7V x 17600mAh = 65.12Wh
 
Viva said:
Only when 8 cells are connected in parallel, from what I understand. When connected in a 4s2p configuration, the resulting capacity would be 4400mAh.
Click to expand...
4S2P = 14.8V (3.7x4) 4400mAh (2200x2) = 65.12Wh
 
Viva said:
Thanks, so we're on the same page then. It is marketing speak to say this configuration has a 17.6AH capacity.
Click to expand...
No worries :)

No, there are 2 ways of reporting capacity. The old Ah way which doesn't tell the full story because there is info missing such as the voltage. The better/newer way is to report capacity is in Wh.
 
Tjoker said:
So my Gizzo 8800 died during 4 hours and 25min of load shedding. It ran dead and won't switch on, any suggestions?
Click to expand...

Probably some of the cells in the battery dropped too low and the bms protection kicked in and disabled the battery/unit. Open it up and charge each cell individually to 50% soc and then reconnect it all up again and it should switch on and then charge like normal.
 
Tjoker said:
So my Gizzo 8800 died during 4 hours and 25min of load shedding. It ran dead and won't switch on, any suggestions?
Click to expand...
Is the power supply still working? Try unplugging the loads and just charge it for a while?
 
wingnut771 said:
Is the power supply still working? Try unplugging the loads and just charge it for a while?
Click to expand...
Had it plugged in over night, still don't want to switch on....

airborne said:
Probably some of the cells in the battery dropped too low and the bms protection kicked in and disabled the battery/unit. Open it up and charge each cell individually to 50% soc and then reconnect it all up again and it should switch on and then charge like normal.
Click to expand...
Ok I can try this...maybe replace batteries?

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Will this work?
 
Tjoker said:
Had it plugged in over night, still don't want to switch on....


Ok I can try this...maybe replace batteries?

Takealot.com: Online Shopping | SA's leading online store

South Africa's leading online store. Fast, reliable delivery to your door. Many ways to pay. Shop anything you can imagine: TVs, laptops, cellphones, kitchen appliances, toys, books, beauty & more. Shop the mobile app anytime, anywhere.
www.takealot.com www.takealot.com

Will this work?
Click to expand...
Open it up and measure the voltage.
 
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