Router Battery Backup

Tomtomtom said:
I just did that and they measured about 250-300 mA each (from 1800-2000 new). Even with 6 of them I can't think of a use for 6 Wh of capacity in 18650 form...
Click to expand...
Wow, they must have been cycled a hell of a lot
 
Bundu said:
Wow, they must have been cycled a hell of a lot
Click to expand...

They were junk no-name cells and degraded super fast early on, maybe down to 80% over the first 20 cycles. Then they were held at 100% for a couple of years. This was a replacement for the original battery.

The original didn't do much better and allegedly its cells are Panasonic. But, it's been a more graceful decline, so still usable after 10 years.
 
Coming back to this thread, I got a Elecstor 24000mAh DC-DC UPS earlier this year and decided to do a benchmark on it yesterday.

I unplugged it at ~10:15 and it died at 15:30.

The output watts was 20W non continuous, 11W only for the router and ONT and peaked at 20W while charging a phone as well.

Battery life calculator suggests that the runtime for 20W is ~14 hours.

Which one is more likely, 5.5 hours or 14? 5.5 seems too short and 14 seems to long.
 
Rickster said:
Coming back to this thread, I got a Elecstor 24000mAh DC-DC UPS earlier this year and decided to do a benchmark on it yesterday.

I unplugged it at ~10:15 and it died at 15:30.

The output watts was 20W non continuous, 11W only for the router and ONT and peaked at 20W while charging a phone as well.

Battery life calculator suggests that the runtime for 20W is ~14 hours.

Which one is more likely, 5.5 hours or 14? 5.5 seems too short and 14 seems to long.
Click to expand...

It's rated 75 Wh isn't it?

75/20 = 3.75 hours

So it sounds about right. Your average load was probably more like (75/5.5 = ) 13 W.

(The mAh rating of these things is worse than useless. Capacity depends on a second factor, namely cell voltage, which in this case is apparently 3.125 V. Only use Wh when comparing UPSes.)
 
Tomtomtom said:
It's rated 75 Wh isn't it?

75/20 = 3.75 hours

So it sounds about right. Your average load was probably more like (75/5.5 = ) 13 W.

(The mAh rating of these things is worse than useless. Capacity depends on a second factor, namely cell voltage, which in this case is apparently 3.125 V. Only use Wh when comparing UPSes.)
Click to expand...

Hmmm ok, so that website is talking kak then.
 
Rickster said:
Hmmm ok, so that website is talking kak then.
Click to expand...

100%. The written formula further down that page is even worse. Not even an AI would hallucinate that.

Working backwards, it seems to assume a voltage of 12 V (i.e. lead acid.) They manage not to state this anywhere.
 
Tomtomtom said:
They were junk no-name cells and degraded super fast early on, maybe down to 80% over the first 20 cycles. Then they were held at 100% for a couple of years. This was a replacement for the original battery.

The original didn't do much better and allegedly its cells are Panasonic. But, it's been a more graceful decline, so still usable after 10 years.
Click to expand...
I've only got high quality branded cells out of genuine OEM laptop batteries, Samsung/Panasonic/LG etc, most of which were not far off their rated capacity.
 
airborne said:
I've only got high quality branded cells out of genuine OEM laptop batteries, Samsung/Panasonic/LG etc, most of which were not far off their rated capacity.
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If not far off their rated capacity then what was dead about the pack?

One thing I can say is these cells I retrieved were well-balanced... All equally dead.
 
Tomtomtom said:
If not far off their rated capacity then what was dead about the pack?

One thing I can say is these cells I retrieved were well-balanced... All equally dead.
Click to expand...
Sorry by dead pack I mean from a dead laptop. I used to know a guy that ran a pc repair shop and I’d buy battery packs off him, he always had a whole pile of unrepairable laptops in his storeroom, typically blown motherboards. I was very surprised at how good most of cells were, high quality 18650 cells are remarkably durable.
 
Not sure where to post this.

I have a VRLA gel battery(12V 100AH) that began whistling louder and louder as time went on. I'm not knowledgeable about any of this, so I just disconnected it and I imagine something is wrong. Point of it is to power my pc, router, two monitors during work periods for LS and since I live in Durban, the regular multi-day outages.

Was looking to get a new one, but for one, I'm a little cash strapped at the moment, however it can't wait, and for two, I'm not really sure on the benefits/drawbacks on some of the options. Was looking at these two:

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

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

Would be grateful for any advice.
 
EpicPotato said:
Not sure where to post this.

I have a VRLA gel battery(12V 100AH) that began whistling louder and louder as time went on. I'm not knowledgeable about any of this, so I just disconnected it and I imagine something is wrong. Point of it is to power my pc, router, two monitors during work periods for LS and since I live in Durban, the regular multi-day outages.

Was looking to get a new one, but for one, I'm a little cash strapped at the moment, however it can't wait, and for two, I'm not really sure on the benefits/drawbacks on some of the options. Was looking at these two:

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

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

Would be grateful for any advice.
Click to expand...
Upgrade to LFP and not need to replace battery for 10 years and double your capacity at the same time:
1757768699116.png
 
EpicPotato said:
Not sure where to post this.

I have a VRLA gel battery(12V 100AH) that began whistling louder and louder as time went on. I'm not knowledgeable about any of this, so I just disconnected it and I imagine something is wrong. Point of it is to power my pc, router, two monitors during work periods for LS and since I live in Durban, the regular multi-day outages.

Was looking to get a new one, but for one, I'm a little cash strapped at the moment, however it can't wait, and for two, I'm not really sure on the benefits/drawbacks on some of the options. Was looking at these two:

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

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

Would be grateful for any advice.
Click to expand...
What do you mean by whistling?
Is the battery otherwise working fine?
 
wingnut771 said:
Probably a dead cell making other cells overcharge and vent, he should open a window or else a spark could blow up the room with the hydrogen being vented.
Click to expand...
That's what I was wondering, if it’s not the charge circuit making a weird buzzing and it’s the battery entering it’s last days he needs to get that thing out of the house asap
 
wingnut771 said:
Upgrade to LFP and not need to replace battery for 10 years and double your capacity at the same time:
View attachment 1847786
Click to expand...
Could you elaborate? What's different about this one, aside from it's longevity? What's the situation on buying these sorts of things from Temu? Never bought from them but have heard a lot of negatives.

airborne said:
What do you mean by whistling?
Is the battery otherwise working fine?
Click to expand...
Best I can explain. Incredibly high pitched whistle/whine noise. Was working fine, otherwise. Disconnected it and moved it, cause it didn't seem safe.

airborne said:
That's what I was wondering, if it’s not the charge circuit making a weird buzzing and it’s the battery entering it’s last days he needs to get that thing out of the house asap
Click to expand...
It's being taken off my hands on Thursday, so I'm just waiting till then.
 
EpicPotato said:
Could you elaborate? What's different about this one, aside from it's longevity? What's the situation on buying these sorts of things from Temu? Never bought from them but have heard a lot of negatives.


Best I can explain. Incredibly high pitched whistle/whine noise. Was working fine, otherwise. Disconnected it and moved it, cause it didn't seem safe.


It's being taken off my hands on Thursday, so I'm just waiting till then.
Click to expand...
LFP is a different chemistry and much more robust than LA and with its similar voltage profile can do a straight swap out using LA charger. Only caveat is the flat voltage curve its difficult to determine state of charge using voltage, using a shunt can help with this but I don't think its necessary, just set inverter cut off voltage to 12V which is about 10% SOC.
Here is one from TA if Temu is a no:
1757775127040.png

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

1757775369506.png

1757775514094.png
 
Last edited:
EpicPotato said:
Not sure where to post this.

I have a VRLA gel battery(12V 100AH) that began whistling louder and louder as time went on. I'm not knowledgeable about any of this, so I just disconnected it and I imagine something is wrong. Point of it is to power my pc, router, two monitors during work periods for LS and since I live in Durban, the regular multi-day outages.

Was looking to get a new one, but for one, I'm a little cash strapped at the moment, however it can't wait, and for two, I'm not really sure on the benefits/drawbacks on some of the options. Was looking at these two:

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

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

Would be grateful for any advice.
Click to expand...
Is the charge rate higher than 20% of the battery capacity

Ifnit is charge slower ie no more than 0.2c

Switching to lithium then the charge rate can be quicker

If replacing battery you can replace it with a smaller lithium if budget is tight if max draw is low enougb to fit

Since a 50Ah lithium is essentially equal to a 100Ah lead acid apart from max draw

Since recommended capacityused on lead acid is 50%
 
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