Router Battery Backup

agentrfr

Expert Member
Joined
Jul 8, 2008
Messages
4,761
Actually I think one of the reasons these batteries tend to die faster is because they have less time to properly recharge.

I've had loadshedding in stage 2 where power goes off say 21:00-23:00 on day 1, then off again 3:00-5:00 day 2. That means that they don't have a lot of time to recharge probably between sessions (especially since I am running 2x 7Ah batteries in parallel on a charger designed for 1 7Ah battery). So the first loadshedding doesn't deplete the batteries, but the second session does.

And in the case of the sherlotronic psu kills the battery since it let it run to 10v. So the next session it has less capacity, reaches 10v faster and kills the battery even faster.

None of these 12v 7Ah lead cell systems were designed for regular power outrages!
Yes you are right

The charging circuit for 95% of panels assume Pb batteries. Remember that Pb batteries can only charge safely at 0.1C (i.e. a 7Ah battery at 0.7A) and as such the power supply itself is just a capacitive dropper circuit set to an ouput of ~13.8V @ ~1A (300mA for nomal panel operation)

Pb is only 60% couloumbic efficient, so it takes something like 20 hours to fully charge the battery from empty
 

ebendl

Expert Member
Joined
Sep 27, 2004
Messages
3,651
Yes you are right

The charging circuit for 95% of panels assume Pb batteries. Remember that Pb batteries can only charge safely at 0.1C (i.e. a 7Ah battery at 0.7A) and as such the power supply itself is just a capacitive dropper circuit set to an ouput of ~13.8V @ ~1A (300mA for nomal panel operation)

Pb is only 60% couloumbic efficient, so it takes something like 20 hours to fully charge the battery from empty
Thanks for the detailed information -- glad my assumptions were correct.

The voltage across the battery when the Sherlotronics is charging starts off at 13.25 V and seems to be trending upwards over time as the battery gets charged (I assume). Now up to an average of about 13.4 V around 18 hours later:

Screenshot 2020-02-12 at 12.13.04.png
 

RichardZA7

Active Member
Joined
May 9, 2007
Messages
34
Each with their own power pack, or do they share. If they share then surely your usage should be 70mA x 6 = 420mA?
They're split across two power packs. The 70mA is what actual current draw I measured from each power pack's battery, which roughly matches sum of the manufacturer's rated consumption of each sensor. So total draw of all 6 sensors is 140mA (@ 12V)

I've ordered a 412 today that I'll connect all 6 sensors to instead of the two power packs as they have killed my batteries (per earlier post) despite it being impossible at that current draw for the batteries to have been drawn below 50% DoD (they're 8Ah Gel, about 8 months old).

Based on the 412 having 8800mAh @ 3.7 that and assuming 90% efficiency gives 2442mAh @ 12V (if my math is correct) which at 100% DoD will run the sensors for 17 hours. Will post feedback.

Probably going to order 430 or 860 for router and fibre once they in stock.
 

HaNsA

Expert Member
Joined
Jul 13, 2006
Messages
1,973
I'm planning on going the Sherlo route to power my Asus router (it requires 19V). Can someone please recommend an excellent buck boost device? Please supply a URL. Alternatively, please point me to a decent store in the DBN area.

Thanks.

Bought something similar from amazon.
 

fish

Well-Known Member
Joined
Oct 25, 2005
Messages
310
Just came across this thread...

I tried searching but couldn't find out if the Ratel 430P could power (CPE, Unifi USG and Unifi AC PRO)
Has anyone here got something similar or do I need to get the 860?
 

Speedster

Executive Member
Joined
May 2, 2006
Messages
9,298
Just came across this thread...

I tried searching but couldn't find out if the Ratel 430P could power (CPE, Unifi USG and Unifi AC PRO)
Has anyone here got something similar or do I need to get the 860?
Easiest would be to determine the volt / amp requirements for your devices. If they're 12v and less than 30w combined the 430 will be your answer.
 

fish

Well-Known Member
Joined
Oct 25, 2005
Messages
310
Unifi USG is 12v @1amp = 12w and CPE is 12v@0.5 = 6w
Then Unifi AC Pro is POE @ max power 10w
Therefore total 28w just under the 30w
 

RichardZA7

Active Member
Joined
May 9, 2007
Messages
34
They're split across two power packs. The 70mA is what actual current draw I measured from each power pack's battery, which roughly matches sum of the manufacturer's rated consumption of each sensor. So total draw of all 6 sensors is 140mA (@ 12V)

I've ordered a 412 today that I'll connect all 6 sensors to instead of the two power packs as they have killed my batteries (per earlier post) despite it being impossible at that current draw for the batteries to have been drawn below 50% DoD (they're 8Ah Gel, about 8 months old).

Based on the 412 having 8800mAh @ 3.7 that and assuming 90% efficiency gives 2442mAh @ 12V (if my math is correct) which at 100% DoD will run the sensors for 17 hours. Will post feedback.

Probably going to order 430 or 860 for router and fibre once they in stock.
Hooked up Ratel 412 to external sensors instead of power packs and tested with AC off for 3 hours and it was still on 100%.
 

Thor

Honorary Master
Joined
Jun 5, 2014
Messages
39,617
Just came across this thread...

I tried searching but couldn't find out if the Ratel 430P could power (CPE, Unifi USG and Unifi AC PRO)
Has anyone here got something similar or do I need to get the 860?
I have the USG Pro, UAP AC PRO, raspberry pi.

The draw form that was only 20watt so the 430P should work.
 

Vuilhaas

Active Member
Joined
Jun 5, 2017
Messages
32
Only one output port. Also, 8-10 week lead time.
Yeah... They can supply a splitter so you can supply two 12v devices but for a cost obviously.

Seems the Ratels are pretty good value compared to this.

I've got my beady eyes on the 860p. It's a bit pricy but the specs are really good!
 

chickenbeef

Executive Member
Joined
Sep 10, 2008
Messages
8,368
Adding a second 7AH battery in parallel to my Mecer 650va UPS seems to have gotten around the 2 hour hard limit :/

Battery voltage was still above 12v when I checked at 2h5m
 

Anthro

Expert Member
Joined
Jun 13, 2006
Messages
2,581
Adding a second 7AH battery in parallel to my Mecer 650va UPS seems to have gotten around the 2 hour hard limit :/

Battery voltage was still above 12v when I checked at 2h5m
Would you mind showing your work ?
I am wanting to do the same on a 1000va and not too sure how to go about it (not being too ugly)
 

chickenbeef

Executive Member
Joined
Sep 10, 2008
Messages
8,368
Sorry folks, it's not neat. The batteries are outside the UPS case and I drilled extra holes into the UPS case for ventilation.

It's all hidden away in a ventilated cupboard so I didn't worry too much about the looks when hacking it together :)
 
Top