As part of this project I also am trying to make this:
More manageable.
The specs: UPS: Apc unit has cold start ability , but only a 12 7Ah battery.
Battery bank:13Vdc 48Ah AGM batteries Batteries are 6V 12Ah wired up for 12V gives me 12V @48Ah !!!
The mil-spec router has a near constant draw of 12.5Vdc 1.3A with 3 CAT5 connections and 4 SSID connections all with MSN running on Chrome.
The UPS was really never meant to charge this many batteries, and it will eventually not be able to keep up with the current draw, hence the reasoning behind the large bank.
APC is known for constantly charging up batteries even once they are fully charged.
During my testing for charge, it puts out a voltage of 13.5 (No load ). I connected an AGM battery pack with a voltage reading of 12.3 , this UPS topped out at 0.25Amps. This is a constant. Once the battery's voltage was up reading 13.2 it was still running 0.25Amps.
It's nice having 2 digital meters!!
My PI eyed idea is this: hook up all the 6Vdc AGMs I have, let it charge them up and run the system. This poor little charging will take a week to completely recharge
.
The router has pretty interesting programmable settings. I have adjusted the minimum voltage cut-off to be 12.5 ( I know this is too low but the
TEST battery is bulging and will not ever fit back into the case). I was able to test that the cutoff works. This was important!
Once the weeks worth of charging for the battery bank is finished I will set the cutoff to be 12.8. Using the AGMs I should get about 30Ahrs of run time before the router shuts itself off due to voltage minimum at which point the UPS will continue to recharge the batteries.
Once ALL of this testing has done a repeated a few more times, I'll move the LiFePO4s into the spot for testing as well.
I know the Li batteries will not be able to last more than a couple hours (4 at most) but it's their portability that counts. The AGMs are hard to beat when it comes to W/kg but this will be a good exercise in taking stuff that would normally be recycled and making them useful again.
NOT to mention all of the learning I will get.