Best Posts in Thread: Brownout vs Internet Connection

WTF are you running? 1200 ah of LiFePO4 is a lot of battery capacity. Remember LiFePO4 has a much greater Depth Of Discharge ("DOD").
To maintain a decent life expectancy (3 years occasional use, 1 year daily use) lead acid batteries DOD should be kept within 25% of the total capacity. So a 1,000 ah system is only useful for 250 ah draw.

On the other hand LiFePO4 batteries can easily handle 80% DOD. So you only need a 300 ah bank for the same 250 ah draw.

LiFePO4 are much lower cost for the same typical draw capacity.

1) Because LiFePO4 can repeatedly support a much larger DOD you can purchase a much smaller LiFePO4 battery bank verses lead acid. As stated above you need to purchase 1,000 ah of lead acid to regularly draw only 250 ah. This same draw can be supported with only 300 ah of LiFePO4. (This is for a solar system that is used daily. A lead acid back up system that is only used occasionally can get away with 40% DOD)

2) LiFePO4 Supports many more discharge cycles and has a longer overall lifespan than lead acid. Lead acid batteries only support 400 cycles or 4-5 years if on stand-by. LiFePO4 on the other hand support 2,000 + cycles and has a stand-by life span of 10 - 20 years.

https://www.powertechsystems.eu/home/tech-corner/lead-acid-battery-downsides/

https://www.power-sonic.com/blog/lithium-vs-lead-acid-batteries/

If you are only using them for backup, you should get another 4 years out of your current batteries.

 

Are you sure your router is 5 volt?
Most routers are 12 volt.

If your router is only 5 volt then you should consider getting a LiPo power bank. these are the power banks people use to charge their mobile devices.

I have had great success with LiPo power banks used in small solar solutions for the wife's family. With a small MPPT controller and 5 volt buck converters a 30 watt solar panel can charge the power bank and their mobile devices during the day. At night they run 5 volt led lights for hours. I wired all the lights with wall switches so they can be turned off when no one is in the room. Great solution.

In your case you only need the power bank and a USB charger.

Power banks are a challenge to by on Shopee or Lazada because there are so many scammers who misquote the specifications. Always check the rated capacity and rated energy in the technical specifications instead of what is stated in the text.

Shopee has a 3 day return policy. If you do NOT click the received button, you have the opportunity to request a refund or a refund and return within three days of delivery. Just explain how the device is not what was advertised and include a picture proving the case.

If you are planning on a larger system, do not buy a system based on lead acid batteries. LiFePO4 batteries have dropped in price. They last much longer than lead acid and have a greater depth of discharge.

 

I have battery back up, that runs my modem and router, PLDT home fibre. lead acid deep cycle batteries wired in series to give 24v.
Had no problems with it all day. Only used 3% of battery probably it would run a modem for a weeks

 

3,000 PHP per month is a low electric bill. I would not be able to size your system based on the electric bill alone. I would need a list of what you want to run and for how long.

Most of my solar and battery experience is completely off grid on a boat. Includes small refrigerator, occasional microwave, occasional power tools (3 total) during sunshine 1200 wh overnight (computer with 30 inch monitor, lights, small refrigerator).

Even now on land, I tend to use 12 volt for as many things as possible. (Fans, Intel NUC computer, 12 volt monitors, etc.) This reduces the loss of going through the inverter. When running off of batteries energy efficiency is critical.

If I was on the grid I would only want a back-up for my entertainment and fans. Why bother with the hassle and expense of backing up the washing machine, etc?

I have a few light bulbs with their own batteries in light sockets here and there around the house. This way there is light during brownouts without having to get involved with the house wiring. Somehow these light bulbs sense when there is no electricity. During brownout if the switch is turned on they turn on and turn off when the switch is turned off.

https://shopee.ph/CATA-LED-Light-Bu...rproof-IP44-i.375461370.3683119718?position=7

 

You are welcome Mr. Bobbit,

You should add a fuse like the motorcycles have. You can get these at the motorcycle parts store.

Be careful using a "car" (starting) battery. Lead acid batteries come in two types. Starting and deep cycle. Deep cycle batteries are what you need for significant discharge. A car starting battery could be ruined in a few discharges.
https://www.centurybatteries.com.au/products/deep-cycle/car-vs-deep-cycle

Oops. 30 years ago there was a difference between one smart battery charger and another. Now days all the smart battery chargers are the same. A smart battery charger can be purchased online for 600 PHP. They typically have the following characteristics:
14.5 - 14.7 v constant current mode because the battery can take more than the battery charger can deliver.
14.5 - 14.7 v Constant voltage mode because after some time the battery charger can deliver more amperage than the battery can absorb.
13.8 v float charge. When the charge current drops to within 1% of rated capacity, the battery charger drops its voltage so it will not overcharge the battery.
https://www.power-sonic.com/blog/how-to-charge-a-lead-acid-battery/

This can be a problem long term because the router (1 amp) + the parasitic battery loss exceeds 1% of the battery capacity. As a result the battery charger will stay in the "high" voltage (14.5) mode and overcharge the battery. For solar systems this is not an issue because the battery gets a rest every night. Keeping the voltage high for a significant part of the day is ok if the battery gets a rest or discharge.

Thank you for the tip. The new QC3 spec is a great feature. In the past charging the battery bank was a problem because it only accepted 1 amp at 5 volt = 5 watts. It took too long to charge. Now with the QC3 spec it makes a great battery for a small solar installation.

 

I don't have a float charger, I charge the batteries when they reach DoD or when I know there is a scheduled brownout.
My 24v inverter powers all 220v AC appliances. The router and modem automatically step down 22v to 5v.

Going to upgrade my system to a 3kw solar off-grid system, when I get back on my feet, just for brownouts only.

 

Jimeve, Do you have a float charger on your setup all the time? And do you use an inverter from 24V to AC for the 5V 1A for the router or DC24V to DC5V? Trying to do the same to keep the router up in between power outage and generator start-up.

Filproducts connection stayed on all day in Bong-Ao Valencia, we had the power out solid until mid afternoon. I heard some people had the power back on for a few hours midday.