Need a powerbackup



  • Hello guys,kindly assist.. I know this topic is not related to any of pfsense topics bit just need help. So i have been running a wisp for a while now and one of the major challenges i have encountered are power blackouts although not often. Currently i have a mecer 650VA Ups, which i connected to an external car battery. It runs for about two hours.. The challenge i have is the charging system since the ups is designed for small 12V batteries.. so it doesnt charge the battery effectively.What would you guys advice for an affordable system that can power the system for 24hrs incase of power blackouts..



  • @OpenWifi

    Unless everything else is running what's the point. A UPS is intended to keep things up long enough to get past short outages and then trigger a proper power down on longer outages.


  • LAYER 8 Global Moderator

    Moved this to General discussion section.. Also I edited your post - forum was representing your battery. it as link.. I put space after the period.. Pretty sure you didn't want that as a link ;)

    You want to run your system(s) for 24 hours off battery? That is going to require a lot of batteries ;) Or a REALLY big one!

    As mentioned the typical ups is meant to handle short outages, and when the run time gets low proper shutdown of the equipment.. Run times would be more in the say 30 min to 1 hour range for a typical home ups with min amount of load on it..

    Go here
    https://www.apc.com/shop/us/en/tools/ups_selector/

    Put in our requirements..

    Price is not going to be cheap ;) But sure you can get 24 hour run times.


  • Netgate Administrator

    What exactly are you powering from this?


  • LAYER 8 Global Moderator

    That for sure is a min amount of info to know if wanted to work out what system would need to run on battery that long.

    I have my networking gear on a couple of different ups here.. I can get a good solid 30 minutes of run time for modem, pfsense, switch(es), nas and 3 APs... But 3 different ups used. This handles almost all power outages.. Unless something really goes wrong.. We were without power for 3 days one time... Power company even reimbursed for stuff that was in the frig, etc..

    From that link I provided even just a few hundred watts and 24 hour run time going to be a few $K in cost..

    If your really looking to such long run times, your better option would be to get a generator, now all your ups has to do is provide power while you switch over to generator.



  • Nat gas generator, through a power conditioner. $$$


  • Netgate Administrator

    No response. But my followup suggestion here would be that if you're running all low power, low voltage equipment like APUs and access points etc then you should consider some sort of DC-DC scheme.
    Running a UPS where everything is converted from 12V DC (in this case) to mains AC only to be fed into power bricks to get back to (probably) 12V DC is very inefficient.

    Steve



  • @stephenw10 , sorry for the delay, was out for the weekend to somewhere with poor signal. What i need to power is my pfsense installed on CPU, a switch, about five P.O.E access points and 3 routers.Thank you for the suggestion but found out i could use a tripplite 1250 APS but it is very costly guess i will have to go back to the drawing board


  • LAYER 8 Global Moderator

    @OpenWifi said in Need a powerbackup:

    i will have to go back to the drawing board

    Telling you trying to do this off Batteries is going to be $$$$... You can get a cheap gas gen for like 200$ that can do 1200W that would give you 24 run time off a few gallons of gas..

    You have your UPS that gives you say 1 hour of battery... Which gives you time to start up the gen, and plug into the gen vs your normal power.. It's not automated or anything - but can be done on the cheap! You just need to make sure get an alert that can wake you up if power goes out at say 3 in the morning..

    Here you go
    https://www.amazon.com/Pulsar-Portable-Gas-Powered-Generator-PG1202S/dp/B00EFZQ53W
    $140

    Shit that is the cost of your everyday home UPS... Actually I think I spent more on my latest ups..



  • @OpenWifi said in Need a powerbackup:
    Currently i have a mecer 650VA Ups, which i connected to an external car battery.
    The challenge i have is the charging system since the ups is designed for small 12V batteries.

    If you're looking for long run times you probably want an inverter/charger and deep-cycle batteries. You are correct that your current setup isn't ideal - the charger in that UPS is designed for small 12V batteries and likely does not provide sufficient charging current to charge the external battery properly. Also, car batteries are designed to provide a lot of current quickly but are not deisgned for frequent charge/discharge cycles. What you need are deep-cycle batteries designed for backup/solar/marine use. You want ones that are "AGM" or "Gel" sealed type, not the old "wet" type that requires adding water.

    I live in a country with frequent power blackouts, sometimes lasting days. When the power is out the main essential things I need are a couple LED light bulbs, my server rack which contains my pfSense router, ISP modem, switch, Ubiquiti Unifi controller then in another room another switch, Access Points, Mac Mini, etc.

    Yes, you could achieve runtimes with lots of UPS, or one big UPS, but it will be a lot more expensive than getting a good pure sine wave inverter/charger and some deep-cycle batteries. I have a 3000w 24v inverter/charger hooked up to 2 x 200ah 12v AGM batteries and my above setup gets close to 48hrs when the grid power goes down.

    I still use an APC UPS between the inverter and the devices though, because the UPS model I have gives network shutdown capability as well as providing quicker switchover times than the inverter. But because the UPS is running off the inverter the capacity of the UPS is not really important as it only ever kicks in for a few seconds when the inverter switches over.

    Here's an old photo of my setup:

    https://imgur.com/a/Q97X0mo

    From left, 2 x 200ah AGM batteries, Outback VFX3024E inverter/charger, A Sollatek automatic-voltage regulator (which isn't really necessary). The red/yellow switch is a changeover switch to manually choose mains direct bypassing the inverter, or through the inverter. The box marked "AVS" on the wall is an automatic voltage switcher and surge protector to disconnect the mains in case of over/under voltage or surges.

    You likely don't need something that complex, and could get by with a much smaller inverter/charger, but in my experience an inverter/charger is a much preferable solution to a generator because everything is automatic, it produces no noise, the changeover is close to instant, and requires no maintenence such as replenishing fuel, oil etc. But the first thing to do for sizing a system is to actually measure the maximum wattage that all your devices consume.

    PS - The idea someone posted of running a 12v power distribution system is actually a good one, and it's true that it is more efficient, but it's also like more complex and less flexible... for example with a 120/240 system you can also run devices that only have 120/240v input, charge laptops, phones, etc.


  • LAYER 8 Global Moderator

    And how much did that setup cost? 1 of those batteries on amazon is 300-400$, your VFX3024E what $1500?



  • @johnpoz - yes not cheap, but when you live with frequent power cuts sometimes 24-48hrs long and need to work from home, it's needed. Batteries were $270 each, inverter was $1000 secondhand though costs $2500 new where I am. I bought it to run a whole house (including fridge but minus high wattage kitchen items which you exclude at the consumer unit level) and originally had 4 of those batteries. Outback and Victron are probably the leading brands of inverter/chargers, but you can also get much cheaper models from other companies. Most telcos here use a similar setup for their 4G transmission towers, exchanges, etc.
    Not sure exactly what the OP's needs are but they say they run a WISP so.... In any case the key is sizing the system - in terms of what your maximum and average power consumption is and duration needed, only then can you really work out what is needed, but for only running network items you could probably make do with a much smaller inverter and a single battery.
    The point is for really long duration backup times, it's probably more economical to use an inverter and battery setup than very high capacity or multiple UPSes, and replacing or purchasing a single 200ah battery is likely cheaper than 200ah worth of much smaller e.g. 17ah UPS batteries. But a lot also depends where you live and what's available.
    Also of note.... with the the way deep-cycle batteries work, including in UPSes I imagine, batteries in a larger battery system specced so that it regularly only discharges say 10-30%, will have a way, way longer useable life than a smaller system that regularly discharges say 70% or goes completely flat during regular cuts....
    https://www.civicsolar.com/article/how-does-depth-discharge-factor-grid-connected-battery-systems
    http://www.solar365.com/solar/photovoltaic/deep-cycle-batteries-discharge
    If you did want to go down the gas generator route, and are using sensitive electronic equipment, I highly recommend using an inverter generator as the power output is much more stable. The Honda units are great, and relatively quiet: https://powerequipment.honda.com/generators/inverter-generators
    When my inverter ran the whole house I also had the Honda EU1000i model for use on really long cuts when the inverter batteries were finished, hooked into the server rack with an APC transfer switch.


  • LAYER 8 Global Moderator

    @occamsrazor said in Need a powerbackup:

    go down the gas generator route, and are using sensitive electronic equipment,

    Well no you wouldn't plug direct into the gas generator ;)

    But from his reaction to the cost of just a tripplite, I think a simple gas generator and a smaller ups to plug it into is more in his budget.


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