Finding The Right Batteries

[Huggybearman]

Huggy...take pity on us mere mortals (or those of us who are challenged by changing light bulbs :lol: )

How much does a set up like that cost? Are the parts readily available in the Philippines or must they be imported?

I am one of those risk versus benefits type guys.

I read and understand your unique requirements for your wife's work. What I am wondering is if the initial investment is worth for the average "Kano" who wants a back up in case of emergencies.

Great post though (even though I didn't understand most of it :hystery: )

Hi Scott

I am fortunate that I brought the inverter, charger and the Smartgauge with me from the UK. The batteries I got locally here in CDO but I know you can get them in Cebu and Manila. I have also seen them in Home Plus and I have also seen a pure sine wave inverter there. It was only 300 watts and cost IIRC around 5000 php. Pure Sine wave is better than Modified (or quasi) Sine Wave. For example my pedestal fans don't like running on modified wave. They are clearly unhappy, are much noisier and smell like they are overheating.

To give you an example of costs, the batteries were 8000 php each, the 1000 watt invertor was £350 which is around 24,000 php, the 4 stage charger was £120 (8000php) and the Smartgauge battery monitor £130 (about 8700php) there is also a fuse and isolation switch which adds another £40 or so. (2600php). But they are good quality components that can be left on permanently to make it a genuine UPS. You could make one from locally sourced components purely as a back-up system for a lot less. Perhaps a third of the price.

I also had to make up the box which was from a sheet of 3/4" ply. A couple of hinges, double electrical socket, three handles and six small castor wheels so I can move it around easily completes the list.

As an added precaution I have a plug-in voltage regulator between the wall outlet and the UPS which the charger plugs into. It would be ironic to have the UPS blow up due to a power surge!

It's not a cheap solution, but with the pattern of un-scheduled rolling brownouts we have here, it is an essential requirement for my wife's teaching. There is nothing more frustrating than her coming to the end of an hours tutorial and then suddenly the power goes off! In that event she doesn't get paid for that hour so there is a cost implication.

As to whether something like the set up I have here is worth it to you is debatable. I must say, having a system that means, apart from not being able to run the A/C, that we are for all practical purposes, unaffected by a brownout, at least in the short term, is a god send.

Ken

Edited January 6, 2016 by Huggybearman

[earthdome]

 

Fun to talk about, but is it a) cost effective, b) as safe as a gas generator and c) oh there must be a C but my brain is freezing up right now

 

When you put it that way, a small generator may be more cost effective if you don't mind running to the gas station to fill it and if it does not cost too much in repairs and maintenance.  Of course there is also the noise factor and the inconvenience (with batteries you just flip a switch but generators often need a bit more setting up). 

 

I mentioned RVs in my last post.  Thinking back on it (I spent a lot of months living in an RV) almost all of them have battery and inverter backup for areas where you cannot plug in to the power lines and only the higher cost RVs have a generator.  Is that because batteries are cheaper in North America?  Or because generators are more expensive?  Or are the RV manufacturers seeing something that we are missing here?

 

 

I major difference in your comparison is that you are comparing an RV designed to use DC power to a home with things designed to use AC. Most things in an RV are powered by DC which is more efficient than going through an inverter.

[florin1106]

I am also one of the 'wimps' who does not handle brownouts very well. We have our fair share of power outages here and they can last up to four hours. My good lady teaches English over the internet for a Taiwanese based school so it is important that the internet is protected in such circumstances. So I knocked together a UPS which has a 1000 watt pure sine wave inverter running from two locally sourced 12v 100 amp/hour deep cycle, maintenance free batteries. These are wired in parallel to provide 12 volts and 200 amp hour capacity. They are permanently connected to a four stage 'intelligent' charger which keeps the UPS charged and the TV, three pedestal fans, cable TV box and internet are permanently run off it. In the event of a brownout I also attach a couple of LED table lamps and that keeps us entertained and comfortable for about four hours. All the equipment which runs off the inverter totals around 300 watts. At 12 volts that amounts to around 25 amps current draw. It is not a good idea to discharge your batteries below around 50% state of charge, to prolong their life, so my 200 amp hour capacity will give around four hours at 25 amps down to 50%.

So, to answer the OP's question, to run a 1500 watt inverter would require a current draw at 12 volts of around 125 amps. So ideally you would need around 500 amp hour of battery capacity to run 1500 watts for four hours. That would need to be doubled to protect your batteries down to a 50% state of charge. So around a 1000 amp hours of battery capacity would be needed. I have fitted a battery monitor called a Smartgauge which indicates the state of charge so I don't go below the desired 50%. Another thing to bear in mind is the continuos rating of the inverter. On start-up some equipment have an initial current draw considerably in excess of their rated power. An example would be a 1HP air conditioner. Its continuous rated power would be around 900 watts but on start up could be three times this.

It is also important to use deep cycle batteries. Automotive batteries are built differently, for a different purpose, and their life will be very short lived if used for running an inverter for any length of time.

For prolonged power outages I also have a little Honda Eu10i inverter generator which is very economical and quiet in operation. The gennys you can buy cheaply in the likes of Ace Hardware are very noisy, and use a modified sine wave which is not suitable for all types of equipment.

Ken

Good job Kenny

[Dave Hounddriver]

On 1/5/2016 at 8:57 PM, Huggybearman said:

So, to answer the OP's question, to run a 1500 watt inverter would require a current draw at 12 volts of around 125 amps. So ideally you would need around 500 amp hour of battery capacity to run 1500 watts for four hours. That would need to be doubled to protect your batteries down to a 50% state of charge

There is some good info in this thread but I have found a "calculator" on line that has me wondering about these numbers.  The calculator is here: https://www.batterystuff.com/kb/tools/calculator-sizing-a-battery-to-a-load.html

To start with, let me say the area I live in is now having frequent 1 and 2 hour brownouts with occasional 8 hour brownouts.  I have a 1500 watt inverter but lets say I will only average 1000 watts of usage over a period of hours.  The calculator says that 1000 Watts/220 volts = about 4.5 Amps. I put that number in the calculator and input 8 as the number of hours I want to maintain that draw and it tells me that I will need a battery rated slightly less than 100 ah / 20 hours.  That sounds more reasonable and I can pick up one of those for 10K pesos.  I can charge it when the power is on and have a light, a fan, and my Internet all plugged into that for the duration of any brownout.

Am I reading that calculator right?

[Gary D]

One problem that needs to be considdered when power is out due to a typhoon is that your solar panels probably got wrecked at the same time.

[Huggybearman]

2 hours ago, Dave Hounddriver said:

There is some good info in this thread but I have found a "calculator" on line that has me wondering about these numbers.  The calculator is here: https://www.batterystuff.com/kb/tools/calculator-sizing-a-battery-to-a-load.html

To start with, let me say the area I live in is now having frequent 1 and 2 hour brownouts with occasional 8 hour brownouts.  I have a 1500 watt inverter but lets say I will only average 1000 watts of usage over a period of hours.  The calculator says that 1000 Watts/220 volts = about 4.5 Amps. I put that number in the calculator and input 8 as the number of hours I want to maintain that draw and it tells me that I will need a battery rated slightly less than 100 ah / 20 hours.  That sounds more reasonable and I can pick up one of those for 10K pesos.  I can charge it when the power is on and have a light, a fan, and my Internet all plugged into that for the duration of any brownout.

Am I reading that calculator right?

Hi Dave

In your example you are not running an inverter from 220v, you are running it from 12 volts. If you have a 220v power source you do not need an inverter. The whole purpose of an inverter is to convert 12v (or 24v) up to either 110v or 220v (or even 240v) to run mains voltage appliances from a low voltage source.

So in your example of running a 1000 watt appliance from 220v your figure of 4.5 amps is, at face value, correct. (1000 / 220 = 4.54 amps) Except of course you would not run a 220v appliance from an inverter powered from a 220v source! 

However, if you are running a 1000w appliance via a 12v inverter to provide 220v then your current draw would be 1000 / 12 = 83.3 amps. 

So if you wished to be able to run a load of 1000w for 2 hours then your total current use would be around 166ah. To avoid damage to the battery you would need a battery capacity of at least 330ah capacity. The more the better.

If you return to the calculator you provided the link to and insert 83 amps and not 4.5 then your calculator will show a battery size (flooded battery option) of about 640 ah which seems excessive for a depth of discharge to 50%. 

Using AGM batteries, which I use, your calculator estimates 410ah.

In your example, to run your 1000w for 8 hours your calculator says you need a flooded battery capacity of 1726ah not 94ah as suggested.

You should also bear in mind the start up current of the appliances you intend to run off your inverter, which can be considerable. For example an air con unit can have an initial start load of three times its running draw. My 1hp unit normally draws 945w but on start-up can draw up to 2700 watts. Not that I am suggesting you should run an aircon from your inverter, but nevertheless these start up loads need to be taken into account when selecting an approriate inverter/battery combination.

I hope that helps.

Ken

[Jollygoodfellow]

2 hours ago, Huggybearman said:

Hi Dave

In your example you are not running an inverter from 220v, you are running it from 12 volts. If you have a 220v power source you do not need an inverter. The whole purpose of an inverter is to convert 12v (or 24v) up to either 110v or 220v (or even 240v) to run mains voltage appliances from a low voltage source.

So in your example of running a 1000 watt appliance from 220v your figure of 4.5 amps is, at face value, correct. (1000 / 220 = 4.54 amps) Except of course you would not run a 220v appliance from an inverter powered from a 220v source! 

However, if you are running a 1000w appliance via a 12v inverter to provide 220v then your current draw would be 1000 / 12 = 83.3 amps. 

So if you wished to be able to run a load of 1000w for 2 hours then your total current use would be around 166ah. To avoid damage to the battery you would need a battery capacity of at least 330ah capacity. The more the better.

If you return to the calculator you provided the link to and insert 83 amps and not 4.5 then your calculator will show a battery size (flooded battery option) of about 640 ah which seems excessive for a depth of discharge to 50%. 

Using AGM batteries, which I use, your calculator estimates 410ah.

In your example, to run your 1000w for 8 hours your calculator says you need a flooded battery capacity of 1726ah not 94ah as suggested.

You should also bear in mind the start up current of the appliances you intend to run off your inverter, which can be considerable. For example an air con unit can have an initial start load of three times its running draw. My 1hp unit normally draws 945w but on start-up can draw up to 2700 watts. Not that I am suggesting you should run an aircon from your inverter, but nevertheless these start up loads need to be taken into account when selecting an approriate inverter/battery combination.

I hope that helps.

Ken

You can say that again.  Obviously know your stuff 

[mogo51]

9 hours ago, Dave Hounddriver said:

There is some good info in this thread but I have found a "calculator" on line that has me wondering about these numbers.  The calculator is here: https://www.batterystuff.com/kb/tools/calculator-sizing-a-battery-to-a-load.html

To start with, let me say the area I live in is now having frequent 1 and 2 hour brownouts with occasional 8 hour brownouts.  I have a 1500 watt inverter but lets say I will only average 1000 watts of usage over a period of hours.  The calculator says that 1000 Watts/220 volts = about 4.5 Amps. I put that number in the calculator and input 8 as the number of hours I want to maintain that draw and it tells me that I will need a battery rated slightly less than 100 ah / 20 hours.  That sounds more reasonable and I can pick up one of those for 10K pesos.  I can charge it when the power is on and have a light, a fan, and my Internet all plugged into that for the duration of any brownout.

Am I reading that calculator right?

Seems you have the calculations right Dave, but don't take my word for it.  I am pleased you have your priorities right ie. internet on the 'must have' list.  What about the fridge to keep the beer cold????  You may have to redo the calcs.

[AlwaysRt]

9 hours ago, Huggybearman said:

I hope that helps.

I have been trying to figure this out for months. I have a very similar load requirement as you do (TV as monitor, laptop, router, fan). My first idea was to replace my 12v 7Ah APC 650 UPS battery with a 12v 100Ah battery (I am shooting for 1-2 hour runtime vs your 4 hour). I have been convinced by research I would burn up the inverter and/or the charger as the UPS was not designed to discharge or charge for hours. All the information I can find jumps over your setup, either discussing a UPS or whole house solutions.

What inverter and charger do I need to look for here in the Philippines that is quality but not way over capacity? I don't see a need to have an inverter and charger sized (and priced) for running a house for a day when I just want to watch a movie or comment on the forum for a couple hours.

[Dave Hounddriver]

24 minutes ago, AlwaysRt said:

What inverter and charger do I need to look for here in the Philippines that is quality but not way over capacity?

Here is where I cannot wrap my mind around things.  Decades ago i had an RV that would run for 8 hours easy on a couple of old batteries.  The fridge was 3 way so I was not running the fridge off battery unless the engine was running but there was also an inverter so I could plug small 110 Volt appliances in it.  All this on one RV battery.  So how complicated can it be.  To read all the stuff on the Internet these days sure seems like everyone is overthinking this.  If I could just set up my house like I had my RV then I would be in heaven and the funny thing is, I am not running any more stuff in this house than I did in the RV (except I had no aircon in the RV but I am not looking to run aircons off batteries) and the house is about the same size as the RV I lived in so why is it so confounded difficult to set it up?