Inverters Made in the DR

[J D Sauser]

Erm... Cobraboy.
I don't know if I misread your last post with your calculations.
But if you have 4 (?) batteries with a nominal capacity of 220AH each at 6 Volts... you have effectively a theoretical POWER reserve of 5280 Watts (5.8KW). The formula being Volts x Amperes. Amperes at 6 Volts are not synonymous of the same power as Amperes at 110/220 Volts. Only Watts compare like apple to apples independently from the voltage(s).
Now, above figure is still without accounting for deductions, like you not wanting to completely drain your batteries, the inverter conversion process, modified sine wave, energy lost in heat, etc. Once you have the data of those losses and deductions applied to above theoretical number, you then divide the result by the amount of hours you expect to run on the inverter continuously until you can reload to get your KWh rate and compare it to your average KWh consumption.

I am no electrician, so maybe I am loosing it here?

... J-D.

 

[cobraboy]

Oh well, Sometimes calculations are just that, calculations, I am talking by experience here, not just babbling stuff, We've had an inverter since 2000 first with 8 batteries and then with just 4 (really expensive to change 8 every 2 years). And the longer blackout we had was one time when Edesur disconnected us from the main supply as somebody forgot to pay the bill, with 8 batteries and the fridge running (Mabe) the inverter lasted exactly 19 hours, by then we had an small apartment with only 6 lights on, 2 TV's, couple of ceiling fans and a desktop PC.

Now with only 4 batteries we don't bother connecting the fridge with the inverter as we know by experience that will last 5-6 hours at most (bigger apartment may have something to do with that too).

Let's wait the real test to see if it matches your calculation sheet.

You may be correct. I want to thank J D for pointing out to me the error of my math. You can combine voltage or capacity, but not both. My bank may last 20 hours, less than I figured. AZB has a point: I may want 4 more batteries.

Thanks!

 

[J D Sauser]

Glad we could help catch the glitch.

Here is some interesting reading regarding the effective usable capacity (recommended drain) of "deep cycle" batteries:

...

• Deep cycle batteries are designed to be discharged down as much as 80% time after time, and have much thicker plates. The major difference between a true deep cycle battery and others is that the plates are SOLID Lead plates - not sponge. This gives less surface area, thus less "instant" power like starting batteries need. Although these an be cycled down to 20% charge, the best lifespan vs cost method is to keep the average cycle at about 50% discharge.

Source and interesting reading:

• Deep Cycle Battery FAQ
• Battery Tutorial | BatteryStuff.com

That alone reduces your effective POWER reserve by 20% to 50% from the theoretical result of multiplying Voltage (V) by nominal (max) capacity (AH). aranoid:
Above article also shortly mentions an other phenomenon and it's reason (which has escaped me until now), which is why deep cycle battery inverter systems are commonly not rated for use with power demand surge appliances like AC's, fridges and water pressure pumps (there are special pumps for these applications). Again, larger battery banks should have a better demand surge handling.

... J-D.

 

[ExtremeR]

Not to beat on a dead horse but I grabbed a pencil and I made my own calculations based in the information you gave us Cobraboy.

You mentioned that you consume an average of 18,450 Watts per day (24h cycle) in your house. If we take into account the calculation made by JD Sausser that your bank of batteries only have 5280 (220A X 6V X 4Batteries) Watts of power accumulated when fully loaded. By my calculations that amount of energy will last you (assuming you don't change your consumption habits) only 6.1 hours of energy taking into account the loss of efficiency.

Here is my math:
18,450W / 24h = 768Wh
5280W / 768Wh = 6.875 hours of energy

Now let's take out 10% from the energy stored due to loss of efficiency:
5280 - 10% = 4752
4752W / 768Wh = 6.1 hours of energy, right along the line of what I was thinking.

Please correct me if I made something stupid with my math .

 

[J D Sauser]

Not to beat on a dead horse but I grabbed a pencil and I made my own calculations based in the information you gave us Cobraboy.

You mentioned that you consume an average of 18,450 Watts per day (24h cycle) in your house. If we take into account the calculation made by JD Sausser that your bank of batteries only have 5280 (220A X 6V X 4Batteries) Watts of power accumulated when fully loaded. By my calculations that amount of energy will last you (assuming you don't change your consumption habits) only 6.1 hours of energy taking into account the loss of efficiency.

Here is my math:
18,450W / 24h = 768Wh
5280W / 768Wh = 6.875 hours of energy

Now let's take out 10% from the energy stored due to loss of efficiency:
5280 - 10% = 4752
4752W / 768Wh = 6.1 hours of energy, right along the line of what I was thinking.

Please correct me if I made something stupid with my math .

Nothing stupid there.
Just need to take another 20% to 50% off because we are not going to drain the batteries further than 50% to 80%.

So, we're down to 3 to 4 Hrs. with 4 and 6 to 8 Hrs on 8 batteries.

... J-D.

 

[cobraboy]

My error in battery capacity came from installing similar systems on larger sailboats. Difference...and a substantial one...is all but the a/c, wh and various cabin plugs are 12v...all nav devices, autoplots, radios, radar, cabin and running lights and fridge.

LOL...yes, substantial difference with a 110v/24v system.

 

[cobraboy]

Nothing stupid there.
Just need to take another 20% to 50% off because we are not going to drain the batteries further than 50% to 80%.

So, we're down to 3 to 4 Hrs. with 4 and 6 to 8 Hrs on 8 batteries.

... J-D.

The old house had a 3624 system with 8 not-so-great batteries. The power load was identical if not slightly larger. We got 28 hours on the system during the longest balckout we ever had.

 

[waytogo]

When you were pricing with this company, did you ask the difference in price from a 3.6 to a 5.0?

 

[J D Sauser]

The old house had a 3624 system with 8 not-so-great batteries. The power load was identical if not slightly larger. We got 28 hours on the system during the longest balckout we ever had.

Hmmm... math is math, CobraBoy. You know you can't get more out of a battery than what is in it. Are you sure the old house system did have the fridge, AC and water pressure pump ON the inverter power? Most systems are wired so they are not.
Here I run a similar system. We have about the same EdeNorte bill and get about 20 + Hrs... but the kitchen is virtually disconnected except for the lights and there is no power going to both, AC and pressure pump (the later really being bothersome).

Btw., I'd join in on WTG's suggestion to at least check out the price difference for a 5K inverter.


... J-D.

 

[bob saunders]

So if you have a 5K inverter how many batteries should you have?

 

[waytogo]

I believe that the 5 k gives you more energy capacity at any given time. The amount of batteries give you longevity.

 

[J D Sauser]

So if you have a 5K inverter how many batteries should you have?

The inverter power ratings only limits the max peak or continuous power the inverter can safely process. One tries to have an inverter which rating is a good percentage above the needed power.

It would be the batteries capacity and number of batteries which would have to match or better top the total power need over the target time period one designs an inverter system for.

However, eight 220AH/6V batteries would be a typical bank for a 5K inverter too.

... J-D.

 

[cobraboy]

I find it interesting that US Battery does not have a US 245 in their product line. It would be very disappointing if they were "private labeling" a battery incorrectly. (I have been burned by another battery importer/vendor, based in Santiago, labeling a 208 AH battery from Crown Battery, which they labeled as an "Energy" battery with a 250 AH rating - highly unethical)

Regarding US Battery's product line please see

U.S. Battery-Product Line

I don't see a US 245 battery shown at the US Battery site.

The label is clear (the pic may not be, it's taken with my cell phone as my real my camera is being repaired repaired).

Look closely at the white rectangle: "Made With Pride in the USA by the U.S. Barrery Mfg. Co."

Note the label also says "International Warranty". Perhaps made for the export market?

 

[cobraboy]

The inverter power ratings only limits the max peak or continuous power the inverter can safely process. One tries to have an inverter which rating is a good percentage above the needed power.

It would be the batteries capacity and number of batteries which would have to match or better top the total power need over the target time period one designs an inverter system for.

However, eight 220AH/6V batteries would be a typical bank for a 5K inverter too.

... J-D.

Emphasis on continuous power. Most well designed inverters will allow a 100% "overpower" for 5-10 seconds...not continuous...for motor start up.

 

[cobraboy]

Hmmm... math is math, CobraBoy. You know you can't get more out of a battery than what is in it. Are you sure the old house system did have the fridge, AC and water pressure pump ON the inverter power? Most systems are wired so they are not.

... J-D.

The configuration there was the same as here, but I had no a/c there.

The fridge was on it. The water heater and pump were 220v and NOT on it.

 

[El Rey de Mangu]

The configuration there was the same as here, but I had no a/c there.

The fridge was on it. The water heater and pump were 220v and NOT on it.

This thread, as stated above, could be in the running for "best DR practical advice of mthe year".

Most of us all want to be home engineering "experts", but truth is, it is not that easy.

I run the same system listed above, modified protrace but with 8x6V 250 Amp battery bank.

What this provides is approx 6v*250A*8 und = 12,000 watts. What this gets me is about 20 hours running half the house (average) 20cu ft fridge (Mabe) included. When I unplug the fridge, I get about 50% more utilization.

We also use EdeNorte, which of late, is sh--. For example, my 220 comes in at a whopping 190, sometimes less. The 110 varies at 90-something to 120.

FOR THIS, I use a 5K regulator (which is copper-based transformer with 3 salida (110,220, and 240). This unit installed and 1 year warranty cost me 18K pesos. It is custom-made in SDO. (there is an assembly line "Nippon American" I believe and these are generally sh-- aluminum-based transformers and are a waste of money).

When the light comes in low (most days), I jack up the transformer to the 240V salida, and this "ups" the juice and my 220 12,000BTU hums along nice and cold. The transformer also steps up overall household juice so we are able to run 2 spilts (110, 9000btu and 220 12000btu) and my 20 cu ft fridge, along with ceiling and floor fans, etc. and 32 inch LED.

The whole deal cost me 50K pesos intalled and full warranty 15 months. I am very satisfied.

 

[J D Sauser]

The label is clear (the pic may not be, it's taken with my cell phone as my real my camera is being repaired repaired).

Look closely at the white rectangle: "Made With Pride in the USA by the U.S. Barrery Mfg. Co."
Note the label also says "International Warranty". Perhaps made for the export market?

Nice! But... -erm-... who is the lucky one to have the privilege of honoring this Int'l warranty here in the DR? :cheeky:

The configuration there was the same as here, but I had no a/c there.

The fridge was on it. The water heater and pump were 220v and NOT on it.

So, no AC nor water pressure pump. Washer/dryer, microwave outlet?
Also an other item often forgotten which was certainly NOT on, when running on the inverter, is...
charging the batteries! That may seem ridiculous... but I have a funny feeling it may easily amount to one or two KW a day when on the grid for homes which use their inverter only for short "switch over" black outs and "maintenance" and much more -evidently as much as used from the batteries during blackouts plus losses both ways- where larger blackouts are common. All energy which you don't use when you are running on the batteries.

Talking about batteries: Ever looked at those:
Rolls
I've only seen one home equipped with those here in the DR (in Sosua). That home had a huge bank of these and an imported inverter which looked like it was designed to run a nuclear facility should it ever run out of Plutonium bars.


... J-D.

 

[cobraboy]

Nice! But... -erm-... who is the lucky one to have the privilege of honoring this Int'l warranty here in the DR? :cheeky:

Inverluz said the honor the warranty themselves.

So, no AC nor water pressure pump. Washer/dryer, microwave outlet?
Also an other item often forgotten which was certainly NOT on, when running on the inverter, is...
charging the batteries! That may seem ridiculous... but I have a funny feeling it may easily amount to one or two KW a day when on the grid for homes which use their inverter only for short "switch over" black outs and "maintenance" and much more -evidently as much as used from the batteries during blackouts plus losses both ways- where larger blackouts are common. All energy which you don't use when you are running on the batteries.

I might use the microwave for a couple of minutes while on inverter: 1200w for maybe 2-3 minutes. Not a massive power draw. I don't use the washer...I have plenty of clothes to wear. There are 5 lights on outside when dark...12 hrs MOL...4 are 23w CFL's and one is a 50w CFL "security" light on a pole. Maybe 3-4 lights on inside at nite, either 11w or 23w CFL's, for 3-5 hours max. 2 laptops and 1 desktop on at all times, as are the modem and wireless router. There may be a bathroom light on at nite for a few minutes each. We rarely run fans here in the mountains. Might run a fan in the BR at night because of no a/c. When the power goes off for more than an hour I turn the fridge/freezer temp up.

I guess opinions vary, but I don't see the above as huge power drains. Not DR campo, but not a massive power pig. I'll run some numbers, but I suspect the water heater being on for 30 minutes+ a day (on a switch), the a/c being on 8 hours a night, and the water pump (on a switch) running an hour MOL a day are a big % of the 550kw we consume.

My goal is to have power when Edenorte shuts down this "24 hour community". I want enough to live normally until the power returns, not more, and certainly not less (so I may add 4 more US 245's.)

Talking about batteries: Ever looked at those:
Rolls
I've only seen one home equipped with those here in the DR (in Sosua). That home had a huge bank of these and an imported inverter which looked like it was designed to run a nuclear facility should it ever run out of Plutonium bars.


... J-D.

I know Rolls very well. Might be the best deep cycle batteries available, period. Hugely expensive. I crewed on a rich guys mega Swan 65 that had a HUGE bank of them on "rollers" that could be mover 2' in all directions...to act as moving ballast. The big ones are BEASTS for sure.

You should see mountainfrog's (former DR1 poster and German engineer) electrical and battery set up in LT. Seriously impressive.

 

[bigbird]

...........My goal is to have power when Edenorte shuts down this "24 hour community". I want enough to live normally until the power returns, not more, and certainly not less (so I may add 4 more US 245's.)...............

Why not give it a test run? Turn your main circuit breaker off to simulate a power outage and see how long the batteries will last.

 

[El Rey de Mangu]

Why not give it a test run? Turn your main circuit breaker off to simulate a power outage and see how long the batteries will last.

I think he said he had 4x6Vx245A=5880W total bank reserve. If the average hourly house consumption is 1000W (to keep the numbers even), than this only goes 5.88 hours (depending on battery charge quality, appliance efficiency coefficients, etc.)

Harldy enough to endure a lasting outage. As I said, my 8x6x250 only takes me about 20 hours with the fridge connected.

If you don't have US30K to plunk down on an off-grid solar/wind blended solution, may consider a silent 5K Honda backup (that's what I have on the roof and you don't even hear it).