washing machine off solar?

[jamjamdave]

Running modern washing machine on solar energy with 350W pure sinewave inverter

I did a bit of research on running a washing machine on a small solar system this year (2013) and didn't get much up to date info. I have done it successfully now, so I thought I'd post the info here if anyone is interested as this was one of the better discussions on the issue:

PV system:
1x 80W PV Panel
1 x 100Ah battery
350W 12V Victron pure sine wave inverter

New LG washing machine:

http://www.lg.com/za/washing-machines/lg-F10B8QDP5

Cost: about US$ 450
Energy Rating: A+++

We run this once a week and it works perfectly. We run it on the following settings:
*Main setting: Cotton Eco
*Temp: Cold Wash
*Spin: 400rpm
water usage: 40L for 7kg load
Total elec usage: about 100Wh
Running time: 2 hours
Peak energy usage (beginning of spin cycle): 250W (for a minute or so).

Of course it is not possible to have hot washes on this system - the inverter wouldn't cope. And the spin speed mustn't be above 400rpm. The clothes are spotless after a cold wash - and I do lots of dirty outdoor work!

I have another similar LG washing machine (8kg) that I use at our lodge - it runs on a 1600W inverter shared with 2 Bosch fridges and 2 AEG chest freezers, and that spins easily at the highest speed, 1200rpm, with a peak load of about 550W at the beginning of the spin).

So if you want to get a washing machine off grid, go for a new LG A+++ machine and wash cold.

Next project: dishwashing machine that uses solar heated water only (no heating element)!

[russ]

Thanks for the post Dave - anyone off grid will certainly be interested!

The next step shouldn't be hard.

[ChrisOlson]

Thanks for that reply. It answered a LOT of my questions. I had been going under the assumption that an Optima Yellow would be better than a traditional deep cycle -- sounds like a DieHard Marine would do a better job and cost less.

Brian, you may not be monitoring the thread anymore. But the DieHard Marine battery is also not a good choice. If you want a 12V battery that will yawn and run your washing machine without even breaking a sweat, look at one of these:

http://www.altestore.com/store/Deep-Cycle-Batteries/Batteries-Flooded-Lead-Acid/Surrette-Batteries-12-Cs-11Ps-12V-357Ah-20Hr-Flood-L-Acd/p1636/

These are the type of batteries you need for off-grid solar. Traction batteries like this are designed for floor sweepers, small lift trucks, etc., as well as stationary applications (like RE/solar, telecom backup, etc), and they have a design life exceeding 2000 cycles @ 80% DoD. They are expensive up front but cost roughly 1/2 over the long term of what you will spend on batteries of DieHard Marine, et al, quality.

The battery will be the single weak link in your off-grid solar experiment or project. Do not make the mistake of buying hybrid type with thin plates.

Otherwise I think you can ignore the cost analysis of why you should not do this and just continue using grid power. I see that you have an interest in solar, want to try it to see how it works, and want to run something substantial with it to prove to yourself that it really does work and learn about it. It can be considered a hobby or experiment - and people can spend money on way worse hobbies than solar power. So go for it. It will be fun and educational. And you will find that it DOES work.

So on to the details:
The Peukert Effect will be negligible if you use the washing machine during the day. The solar panels will be supplying power to the inverter as well as the battery. Washing machines do not draw a continuous 8 amps @ 120V. They only draw that during the wash and spin cycles when the motor is running. Otherwise all that is running in the washer during fill is some selenoids and timer/electronics, which is a substantial portion of a full wash cycle.

So besides the battery, you want an inverter sized to run at at least 25-30% rated load. Inverters do not reach peak efficiency until they are loaded to that level. So I would say a minimum 1,000 watt pure sine wave inverter (your washing machine timer and motor will be lots happier on pure sine wave). And maybe size the inverter larger based on the fact that you might like this system and decide to add additional loads to it later.

That battery I pointed out can wash clothes all day without fully discharging it - with no incoming solar power at all. It can supply about 3 kWh of usable energy from your inverter from fully charged to 80% discharged. You see people here talking about discharging only 20% or 50% and your battery will last longer? Forget that - buy a good battery that you can actually USE its capacity and you won't have this problem having to buy four of them to prevent discharging them below 50% DoD. A real battery will run more cycles at 80% DoD than a cheap one will run at 50% DoD. So your cost/kWh of storage over the long term is much less. Most folks base these recommendations on batteries like the Trojan T-105, L-16REB, etc.. These are toy batteries with thin plates, they only have a 5-7 year design life before they drop to 50% of their original capacity, and they should be avoided like the plague for off-grid solar applications.

There are tools on the internet - PV Watts is a good one - that you can use to estimate how much energy you can produce from solar panels. Batteries do not charge at 100% efficiency. During bulk charge stage the battery will readily accept amp-hours and be almost 100% efficient. But during absorb stage the battery creates heat and you lose some of your solar power to that heat. So you get less amp-hours out of the battery than you put into it.

Your battery can deliver about 300 amp-hours from 100% to 20% SOC. At 80% charging efficiency you will need about 375 amp-hours to recharge it. Most of this will be spent at voltage averaging 13.8V. So that equates to about 5,175 watt-hours to recharge your battery if it is fully discharged. The battery can accept bulk amps at C/10 or ~38 amps. So charging wattage will be slightly over 500 watts, and it will require over 10 hours to fully recharge your battery.

Solar panels rarely make their full nameplate wattage. Figure about 75% of nameplate on a "good" day. So to get 500 watts of actually charging power, you will need at least 670 watts of installed solar power. Based on the fact that we get cloudy days, partly cloudy days, and more days that are less than ideal, that we get ideal days, I would say 750 watts is the bare minimum, 1 kW of installed solar capacity would be better. Could you do it with less? Yes, you could. But if you want to reliably power your washing machine on off-grid power every time, without ever having to revert to grid power or generator to run it, install 1 kW of solar panels. If you want to schedule when you can use the washer based on how much incoming solar power you have when you want to use it, then you could do it with 500 watts of installed capacity.

Hope this helps - good luck with your project!
--
Chris

[Mike90250]

.....

Next project: dishwashing machine that uses solar heated water only (no heating element)!

Mist dishwasher soap and machines require water at about 145F - usually the internal electric heater boosts the temperature up to that.

Good job with the washer.

Bit of advice, get some more solar, your battery likely sits quite low for a day or three before it gets fully recharged, and may suffer a little bit of incremental sulfation as it does.

[Sunking]

Brian, you may not be monitoring the thread anymore. But the DieHard Marine battery is also not a good choice. If you want a 12V battery that will yawn and run your washing machine without even breaking a sweat, look at one of these:

http://www.altestore.com/store/Deep-Cycle-Batteries/Batteries-Flooded-Lead-Acid/Surrette-Batteries-12-Cs-11Ps-12V-357Ah-20Hr-Flood-L-Acd/p1636/

These are the type of batteries you need for off-grid solar.

I agree with you on that point.

Traction batteries like this are designed for floor sweepers, small lift trucks, etc., as well as stationary applications (like RE/solar, telecom backup, etc), and they have a design life exceeding 2000 cycles @ 80% DoD.

This is incorrect. They are not Traction, Forklift, Floor Sweeper, or Telecom. Not even close. They are True Deep Cycle batteries, and as such have fairly high internal resistances which means they cannot deliver very high discharge rates. Go beyond C/4 and the voltage sag will trip inverter low voltage cut off.

Traction, Forklift, Floor Sweeper, and Telecom batteries are a completely different design that have very low internal resistances so they can deliver very high discharge currents, and very high charge currents. To do that means thinner, lighter plate material and the trade-off is fewer cycles. You cannot have both internal low resistance and high cycle life. They are contradictory terms.

[SolarShadow]

jamjamdave,
Your setup may be working right now, but I suspect it won't last too long. You are pulling that battery at least to 50% DOD and possibly further due to the short heavy draw so the battery is somewhat under rated and being stressed. Add to that you are marginal on charging the battery back up with only 80 Watts of pv. Now this could be even worse if you are not using a charge controller to stop any overcharging.

You may not want to go for one of the large expensive batteries for this as there are golf cart batteries that can be had reasonably cheap and you may want around 200 watts in pv to charge them up with a controller and it may last a few years for you.

[ChrisOlson]

This is incorrect. They are not Traction, Forklift, Floor Sweeper, or Telecom. Not even close. They are True Deep Cycle batteries, and as such have fairly high internal resistances which means they cannot deliver very high discharge rates. Go beyond C/4 and the voltage sag will trip inverter low voltage cut off.

The Surrette 12-CS-11PS applications are listed by Rolls as motive power, stationary power and marine. They are pretty good at higher discharge rates.

At the 2 hour rate (86 amps) the 12-CS-11PS will maintain nominal voltage for the first 4 minutes from a fully charged state. The C/10 load test spec at 1.265 SG and 25C is 5 minutes with maximum "sag" to 12.21V, recovery time after load is removed is 1 minute and recovered voltage after that minute should be 12.52 or better. They have a 10 year warranty and 15 year design life on stationary power applications @ 3,000 cycles, or 2,020 cycles to 80% DoD on motive power applications.

They are a very good battery with sediment cleanout, replaceable cells, dual container, and 1 gallon electrolyte reserve over the plates, per cell.

The nice thing about the 12-CS-11PS vs steel container traction batteries is that they only weigh 275 lbs so two people of reasonable strength can lift one and move it around. They are also available in 8V (8-CS-25PS), 820ah (railroad locomotive applications). Three of those make a nice 24V battery, or 6 of them a nice 48V battery. However, the 8V version weighs 425 lbs each.
--
Chris

[Sunking]

The Surrette 12-CS-11PS applications are listed by Rolls as motive power, stationary power and marine. They are pretty good at higher discharge rates.

At the 2 hour rate (86 amps) the 12-CS-11PS will maintain nominal voltage for the first 4 minutes from a fully charged state. The C/10 load test spec at 1.265 SG and 25C is 5 minutes with maximum "sag" to 12.21V, recovery time after load is removed is 1 minute and recovered voltage after that minute should be 12.52 or better. They have a 10 year warranty and 15 year design life on stationary power applications @ 3,000 cycles, or 2,020 cycles to 80% DoD on motive power applications.

They are a very good battery with sediment cleanout, replaceable cells, dual container, and 1 gallon electrolyte reserve over the plates, per cell.

The nice thing about the 12-CS-11PS vs steel container traction batteries is that they only weigh 275 lbs so two people of reasonable strength can lift one and move it around. They are also available in 8V (8-CS-25PS), 820ah (railroad locomotive applications). Three of those make a nice 24V battery, or 6 of them a nice 48V battery. However, the 8V version weighs 425 lbs each.
--
Chris

You are preaching to the choir and just confirmed what I said, they have a high internal resistance (.008 Ohms @ 100% SOC) and not suited for high current discharge applications.

As you stated at C/10 voltage sag will be 4%. Maximum design allowable total including battery voltage sag, and wiring losses is 2 to 4 % They are not traction batteries by any means. Hit those with a 1C discharge rate (121 amps) like a traction motor will put on them an even higher up to 5C and the voltage sag drops down to 11.5 volts. Include wiring losses and your inverter trips off-line immediately from under voltage. Put a 5C discharge on them or 500 amps and they sag down to 8 volts. Even most vehicle SLI car batteries can do better than than that. Your average 12 volt 60 AH SLI battery in your car can out perform that as most car batteries have a CCA of 500 amps or better. Your typical 12 volt 60 AH BCI Group 27 SLI battery has a CCA of 650 amps or an internal resistance of .008 ohms.

A true traction or stationary battery of like voltage and capacity (12 volt @ 350 AH) will have an internal resistance of about .002 to .003 Ohms. Hit them with that same 121 amps and it sags only to 12.2 to 12.3 volts. There is no comparison or argument that can be made.

ROLLS are excellent batteries, but they are not Traction batteries, they are a True Deep Cycle battery. They cannot be used for hybrid applications like Starting or Fork Lifts. It is physically impossible by design and physics. They are also not as good as claimed. The 5000 series has a 10 year warranty. When used in DEEP CYCLE application will last about 5 years until capacity drops to 75% and need replaced. That 10 year warranty is a 3/7. I have used thousands of them in the last 30 years professionally. I would never use them in a Stationary application in a telephone office. Nor does any other professional. They are not made for it. You will ot find them in Fork Lifts or Electric Vehicles either. The internal resistance is too high. Most of your traction batteries are AGM with a few being flooded.

[FloridaSun]

New LG washing machine:

http://www.lg.com/za/washing-machines/lg-F10B8QDP5

Cost: about US$ 450
Energy Rating: A+++

We run this once a week and it works perfectly. We run it on the following settings:
*Main setting: Cotton Eco
*Temp: Cold Wash
*Spin: 400rpm
water usage: 40L for 7kg load
Total elec usage: about 100Wh
Running time: 2 hours
Peak energy usage (beginning of spin cycle): 250W (for a minute or so).

hmmm... Two hours to do a load? Seems excessive.
I have a year old Maytag, 102L capacity compared to your 58L LG. Did a half load this morning and the maytag consumed 100Wh total, same as yours. Wp was much higher with it's 800rpm spin cycle but run time much less, closer to 45 minutes before ready to hang on the solar clothes dryer.

[ChrisOlson]

ROLLS are excellent batteries, but they are not Traction batteries, they are a True Deep Cycle battery. They cannot be used for hybrid applications like Starting or Fork Lifts.

Well, I don't know exactly what to tell you - the 24V electric forklifts running around at the local Menards have two Rolls 12-CS-11PS batteries in them.

We also have two of them in our yacht for starting batteries for the Cat 3406 diesels. In a marine application the 12-CS-11PS has MCA rating of 1,056 amps for 30 seconds @ 0°F. In the boat they double as standby power for lighting, navigation, radar, radios, and control systems when the onboard genset is shut down.

Diesel Supply, where we got our Surrettes from, uses the 8V version of it with four in series for 32V starting on EMD diesel-electric locomotives. And in the locomotive they double as standby power to keep the electrical systems in the locomotive powered up 24/7 when the V-16 EMD diesel engine is not running.

So "can't be used" must need some qualification because they work fine here, along with everybody else that I've seen use them in motive power and marine applications.
--
Chris

[Sunking]

Well, I don't know exactly what to tell you -

Simple look at the specs.

First they list them as DEEP CYCLE
CCA = 845 amps
MCA = 1056 amps.

Do you understand what those numbers mean? Cold cranking amperes (CCA) is the amount of current a battery can provide at 0 °F (−18 °C). The rating is defined as the current a lead-acid battery at that temperature can deliver for 30 seconds and maintain at least 1.2 volts per cell (7.2 volts for a 12-volt battery). From that you can determine internal resistance @ 0 degrees C = [12.6 - 7.2] / 845 amps = .0064 Ohms.

The 12CS11PS is a 12 volt 357 AH battery @ the 20 hour discharge rate which weighs in @ 272 pounds. Now take a look at a much smaller ROLL Marine battery 12 volt @ 260 AH S12-290AGM. It has a CCA = 1830 amps over 100% more cranking amps. With that you can determine it has a internal resistance of [12.6 - 7.2 volts] / 1830 amps = .0029 Ohms @ 0 degrees C. It even list the Internal Resistance at Room Temp of .0018 Ohms which means a Cranking Amps = [12.6 - 7.2] / .0018 Ohms = 3000 amps

Can you use the 12CS11P as a Traction or Cranking Battery? Sure you can if you do not know what you are doing and willing to sacrifice performance from ignorance. If your life depends on performance and you know what you are doing would use a real Traction Battery or Marine Battery which is designed to do what it is claimed to do.

Heck even a much smaller ODYSSEY PC2250 blows the ROLLS 12CS11PS out of the water and it is a 12 volt 125 AH battery @ C/20 (1/3 the capacity of the Rolls) with a CCA = 1225 and MCA = 1550 amps.

I agree the Rolls is a great DEEP CYCLE, but a very POOR Traction or Cranking battery. The Rolls 12CS11PS is designed as a DEEP CYCLE battery. Not a Hybrid (Marine, Traction, Stationary, Golf Cart, Floor Sweeper, Fork Lift, ect...) or a SLI (starting-lighting-ignition) application as you stated. The Rolls battery is designed to deliver at most a C/10 discharge current for a extended period of time. Hybrids are designed to deliver 1C or more for extended period of times. To do that means the internal resistance has to be low. To get low internal resistance the plates have to be thin and many plates. When you do that you give up cycle life. You cannot have both low resistance and long cycle life in a lead acid battery.

[thastinger]

we REALLY need the popcorn eating emoticon on here

[Sunking]

we REALLY need the popcorn eating emoticon on here

Here you go.

[ChrisOlson]

Can you use the 12CS11P as a Traction or Cranking Battery? Sure you can if you do not know what you are doing and willing to sacrifice performance from ignorance.

Sunking - you are very confusing. Where do you get your information from? Have you ever worked with or on a 12-CS-11P battery? They are all deep cycle batteries. The 12-CS-11P has Rolls' world-famous CS plates. CS = Cranking/Starting. They have sailed the Atlantic from Texas to Nova Scotia for 20 years in marine diesel starting/deep cycle applications, on railroads for locomotive/car power, and small electric "order picker" lift trucks. The CS plate code is their .265" positive 4% antimony grid.

Their FS plates, also used in marine deep cycle, are smaller motive power batteries. FS = Floor Scrubber. They are thinner, .170" positive grid, designed for less intensive cycling and shorter life. All of Surrette's lower price point marine deep cycle batteries have FS plates.

It does not matter that batteries of lesser ah capacity might have higher CCA or MCA rating. That just means the smaller battery has more and thinner plates, probably of lead-calcium grid. These types of batteries are not designed for dual cranking/starting and deep cycle application like on a yacht or trawler. The Rolls 12-CS-11P is. You size the number and size of batteries to the amp requirement for starting your propulsion engines. If the propulsion engine starters are 24V, 450 amp, then the 12-CS-11P is more than adequate (in series) to start those engines.

The 12-CS-11P is identical to any steel container forklift battery except it is dual prope container, so it is spill proof. You pop the cover off it and inside are six 2V forklift style "jars" all connected together with bolted interconnects. You get a bad "jar", you simply pop the cover off, unbolt the defective "jar", lift it out and drop in a new one.

Surrette has only started advertising these different batteries for "renewable energy" in the last 10 years since "renewable energy" has become all the rage. But they have not designed special batteries for it until just recently - and most of those AGM. The 12-CS-11P, as an example, has just been put in their "RE" line as being suitable for RE applications. But it is the identical battery that has been used in motive and marine power for 20 years.

Surrette's main business was NOT RE. It was marine and industrial motive power, and had been for over 60 years. John Surrette, widely considered to be the father of modern deep cycle batteries, designed the first ones in 1935 for fishing trawlers on the Atlantic - not for off-grid solar. When Jamie Surrette took over the company in 1996 less than 1% of their business was renewable energy or solar storage. Today it has grown to about 50%.
--
Chris

[jamjamdave]

jamjamdave,
Your setup may be working right now, but I suspect it won't last too long. You are pulling that battery at least to 50% DOD and possibly further due to the short heavy draw so the battery is somewhat under rated and being stressed. Add to that you are marginal on charging the battery back up with only 80 Watts of pv. Now this could be even worse if you are not using a charge controller to stop any overcharging.

You may not want to go for one of the large expensive batteries for this as there are golf cart batteries that can be had reasonably cheap and you may want around 200 watts in pv to charge them up with a controller and it may last a few years for you.

We generally do just one wash a week. I start the wash at 11am on a full battery and we're done by 1pm. By 2pm the battery is full again - I do have a cheap controller. I have installed loads of PV systems in the last 10 years and a big consideration here in Africa is cost - to a much greater extent than in first world countries. Here (rural village Africa), salaries range from US$100 to a maximum of US$400 per month (with 60% unemployment rate) and thus installing 200W of PV to generate 100Wh per week would be overkill.

Of course I will be lucky to get 3 years out of this battery, but at a cost of $100/battery that is acceptable. The forklift batteries don't really work in these small applications. Even the Trojan's are a problem as the cheap controllers max their absorb voltage at 14.4V which isn't enough to fully charge a Trojan which leads to one or more cells going "dormant". The only solution to this undercharging by cheaper controllers seems to be the very expensive controllers (MX60 or Steca Tarom) but then those cost more than the rest of the system combined! Hence the cheaper "deep cycle" batteries (I know they aren't really deep cycle) are best for the budget solar consumer.

I supply rural village homesteads with small solar systems that run lights, TV, small appliances for $690 including installation. In that price range, the considerations for sizing of panels and type of equipment used are very different.