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Battery and Pump Advice Please

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66
Evening all,

Just after a bit of help please.

What leisure battery and mains charger are you all using for it? & if I upgrade my battery (I currently use small ones) will I have to upgrade my Pump to cope with the power? (might seem stupid but hey ho)!

Cheers

 
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Pump won't be affected except will run longer on bigger Ah battery. I have a 115Ah battery from Halfords, charger is a Numax 10amp. 

 
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Its important to have a good quality battery and smart or intelligent charger.

Your pump will draw between 4.5 and 5 amps an hour if you are working with a controller. We estimate that we spend about 1/2 the working day actually cleaning windows. It does depend on what we are doing as it can be up to 80%.

So an 8 hour day would mean we could use between 20 and 32.5 amps from our battery storage. So starting the day with a fully charged 115 amp battery would mean we could end up with between 95 and 82.5 amps at the end of the day.

For a leisure battery to service you well you need to recharge it asap and not let it drop below 50% charge too many times. This means that we only have 57.5 amps to use if we adhere to this rule of thumb.

So we would need to religiously recharge that battery every second night.

As per @Aqua-pure Portadown we run a 115 amp battery with a split charge relay. We also have a Numax intelligent 10amp leisure battery charger for motorhomes and plug that in every night in winter and every second night in summer.

Batteries need to be kept as fully charged as possible in winter as the cold makes them much less efficient - some expert said up to 25% less efficient.

In winter, I put a heater into the van anyway, so adding the charger only takes a couple of seconds.

.

 
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A bit of simple physics here:

First of all, two things you're certainly familiar with:

Voltage (measured in volts (V)) used to be called electrical pressure, and that's pretty much what it is. It's the energy available to push the electricity around the circuit.

Current (measured in ampere (A)) is the measure of the flow rate of electrical charge.

They are both directly analogous to water pressure (V) and flow rate in litres per second or gallons per hour etc. (A).

Now for something that you might not be familiar with:
 

Electrical charge (measured in coulombs (C)) is a measure of the quantity of electrons. It is directly analogous to a quantity of water measured in litres or cubic meters etc. Just as we measure the flow rate of water in litres per minute, electrical current is measured in coulombs per second which is the same as ampere: 1A = 1C/s.

The capacity of a battery is measured in Amp hours (Ah) and is a convenient measure of the amount of electricity stored. It's directly analogous to the capacity of a tank measured in litres. It's not a quantity used by scientists, they use coulombs (C), but Ah is a more convenient unit for us everyday Joes.

So when you use your battery to power a pump or anything else, you aren't using up voltage or current, you're using up Ah. This is easily understood if you use the water analogy and realise that you're not using up pressure or flow rate, you're using up litres of water as it drains from the tank.

So a bigger battery has a higher charge storage capacity just as a bigger tank has a bigger capacity.

If your pump draws a current of 3A and you're using it for 5 hours, you've used up 15 Ah. That might make you think that you could get away with a much smaller battery. But the batteries work better and last longer if they are only partly drained and then recharged. That extra capacity you have in your battery is there to ensure longevity.

To summarise:

  • Voltage is like water pressure
  • Current is like flow rate
  • Capacity is the same in both.


Hope that helps a little.

 
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A bit of simple physics here:

Voltage (measured in volts (V)) used to be called electrical pressure, and that's pretty much what it is. It's the energy available to push the electricity around the circuit.

Current (measured in ampere (A)) is the measure of the amount of electricity (measured in coulombs (C)) pushed around a circuit.

They are both directly analogous to water pressure (V) and flow rate (A).

The capacity of a battery is measured in Amp hours (Ah) and is a convenient measure of the amount of electricity stored. It's directly analogous to the capacity of a tank measured in litres. It's not a quantity used by scientists, they use coulombs (C), but Ah is a more convenient unit for us everyday Joes.

So when you use your battery to power a pump or anything else, you aren't using up voltage or current, you're using up Ah. This is easily understood if you use the water analogy and realise that you're not using up pressure or flow rate, you're using up litres of water as it drains from the tank.

So a bigger battery has a higher charge storage capacity just as a bigger tank has a bigger capacity.

If your pump draws a current of 3A and you're using it for 5 hours, you've used up 15 Ah. That might make you think that you could get away with a much smaller battery. But the batteries work better and last longer if they are only partly drained and then recharged. That extra capacity you have in your battery is there to ensure longevity.

To summarise:

  • Voltage is like water pressure
  • Current is like flow rate
  • Capacity is the same in both.


Hope that helps a little.


Excellent post. :1f44d:

Explained in simple terms using everyday things we are familar with to illustrate and help us understand how it works.

 
Excellent post. :1f44d:

Explained in simple terms using everyday things we are familar with to illustrate and help us understand how it works.


It used to be my job. I'm a retired maths and physics high school teacher! Now cleaning windows and happier than I ever was teaching.

 
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I didn't know that. Thanks.
Yes. A litre of water is a certain number of molecules of H2O. A coulomb of electricity is a certain number of electrons. They are precisely the same idea. The flow rate is measured in litres per minute; current is measured in coulombs per second. Again, exactly the same idea.

So, to answer The Cleaning King's question directly: No, there is no need to upgrade your pump. A larger battery has exactly the same voltage as a smaller battery. It stores more energy and so can do more work, but the voltage and current drawn are exactly the same.

 
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Yes. A litre of water is a certain number of molecules of H2O. A coulomb of electricity is a certain number of electrons. They are precisely the same idea. The flow rate is measured in litres per minute; current is measured in coulombs per second. Again, exactly the same idea.

So, to answer The Cleaning King's question directly: No, there is no need to upgrade your pump. A larger battery has exactly the same voltage as a smaller battery. It stores more energy and so can do more work, but the voltage and current drawn are exactly the same.


It just shows that there is always something basic to learn no matter how old you are.

I always knew that the moving of electrical energy is actually the moving of electrons from one atom to another - electrons being past down the line as it were. However, its never dawned on me that this would be measured in smaller quantities such a coulombs. As I said earlier, I've never heard of them. However, milliamps I'm familiar with, but I've just found out today that there are also microamps. I loved physics at school in Africa but for O level standard in the 1960's we were never taught this. 

On a slightly different note we learnt sine and cosine in maths but the last time I used it was during my maths exam before leaving school.

Then I find out that there isn't just Coulombs; there are lot of different values of coulombs - decicoulomb. millicouloub, nanocoulomb just to name a few. I better rest my brain before I end up with a stroke.

The only consolation is that I haven't needed to use it so far in my life - if I had I would have been aware of them - so I wonder if this is the last I ever get involved with this unit of electrical energy (if that's the right description.)

 
It just shows that there is always something basic to learn no matter how old you are.

I always knew that the moving of electrical energy is actually the moving of electrons from one atom to another - electrons being past down the line as it were. However, its never dawned on me that this would be measured in smaller quantities such a coulombs. As I said earlier, I've never heard of them. However, milliamps I'm familiar with, but I've just found out today that there are also microamps. I loved physics at school in Africa but for O level standard in the 1960's we were never taught this. 

On a slightly different note we learnt sine and cosine in maths but the last time I used it was during my maths exam before leaving school.

Then I find out that there isn't just Coulombs; there are lot of different values of coulombs - decicoulomb. millicouloub, nanocoulomb just to name a few. I better rest my brain before I end up with a stroke.

The only consolation is that I haven't needed to use it so far in my life - if I had I would have been aware of them - so I wonder if this is the last I ever get involved with this unit of electrical energy (if that's the right description.)


OK. Here's a bit more physics for you ... 

1 coulomb is about 6 240 000 000 000 000 000 electrons.

milli means one thousandth

micro means one millionth

nano means one billionth (i.e. one thousand millionth)

the next smallest are pico and femto each of which is one thousandth smaller still.

deci means one tenth, but it's hardly ever used today. The only place I can think of is in decibels. The unit of sound intensity is the bel, but it's inconveniently large, so we use decibels instead.

In ordinary electrical conductors, electrons don't jump from one atom to the next; they sort of drift. The inside of a conductor consists of a crystal of ions with their conduction electrons forming what is frequently referred to as a sea of electrons. If you think of a wire like a tube with electrons trapped in it, you're getting there.

In semiconductors, the electrons do actually jump from one atom to the next. 

Where in Africa were you? I taught in Sudan, Tunisia and Libya.

And, yes, life's greatest joy is learning new stuff. I'm loving this forum learning all sorts of stuff I never knew about pure water, soft washing chemicals etc. There's a wonderful bunch of guys on here all willing to help each other out and seek help when needed. Learning isn't about school. Learning is about life.

 
Last edited by a moderator:
OK. Here's a bit more physics for you ... 

1 coulomb is about 6 240 000 000 000 000 000 electrons.

milli means one thousandth

micro means one millionth

nano means one billionth (i.e. one thousand millionth)

the next smallest are pico and femto each of which is one thousandth smaller still.

deci means one tenth, but it's hardly ever used today. The only place I can think of is in decibels. The unit of sound intensity is the bel, but it's inconveniently large, so we use decibels instead.

In ordinary electrical conductors, electrons don't jump from one atom to the next; they sort of drift. The inside of a conductor consists of a crystal of ions with their conduction electrons forming what is frequently referred to as a sea of electrons. If you think of a wire like a tube with electrons trapped in it, you're getting there.

In semiconductors, the electrons do actually jump from one atom to the next. 

Where in Africa were you? I taught in Sudan, Tunisia and Libya.

And, yes, life's greatest joy is learning new stuff. I'm loving this forum learning all sorts of stuff I never knew about pure water, soft washing chemicals etc. There's a wonderful bunch of guys on here all willing to help each other out and seek help when needed. Learning isn't about school. Learning is about life.


Born in Johannesburg, lived my early life on the Copperbelt what is now Zambia, then in what is now Zimbabwe and finally back in Johannesburg for 11 years before coming to the UK 22 years ago.

 

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