Advice on buying generator please

[ice man]

OK I have ad a brief go at the maths on how long that 200 amps/hr battery should last on 8 fridhes

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I am sure that this will be completely wrong! So please correct me

Fridges
0.5kWh a day x 8 fridges = 4kWh a day = 4000Wh /24hr = 166.6Wh

Battery
200Ah x 12V = 2400Wh

2400Wh/ 166.6Wh = 14.4hrs of battery life

I have just rang the above company about there batteries and asked him how the maths on 200AH work. And he states that that figure will be for 100% discharge which he strongly dose not recommend!
He said to aim between 30-50% of discharge to prolong the life of the battery. So meaning if I worked at 50% then 200AH would now only be 100AH

So if I have gotten all of this right then. If I am aiming at charging my batteries twice a day at a 30-50% discharge then I am going to need 2 of the above battaries for this equation to work?

 

[pc1966]

But the overall power consumption (W) is still the same right!
If this was an advantage then all cars and bikes would be 48V

Electric cars often are 48V

Larger vehicles, boats, etc, often are 24V.

You need to look at the peak demands, what sort of inverts are available (i.e. are they 12V, 24V, etc) and then how they can be hooked up and protected. Cables rated to carry 200A for any length of time are pretty large and difficult to work with, and you (or the designer) need to consider aspects such as a breaker for fault/overload protection and to allow the supply to be isolated for maintenance work.

 

[ice man]

Electric cars often are 48V

Larger vehicles, boats, etc, often are 24V.

Well the last time I looked inside my engine bay it was a 12V battery.
The reason large vehicles are 24V and boats 36V. Is because they are longer then cars and the brake lights would flicker on a lorry at 50 feet at 12V

 

[ice man]

BTW I got this data sheet from the manufature of the drinks cooler

The data sheet for this beer chiller says it power consumption is 627W. The beer chiller will only work when beer is being drawn off of the beer tap.

So if we said I was to sell 100 pints a day at 30 seconds a pour would mean 50 minutes of use per day.
Which is (50mins/ 60 mins) 0.83 of an hour. X 627W = 522.5W total power consumption for this machine for one day.

So the battery in question is rated at 200AH x 12V = 2400Wh total battery life. But at a 50% discharge equates to 1200Wh battery power

1200W/ 522.5 = 2.30 days before the battery needs charging.

With out doing the maths or anything. Dose this sound about right for a load of this kind on a battery of this size?
Thanks

 

[ice man]

Now I am going to move on to the generator that I would need to charge my batteries up
Again based on my maths. But no one has commented yes as to if they are spot on or far out!

for the 200AH battery in question
200AH x 12V = 2400Wa @ 50% discharge = 1200Wh

if I want the generator to run for say half an hour to charge the battery then I am going to want a 2400W generator right? (1200Wh x 1/2hr)

So for charging 2 batteries in half an hour dose this mean a 4800W generator?
Thanks

 

[marconi]

My #34 second paragraph- you have not provided the information.

 

[ice man]

My #34 second paragraph- you have not provided the information.

Im not quite so sure what you are asking hear but......

As I said I am no expert in batteries and brands of but I reckon there will be a difference between the battery life and guarantees/specifications of performance when it is used primarily for a few seconds to crank an engine and when used regularly for prolonged discharge to a deeper depth of discharge. Hence the rather odd phrase 'leisure battery'. I know nothing about the Platinum make.

To do the analysis of battery and generator charging I need to know how long the battery alone must provide power and remain above 50% discharge. In my clients case from shut up shop 7pm Saturday evening to opening up 7am Monday morning.

Leisure battery or better term deep cycle batteries are not what you find on a car! car batteries use a different type. Commonly refered to as CCA (cold cranking amps). A deep cycle battery will simplely not start an engine and a CCA battery will not last as long as deep cycle.

Anyone in the motor trade will know all about Platinum batteries. They are one of the best!

But again I am not quite so sure what you are asking hear. Because if I had the 200AH battery in question that I would discharge it to 50%. Then what size generator would you recomend if I wanted to charge it up for say 30 minuts?
Thanks

 

[marconi]

I’m out of this. Over to others.

 

[ice man]

???????????????????

 

[ice man]

right well I think we are not going to get a stright answer hear so best pack it all up and close down my account