Cost of charging 2 batteries

50Twuncle

Could someone please tell me roughly what it costs to charge a pair of 12v 35Ah batteries ?
At about 14p per kwh
I can't remember how to work it out...
thanks

st999

at a rough guess, 10p?

Heedtheadvice

Worst case rule of thumb approx .....ish
Two batteries 75Ah 12v about (12*75) 800VA power so allowing for efficiency losses call it 1000watts. Just about 1kW so 14p.

Lots of other factors to consider but that might be close enough?
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Is that ok uncle? I can call you uncle can I not without getting banned by admin?

50Twuncle

Thanks Both
This is for my new "toy" - a mobility scooter
It has 2 x lead acid batteries and will need regular charging....
Just wondered what it would cost .

Strider590

You simply can't work this out at all, you don't know the specifications of the charger. You don't know how much current it's putting into the battery and therefore don't know how long it'll take to charge and a battery takes less current at 90% than it does at 20%, so you can't even work from a constant value.

The only way to know, is to plug it into a power consumption meter.

firefox1956

Heedtheadvice wrote: »

Worst case rule of thumb approx .....ish
Two batteries 75Ah 12v about (12*75) 800VA power so allowing for efficiency losses call it 1000watts. Just about 1kW so 14p.

Lots of other factors to consider but that might be close enough?
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.
.
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Is that ok uncle? I can call you uncle can I not without getting banned by admin?

If Uncle is his first name probably not
:rotfl::rotfl::rotfl:

were

Listen to Stryder590 for good advice. Nice to have known you But even using a power meter it will vary due to below, and temperature too.

Stolen from a battery page "The Lead Acid battery is not 100% efficient at storing electricity - you will never get out as much as you put in when charging. Overall, an efficiency level of 85% is often assumed.
The efficiency will depend on a number of factors including the rate of charging or discharging. The higher the rate of charge or discharege, the lower the efficiency.
The state of charge of the battery will also affect charge efficiency. With the battery at half charge or less, the charge efficiency may be over 90%, dropping to nearer 60% when the battery is above 80% charged.
However it has been found that if a battery is only partially charged, efficency may be reduced with each charge. If this situation persists (the batteries never reaching full charge), the life of the battery may be reduced."

Heedtheadvice

All true about accuracy chaps......But come on my uncle only wants an approximation!
:rotfl::T

were

About 14p

https://ccfmobility.co.uk/2009/09/29/mobility-scooter-faq-battery-charging/

from http://lmgtfy.com/?q=uk+cost+to+charge+mobility+scooter

50Twuncle

Thanks all
Somewhere between 10p and 20p is accurate enough for me

forgotmyname

How efficient is the charger? Whats does the label on the charger show as its max current?