Model Boat Mayhem
Technical, Techniques, Hints, and Tips => Batteries & Chargers => Topic started by: david48 on October 14, 2015, 11:20:45 pm
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Thinking of buying 2 No 12v 9 Amh for my Fairmount Alpine (Component Shop sold out ) .
http://www.batterymasters.co.uk/Product-ULTRAMAX-NP9-12,-12V-9AH-20HR-SEALED-BATTERY-(AS-7AH,-7.2AH,-7.5AH-8AH)-with-4.8mm-0.187-WIDE-MALE-SPADE-CONNECTIONS_1377.aspx (http://www.batterymasters.co.uk/Product-ULTRAMAX-NP9-12,-12V-9AH-20HR-SEALED-BATTERY-(AS-7AH,-7.2AH,-7.5AH-8AH)-with-4.8mm-0.187-WIDE-MALE-SPADE-CONNECTIONS_1377.aspx)
When I had a look at the spec sheet I was not sure what the table at the bottom was telling me . Please can some one explain please
David
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The table seems to be a tabular form of the graph above it.
Just voltage (V) x current (A) = watts (W) against time it can supply that wattage.
In the first box it says it will deliver 9.6 volts drawing 32.4 Amps but it'll be flat in about 5 minutes. The voltage might start off at 12v but any load drawing that much current will pull the voltage down quite quickly at that rate.
Not even sure that it would be that efficient, looks like a generic made in China gel cell but if it's the right price and you're not drawing huge currents it'll be okay. Just make sure you get a decent gel cell charger, they don't like being over charged by a boggo 12v wet lead acid car type charger ( guess how I found out!)
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Hopefully your motors and accessories are not drawing 32 amps.
If your motors draw 3 amps each, then if the batteries are in parallel, you should get
at least three hours or more of running time.
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This is probably why nobody reads the small print. I guess that the voltage on the left is what you get down to after the time (across the top) drawing the current in your chosen box. Pull 32A, after 5 minutes the voltage will drop to 9.6 volts.
But really, what Umi said.
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Thanks all for the input ,I was only looking because Componant Shop are sold out , I hope by Warwick thy have stock .
David