First find the current which is 250/12 = 21A rounded off. So you would need 6 of the batteries in parallel to get a bit more than 1 hr and probably 11 batteries in parallel would provide around 2 hours of operation. This is not precise since the power supply wouldn't always consuming 250 watts of power.
infact i think the power supply be replaced with new one. infact i think the power supply be replaced with new one.
It would depend on the voltage needed by the heater. A 240 v heater would need twenty 12 v batteries connected in series but this is a very dangerous electrical supply that needs proper installation by an electrician. With a load of 6 amps the battery (assuming average car batteries) would supply the heater for about 6-8 hours when there is no wind.
You can measure the current and power of a 'power supply', using an ammeter and a wattmeter. With the power supply connected to its load, the ammeter must be connected in series with the power supply's input. The wattmeter's current coil must also be connected in series with the power supply's input, and its voltage coil must be connected in parallel with the supply, taking the instrument's polarity markings into account.
The source for an electromagnet can be any electrical supply. Batteries or derived from the mains, using a transformed and rectified supply.
In an uninterrupted power supply there has to be a source of power when the electrical utility is not there. The only supply that is available is a battery that is in or connected to the UPS.
If two batteries are connected in parallel (i.e anode of first with anode of other and cathode of first with cathode of other), then they cannot be charged using 12V, it may damage them.But if anode of first is connected to cathode of other (i.e. Batteries in Series) and cathode of first with cathode of 12 V supply (i.e. cathode of charger) and anode of second with anode of 12 V supply(i.e. anode of charger) then both the batteries can be charged using 12 V supply, easily.
Two batteries can supply more current than one if they are connected in parallel.
UPS's recharge the batteries during normal power. The recharge current will make the batteries temperature rise some.
Note: When interconnecting A200 batteries (cells), they must be identical in voltage and amp rating! Batteries may be connected in series. The positive terminal of the first battery is connected to the negative terminal of the second battery; the positive terminal of the second is connected to the negative of the third, and so on. The voltage of the assembled battery is the sum of the individual batteries. The batteries are connected: + to - to + to - to + to -, etc. The capacity of the battery is unchanged. Batteries may also be connected in parallel. The positive terminal of the first battery is connected to the positive terminal of the second battery, the positive terminal of the second is connected to the positive of the third; the negative terminal of the first battery is connected to the negative terminal of the second battery, the negative terminal of the second is connected to the negative of the third and so on. The batteries are connected: + to + to + and - to - to -. In this configuration, the capacity is the sum of the individual batteries and voltage is unchanged.
When connected to a normal power supply a UPS takes enough power to keep its battery charged and passes the power through to the device to which it is attached. When normal power fails the UPS uses its batteries to deliver clean power to the attached device.
Class I
The voltmeter is connected across the supply and the ammeter is connected in series with the supply.
Several identical batteries connected in parallel supply the same voltage as a single one of them does, but will power the same device several times longer than the single one can before running down.
infact i think the power supply be replaced with new one. infact i think the power supply be replaced with new one.
it should be connected to a breaker in the distribution panel.
If the batteries are incorrectly connected, the batteries will cancel out each otherโs energy and quickly flatten each other
autos lead acid batteries are wet cell