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A. Calculate the nominal input current using the nameplate (Serial Number label) Divide the number of watts be the input voltage and add 20% eg. ST35-II = 560 W / 240 V = 2.33 x 1.2 = 2.8 A eg. ST20-II = 330 W / 240 V = 1.38 x 1.2 = 1.7 A
A. Battery cut-off is nominal 10.5 V with or without mains present. *Battery reconnect is for battery (external voltage) >9 V when mains present and nominal 11.65 V when mains is not present.
A. The Power supply has a Low Voltage Disconnect (LVD). To help maintain good battery life, as you are probably aware, it is not good to run the batteries all the way down. The Power Supply will disconnect at 10.5 +/- 0.3 V. It will then re-connect once the voltage has recovered to 11.65 V +/- 0.3 V. It will reconnect if mains is present and battery voltage is > 9.0 V. (The 9 V is pull in voltage on LVD coil). If no mains is present it will reconnect when battery voltage recovers to 11.65 +/-0.3 V.
A. a) petrol / diesel powered generator is ok (provided sine wave output)
b) they can use the 12 V ext input to also get power (from car or the +12 V source) for powering and also charging of backup battery.
1/ A Pure Sine Invertor should be OK as long as the generated Voltage is within the ST Spec of 230 to 240 Vrms ±10%.
2/ A high pitched squeal is unusual, the question here is, "Does it make that sound if run from normal mains voltage?", this will narrow the issue done to either the generator or the ST.
3/ Does it indicate that the generator is not what it is claimed to be? No, it could well be exactly as claimed, however if the generator is not high enough power then it may not be able to provide the peak current required by the ST 20 II. Check the generator specs to ensure that it can deliver at least 350 W at power factor (PF) of 0.7.
A. Simple answer is to turn off the SETEC ST Power supply when charging the battery from the "multi stage charger", but this means that any loads lights etc) will be operating from the battery / charger and not from the ST Power supply. Note: The ST unit may still function if both chargers are active depending on what voltage the "multi stage charger" is outputting. The best solution would be to use a ST-II series charger that provides all battery features required for extended Battery life.
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A. Yes they can. However it is recommended to use the Lead Acid battery
A. Yes you can, however the ST 35-II is a better option for the charging capabilities and will have a longer life span.
A. 1). ST 35 is a simple "Float" charger, the output (battery) voltage is set to 13.65 V and current limited to 10 A.
Note: the ST35-II is a "3 stage smart charger"
2.) The ST35 (and ST35-II) is designed for use with "Gel" type batteries. Due to the higher "Charge" voltage required for "AGM" type batteries, we cannot guarantee that "AGM" batteries will be fully (100%) charged under all conditions (i.e. in cold environments). Under normal conditions, both battery types should achieve close to 100% capacity.
3.) The type of generator used will impact on how the ST35 works. Tests have shown that generators that provide a square wave output have a lower peak voltage and may not provide the voltage required to run the ST35.
The AUX in provides another source to operate the output loads and charge the battery. It is has a diode ensures only current can enter the ST product through the AUX in.
Any appropriate source connected to this input should be current limited to the same rating as the battery fuse, that is an external fuse of rating 20 A from ST20-II and 30 A for ST35-II. If an input as described of 14 V and 50 A were used, the battery fuse would blow if the battery was low enough to accept 50 A or if there was combined battery and loads that amounted to 50 A, the isolation diode could overheat and fail.
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A. The ST35-II does cause interference (or humming) on the AM band in some installations. The interference occurs when there is no load on the ST35-II due to pulse skipping, eg the battery not connected when plugged into 240 V mains. One suggested way to reduce the pulse skipping is to lightly load the ST35-II by turning on a light. Physically moving the radio or the ST35-II (more difficult) can sometimes help reduce or stop the noise.
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A. There is no user adjustable way of disabling the charging system on this unit.
A. The trickle charge is not user adjustable, it is set at 13.8V in the factory. If your battery is very flat (say <9 V), then the unit will be charging at 1.2 A. However, above this it should be charging at 5 Amps.
A. Yes it is safe to leave it plugged in to 240 V continuously and yes it does act as a float charger and will not overcharge the battery.
A. 1.) Check the fuses 2.) The ST20 will not connect the Aux input voltage to the battery unless the battery voltage is above approximately 9 V.
Note: If the battery is not connected, the voltage at the BAT+ terminal will read 0 V.
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There should be no problem operating from both 240 V and AUX in as long as the AUX in does not exceed the 14.8 V limit defined in the manual. The AUX limit of 14.8 V must not be exceeded or damage to internal components will occur. It is possible that the power supply will operate in a hiccup mode if the AUX input voltage is above the voltage that the power supply is trying to regulate at, however this should not cause any problem.
If the system addition is a battery operated invertor that will run from the battery connected to the ST20-II output. If the owner were to simply plug the ST into the inverter, then if the invertor was true sine wave, the energy would circulate and be converted to heat in the ST and the inverter. This is will just flatten the battery.
Installing an isolating diode as suggested would prevent the energy circulation by preventing the ST from charging the battery, however it would also prevent charging with grid mains connected unless a switch was also installed. The Switch and Diode would have to be rated for greater than battery fuse current under continuous operation, this would be expensive (Diode rating Schottky 30 V 40 A continuous as minimum with heat sinking).
The best solution is to have the ST switched off at the mains (not plugged into the inverter), that way the ST will continue to provide the low voltage disconnect (battery deep discharge protection).
Summary - disconnect the ST20-II from the "240 V".
Our suggestion is to get an auto electrician to review your setup. If a battery is installed then:
Battery Positive should be connected to the ST terminal BATT +VE
Battery Negative to ST terminal BATT –VE
Any other wiring won't permit the ST to charge and provide Low Voltage Disconnect protection for the battery. The Aux In +VE is not designed to be a battery input, it is for external power sources to supply power to the system and charge the battery when mains power is unavailable. The configuration described won't charge the battery due to an isolation diode on the input of the Aux In +VE.
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