Using the Phoenix MultiPlus to reduce operating cost of a ... - Ysebaert
Using the Phoenix MultiPlus to reduce operating cost of a ... - Ysebaert
Using the Phoenix MultiPlus to reduce operating cost of a ... - Ysebaert
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3. Why should <strong>the</strong> inverter/charger be a Victron <strong>MultiPlus</strong>?In <strong>the</strong> previous section we saw that <strong>the</strong>re are potentially huge benefits and <strong>cost</strong> savings <strong>to</strong> bemade when an inverter/charger is added <strong>to</strong> a system with ac-genera<strong>to</strong>r. There are manyinverter/chargers on <strong>the</strong> market that <strong>cost</strong> a lot less than a Victron <strong>MultiPlus</strong>. In this section we willshow that, <strong>to</strong> take full advantage <strong>of</strong> <strong>the</strong> potential benefits, <strong>the</strong> inverter/charger must be a Victron<strong>MultiPlus</strong>.Apart from obvious benefits such as <strong>the</strong> clean pure sine wave output, ultra fast ac-transfer switch,marinized construction, high quality built and an organization behind <strong>the</strong> product which has beencommitted <strong>to</strong> R&D and cus<strong>to</strong>mer support for over 30 years, <strong>the</strong>re are five specific features <strong>of</strong> <strong>the</strong><strong>MultiPlus</strong> that are essential in achieving <strong>cost</strong> savings when using <strong>the</strong> inverter/charger with <strong>the</strong> acgenera<strong>to</strong>r.3.1. AC input power managerUnique <strong>to</strong> <strong>the</strong> Victron <strong>MultiPlus</strong> is <strong>the</strong> ability <strong>to</strong> set a power level that <strong>the</strong> unit will try <strong>to</strong> maintain atits ac-input terminals. The <strong>MultiPlus</strong> has 2 levels <strong>of</strong> ac power management. The first level isPowerControl.PowerControlThe PowerControl functionality enables <strong>the</strong> <strong>MultiPlus</strong> <strong>to</strong> au<strong>to</strong>matically increase and decrease <strong>the</strong>charge rate <strong>of</strong> its charger depending on <strong>the</strong> power demand at <strong>the</strong> ac-output <strong>of</strong> <strong>the</strong> Multi. ThePowerControl functionality <strong>of</strong> <strong>the</strong> input power manager is best unders<strong>to</strong>od by looking moreclosely at fig. 2.The blue line shows <strong>the</strong> power through <strong>the</strong> Victron Multi. When <strong>the</strong> blue line is above 0, <strong>the</strong>inverter <strong>of</strong> <strong>the</strong> Multi takes power from <strong>the</strong> batteries <strong>to</strong> supply ac-power <strong>to</strong> <strong>the</strong> ac-loads. When <strong>the</strong>blue line is below 0, <strong>the</strong> charger <strong>of</strong> <strong>the</strong> Multi takes ac-power from <strong>the</strong> genera<strong>to</strong>r <strong>to</strong> re-charge <strong>the</strong>batteries. This ac-power is an additional load <strong>of</strong> 2.2 kW for <strong>the</strong> genera<strong>to</strong>r. As can be concludedfrom fig. 1, this additional load would result in an overload <strong>of</strong> <strong>the</strong> genera<strong>to</strong>r between 18 hours and19 hours, because <strong>the</strong> o<strong>the</strong>r ac loads do increase <strong>to</strong> 6 kW during that period (see fig. 1). Adding<strong>the</strong> 2.2 kW load <strong>of</strong> <strong>the</strong> charger would increase <strong>the</strong> load <strong>to</strong> 6 + 2.2 = 8.2 kW. This overload wouldstall <strong>the</strong> 7.5 kW genera<strong>to</strong>r.To prevent this, <strong>the</strong> input power manager <strong>of</strong> <strong>the</strong> <strong>MultiPlus</strong> will au<strong>to</strong>matically <strong>reduce</strong> its charge ratein order <strong>to</strong> limit <strong>the</strong> <strong>to</strong>tal load on <strong>the</strong> genera<strong>to</strong>r <strong>to</strong> <strong>the</strong> set maximum power level, 6.5 kW in thisexample.If you are still reading, you are ei<strong>the</strong>r an enthusiast or pr<strong>of</strong>essionally involved with power systems.In that case we will let you in on one <strong>of</strong> our best-kept secrets.PowerAssist: <strong>the</strong> secret <strong>of</strong> <strong>the</strong> <strong>MultiPlus</strong>Figure 3 shows again our example power schedule with <strong>the</strong> 6 kW peak in <strong>the</strong> evening.But now <strong>the</strong> genera<strong>to</strong>r has been downsized <strong>to</strong> 5 kW.Choosing a smaller genera<strong>to</strong>r will <strong>of</strong> course <strong>reduce</strong> noise, size, weight, fuel consumption andinitial investment.The 5 kW genera<strong>to</strong>r will however not be able <strong>to</strong> supply <strong>the</strong> peak load <strong>of</strong> 6 kW, even if <strong>the</strong> chargecurrent <strong>of</strong> <strong>the</strong> <strong>MultiPlus</strong> is <strong>reduce</strong>d <strong>to</strong> zero during that period.Now PowerAssist, <strong>the</strong> second level <strong>of</strong> ac power management is needed. With PowerAssist <strong>the</strong><strong>MultiPlus</strong> can temporarily supplement <strong>the</strong> genera<strong>to</strong>r ac-power with power from <strong>the</strong> battery. Infigure 3 this is visible between 18 hours and 19 hours: even though <strong>the</strong> genera<strong>to</strong>r is running, <strong>the</strong><strong>MultiPlus</strong> is inverting (blue line above 0) instead <strong>of</strong> charging, thus providing <strong>the</strong> additional acpowerthat is required on <strong>to</strong>p <strong>of</strong> <strong>the</strong> genera<strong>to</strong>r output.With one <strong>MultiPlus</strong> 24/3000/70 an additional 3 kW can be added <strong>to</strong> <strong>the</strong> genera<strong>to</strong>r output!4