How to Choose to right Size Off-Grid Power Inverter ?? August 04 2020

Q: Firstly, what is an inverter?

A:  A device which changes direct current (DC) into alternating current (AC) Power.
Example: It may turn (convert) 12v, or 24v or 48v DC into 230V AC power (so you can run standard AC appliances that you would normally plug into the wall).

Q: What size of inverter should I use?
A: The size you choose will depend on the watts of the appliance or tool you want to run (find the power consumption by referring to the specification plate on the appliance or tool). We recommend you to buy a larger model than you think you’ll need (at least 10% to 30% more than your largest load).
Example: You want to power a computer with 20” LED screen and a lamp. Computer and Screen: 300 Watts. Light Wattage: 75 Watts.
Total Needed: 375 Watts.  For this application, you would need a minimum of a 450 Watt inverter but we would recommend a 600w inverter which is the MINIMUM wattage we would supply.

You should always consider a larger unit than your minimum requirements, as there will likely be a time when you wish you would have bought a higher capacity model. If the wattage of the appliance or tool is not listed explicitly on the specification, you may use the following formula. Multiply: AMPS x VOLTAGE = Watts.

Example: On the microwave shows 5.22 AMPS for continuous use. The
Wattage is 5.22 AMPS x 230 V = 1200.6 Watt.

Q: Why can the 1500 Watt inverter not run my 1200 Watt microwave?
A: The power commonly advertised for microwave ovens are the cooking power (the power delivered to the food) not the power actually consumed by microwave oven. The microwave ovens might consume 40% to 100% more than its advertised cooking power. The recommended inverter to run 1200 Watt microwave is 2500 Watt or larger.  Often the Microwave manufacturers only show the "constant" wattage rather than the peak wattage that their unit will use.  Many microwaves cycle the power (on and off quickly) to give a lower constant wattage shown but in reality they are still using the higher peak wattage (from the inverter) even if it's only for a short time. 

The best microwaves for Off-Grid usage are the Panasonic INVERTER Microwaves as you have the ability on these units to run them at half power and rather than cycle the power (with high peaks) the power input / output of these units is able to keep constant at a lower rate, or which ever power level you set it to.  A 1200w Panasonic Inverter Microwave will typically run happily from our 2.2kW Inverters while many other cheaper 1200w microwaves may not.

Q: What is meant by the terms “continuous wattage” and “peak surge wattage” on the inverters?
A: The “continuous wattage” is the wattage that the inverter can supply 24/7 as long as the DC input power supply is in good condition (usually, the DC power supply is a car battery) The “Peak surge wattage” is the maximum wattage that the inverter can supply for very short period of time (a split of a second or sometimes 1 second or a half second etc)

Note: Induction motors such as air conditioners, refrigerators, freezers, microwave ovens, and pumps may have a start up surge of 3 to 7 times the continuous rating. Heat generating appliances such as hair dryers and water heaters will have high peak surges as well.

Example: If the microwave oven has peak surge which is 4 times the continuous wattage, the 1200 Watt continuous microwave ovens will have 4 x 1200 Watts = 4800 Watts peak surge. The recommended inverter to run 1200 Watt continuous and 4800 Watt peak surge microwave is 2200w constant / 4800 Watt Peak Inverter or larger. In general, induction motors require an initial surge of power to start up (“starting load” or “peak load”). Once started, the tool or appliance requires less power to continue to operate (“continuous load”).

Q: What is meant by inverter efficiency?
A: Inverter efficiency tells you how much power (as a percentage) is lost in the conversion.
Example an inverter with a 90% efficiency rating will have a 10% loss.  This means to run a 1000w load / appliance you are actually using 1100w of real DC power / battery power etc.

Q: What is inverter overhead power consumption?
A: When an inverter is producing ANY AC output (even just to run a 10w LED light bulb for example) it will have an overhead power consumption (per hour).  Typically for many larger inverters eg 3kW - 5kW in size this may be around 50-70w (per hour) and in some inverters cases this could be as high as 120-140w (per hour).  With smaller inverters (eg 2000-2200w size) you are often looking around 30w per hour overhead power consumption, so that usually needs to be added into your 24 hour power consumption calculation to get a more accurate power consumption

Q: What is idle power consumption?
A: An inverter when it has NO load (0w of load) running can sometimes enter into an IDLE power saver mode, and sometimes that may bring the overhead consumption of the inverter down from 30w to say 15w for example (saving you some power per hour).  The only problem with this is that in order to kick the inverter OUT of power saving mode back to delivering a nice constant stream of power often requires running at least 120w worth of loads (eg switching on a kettle or a TV screen / computer screen etc), however if you were just switching on 1-2 x 10w LED light bulbs then often with just a 10-40w load the inverter would NOT have enough load present to KICK it out of Power Saving Mode and as such you get flickering of lights or other weird problems and issues.  As such we usually recommend for MOST clients to NOT enable the Inverter Idle Power Saver Feature as usually for most people it will cause many issues and only result in headaches rather than any real world power saving.  For all of our power calculations we always factor in for an inverter running 24/7 in normal output mode with it's normal overhead power consumption and we recommend you calculate in this manner also.

For this reason the default setting for most (actually almost all) inverters is with the power saving mode turned OFF as the default setting.  Some AC appliances will refuse to run correctly when it's turned on hence we in 99% of cases we don't recommend enabling it.

Q: What is Pure Sign Wave and what is Modified Sign Wave / Square Wave Inverter?
A: Inverters can be built to 2-3 different main AC output power standards and these are typically split into Pure Sign Wave Output (a nice rolling AC Sign wave) which is compatible with 99.99% of normal AC appliances, and the other type is the cheaper Modified Sign Wave (otherwise known as a Square Wave) AC Output.  We ONLY recommend and supply the Pure Sign Wave Inverters as these run happily with normal AC appliances without causing issues.  In turn inverters that have a modified sign wave / square wave can sometimes shorten the life of some AC appliances or cause issues / problems because of the more squared edges and less smooth power (for the AC Output curve) of the AC power that they supply.

This is now the end of this posting regarding Small / Mobile Off-Grid Power inverters, we hope that you were able to learn alot of useful information. If you need info regarding larger off-grid Inverters eg to run 5kW or 10kW or 15kW worth of loads, or regarding on-grid or hybrid inverters, or if there's a question you have or something that you are confused about or something we've not covered that you want to know about please feel free to email us or fill out the contact us page, or give us a call so we can best assist you further.

Why is there such a mixed experience with solar power / batteries? April 18 2020

How can 1 person have such a great experience and another person have a bad experience with batteries, solar panels and solar power systems ?

Solar and Battery Confusion ??

It's recently come to my attention that there are many grey market parallel importers out there who simply just import and sell items for no other reasons other than to simply make profits.  Sadly it's the intention of these people usually to just be interested in making the profits (as their primary motivation) but not being able to give correct real world advanced technical advice or technical support to their clients.

This then has lead to many people wondering WHY items they purchase elsewhere gave them a poor experience and why items they purchased from us gave them a great experience?  In their minds they thought they were buying what looked to be the same (or very similar) items.

We've heard this with batteries, inverters, solar panels and entire solar systems in fact.  In some cases we've seen some people only get 2 years of life from their batteries that they expected to get 10 years life from, and in other cases their entire system yearly power production was down to 40% of what it should have been (they had lost 60% of their output) and other similar occurrences.

With many items we supply at Hitek we've done thousands of hours of R&D (research and development and technical testing over many of our key items combined) to ensure our products and systems actually deliver great results for real world NZ conditions.  Often many of our items we get produced for us will have changes or internal variations or adjustments made specifically at our request so that they deliver a better real world experience for our customers here in real NZ system conditions, yet when people try to source their own version of an item it will often be a different spec internally from what we are supplying and in turn it won't perform as well in real world applications.

Not only this but often our method of configuration and / or implementation of the items or systems will be different due to our 12 years of vast technical knowledge and hands on real world experience with this technology as a specialist in this area.  This means that even just a voltage adjustment of say 0.4v difference (less than 1 volt) or even a temperature adjustment of just 5 degrees C can have a HUGE real world affect on whether you have an average result from your system or whether you have a great experience. 

If you think about it Solar Power Systems (making them work really well) have alot in common with baking a cake.  You could give 12 different people all the same ingredients and just depending on the way they put them together, the order they put them together, what settings are used for the mixer and oven etc and you end up with vastly different results.  The ones implemented poorly will FLOP and the ones implemented well will be amazing (yet in these cases the same $$ was spent on the ingredients), and this is the reality of the world we live in today.  One could even then say well the guy who had the flop now has to end up buying the ingredients again and wasting their time + energy to have a go a second time just to try and get the same good result that the other guy got the first time.  This is why often thinking you are saving a few bucks and up as a FALSE ECONOMY, as it ends up costing you more than to do it right from the start.  How many of you have ever watched Jamie Oliver on TV and thought that looks amazing what he's made, and you use the same ingredients and yet what you end up making turns out looking and tasting nothing like what you had seen him make?  If however you practiced and made the same thing 50 times over likely by the 50th attempt what you've made will be much better than the 1st attempt. The exact same is true for solar power systems and battery systems today except instead of $15-30 of cake mixture involved there's often $5000 - $90,000  dollars involved, so not something you want to be getting wrong and repeating.

With items we supply we are happy giving this correct technical advice / support away for free but only for items and systems we've supplied and we only give that advice / support away to the direct person or company we sold to, however with items supplied by other companies you cannot phone us up for free technical advice / support for items we have not directly sold or supplied you.  In turn we charge for technical support for anybody wanting technical advice / support for items or systems we did not directly supply and we may simply deny technical support for items purchased elsewhere also.

The real key point here though is that often a person may think that they're saving $40 or $60 buying what they thought was the same or similar item from a trading company, only to find that because of lack of advanced technical support / technical advice they end up with a poor experience that then means they're still unhappy with the result even after their purchase, yet if they had purchased through Hitek they wouldn't be in that same position and they would be assured of having a good experience and correct technical advice / support available.

Often when people are spending $2000 through to $90,000 then you really must think long and hard about what VALUE that advanced real world technical advice and technical support is actually worth to you if it means the difference between having a good long term experience from your hardware and your systems or having a poor experience from your hardware / systems and potentially replacing expensive items much sooner than expected.  Eg if you spent $4k on batteries and then you only got 2 years of life from the batteries as a result of running them in the wrong environment or with wrong settings then even if you thought you had saved $300 at time of purchase, you actually just cost yourself an extra $3700 after 2 years as a result of the consequences of that decision.

Buying and running solar items and solar systems is NOT like buying a new fridge from your local white-ware store.  With a fridge you basically just plug it in and away you go, you'll get the same experience no matter who plugs it in, but with batteries, inverters, solar panels, solar systems the same is NOT true at all, in fact it's very far away in real world reality.

With solar panels themselves they are rated as their "Peak Power Wattage" that only tells you what the panels will do during the best day of the year during the best part of the day (eg 12pm) on a clear sky sunny day during the peak of summer, however it does NOT tell you anything at all about how the panels will perform for you during a cloudy or overcast day, or during Autumn, Winter, Spring etc.  In turn our main focus with our solar panels has been real world NZ testing and NZ panel development right here in New Zealand to actually ensure our panels are tested back to back against other top brands of panels from around the world to ensure that our panels actually typically give HIGHER / BETTER real world power output in real NZ conditions than typical conventional panels.  In many cases back to back testing (including independent client feedback) has found that often many of our panels are able to give between 50% extra power per panel and often even up to 30% greater power (per rated panel watt) in real world NZ conditions.  This means we've had 1 of our 330w panels give up to 50% more power on a cloudy NZ day compared with a 1 year old 330w conventional panel supplied by another company.  Why this is critical is that for many system owners (including off-grid systems and RV's etc) the cloudy days are when you are needing that extra power the most, and so if a panel is only efficient at producing power in the peak of summer but terrible at producing power on a cloudy or overcast day then even though it may have the same Peak wattage label rating as our 330w panels that does not tell you anything about how similar (or dis-similar) the real world NZ power output will actually be between their panels vs our panels and in fact many companies in NZ have not even done ANY of their own real world back to back testing to even directly compare their panels vs other panels in real NZ conditions, and I can assure you just testing the comparison in China does not tell what or how they will perform like here in NZ as our atmosphere conditions are very different here.  It's well known that many panels designed for usage of solar power systems in China may run happily there for 10 years without issues and then as soon as those same panels are used here in NZ they may perform poorly or even fail after just 2-4 years, and people say why?  They don't understand that the panels need to be built to a different and higher (NZ specific) spec as our conditions here are very different, and this is exactly why we don't just import random panels and items from China and why we do our own development and testing of our panels and many items we supply to ensure the really will give a long life and best results here in real world NZ applications, but I'm not aware of any other companies in NZ that do this to the extent that we do.

Long story short, when you are buying your solar system or battery related hardware or items then you want to be dealing with a company who really cares about ensuring that each and every client ends up with a great real world experience, rather than a company who doesn't offer (or often even have the ability to offer) to advanced technical support to ensure you can even end up with a great experience because their primary concern is just making sales and lining their pockets (this is the opposite of what Hitek is about).

Our company slogan is "Empowering your world" as it's our goal with ALL of our systems to actually help  empower our customers, and part of this means being able to give them correct real world advice or technical support to ensure they can achieve a good experience, and this is our primary goal (not lining our pockets).

Because we are "Official" agents of the brands we use and supply then we get direct technical support and access to alot more advanced technical information than someone who is just grey market importing a brand and in turn is LOCKED OUT of the official manufacturer support channels.

I hope this article proves useful to really help people better understand why and how so many people can have bad or poor experiences just from buying hardware online from random sellers when in their mind they thought they were buying the same (or similar) items.  As the old saying goes "It's all in the detail" and when you don't even know what you are looking for in the first place, you don't know what correct questions to ask and in turn the critical details are often missed until it's too late and by that time you find out you have a poor experience and nobody there to properly assist you to get things running right for your site.

This is why we hear that around 80% of NZ solar systems running here in NZ today are giving LESS than optimal results or have not met the clients expectations or are not giving the power output or savings that a client had expected at the time of purchasing, yet for our clients and our systems we have amazing results and amazing success stories from the last 7500+ systems we've designed and supplied.

We have a saying that is "You don't buy Solar Panels or Batteries to just sit there and look pretty", meaning that unless they are doing their job and doing it well then there's no point on having them as if all they are doing is just sitting there looking pretty and not giving you good real world results and not giving you good real world savings then there's really little point having invested in them in the first place if they're not working well for you.

Many people don't realize that we actually DO have a price match policy*, which means if you do see the exact same make + model items as we are offering and it's in stock in NZ (currently in stock available) not coming on a shipment a few weeks away, and it's a public listed / advertised or quoted price that you can reference, then we are able to often match (or beat) that price under our price match policy.  What this means is that if you were thinking about buying elsewhere because you thought were were getting something slightly cheaper then PLEASE talk with us first and ask about this policy, as the very worst thing we can possibly come back to you saying is "sorry we can't help" but more often than not we may be able to come back to you saying "Congratulations" we can assist you with that.  There's a great saying "If you want something, it's best to ask", so we encourage our clients to please talk with us and at least ask us to allow us to best assist you rather than just assuming we may not be able to help you.

If you have an existing solar system (or battery system) that was purchased elsewhere or supplied by someone else that is not performing well for you or you are having constant issues then please feel free to give us a call and we will see how we are able to best assist you to help.