We all like the idea of free energy, well who wouldn’t? Over the last few years we have all seen an explosion in domestic solar electricity (PV) installations in areas of the world that you would have often questioned there effectiveness. A great deal of this has been down the the large government subsidies that are available if you have them fitted. So lets start with some basics:
Based on the UK:
- Domestic Roof PV – Large systems up to 3 KW Grid Tied will probably set you back a staggering 10,000 Pounds, yes thats right the most expensive silicon you’ll ever buy!
- Off Grid PV – Small system charging a bank of batteries that you then draw your power from. These are separate to the system above, and you should never join your Off Grid system to your ring main in your house
Lights are one of the biggest drains on the electricity network, yet if all houses had LED lights, and a small off grid solar system, in theory the lights would cost nothing to run. While I don’t consider myself a so called “tree hugger” we all can do our bit to protect our environment. We take energy for granted and never think about what we are using, we have grown wasteful in our use of power, but through education and cost this is slowly changing.
Getting the best from PV panels depends on a number of factors:
- Type and size of panels
- Location in the world
- Facing south at peak times
- Storage capacity of batteries
- Types of controllers
- Size of cables
While it can be plug and play there are lots of considerations if you intend to make full use of the power.
So I have a small off grid system comprising of low voltage panels (High Voltage ones are used on on grid systems):
- Single 100W Panel (Poly)
- Folding Portable 100W Panel (Mono)
- MPPT Solar Controller Rated at 30A
- 104aH Lucas GEL Battery
- 1000W Pure Sine Wave Inverter
This system charges my laptop, phones and other portable device.
So whats all this got to do with the Goal Zero Yeti 1250?
Well apart from the solar panels what you see above is inside one portable(wish) case, which means you have the convenience of a highly portable(wish) power system with plenty of juice.
So while Goal Zero call it a solar generator, it really isn’t that in practice, its a store and use system for power, and it is very good at it, with some irritating points that GZ should have rectified by now, if they are serious about product development.
Lets get on with the unit, firstly if you live outside the USA then finding one will be difficult, they are not as common in the EU as they are in the USA. Don’t forget that if you do buy one, make sure it comes with the correct inverter and sockets. Stock photos tend to be the USA version, so ask your supplier first.
So lets get the basics out of the way:
Its HEAVY 50kg hence why it come with a removable wheel cart. (The main weight is from the AGM 100Ah Battery)
Dimensions 28cm x 41 x 37cm
Port wise it has the following OUTPUTS:
- 2 * UK Sockets – Total load of 10Amps or 1000W (Peak of 1500 but you will more than likely damage the inverter)
- 3 * USB Sockets total load of 2.1Amps (2.1 is shared across all 3 ports)
- 1 * 12V CLA Max 10Amps (I would stick to a max of 8)
- 2 * 6mm Output Sockets 12V 10Amps – These are for the Goal Zero LED chain-able lights
- 1 * 12V Anderson Power Pole 30Amps
All these have there own power on off button, and given what I have seen in the circuits inside they are fused, but these fuses ARE NOT easily accessible, rather poor if you ask me, a simple circuit breaker reset system could have done the trick here, instead they chose the cheeper blade fuse option.
Port wise it has the following INPUTS
- 2 * 8mm Input sockets designed mainly for the wall power supply and or the Goal Zero Solar Panels
- 1 * Anderson Power Pole Socket 16-48V 20Amps or 240W (Designed for other solar input)
As far as I can tell all of these inputs go into the MPPT charge controller, which in turn regulates the power to the battery. I would take the LCD readout with a “pinch of salt” there are no technical specifications around its accuracy.
What other sockets are there?
- 1 * 180Amp 12V Anderson Power Pole connector, Goal Zero call this a chaining port, so that you can add another (same sized and type) battery to increase the capacity of the system.
NOTE: This supply is connected directly to the battery, and is fused, which are under the rear cover of the unit. (4x 50A fuses in parallel)
The unit comes in a large well packed box with access to the charging ports, but i very much doubt distributers keep them charged, so dependant on storage you MUST charge it on arrival. In fact there is a big sign on the outside of the box and another inside telling you to. You will also get a large “Allen” key to help put the cart on to the yeti and also to open the top of the yeti should you need to remove and replace the battery. You get a brief sheet, reminding you to download the manual and a manual explaining how to assemble the cart.
Hey, don’t forget to plug it in! If you want to learn more about AGM batteries and how to get the best from them, then click here.
So the unit is well made with a solid metal interior with a plastic shell on the outside. The Yeti comes with a “Cart” that allows you to roll the unit on some wheels, which is great and works well, but the handle and supports don’t pack away so there either on or off. I show you some photos later so you can see.
There is a lid on the top with a magnetic seal, with the tips on using the Yeti printed on the underside of the lid along with the serial number. Its big enough for the wall charger, but you won’t be putting you solar cables in there unless you by the Goal Zero panels. On the four corner of the top are the bolts that hold the lid and carrying handles down to the main unit. These are well designed and are a blessing when moving it around, which I suggest you do as a pair, unless you want a bad back.
So thats it for the outside, the unit is NOT designed for bad weather, maybe a light drizzle but i would keep the inout and outputs at the front protected as there are NO seals to prevent moisture getting into the circuits.
So this brings me to the small LCD display, which gives you your SOC (The battery indicator, which goes from 20% to Full, at 20% your Yeti will turn off the inverter, without warning, no low power red light no buzzer, just off it goes. I have no idea why Goal Zero did this, but I would imagine it is because so heavy load devices will fool the unit into thinking its out of power when it isn’t, in other words for a short period of high drain the unit will think the battery is going flat. Either side of the Battery Indicator, on the left, is the Input power in Watts and on the right the output power in Watts. There are other icons, such as overheat, inverter fail etc. These are briefly described on the underside of the lid.
The battery indicator, i assume, is based on battery voltage. The input and outputs, well i have no idea how the unit measures this or how accurate it is. The LCD is also backlit by pressing the button adjacent to the LCD. When the unit is unplugged from any inout and powered off the screen is blank, so it doesn’t draw any power.
Do yourself a massive favour and don’t try and see how much power the inverter will deliver, I have seen youtube videos of people running power saws and all manor of high drain devices, while it may run them (briefly) you will probably irreversible damage the inverter. The inverter won’t cope with such a large internal rush of current to get the device going.
I may try a low power 700W microwave but even these so called low power devices will still over draw especially on start up. If you need to run a microwave or a power saw, then I suggest you either buy a generator or have a much larger inverter starting at around 3000W Pure Sine Wave.
Well not much to tell you about the outputs, the UK version comes with 2 sockets, there are no socket switches so once the inverter is on the sockets are live, you cannot turn them of individually.
The 6mm outputs supply power to Goal Zeros LED lights, if you buy the various adaptors and cables they supply, you can retro fit your own cables, but keep the output to the specifications above.
The 12V Anderson PowerPort output, I have yet to use and I can’t tell if this goes direct to the battery or via one of the hidden fuses.
So from the outside this is a well designed and built unit. Depending in the charge status the battery can take some time to fully charge, once fully charged the input reading will be 0 Watts.
Well you can of course use the mains power with the supplied wall charger which works at up to 5 Amps at 16V, as seen in the photograph. I should also add the the negative terminal connector has a temperature monitoring probe connected, so I assume that the MPPT controller can alter the battery input voltage based on temperature. Not that it helped me much, as you can read later on.
Why not use the sun? Its almost free 😉
You can charge via the 8mm inputs if you use the rather expensive Goal Zero panels, or via the Anderson port using your own adaptor or Goal Zeros MC4 to Anderson adaptor cable (Photo) The combined input limit for the 8mm ports is 10A/160W so if you do use 4 * Bolder 90 Goal Zero panels then you need to split them so that each pair are plugged in separate 8mm ports.
This to me is an very expensive option, portable solar panels are available at far cheaper rates with MC4 connectors, no need to for a charge controller just plug the cables into the anderson port with the appropriate adaptor, no need to use the 8mm ports as the Anderson port will take the full output of up to 300W (Taking into account loss etc this is roughly the highest you could go) (PHOTO)
As there are no detailed specifications or power graphs on the MPPT controller it is to difficult to understand what its doing, if you were to go out and buy an MPPT controller you would be provided or at least be able to download the power graph.
Now this where it can get complex, solar panels can be linked to provide the same voltage at a higher amperage or you can link them (in series) to increase the voltage but keep the amperage the same. Remembering that MPPT controller can work with high voltage and in certain conditions can harvest more energy than if you link them in parallel. This is described in the Boulder 90 Manual and a picture of the suggested method is below. You should be aware that the maximum voltage the MPPT controller can handle is 48V therefore you won’t be able to link (in series) more than 2 100W panels.
You can mix and match solar and wall power, its not clear how the controller prioritises which one does what, but I am led to believe the greater outputs takes priority. How do I charge it? Well solar when I can, but for maintenance charging (once fully charged), the wall charger.
There is really no more to it than that, apart from my observations below which i would read if you have read through to hear so far 😉
Some classic examples of questions people ask:
Will this run my fridge and freezer for X – Well you need all the specifics, the exact power requirements of the devices, are they starting up fresh so they have to get cold first etc, all this needs to be factored in, its not a plain yes or no answer. My freezer pulls nearly 400W when running (and thats when its already -27 Degrees C) so that the power requirements in short bursts to maintain its low temperature.
Will this run an electrical heater – No, these are NOT designed to run heaters, regardless of what Goal Zero say, heaters eat electricity. If you want warmth get some more clothes!
Will this run my log cabin – The LED Lights yes, and some low powered mains devices that can’t run from 12V, but you must collect more power than you use! otherwise your power will run out.
If you want to use the Yeti 1250 then you need to collect more energy than you use, or you will eventually run out.
Issues that Goal Zero should really address:
- The internal charger has a terrible time charging the battery if you run it down to around 20% power, in fact mine unit got so hot I had to remove the battery, worried that the battery was fried or the unit damaged; i left it on my work service over night to cool down, using a volt meter is was at a steady 13.6V 100% charged. However the Yeti insisted on pumping is 60-80W slowly cooking the battery, so i used my CTEK MX10 in AGM mode to see if the battery was cooked. After several hrs of absorption charging the battery was full. I disconnected the charger and placed it back into the Yeti powered it up, before powering it down and plugging the wall charger in, initially running to 40W input the charger soon settled down and then finally to Zero. So all fixed.
- Interestingly the unit is equipped with a temperature sensor on the negative terminal, so the MPPT controller down have a temperature controlled charging system, which is good news.
- The internal wiring should be better protected, (SERIOUS RISK OF ELECTROCUTION) the wires a tight inside and in several places the wires had been pinched and one had cut through the insulation, the circuit board that operates the front panel is of generally old design, and you can see where modifications have been made without changing or redesigning the circuit board, for example components added on top of other components.
- In places the fittings are tight, and the quality control should have picked up, wiring pinching and other issues on my unit, in fact I am glad I opened it, as I found one of the controller wires was bare where it had been pinched. Simply adding some cushioned tape to the underside of the plastic would fix this or alter the design of the plastic cover on the control panel.
- The circuit boards are dated 2012 which suggests that no real change has been made since that date, the inverter is enclosed and I didn’t look at it, however it is well cooled with 3 fans, all of these are NOT thermal controlled, so if the unit gets hot the fans run at full speed or no speed, as the fans are 2 wire versions. I found that odd, I can’t see why a thermal fan couldn’t have been fitted, nearly all external inverters have RPM controlled fans.
- NO low voltage or battery capacity alarm! The inverter just cuts out at roughly 20% which must be calculated via battery voltage, I would imagine this wasn’t added, as when running a high power device like a fridge and freezer the battery voltage may drop low and then pick back up as the inverter loads on the power.