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Small Cabin Forum / Off-Grid Living / New inverter test now complete
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# Posted: 5 May 2017 12:35

Okay. If you've followed my posts you know I'm a champion of off grid solar. And, with 7 years living on off grid solar I've learned a thing or two.

So I've always touted European inverters. Quite honestly I still do. Off grid means reliability. The fact I'm 4 years without any down time sort of indicates how I'm doing.

Now I've noticed that the world's manufacturing has really developed over the passed 5 years. So recently I looked at a CNBOU 2kw inverter. They make some pretty bold claims about the efficiency.

Test results with pretty pictures:

Short form: Wow. Bold but accurate.

# Posted: 7 May 2017 10:09

I was asked about whether I thought the inverter was better than the European models.

No. For two reasons.

One: They don't have the record for longevity.

Two: Some features are still missing. For instance the Victron has "auto restart." So if the inverter shuts down due to overload the Victron will automatically restart after a set period of seconds.

The CNBOU will require that you change a fuse.

# Posted: 7 May 2017 22:02 - Edited by: jaransont3

Nice testing and report out, creeky. I am interested in one of these as a replacement for the Tripp-Lite inverter/charger we are using now.


The Tripp-Lite is still working great, but it is NOT true sine wave and the cooling fan is pretty loud when it runs and it has a bit of a hum to it when it is operating.

So I am looking at the 1000W CNBOU as an upgrade, but it is only the inverter. I understand I would need a separate charge controller, but which one/size/etc. CNBOU has 10A, 20A, and 40A MPPT controllers. The Tripp-Lite has a 20A 3-stage controller built in.

I am not running solar yet. I use a 3000W Honda Inverter generator for primary power and charge/invert two GC-2 6V LA Golf Cart batteries for power over night or when we are away from the cabin for the hours at a time. The batteries only have to run a compact frig, a few LED lights, the 12V on-demand Shur-Flo pump when necessary, a couple of phone charges, and maybe the ceiling fan once we have pure sine wave. (the ceiling fan doesn't like the Tripp-Lite so we only use it when the generator is running right now).

So I am thinking a 20A charge controller would be fine, given our loads, batteries, and the fact that one has been working for us for years. What are your thoughts?

BTW, I would love to go to Lithium-Ion/Polymer batteries since we haul the battery pack back and forth to the cabin all the time, but I have not been able to make hide nor hair of what I need to be equivalent or slightly higher capacity than the two GC-2s I have now. The ratings are confusing since they all seem to use different units/etc. Any insight there would be great.

Thanks again for being so thorough with your evaluations.

# Posted: 8 May 2017 00:10

Been poking around the internet....without solar, It doesn't look like I need the MPPT controller. I just need a transfer switch/charge controller like the Tripp-Lite unit has built in. There are some pure sine wave inverter chargers out there. Any experience with AIMS Power or others?

# Posted: 8 May 2017 09:55

Well. There's lots of variables here.

I'm recommending 48v now. My how things have changed. But after actually building a 48v system my old 12v. With its lead batteries, hmmm. How to describe it.

48v means your solar efficiency gets a 2-3% boost. And your inverter gets a 5-6% boost.

You give up some 12v appliances without a dc-dc converter.

The CNBOU has an inverter charger. But not in 48v. In 12 and 24. Also the 24v "Helios" is out. Its a bit big for you now. But it might work longer term. The "Helios" is a all-in-one. I've been waiting for my test unit for quite awhile. Years in fact. But with a deposit only for a few months. smile. Just seems longer. I need 48 for my batteries. The advantage to the all-in-one is that everything is plug and play. This will be great for campers.

Most of the non-commercial brands are just that. Brands. Made in who knows where with who knows what. So I won't slag them. But I can't recommend them either. Aims I know nothing about.

You could look at Samlex. Yup. Its a brand. But they've done a good job for a long time. Victron is of course an excellent mfct.
And remains my two thumbs up recommendation.

For now. If I were you I would try to bypass the inverter on the tripp light and just use the charger for my batteries. Then use the 1kw CNBOU for powering the fridge and fan. That would be your least expensive short term solution.

When the genny's running you're using it to power the loads. Then just turn off the tripplitt/genny and turn on the CNBOU. Bit of a kludge. But ...

When you go lithium think carefully about 48v. More than efficiency its an easier install. Thinner wire. Lower amps. Etc.

Btw. With lead my rule of thumb was 1w solar to 2a lead (12v). With lithium I find 1w solar for .65a lithium. The combination of much higher efficiency and deeper discharge. You just need less battery.

Good luck. (and buy some panels. smile. for interest. How much gas do you burn each season?)

# Posted: 8 May 2017 12:31

Thanks for the input. I will have to do a little digging into the Tripp-Lite and see if I can only use the charger half of it.

Right now we only spend about a week at the cabin each quarter. We generally burn 7-8 gallons of gas during the course of the week. At $2ish a gallon it is not too bad. Probably around $100 per year in fuel. Add another $20-30 for oil changes on the generator. We spend way more than that in gas driving the 830+ miles one-way to the cabin each trip.

Solar is definitely in the cards when we start spending more time there after retirement in 6-10 years.

Would love to carry around a smaller, lighter Lithium battery pack. The lead acid batteries box with the inverter/charger is over 150 lbs to lug around.

# Posted: 8 May 2017 15:53

I'm going to throw in a few comments - I fully understand that everything is a balance between cost, convenience etc so "one size does not fit all". All my comments are based on the limited use of a few times a year and the eventual plan to upgrade - do you need to spend much money now?

Why are you lugging the battery pack (and inverter) back and forth each time? If not for security reasons, then why not leave it and hook up a small trickle feed panel (ones you stick in the window) so the batteries will be fully charged each time you arrive and ready to go? I'm not sure where you keep the batteries now (outside or inside) but if you could more permanently "package" things with the proper connections, it might be a lot easier.

Can you enclose the Triplite in a box (with ventilation) so the noise is reduced (separate compartment from the batteries)?
Although a pure sine wave inverter has advantages for sensitive electronics, it also costs more and often it is not really needed, especially for such limited use and if you understand the trade-off. The fridge motor might run a little hotter and the fridge might last a bit less time but given you are only using it a few weeks a year, likely not a real issue. Also, as the inverter is already equipped with an automatic transfer switch and charger - if you can keep it (and keep things simple) it has advantages.

Although not cheap, you could replace the ceiling fan with a 12v model - run directly off the batteries. Some really nice ones that do not draw a lot (especially if you add a proper speed controller). This might not be feasible depending on how your cabin is wired but if so, would allow you to run the fan even without the generator.

Again, some of these suggestions are based on the possibility that you will be upgrading everything in a few years so it might make more sense to make do with what you have until then.

My system - Initially: 2x Trojan T105 batteries, Xantrex HF1800 inverter/charger used with Honda generator to charge every couple of days (at worse): then added 2x165w panels and charge controller. Inverter is normally off as all normal things run from 12v (including ceiling fan, pump, lots of lights), turn on inverter for vacuum, other 120 things). The main system is shut down when we leave but a "security circuit" runs off the "load" connection on the charge controller to power motion sensor lights.

# Posted: 14 May 2017 09:47

I wrote a "simplified off grid solar system schematic". It has the settings you need to document in building/specifying your system.

There is no explanatory text yet (the whys?) but I'm getting there. I would appreciate feedback.

One thing: we all go our own way with solar. Different needs. I myself found 12v dc expensive and so I went all 120v a.c. You do save quite a bit of money on fixtures/appliances. Just light bulbs alone! Not to mention initial wiring etc.

# Posted: 14 May 2017 11:12

Some additional data from my experience. As Raz notes, it is simple to add a small trickle charger to your system to keep batteries topped up. My system is 4 panels (1000W) for use while I'm at the cabin in summer. These are flat on my roof. I also have a small panel that is mounted on the roof vertically that is used over the off-season (8-9 months fall-winter-spring) to keep the batteries topped up. It's vertical so there is no snow accumulation, and is a good angle for winter sun (we're at 60 degrees latitude). Probably not really necessary, as good batteries will hold a charge over winter, but it is added protection.

I ran a 12V solar system in our off-grid house some 35 years ago. Unless your loads are very simple, it is well worthwhile to go inverter to 120V. As Creeky said, you will save considerably on fixtures etc. Especially if you look at 12V fridges of any size. For some reason, these fridges are outrageously expensive (like 3-4x) compared to a standard home fridge. You can find 12V lights etc. at RV stores, but typically they are cheaper made and more expensive cost.

Also, as many have noted, the most efficient solar systems will be higher voltage (smaller wire etc.) but there are very few options for 24V or 48V fixtures and appliances.

Just my two cents of experience.

# Posted: 14 May 2017 12:38 - Edited by: ForceFed70

Lots of inexpensive 12V LED and fluorescent (almost as efficient as LED) fixtures out there from the RV industry. Along with 12V switching, etc. If you have a 12V power system I think it's a mistake to use AC for lighting.

Totally agree with you about higher voltage systems like 24V tho. Much harder to find fixtures, and when you do they're pricy. Probably better off to go AC in that scenario.

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