Inverter chat

[Bossrox]

What inverter are you using & hows it holding up for you?

I ordered a Reliable Electric brand 4kw sine wave inverter off Amazon for about $450 which is Chinese & can be a gamble from the reviews I've seen so I added a 3rd party extended warranty to it just in case & will give some initial testing results on it after I get it fired up. Still have to decide on what charge controller I'm going for tho so it'll be a couple weeks likely before I do an update.

Update: I ordered an Epever 80 amp mppt charge controller for the system but I just realized something about the inverter that it has a non adjustable low voltage shutdown somewhere between 21 & 21.5 volts which would bring a battery down to near dead so now I have to come up with a circuit that can auto kill the inverter before it takes the batteries down below 50% discharge so they don't get destroyed from deep cycling. Any ideas for that out there? I've found a circuit & posted it further down.

Update 2: Well that inverter seemed to work pretty good & fired up my heavy load table saw without a strain but after getting everything put together & wired into the house, I fired it up & it worked except the output of that Reliable brand inverter was unstable causing my lights to flicker & that's not acceptable so it's getting sent back.

I've found another brand called Solinba, a 4000w, 12,000w surge low freq model that's about double the others price but seems to be a better gamble for a chinese job. Pretty hefty in weight too, about 55 lbs, in a big roomy cabinet on wheels & mostly good reviews on amazon & other sites tho not that many yet but I'll give a report on it later after I get it.

That inverter I'm sending back may have done well for general purpose use so I can't totally knock it but not really geared to be well integrated in a solar system.

Update 3: Got the new Solinba inverter & the company, at no charge, kindly custom modified it to shut down at 22.7 volts so it wouldn't drain the batteries too low. I opened it up for a peek at the guts & looks pretty good. I was informed it would take up to 6 weeks to get it but amazingly it showed up here less than a week after ordering. I don't know if my mentioning to them I was doing a video of it had anything to do with it but if so, cudo's to Solinba for that & yeah, I'm doing a youtube video of this unit which will be posted here when it's done.

I've run my 1st test on it to find out what state my used batteries were in by running a light load of a 750 watt heater for 3 hours straight, the inverter performed perfect, the batteries better than expected with a 40% discharge where it should have been 50% going by the specs.

I now have a video of the Solinba & here ya go.

Update 4: Well the Solinba was running great 24/7 for a couple months on my new set up but 1 day the output transistors exploded under a pretty low load. No idea what caused it but the company gave good customer service, sent the parts & paid the shipping, so now it's been back up a couple weeks running, seems to be ok so far but hung up & shut down for the 1st time trying to start my 120v well pump with a light load active so to prevent possible inverter damage from that happening again, I switched the pump permanently to utility power, being the pump runs very little anyways & hardly make a dent in my utility bill.

Will see if the inverter holds up better this time as it's getting used vigorously.

Update 5: A couple months now since the inverter repair & holding up just fine so far & with some freaky luck, I was on ebay browsing the high powered inverters & ran across a Solinba 4kw split phase 120/240 volt sine wave inverter they had up for auction, so I bid on it & won it for $260 shipped. That's a thousand $$$ inverter, so what an amazing stroke of luck! Great to have a back up now just in case.

Update 6: I sprung for a new 6kw inverter made by a company called Genetry Solar. I've had it up & running about 3 months now & it's doing pretty good so far but it has a dirty sine wave that my washing machine wouldn't run on but some filter capacitors fixed that & except for some video distortion on my camera monitors, I can't say too much bad about it except I had to wait an irritatingly long time for it to get sent. Cost was a hair over a grand & that's a bargain for a stout inverter.

[Bossrox]

Battery low voltage cut-off circuit found

Well, got lucky & found a pretty basic circuit that claims it can do the job I need it to, to keep my elcheapo inverter or any other inverter that allows that deep a discharge from draining the batteries too low. Basically, once the voltage to kill the inverter at is set, a relay would replace the inverters on off switch. I've run this by someone to examine if the circuit looks tangible being I don't know electronics to well & to get proper component values for a 24 volt system so I can build it & test it out, will update this once it's made with component values for 24 volts.

Anyways, here the info I found but couldn't find who to give credit for it.



Here is a very useful project for a low battery voltage cutoff or disconnect circuit. Rechargeable batteries deliver very good performance and lifespan if taken care of. There are many things which can be done to take proper care and protect your rechargeable batteries which are, not over charging them, don't charge them in fast mode & don't let them get fully discharged.

When batteries are deeply discharged frequently, their life will get shorten drastically and be toast in no time. Therefore it is better to disconnect your battery from the load when your battery gets weak. But it is very difficult to check and disconnect from the load every time they require charging so the circuit shown here will do this job very efficiently by automatically monitoring the voltage of the battery and disconnect the battery from the load on an adjustable preset low voltage level of the battery.

The circuit is very simple to build and using few components. The heart of the circuit is a TL071 operational amplifier IC that is connected in comparative mode here. The 10K variable resistor is used to adjust the desired voltage level on which you want to deactivate the relay or disconnect the load from the battery. A 2N3904 transistor is connected at the output of the IC to drive the relay. The 5.1V zener is used as a voltage reference.

The circuit can be used with any type of batteries for example 12V, 9V, 6V, 5V etc. Only you have to change the 5.1V zener diode value according to the battery voltage type. For example if you want to use the circuit with 6V battery then simply change the zener diode value to 3.1V. End of authors article.

My guessing here is from this info, the zener diode for a 24 volt system will likely be around 12v, will find out soon if I'm right & now my source tells me everything should work ok but for a 24 volt system, to use a 16 volt zener diode. Will build this after everything is set up & get back to y'all.

Update: The company for the new inverter I ordered was good enough to modify the low voltage cut-off up higher so I may not need to build that circuit after all, will see what happens.

[Bossrox]

AC chargers built into inverters a big waste!

I can't for the life of me figure out why inverter makers are putting AC chargers in most of them? If you've been hangin' around solar long enough, you'll know it takes about 30% more power to restore lead acid batteries than what you get out & even the lithiums is about 10% loss.

So why on earth would anyone want to flush down the toilet 10 - 30% of your AC power you could have used to run your load & offer inverters without chargers for those who don't want 'em that would cut the inverter cost down as well. A mystery I'll never understand.

[Bossrox]

Not impressed anymore with Solinba inverters

I just had my 3rd board die on me in 2 years altho Solinba has been outstanding in replacing those boards quickly, having that much trouble in that short time has shown they don't hold up very good.

So I started looking into other brands with a decent price & came up with Genetry solar's custom build inverters. I shot them an inquiry but got no response as yet. A company that won't respond will not get my biz However they have a 6kw model for around a grand that they say will run the full 6kw continuously & comfortably whereas the Solinba 8kw I was looking at, the company told me it would run very hot & not what I want to hear.

Will see if I can get a response out of Genetry & hopefully so, their inverter appears to be a good reasonably priced unit.

Update: I did get their inverter & it has been doing well

[Bossrox]

6kw Genetery inverter has been ordered

Finally got a hold of someone over there with many back & forth chats. Their standard inverters are 120/240v split phase however I don't use anything 240v & they're customizing a unit for single phase 120v & adding a remote on/off switch connection.

What's great about their inverters is the ability to change output voltage & the Hz setting within 1%. Also this inverter is rated to deliver the full 6kw without a strain unlike my Solinba's, I'd have to run external fans to keep them from overheating & dubious they would last long under full power.

I'm in the process of upgrading my wiring to handle the extra power I'll have & there will be a video forth coming on this shortly after of the unboxing & testing.