Electronics Question - Will This Work? / And Another Question

[Wire Weasel]

Hi Group, Was given a China Chicago Tool 2000/4000W inverter today that doesn't work. Can anyone suggest common failures for these things .... some places to start looking? Haven't been inside it. I'll look for blown protection diodes on the input in case it got hooked up backwards. Any other ideas? I am not a proper tech but have a good VOM and can do the basic things.
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This thing had me thinking - Look at a vehicle. You have an alternator connected to battery. With engine running the alt runs the loads and floats a charge over to the battery .... but it's all connected. If needed, load draw could come from the battery as well.
Now look at a battery by itself with say a solar panel connected to it with a correct regulator circuit. Daylight charging and loads being pulled ..... it's all connected. The battery is providing load current and being charged at the same time.
Now consider a battery with an inverter connected. One of the loads on the inverter is a (whatever size) battery charger going back to the battery. Will such a setup extend the load-life of the battery? Or would it become more like a 1 to 1 in & out with no gain to be had? I realize the battery will eventually draw down due to resistances and component heat losses ..... but would that EXTEND the battery life? I further realize that the "re-charger" might need to be special-regulated and/or directional current flow diodes or something might need to be employed to get it to work. ??

 

[brandon7861]

Adding a charger powered by the same system is only adding the inefficiencies that come with it. It will only kill the battery faster.

A bunch of things can go wrong with the inverter. Visual inspection comes first. If you dont see anything visibly damaged, no cracked switching transistors, no bulged or leaky capacitors, no burnt traces, then you can move on to giving it power.

A current-limited supply is nice because if something did short and blow the fuse before anything else let the smoke fully escape, you have a chance to give it just enough power to heat what went bad but not enough to blow it to bits. Thats where a cheap thermal camera is worth its weight in gold.

If the bad part is an open circuit, it will take more serious investigation, and chances are, more than one thing is cooked. In any event, I would check those big transistors on the heat sync. Get a part number, find the datasheet, then, with knowledge of what they are, you can test them.

Got good pictures of the board so we can help hunt for damage?

 

[BC Coyote]

Wire Weasel.... Make sure you are hooking it up to a GOOD battery, not some half-ass cheap POS with low voltage.
Make sure your connections are really really good and tight.
Make sure you are giving it the right input voltage.......some inverters run on 12 volts DC, others require 24, 36 or even 48 volts DC input.
Make sure the load you are trying to run on it is less than the rating. I'm puzzled by the 2000/4000 watt thing. Is it a 120/240 volt output ? Either way, the ratings tend to be exaggerated (just like amps!).......if it says 2000 watts max I wouldn't expect more than 1000 watts full cycle, or 1500 watts at 50% duty cycle.

If it's just totally dead I would toss it......they are notoriously difficult to fix, and the problems are often with the Chinese ROM chips that are the basis of nearly all of them.

 

[AudioShockwav]

On the battery charger.
No.
Any heat/loss is lost forever and simply drains the battery faster.
You lose energy in the charger as heat.
You lose energy in the inverter as heat caused by the extra load from the charger.
Better to skip the charger.

73
Jeff

 

[Wire Weasel]

Adding a charger powered by the same system is only adding the inefficiencies that come with it. It will only kill the battery faster.

A bunch of things can go wrong with the inverter. Visual inspection comes first. If you dont see anything visibly damaged, no cracked switching transistors, no bulged or leaky capacitors, no burnt traces, then you can move on to giving it power.

A current-limited supply is nice because if something did short and blow the fuse before anything else let the smoke fully escape, you have a chance to give it just enough power to heat what went bad but not enough to blow it to bits. Thats where a cheap thermal camera is worth its weight in gold.

If the bad part is an open circuit, it will take more serious investigation, and chances are, more than one thing is cooked. In any event, I would check those big transistors on the heat sync. Get a part number, find the datasheet, then, with knowledge of what they are, you can test them.

Got good pictures of the board so we can help hunt for damage?

I can take pics later. Just got the thing yesterday. Will probably pop the cover today. Thanks for all the tips. Would be nice if I could get 'er fixed. Likely a $200 unit for the size

 

[Wire Weasel]

Wire Weasel.... Make sure you are hooking it up to a GOOD battery, not some half-ass cheap POS with low voltage.
Make sure your connections are really really good and tight.
Make sure you are giving it the right input voltage.......some inverters run on 12 volts DC, others require 24, 36 or even 48 volts DC input.
Make sure the load you are trying to run on it is less than the rating. I'm puzzled by the 2000/4000 watt thing. Is it a 120/240 volt output ? Either way, the ratings tend to be exaggerated (just like amps!).......if it says 2000 watts max I wouldn't expect more than 1000 watts full cycle, or 1500 watts at 50% duty cycle.

If it's just totally dead I would toss it......they are notoriously difficult to fix, and the problems are often with the Chinese ROM chips that are the basis of nearly all of them.

Hooked to my truck to test. Didn't power up and there was some slight sparking around the clamps at the battery so I immediately stopped for further investigation.
2000 continuous
4000 surge

 

[Wire Weasel]

Another funny about these inverters - Have this friend nearby who ONLY has these around for like Winter Storm power outages. I have 2 diff. portable gas generators. I was questioning him about why he went with these and said "so I don't have to mess with a owning a gas generator" - yet he has to connect them to his vehicle and run his engine for hours at a time to power his house ..... refrigerator and things.
This friend is a mechanic and a handyman and knows how to maintain equipment and has plenty of storage space for a generator ....... I thought it was an odd choice but to each his own

 

[BC Coyote]

there was some slight sparking around the clamps at the battery

That's your problem right there. As I said above, all connections have to be really good and tight ! I hope your using actual battery terminals and not those giant oversize gators like the ones on jumper cables. Those are beyond useless for hooking up an inverter to a battery. Proper battery terminals or you're wasting your time !

 

[Wire Weasel]

That's your problem right there. As I said above, all connections have to be really good and tight ! I hope your using actual battery terminals and not those giant oversize gators like the ones on jumper cables. Those are beyond useless for hooking up an inverter to a battery. Proper battery terminals or you're wasting your time !

Yeah it came with like a 3 foot set of heavy cables with heavy clamps like come with large heavy duty jumper cables. Figured that would work to simply power it on and test. It has LED indicator lighted display.

 

[Wire Weasel]

That's your problem right there. As I said above, all connections have to be really good and tight ! I hope your using actual battery terminals and not those giant oversize gators like the ones on jumper cables. Those are beyond useless for hooking up an inverter to a battery. Proper battery terminals or you're wasting your time !

As sits .... Input is reading High Open. 3 Million ohms. Switch on or off is the same. Is that normal?

 

[Wire Weasel]

Also - went to open it up today and the bastard has two high quality steel Security Star screws on it. Don't have those bits. No luck drilling them out yet and have Easy-Out bit set. May have to chisel them off dammit

 

[Wire Weasel]

That's your problem right there. As I said above, all connections have to be really good and tight ! I hope your using actual battery terminals and not those giant oversize gators like the ones on jumper cables. Those are beyond useless for hooking up an inverter to a battery. Proper battery terminals or you're wasting your time !

I have one of those 36A Switching Power supplies around that I could attach 12g wires with secure terminals to tighten down. That should be adequate to just power the thing up and light testing right?

 

[brandon7861]

Hooked to my truck to test. Didn't power up and there was some slight sparking around the clamps at the battery so I immediately stopped for further investigation.
2000 continuous
4000 surge

They have large capacitors that need to charge when first connected. I have a 3000w whistler modified sine and it throws good sparks when first connecting it.

 

[BC Coyote]

Input is reading High Open. 3 Million ohms. Switch on or off is the same. Is that normal?

That doesn't seem right. There should be some kind of difference with the switch in the on position.

I have one of those 36A Switching Power supplies around that I could attach 12g wires with secure terminals to tighten down. That should be adequate to just power the thing up and light testing right?

Yes, that should be fine for testing.

 

[Wire Weasel]

Kaplah! Thanks to BC Coyote for the correct tip about Tight Connections and not to use the Spring Clamp bitches. Connected to my MegaWatt 36A P.S. with tight connections and 12g wire for testing and the thing fired right up and seems to be working fine. Got the bottom cover off first to look around. Blew out a little dust and everything looked good. Has 3 fans which run full time when unit is powered on. Full manual is online. Draws 2.57ADC idling with the 3 fans. Output is 115.3VAC. Set P.S. to 14.0V. Plugged in a corded 8amp drill and it ran normally. No lags or noises. Got lucky on this unit !! Thanks again ! Don't know that I'll ever use it as I have 2 portable gas generators so I'll probably sell to someone who can use it.