Troubleshooting problem with off-grid system - charge controller and inverter

[Seanmclainbrown]

Hi all,

I'm new to solar and have bought an entry level system that I'm having trouble with. Here's my setup:

180 watt panel system (amorphous)
30 amp/500 watt Thunderbolt charge controller from Harbor Freight
4 6volt Trojan t-106 wired in series/parallel
5000 watt continuous inverter (Chicago Electric)

Problem: charge controller and inverter keep tripping even though the devices I have connected are not drawing nearly enough power to cause the trip. I only have computer, a few electronics, and a very small freezer (which is very energy efficient and isn't drawing very much power either).

Any ideas on what would cause the charge controller AND the inverter to trip and shut off?

[russ]

You need to measure actual consumption rather than make guesses. A Killawatt or equivalent will do the trick for most items and an amp clamp for the rest.

[inetdog]

Any ideas on what would cause the charge controller AND the inverter to trip and shut off?

If, for whatever reason, both the CC and the inverter see zero or very low battery voltage they will both go offline.
If the battery voltage immediately comes back up to an acceptable level (probably between 8 and 10 volts for a 12 volt system) then the inverter may still require a manual reset.
If the battery voltage is too low, the CC will assume that something is wrong and will not try to charge. A typical solar-input CC will also behave badly if the PV input stays powered while the battery goes away and comes back.
Check for high resistance in your battery wires and connectors, among other things.

Among the other potential problems is the source of the components (Chicago Electric == Harbor Fright).
Also, the inverter is way too big for the batteries you have. Or for being a 12 volt inverter in the first place, for that matter.
And finally, 180 watts of panel (even if the Harbor Fright spec is to be trusted) is way too small for the battery bank you have.

[Naptown]

If, for whatever reason, both the CC and the inverter see zero or very low battery voltage they will both go offline.
If the battery voltage immediately comes back up to an acceptable level (probably between 8 and 10 volts for a 12 volt system) then the inverter may still require a manual reset.
If the battery voltage is too low, the CC will assume that something is wrong and will not try to charge. A typical solar-input CC will also behave badly if the PV input stays powered while the battery goes away and comes back.
Check for high resistance in your battery wires and connectors, among other things.

Among the other potential problems is the source of the components (Chicago Electric == Harbor Fright).
Also, the inverter is way too big for the batteries you have. Or for being a 12 volt inverter in the first place, for that matter.
And finally, 180 watts of panel (even if the Harbor Fright spec is to be trusted) is way too small for the battery bank you have.

But aside from those few things it all looks great

[PNjunction]

I'm new to solar and have bought an entry level system that I'm having trouble with. Here's my setup:

I'm going to be an ass right up front, and tell you that you bought into a mismatched system - it can be fixed however if you want to continue. You'll hate me (and others) now, but perhaps thank us later when it saves you time / energy / money later. We'll pick this apart in order to save / use some of it depending on how you want to proceed. The goal is to make something out of this so you won't be disappointed early on and get that thing working like it should!

180 watt panel system (amorphous)

This is probably four of the 45-watt HF systems? If so, you've got some real-estate to play with if/when you should decide to go with mono or polycrystalline panels later. The amorphous are about 1 to 2/3 larger. I'm thinking they are all hooked together in parallel with the HF adapter(s).

30 amp/500 watt Thunderbolt charge controller from Harbor Freight

This looks like a Steca PWM charge controller either cloned or rebadged. Ok.

4 6volt Trojan t-106 wired in series/parallel

Big choices here - that bank is way too large for the existing panels. You'll have to either (1) get more panels or (2) buy smaller batteries.

Problem: charge controller and inverter keep tripping even though the devices I have connected are not drawing nearly enough power to cause the trip. I only have computer, a few electronics, and a very small freezer (which is very energy efficient and isn't drawing very much power either).

Aside from the inverter being too big, are you just connecting it to the load terminals of the charge controller and not to the battery bank directly? Is there a deep initial pull of current from the freezer?

Realistically, at the very best your 180w panel system can only put out about 10 amps discounting real world wiring/gear losses. Typically for flooded batteries, the MINIMUM current needed for FLA is about C/12 - max of C/8 (check manual). You've got near 520ah of battery capacity, and this would mean needing about 62 amps charge current - about 6 times more panel capacity than you have now. The Trojan manual for flooded shows anywhere from 10-13% capacity as being the recommended current so you'd be looking at increasing your panel wattage anywhere from 4 - 6 times or so. Sure, you can lead them to an early sulfation demise by not feeding them properly with enough current - but why do that?

Realistically, it's time for a smaller battery. Either keep the existing ones for a future project (keep them charged with a decent charger though!), or sell them off. I'm thinking something near 80-120 ah for FLA deep cycle batteries. If you go with a simple UPS-style agm (like the Harbor Freight "universal battery" which is 35ah agm - the UB12350 rebadged) you'll be near the maximum current for those with that panel (agms typically can accept up to about 0.2 to 0.3C). But will a 35ah agm battery run your loads? At least it shouldn't have a problem charging up in an hour or two in the winter.

What you'll want to know up front is not only your power consumption, but what your hours of solar-insolation are. This differs from visible-daylight hours, and can be gotten online from solar insolation charts. Generically, the solar insolation hours are from 10a to 2pm, being worse in the winter. This is vital to know to figure out if even charging the 80ah battery is possible within a given timeframe.

Harsh - I know. The smaller battery will let you have some fun, while reading / deciding if going with larger panels is going to be worth it - BUT only after you know your power consumption and solar insolation.

[PNjunction]

HF panel interconnect wiring

As a former HF/Sunforce/Maplin user, I forgot to mention one very big thing:

ALWAYS verify the polarity of the wiring in the kits with a voltmeter! This is especially important if you mix'n'match the typical SAE jumpers from these kits with something else. For example, I blew a cheap controller early on when I used the battery clamps from a battery charger kit, to the sunforce panel. Red to Red, Black to Black right? ZAP.

The harbor freight panels I had mismatched the polarities when used with 3rd party jumpers. Blew my mind - and my controller. The voltmeter polarity indicator revealed the problem. This was frustrating to say the least, since the polarities were correct when used with their own products, so I never suspected a mismatch.

I'd definitely check the ouput of each panel, the output of the hub adapter/box that is in use before attaching to the controller just to make sure polarities are ok.