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Need advice on a charge controller

Kenny Konfused

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Joined
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Texas
I have a DIY system that I have setup for a detached garage. The only thing I am powering is a small window unit because in the garage is an antique car.

My system is:

3 – 100 watt Thunderbolt panels from Harbor Freight

400 watt universal solar connector

500 watt charge controller, Thunderbolt from Harbor Freight

100 Ah Lion Energy battery

1500 watt power inverter

Before 1 full charge the charge controller started beeping and felt very hot. The instructions don't inform you what the beeping means. I have read that the Thunderbolt charge controller is not great. Looking for a recommendation for a charge controller for what I have?
 
The smallest common size A/C window unit is about 500 watts. Just exactly how do you plan to power that with 300 watts of panels and one 12 volt battery? What is a solar connector?
 
How long do you plan to run the AC of this system? I fear you might be let down with undersized system and poor performance.
 
The smallest common size A/C window unit is about 500 watts. Just exactly how do you plan to power that with 300 watts of panels and one 12 volt battery? What is a solar connector?
Likey when you need the AC the panels will be putting out 50-60% in the heat. So now your down to 180watts.
 
Victron MPPT 100/30. The quality, support, documentation, and app data is excellent. Invest in quality. These hold their value.
 
THUNDERBOLT SOLAR 30 Amp Solar Charge Controller - Item 68738 / 94790
https://hftools.com/app68738

Is this the SCC you bought? Agreed with a Victron 100/30 is the way to go for a direct replacement.

Now I would double check you’re wiring, the victron has reverse polarity protection, but you might have torched the other unit.
 
THUNDERBOLT SOLAR 30 Amp Solar Charge Controller - Item 68738 / 94790
https://hftools.com/app68738

Is this the SCC you bought? Agreed with a Victron 100/30 is the way to go for a direct replacement.

Now I would double check you’re wiring, the victron has reverse polarity protection, but you might have torched the other unit.
Yes, that is what I have. I have double checked that I have + and - in the right spots on the charge controller, what else should I check?
 
this forum and its members is where you want to get your information and advice from. You have found the ultimate resource for assistance with your journey into solar. If want success, listen and follow the advice given.
 
This is my first venture into solar and I'm taking advice from different people who supposedly know what they are talking about.
My only guess is you can measure the open circuit voltage of your array, you are running your 100w panels in series, right? Prob 60v?

It might be too high for that controller, not sure, but there’s no way 3s of 100w panels will be above 100v rating of that victron unit.
 
My only guess is you can measure the open circuit voltage of your array, you are running your 100w panels in series, right? Prob 60v?

It might be too high for that controller, not sure, but there’s no way 3s of 100w panels will be above 100v rating of that victron unit.
The Thunderbolt panels are connected to a hub that has 8 inputs and 1 output to the charge controller.
 
For a typical 5000btu Aircon unit you likely will need at minimum a 1000w solar setup. My 8000btu LG unit during a typical hot day used 7kWh over a days use with energy saving mode for part of it. You will also need a sufficient inverter (likely 2000w) and enough battery (5kWh).

The setup you have is really only sufficient for some lights and maybe charging your cell phone.
 
3 – 100 watt Thunderbolt panels from Harbor Freight
Works well in series to a proper MPPT controller, garbage in parallel through the solar collector hub.
400 watt universal solar connector
Garbage...
500 watt charge controller, Thunderbolt from Harbor Freight
Garbage PWM, overpriced and underpowered
100 Ah Lion Energy battery
So about 1200wh of power available, good for 2-3 hours of small aircon in good sun but that's about all you've got in the bucket.
1500 watt power inverter
Jupiter 1500w? That's a modified sine wave inverter and not healthy for your aircon compressor.

As the local HF fanboy and employee 9and owner of 3 Thunderbolt 100w kits) I can tell you most of our solar stuff is krap, but it is good for learning so I'm not gonna say anything mean about buying HF stuff, it's affordable and gets your foot in the door.

OK, so an oddity of the HF 100w mono panels is that they work great in series, but when you parallel them up each panel puts out about 30% less than the panel before it, so your 100w panel + a 70w panel + a 40w panel are what you actually see. No idea why, people have done test runs and it is just something odd about their panels.

Fortunately if you get a proper 30 or 40a MPPT controller you can re-head the HF panels with good old MC4's and connect them up in series and get a proper 300+w string. They do punch above their weight class with some people getting upwards of 120w out of a panel so having the extra 10a of SCC can't hurt and doesn't really cost that much more. You don't have to go Victron either, a HQST, RichSolar, Weize, BougeRV, or anything else will really open up your solar harvesting. Pro tip: If there's a USB port on it, it's a FAKE controller with a MPPT sticker on a cheapie PWM box and they laugh all the way to the bank. Figure spending at least $100usd on a good unit. I'd avoid EPEver as there is a known bug in their tracking software.

As mentioned above, the aircon is likely 500w at the minimum. There might be a data sticker on there saying how many amps it draws at what voltage and you can math out the draw from there. There may be an Eco mode that draws less, the best way is to grab a Kill-A-Watt and throw that between the inverter and the aircon to see actual usage numbers. Add in 10% for the overhead of the inverter and that'll tell you how much power it takes per hour to run. Sadly, it's all about the maths with solar.

You have a good start with your battery, inverter, and panels. Now starts the fine tuning and learning that we've all gone through. Getting a proper MPPT involved will help quite a bit, and you'll find you'll likely need more battery to run that aircon on the longer days. Winter is going to suck, just accept that now. ;)

Hang out on here a while and it won't be long before you're posting up about your 1.21Jiggawatt ground mount array and your DIY 40Mwh LFP battery build in a chest freezer with your paralleled inverters. :)
 
Works well in series to a proper MPPT controller, garbage in parallel through the solar collector hub.

Garbage...

Garbage PWM, overpriced and underpowered

So about 1200wh of power available, good for 2-3 hours of small aircon in good sun but that's about all you've got in the bucket.

Jupiter 1500w? That's a modified sine wave inverter and not healthy for your aircon compressor.

As the local HF fanboy and employee 9and owner of 3 Thunderbolt 100w kits) I can tell you most of our solar stuff is krap, but it is good for learning so I'm not gonna say anything mean about buying HF stuff, it's affordable and gets your foot in the door.

OK, so an oddity of the HF 100w mono panels is that they work great in series, but when you parallel them up each panel puts out about 30% less than the panel before it, so your 100w panel + a 70w panel + a 40w panel are what you actually see. No idea why, people have done test runs and it is just something odd about their panels.

Fortunately if you get a proper 30 or 40a MPPT controller you can re-head the HF panels with good old MC4's and connect them up in series and get a proper 300+w string. They do punch above their weight class with some people getting upwards of 120w out of a panel so having the extra 10a of SCC can't hurt and doesn't really cost that much more. You don't have to go Victron either, a HQST, RichSolar, Weize, BougeRV, or anything else will really open up your solar harvesting. Pro tip: If there's a USB port on it, it's a FAKE controller with a MPPT sticker on a cheapie PWM box and they laugh all the way to the bank. Figure spending at least $100usd on a good unit. I'd avoid EPEver as there is a known bug in their tracking software.

As mentioned above, the aircon is likely 500w at the minimum. There might be a data sticker on there saying how many amps it draws at what voltage and you can math out the draw from there. There may be an Eco mode that draws less, the best way is to grab a Kill-A-Watt and throw that between the inverter and the aircon to see actual usage numbers. Add in 10% for the overhead of the inverter and that'll tell you how much power it takes per hour to run. Sadly, it's all about the maths with solar.

You have a good start with your battery, inverter, and panels. Now starts the fine tuning and learning that we've all gone through. Getting a proper MPPT involved will help quite a bit, and you'll find you'll likely need more battery to run that aircon on the longer days. Winter is going to suck, just accept that now. ;)

Hang out on here a while and it won't be long before you're posting up about your 1.21Jiggawatt ground mount array and your DIY 40Mwh LFP battery build in a chest freezer with your paralleled inverters. :)

Good info! While I do buy a few things from HF, solar components are not on that list.

One of the reasons I use Victron components is the programmability. I can tailor the MPPT to exactly what my LiFePO4 battery bank needs.
 
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Works well in series to a proper MPPT controller, garbage in parallel through the solar collector hub.

Garbage...

Garbage PWM, overpriced and underpowered

So about 1200wh of power available, good for 2-3 hours of small aircon in good sun but that's about all you've got in the bucket.

Jupiter 1500w? That's a modified sine wave inverter and not healthy for your aircon compressor.

As the local HF fanboy and employee 9and owner of 3 Thunderbolt 100w kits) I can tell you most of our solar stuff is krap, but it is good for learning so I'm not gonna say anything mean about buying HF stuff, it's affordable and gets your foot in the door.

OK, so an oddity of the HF 100w mono panels is that they work great in series, but when you parallel them up each panel puts out about 30% less than the panel before it, so your 100w panel + a 70w panel + a 40w panel are what you actually see. No idea why, people have done test runs and it is just something odd about their panels.

Fortunately if you get a proper 30 or 40a MPPT controller you can re-head the HF panels with good old MC4's and connect them up in series and get a proper 300+w string. They do punch above their weight class with some people getting upwards of 120w out of a panel so having the extra 10a of SCC can't hurt and doesn't really cost that much more. You don't have to go Victron either, a HQST, RichSolar, Weize, BougeRV, or anything else will really open up your solar harvesting. Pro tip: If there's a USB port on it, it's a FAKE controller with a MPPT sticker on a cheapie PWM box and they laugh all the way to the bank. Figure spending at least $100usd on a good unit. I'd avoid EPEver as there is a known bug in their tracking software.

As mentioned above, the aircon is likely 500w at the minimum. There might be a data sticker on there saying how many amps it draws at what voltage and you can math out the draw from there. There may be an Eco mode that draws less, the best way is to grab a Kill-A-Watt and throw that between the inverter and the aircon to see actual usage numbers. Add in 10% for the overhead of the inverter and that'll tell you how much power it takes per hour to run. Sadly, it's all about the maths with solar.

You have a good start with your battery, inverter, and panels. Now starts the fine tuning and learning that we've all gone through. Getting a proper MPPT involved will help quite a bit, and you'll find you'll likely need more battery to run that aircon on the longer days. Winter is going to suck, just accept that now. ;)

Hang out on here a while and it won't be long before you're posting up about your 1.21Jiggawatt ground mount array and your DIY 40Mwh LFP battery build in a chest freezer with your paralleled inverters. :)
Thanks! I don't yet understand all that you're talking about but I'm working on it. Thanks again!
 
So, one thing about AC units - the compressors may take 500w to run, but to start they will take 5 times that or more. Which is why some are saying 3000w inverter.

If that is an older/ancient window unit you would be far ahead by replacing it with a new unit - it will consume a lot less power over time and the start power required will be lower. If you look at the SEER rating on the tag the higher it is the more efficient the less power it will take.
 

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