Troubleshooting Basic Solar Set up

[Hiltn]

Hi All,

I definitely fall under the noob category when it comes to solar, but I believe I understand some of the basics… any help appreciated.

Got a fairly basic set up -
Kings 160W Solar Panel
Waeco CFX35 Fridge
Kings 115Ah 12V Deep Cycle Battery
Van roof vent/fan (can’t find a rating plate but I’m assuming 1.5-2amps)

My issue is my fridge keeps shutting off in the middle of the night. I have a battery monitor that shuts things down once the battery gets to 10.7V

The battery can also be charged via my Vans engine and I give it a full charge before bed. But the fridge shuts down around 2am. Is there something I’m missing? The fridge’s power consumption is 0.77Ah while set for 5 degree celsius.. wouldn’t a 0.77Ah draw give me a lot of hours of fridge use before the battery gets drained? I understand the fridge uses a decent amount of amps (7ish) upon start up, but after that its smooth sailing, no?

Everything works great during the day while I’m driving around a fair amount and keeping the battery charged, but each night things stop working. The roof vent/fan seems to keep working regardless though.

Scratching my head here, any input/questions is appreciated. Do I need a larger battery bank? Do I have a faulty battery? This is where my head is pointed

Thank you for your time!

 

[DIYrich]

According to this website, the fridge draws 43 watts (3.58 amps at 12v):

Dometic Waeco CoolFreeze CFX35 W Portable Fridge Freezer 12v 24v mains Cool Box

The Dometic Waeco CoolFreeze CFX35W Portable Freezer is a hard wearing, robust cool box with exceptional cooling even in the warmest of weather.

www.waecofridges.co.uk

Assuming 55 amps at 12v available from the battery, that is 15 hours from the battery with no other draws.

I wouldn't draw a Lead Acid battery below 12v (about 50% SOC). 10.7v seems really low. Maybe have the battery tested.

 

[Rocketman]

My guess is you are not fully charging your battery.
I don’t know your equipment- is that a lead acid battery?

A single 160w panel and driving a bit is probably not recharging the battery completely.

Do you have a shunt based battery monitor- like a Victron Smartshunt or BMV712? That can tell you what your state of charge is.

You probably need more charging and possibly more battery capacity. But just guessing here without better data.

 

[DIYrich]

My guess is you are not fully charging your battery.

"The battery can also be charged via my Vans engine and I give it a full charge before bed."

What voltage is the battery being charging up to?

I don’t know your equipment- is that a lead acid battery?

"Kings 115Ah 12V Deep Cycle Battery"
"Deep cycle" is probably lead-acid.

 

[Hiltn]

"The battery can also be charged via my Vans engine and I give it a full charge before bed."

What voltage is the battery being charging up to?


"Kings 115Ah 12V Deep Cycle Battery"
"Deep cycle" is probably lead-acid.

It shows around 14.2V during a nice long drive. But lowers to 12V - 13V once my Van is off.

 

[Rocketman]

How do you know you give it a full charge? Do you monitor the amps going into the battery at absorbing phase to know they are low enough that you actually have a full battery?

This is why I am a fan of a good shunt based battery monitor. It keeps track of every amp going into or out of a battery.

The other option is the battery is too small or has become damaged from extended low charge levels or over discharging.

Is it a sealed battery? Can you check the acid levels to make sure they are covering the plates?

The real answer may be all of the above…
Because it is winter - there is not enough sun and driving to keep the battery fully charged and you are using more than you think you are, so you do need additional battery amps.

But get a Smartshunt or BMV712 to monitor the battery. It has a data feature so you can see how many amps are being pulled from the battery over time - (or volts or State of charge). It also tracks how long since 100%. And one of my favorite features is a “Time Remaining”. At the average of the last 3min (user setable), how long until the batteries reach the state of charge floor of 50% (user setable). I often check that before going to bed to make sure there is plenty time until the solar starts in the morning. It helps me know when I need to run the generator.

Good Luck

 

[DIYrich]

It shows around 14.2V during a nice long drive. But lowers to 12V - 13V once my Van is off.

Hold at 14.2v until amps to the battery reaches 3amps. (bulk/absorption).
Hold at 13.5 volts for a few hours. (float)
Every 30 days, after 14.2v charge, charge at 14.4v for 3 hours (equalization)

After the 14.2v charge (and charge rate declines to 3 amps), you are close to fully charged, and should have most of the 55 available amps.

 

[mikefitz]

Do I need a larger battery bank? Do I have a faulty battery?

Without details of the charging process and battery voltages achieved its difficult to give advice. If the battery is over a year old I would suspect the battery. When the battery is discharged down to 10.5 volts on several occasions its probable damaged
The CFX 35 cool box , when down to temperature will take 1 to 2 amps per hour, depending on conditions. So worst case total drain including fan, is 4Ah. ( unless there are other consumers) Assuming you get 6 hours run time , that's 24Ah.
This suggests failed battery or insufficient charge.
Since its summer I would expect a 160 watt solar panel, with quality controller, to input in the region 50 Ah per day.
Thus if your battery is at a low SOC it will take a few days to charge up. Engine charging, regardless of available charging power will take 4 to 5 hours driving to charge from flat.

The compressor cool box is very sensitive to voltage and will not start if the voltage is too low. Common issues are inadequate cable or poor connections.

have a battery monitor that shuts things down once the battery gets to 10.7V

Do you have details of this device?

 

[Rocketman]

Without details of the charging process and battery voltages achieved its difficult to give advice. If the battery is over a year old I would suspect the battery. When the battery is discharged down to 10.5 volts on several occasions its probable damaged
The CFX 35 cool box , when down to temperature will take 1 to 2 amps per hour, depending on conditions. So worst case total drain including fan, is 4Ah. ( unless there are other consumers) Assuming you get 6 hours run time , that's 24Ah.
This suggests failed battery or insufficient charge.
Since its summer I would expect a 160 watt solar panel, with quality controller, to input in the region 50 Ah per day.
Thus if your battery is at a low SOC it will take a few days to charge up. Engine charging, regardless of available charging power will take 4 to 5 hours driving to charge from flat.

The compressor cool box is very sensitive to voltage and will not start if the voltage is too low. Common issues are inadequate cable or poor connections.


Do you have details of this device?

A Victron smart battery protect. BP65 - get the smart one then you can change the cutoff voltage and restart voltage

can only have loads - cannot charge - no heavy users like inverters. So just pick the proper spot in your system.