MPPT Controller (Victron)

[thomm225]

So I finally hooked up my Victron 75/15 Controller and re-soldered new wires to my panels. It's running on all default settings

I really like the isolation it provides between the panels and the battery and the voltage delivery

Even on a cloudy day, there are around 17 volts on the panel side of the controller. Once the batteries are charged all the way it's like 20 volts plus

Soon I'll take my lap top down to the boat and hook up to the controller and check the performance

This may allow me to get one of the 12 volt coolers......rather than buying ice every trip

[john61ct]

Get an AH counter, and use up 50 AH every day in addition to your usual loads, see how often your solar gets you back to 100%.

An 80AH "excess buffer" would be better if you'd like a fridge thirstier than an Engel portable, to be conservative for non-ideal insolation conditions.

[noelex 77]

Originally Posted by john61ct

Get an AH counter, and use up 50 AH every day in addition to your usual loads, see how often your solar gets you back to 100%.

An 80AH "excess buffer" would be better if you'd like a fridge thirstier than an Engel portable, to be conservative for non-ideal insolation conditions.

If it is a proper compressor fridge such as the 40L Engel, this allowance is a little excessive.

For example, this link recorded 20 Ahrs in use at a fridge setting (2.5° C) in 30°C max ambient temperature.


https://www.campertrailers.org/fridge_draw.htm

[a64pilot]

Use and setting of course really drive that. We use ours as a freezer and just turn the temp setting to max and leave it there, I believe that likely doubles it’s power consumption.
It does do pretty good though, it will get down to -5F or -20C.

For just day sailing and an occasional overnight, an ice box is fine

[Pete7]

If you use the Victron USB widget to the laptop ensure you have internet access at the same time because the Victron software will download the latest updates for the MPPT. Did mine last week to V4.8 I think and that is the second update in the past couple of months.

I find it quite interesting being able to see how much bulk, Absorption and float charge the panels have generated each day. The weekly report gives even more detail but the icon to select it isn't obvious so run the cursor around the page for the links to extra information.

Pete

[john61ct]

Originally Posted by noelex 77

If it is a proper compressor fridge such as the 40L Engel, this allowance is a little excessive.

Exactly, 100% intentional.

Design for worse case scenario, means in average conditions will always have surplus.

[newhaul]

Originally Posted by thomm225

So I finally hooked up my Victron 75/15 Controller and re-soldered new wires to my panels. It's running on all default settings

I really like the isolation it provides between the panels and the battery and the voltage delivery

Even on a cloudy day, there are around 17 volts on the panel side of the controller. Once the batteries are charged all the way it's like 20 volts plus

Soon I'll take my lap top down to the boat and hook up to the controller and check the performance

This may allow me to get one of the 12 volt coolers......rather than buying ice every trip

you will be extremely disappointed in your power usage with a thermoelectric cooler running full time. It will draw 5 amps or there abouts for an approximate 120ah usage.
I run one with an electronic digital thermostat set to maintain 4℃ and when it is running it uses about 50ah per day. But the cost difference between that and the refer system I want will pay for a lot of solar panels. For now.

[noelex 77]

Originally Posted by newhaul

you will be extremely disappointed in your power usage with a thermoelectric cooler running full time. It will draw 5 amps or there abouts for an approximate 120ah usage.
.

Thermoelectric coolers using the Peltier effect are very energy inefficient as well as having limited cooling capacity (although there are promising developments in this field). For a boat it is almost always better to spend a little more for a compressor fridge.

There are plently of portable models available.

[thomm225]

Thanks for the input.

Right now I only have 85 watts worth of panels charging two deep cycle 12 volt batteries. The 65 watt panel faces up and the 20 to the side. I have another 20 watt panel but haven't hooked it up yet.

The panels are my only power source since the outboard doesn't have an alternator

I sailed today though and the thing never came out of Float with autopilot, VHF, Depth, and GPS on

[thomm225]

Originally Posted by Pete7

If you use the Victron USB widget to the laptop ensure you have internet access at the same time because the Victron software will download the latest updates for the MPPT. Did mine last week to V4.8 I think and that is the second update in the past couple of months.

I find it quite interesting being able to see how much bulk, Absorption and float charge the panels have generated each day. The weekly report gives even more detail but the icon to select it isn't obvious so run the cursor around the page for the links to extra information.

Pete

Thanks. I'll see if the my dock still has WiFi.

[newhaul]

Originally Posted by noelex 77

Thermoelectric coolers using the Peltier effect are very energy inefficient as well as having limited cooling capacity (although there are promising developments in this field). For a boat it is almost always better to spend a little more for a compressor fridge.

There are plently of portable models available.

the price difference is quite a bit considering the refer system I'm wanting is 2700 USD
But heck you can run a small dorm fridge off of a small inverter that setup will be under a hundred bucks.

[noelex 77]

Originally Posted by thomm225

Thanks for the input.

Right now I only have 85 watts worth of panels charging two deep cycle 12 volt batteries.....
I sailed today though and the thing never came out of Float with autopilot, VHF, Depth, and GPS on

Unfortunately, 85w is unlikely to give you enough capacity to run other equipment.

[noelex 77]

Originally Posted by newhaul

the price difference is quite a bit considering the refer system I'm wanting is 2700 USD
But heck you can run a small dorm fridge off of a small inverter that setup will be under a hundred bucks.

A portable compressor fridge is available for much less than 2700 USD and importantly it will be reasonably energy efficient.

It will have low installation costs, together with easy and cheap replacement if faults develop. The main limitation is a relatively low capacity unless multiple units are used.

[thomm225]

Originally Posted by noelex 77

Unfortunately, 85w is unlikely to give you enough capacity to run other equipment.

Yeah, it's one step at a time. I wanted to learn more about the MPPT Controllers as compared to the PWM.

PWM was probably all I needed but this MPPT is so much more efficient