Solar Panels B2b And Smart Alternators ...

[andys]

9am - 12.4v 1A
12pm - 12.7v 0.3A
2pm - 12.73 0.5A
4pm - 12.86v 0.2A
6pm - 12.86v 0.1A

So it looks like it does a pretty good job at keeping the voltage at about 0.7v below source as it says in the documentation. I'll check it again in the morning but it looks like I'll be able to leave it on permanently while it's away in the garage. It'll need turning off when I'm using it and I might rig up an illuminated dash switch for that. I know I could use bluetooth but a switch is quicker than getting out the phone, waiting for the app to connect etc, plus I'm more likely to remember to switch it off if it's staring me in the face.

 

[t0mb0]

That’s pretty much how the starter trickle charge in my votronic solar controller works. Why do you need it switched though? I just leave mine on permanently, I’ve never found any real downside.

 

[andys]

That’s pretty much how the starter trickle charge in my votronic solar controller works. Why do you need it switched though? I just leave mine on permanently, I’ve never found any real downside.

Well it takes charge from the leisure battery and feeds it to the starter battery side of the Ctek, which then feeds back through the Ctek to the leisure battery. It didn’t sound like a good idea to have a loop like that, am I overthinking it?

 

[t0mb0]

Well it takes charge from the leisure battery and feeds it to the starter battery side of the Ctek, which then feeds back through the Ctek to the leisure battery. It didn’t sound like a good idea to have a loop like that, am I overthinking it?

I think it’s fine. The CTEK will take the alternator input high and even if the leisure battery side is 0.7v higher, it’ll only result in a tiny bit of back current. I’d give it a try and check there’s no issue.

 

[andys]

I think it’s fine. The CTEK will take the alternator input high and even if the leisure battery side is 0.7v higher, it’ll only result in a tiny bit of back current. I’d give it a try and check there’s no issue.

Thanks, I’ll give it a try. Unlikely to be driving the van for a couple of weeks though, need to find the time to put it back together again

 

[andys]

12.86v and 0.1A this morning and exactly the same when I got home from work, so I'm leaving it on.

 

[stephen ward]

Hi
Im new to this, so here goes!
I've just purchased a fridge -vitrifrigo 51 ltr air lock fridge - a Fulman AGM FK 800 battery, a C Tek D250 SA start stop and a 150W FlexiSun ETFE Solar Panel (Black)1460x540x3mm
the intention is to use the battery and solar panel to keep everything cold without the need to use external power (off grid)
The question is, before I fit, will that do the job?

 

[t0mb0]

Hi
Im new to this, so here goes!
I've just purchased a fridge -vitrifrigo 51 ltr air lock fridge - a Fulman AGM FK 800 battery, a C Tek D250 SA start stop and a 150W FlexiSun ETFE Solar Panel (Black)1460x540x3mm
the intention is to use the battery and solar panel to keep everything cold without the need to use external power (off grid)
The question is, before I fit, will that do the job?

Difficult to say exactly, depends on your use case - most importantly how much sun there is when you’re parked up for more than a couple of days. In general, though, most likely fine in non-winter months.

 

[Alby42]

Hi
Im new to this, so here goes!
I've just purchased a fridge -vitrifrigo 51 ltr air lock fridge - a Fulman AGM FK 800 battery, a C Tek D250 SA start stop and a 150W FlexiSun ETFE Solar Panel (Black)1460x540x3mm
the intention is to use the battery and solar panel to keep everything cold without the need to use external power (off grid)
The question is, before I fit, will that do the job?

What is the voltage output of the solar panel. Make sure the ctek can deal with it

 

[stephen ward]

Thanks, its 150w?

 

[Pete C]

Thanks, its 150w?

It’s the max output voltage you need to find. Compare this with the max input voltage specified for the Ctek.

Pete

 

[Pete C]

I have done some digging for you. The Ctek has a maximum input voltage of 23 volts. The solar panel has an open circuit output voltage of 30 volts. This is too high for that charger, and will damage it, or worse.

You need to find a new charger which can take a higher input voltage, or a new panel that outputs a lower maximum voltage.

Pete

 

[Alby42]

Travelvolts sorted me out with the red arc for the same reason.

 

[travelvolts]

We are currently getting a lot of reports of damaged Ctek Dual 250SAs due to incorrect solar panel voltage. The bad news is that Ctek have said that they cannot be repaired, so proceed with caution. The important figure is the VOC and it must not exceed 23 volts.

 

[OllieGBR]

Ok this came today so I went out and wired it in the van. I used 2.5mm stranded cable, fused at each end with crimped terminals as it won't be very accessible once I put the seat back. I've wired it from the load output of the solar to the starter battery side of the C250DSA, then set the load output to turn on above 13v and off at 14.7v, does this sound about right?

An interesting and unexpected side of this setup is that if you switch the load output to "Always on" then the output becomes live whether there is any solar output or not, and begins to trickle charge the starter battery from the leisure battery.
View attachment 32394

This could be useful if you were on a mains hookup with no decent solar, or in an emergency anytime. For £30 this was a decent add-on and plugs the gap in my electrical setup nicely

Andy - a clarifying question. This is the Victron MPPT and you've connected the load output to the starter battery and configured it for between 13-14.7v?
I have also have the Victron MPPT controller, so wanting to mimic your setup if possible, saves me buying more unnecessary kit

 

[andys]

Andy - a clarifying question. This is the Victron MPPT and you've connected the load output to the starter battery and configured it for between 13-14.7v?
I have also have the Victron MPPT controller, so wanting to mimic your setup if possible, saves me buying more unnecessary kit

Yes but I have connected it via the votronic trickle charger in series with the connection to the starter battery side of the Ctek. I was concerned that a big difference in SOC would cause the starter battery to pull too much current. The votronic was under £30 when I bought it but it went up in price after that. I would imagine it would be much cheaper to rig up a circuit to do the same job if you know more about it than me (presumably a diode and resistor?). It’s a setup that has worked well for me for the last 2yrs