My 2 year second battery, solar and Wit’send rear quarter panel project (1 Viewer)

[Shoredreamer]

Yeah no reason why CTEK shouldn’t do the job.
Are there bad reviews on it?
Does it charge from the alternator when truck is running?

Where’d you ground the battery?

You wanna nerd out? Look at the Simarine Pico. They’ve got an incredible interface and you can monitor anything in your truck, literally. Photo courtesy of @Hyup

 

[Qball]

Yeah no reason why CTEK shouldn’t do the job.
Are there bad reviews on it?
Does it charge from the alternator when truck is running?

Where’d you ground the battery?

You wanna nerd out? Look at the Simarine Pico. They’ve got an incredible interface and you can monitor anything in your truck, literally. Photo courtesy of @Hyup View attachment 2014152

Expedition portal has multiple people complaining about bad solar performance on solar. Strangely I didn’t find too much other review/complains. I’ll try to call Ctek once I get my ammeter to see what went wrong and where.

 

[Qball]

As someone mentioned, get a DC current clamp and actually measure the current flowing out of the panel(s) and out of the CTEK into the batteries. Without some current measurements you're guessing at actually output by just measuring voltage.

I assume your battery is in good condition...

cheers,
george.

Yes, the stupid ammeter can’t get here fast enough.

 

[Qball]

Here is what I found on Ctek documentation:
Temperature compensated charge voltage The D250SA optimises the charge voltage by increasing the charge voltage at temperatures below 25°C/77°F and reducing it at temperatures higher than 25°C/77°F. The functions is always active

Sounds like Ctek reduces the charging voltage at above 77 degrees, this does explain the slow charging. Yes, the people who wrote the manual don't use spelling and grammar checker.

The unit itself will also shut off if the internal temp reaches 122 degrees which could also explain my problem. Sounds like the Ctek doesn't want to charge the battery in warm weather which is pretty stupid. I get the safety thing but that's way too conservative. I'll find out more after I get my ammeter. I'll also try to trick it by placing the temp sensor in the fridge.


This has been an interesting learning experience and I will NOT buy Ctek 250SA smart charger after this even though it does have lots of great features.....except I can't use them! Redarc's documentation state operating temp up to 170 degrees.

 

[george_tlc]

No, that is not likely the problem - unless they really messed up (seems unlikely). Ctek are talking about temperature compensation of the charging voltage. This is just a few millivolts per degree C. All 'good' chargers will do temperature compensation of charge voltage.

cheers,
george.

 

[Qball]

No, that is not likely the problem - unless they really messed up (seems unlikely). Ctek are talking about temperature compensation of the charging voltage. This is just a few millivolts per degree C. All 'good' chargers will do temperature compensation of charge voltage.

cheers,
george.

Maybe, bad part about them and many other chargers is that those type info isn’t easily found. However the 122 shutoff is in the manual and that’s pretty easy to get to, the way I read it is it’s internal temp of the unit which I can’t cheat by putting the sensor in the fridge. 122 is pretty easy to reach in a car in even 90 degree weather. This thing suppose to be easy but it’s having me scratching my head.

 

[Shoredreamer]

Yeah it may be de-rating output even before its shutoff temp of 122*. That’s super low imo. Kinda crazy but the unit likely has to protect itself from melt down or burnout. That has to do with its construction.

Installing a REDARC right now on a 4Runner, in the manual it states the unit will turn off if itself reaches 175*. De-rating begins at 130*. This is why with engine mounting a Redarc, it is crucial to mount it near the grill or in front of the headlights which is where I put mine. This of course is to get optimal results, which, if you pay the money for, you’d want. BCDC for sure can be mounted inside vehicles, which is way more typical in Oz due to 24v dual battery stock systems, their aux battery is mounted in the cargo like yours.

 

[Qball]

Yeah it may be de-rating output even before its shutoff temp of 122*. That’s super low imo. Kinda crazy but the unit likely has to protect itself from melt down or burnout. That has to do with its construction.

Installing a REDARC right now on a 4Runner, in the manual it states the unit will turn off if itself reaches 175*. De-rating begins at 130*. This is why with engine mounting a Redarc, it is crucial to mount it near the grill or in front of the headlights which is where I put mine. This of course is to get optimal results, which, if you pay the money for, you’d want. BCDC for sure can be mounted inside vehicles, which is way more typical in Oz due to 24v dual battery stock systems, their aux battery is mounted in the cargo like yours.

The shut off is crazy low!

Here is what I found on victron and Redarc:

Victron smartsolar unit:
-30 to +60°C (full rated output up to 40°C)
So full rate up to 104
Shut down at 140
Not too bad

Redarc:
Full charging rate at up to 140
Shutdown at 170

The more research I do the more I'm leaning towards Redarc!

 

[Qball]

More updates:

Temp has been surprisingly mild and with 2 solar panels and the fridge set at 25 degrees I have 13.0 V 10 in the morning so the solar charger on the Ctek is actually working well.....under documented conditions.

I took off 1 panel so I want to see if working under normal/low temp condition if 1 panel is enough like how I originally calculated.

In my frustration, I ordered the wrong ammeter so back it goes and should have the new ammeter today but the battery is full so I can only test the solar side.

In the back of the element fridge, it says 6.8amp at 12 volts so maybe I do need 2 panels after all.

Finally what I really want to test is in high temp condition. I am fooling Ctek with the temp sensor in the fridge so I like to know if it gets to 122 would it still work or won’t shut down. If so then I think I’ll just keep the Ctek as the only major problem I found with it has a workaround. This is the only time I’m actually looking for hot weather hahahahaha.

 

[Qball]

Ammeter in!
In the morning things looked pretty good and I can get a steady 10 amp to the battery from 2 100w panels under direct sunlight. With fridge running(5amp) I was still getting around 4.5 amp to the battery so not bad. A little under my expectation still but not bad. I tested each panel I individually and got about 5amp to the battery, not close to the 8 I was expecting but not terrible.

Once battery got to about 12.7 the amperage dropped to 1.4 amp. I’m guessing it’s the float charge phase, however to my disappointment when the fridge turned back on the ammeter showed -4.5 amp. The solar charger is not changing from float charge to more load, looks like the Ctek is not reacting at all to volt and load change.

Than around 5pm the temp got to the 90s and I got 0 amp!!! Guess the 122 degree shutoff is from internal sensor, I was hoping to fool the external temp sensor but no dice! Very annoyed!

Conclusion? I’m definitely getting rid of the Ctek for either a Redarc or separate solar charger like Victron.


Edit: tried to charge using alternator and got 21.4 amp to the battery very consistently so at least it’s descent at DC to DC charging and suck as solar. Ordered a Victron for solar so will see how that goes, really like the idea of bluetooth app to nerd out on data, should be here Tuesday.

 

[Qball]

Finally got my Victron Solar charger, temporarily wired it up and updated the firmware via Bluetooth. All the relevant info with historical trend. Software set battery type/charging profile, can’t think of anything else I can even ask for. That’s pretty smart!


Can’t wait till the sun comes up!!!

 

[Irish Reiver]

@Qball what ammeter did you buy?

 

[Qball]

@Qball what ammeter did you buy?

I’m cheap so I got one of the wireless ammeter with shunt from Amazon. Very simple and work quite well, instructions are next to useless though. However bought that about 2 years ago also which means amazon doesn’t have it anymore. Here is one that looks like a newer and better option:
Amazon product ASIN B07CTJ35F6

 

[Qball]

So it is past noon and here is the result. The Victron has about the same efficiency as the Ctek! HOWEVER with the amount of data Victron has I now finally have a descent understanding of solar efficiency.

1. Shade kills!!! Even with 1/4th of the panel in shade the power drops to nothing.
2. Panel needs to be as close to 90 degrees to the sun as possible. The little bubble or lenses on the Renogy sounded cool in marketing material but in the end still need to be close to 90 degree to get full power....70 out of 100 watts.
3. I read the power graph of the panel wrong! The voltage of the panel stays relatively stable but the Amperage fluctuates, it makes a lot sense to keep voltage high and low amperage to reduce load and power transmission lost
4. Max power I got out of a 100 watt panel is only about 70w. Anyone else has this experience? Has anyone gotten 100 or even 90 watts out of a 100w panel?

Verdict? I’m actually keeping my Ctek and the 2 panels. As much as I love the Victron my ammeter gives me enough information and efficiency isn’t much better. Plus I don’t want more devices unless I have to, also the victron get really hot.

It’s been a great learning experience and I hope others will also from this thread

.....yes I need to go to Macco soon!

 

[mkZero]

The most I've seen on my 100w GZ panel has been about 70w, and that was with really optimizing the angle to the sun on a sunny day. A few degrees off and it would drop a few watts.
You are never likely to get 100w out of a 100w panel. Those numbers are tested under lab conditions to give a uniform and repeatable rating system that all manufactures can use.
Other than the angle to the sun, the elevation and the ambient temperature also affect the output. Higher elevations have thinner air, and so more solar energey is getting through the atmosphere. And the efficiency of the panels goes down with increasing temperature. In theory on a really cold sunny day at high elevation you exceed the rated power.
That's funny about those little bubbles not making any real difference. That's marketing for ya!

 

[DanMedeiros]

As @Shoredreamer mentioned I’m switching when I have time to wrench again. I went with a simarine monitor. It’s way more capable than vixctro

 

[LandCruiserPhil]

All solar panels both on my house and LC output drop once they see 100°.
Flexible panel output is not as good a framed panel after 90°.
Venting the cabin strongly increases fridge efficiency.
A non vented cabin will shut most fridges down in the AZ summer heat.
Heat kills everything

 

[cowboyjack]

Been living off grid solely on solar electric for 16 years now. Actually seeing anything over 70% of rated wattage for a solar panel is within reasonable expectations.

On a perfect day we occasionally 90-95% of rated output from our current set up... it still puts me in shock. Our last system we were lucky to see anything over 60% with much older technology.

 

[Dave 2000]

I like the flexible panel, I use two rigid panels. one is fitted on a slide out at the front of the full length roof rack. There is a second which was going to also be rack mounted but space was an issue with the second spare, so that is now under the fridge. I too like to park in the shade but the second panel now has the facility of about 15 metres of cable, so with two plug sockets at the front and rear of the car I can orientate the panel so at least one is getting full exposure. I note the comment about the 80 alternator not being a smart alternator however, they do reduce voltage as the battery is topped up, something my voltage reading shows after trips of about 30 minutes or so. I went with the two heavy cables to the rear, they can power a rear mounted winch or inverter, for me versatility is key to camping off road.

regards

Dave

 

[Shoredreamer]

My latest observation on a sunny day showing my 110 watt Merlin solar amps pre-mppt and what charge is being put into my aux batt. (I had an almost full battery with no discharge at that time). I could obviously gain from banking all this solar energy I make, maybe toss a third, reserve battery in the cargo area, fully charged for when needed on trips. Main point being, match your solar watts and battery AH storage in a vehicle, since once you top up the battery, you can’t bank excess power created from your panels, hence, a larger panel than needed adds no benefit.