Truma SDG12 MPPT Solor controler

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Read the manual clear as mud how do these controlers work. Now my battery is fully charge 12.7 volts on multy meter , but the controller shows nothing, surely if the battery shows it's charged it would show on the contriller, or dose it shut down if no sun

Big MPPT.jpgs it's discharged
 
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We have the Truma SDC 10 / 20 version which is probably an older one. You should have a green light showing when fully charged. Have you measured the voltage going into the unit from solar panel and also the voltage coming out?

You would need to check your manual to determine which is the solar panel feed.
 
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The far right LED has the wording "Batt Full" If that's not lit then I woukd assume it isnt fully charged.
Do you get any LED's lighting up when it's daylight? If not clearly something is wrong.
 
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The far right LED has the wording "Batt Full" If that's not lit then I woukd assume it isnt fully charged.
Do you get any LED's lighting up when it's daylight? If not clearly something is wrong.
We had one of these on our new bailey caravan had nothing but trouble with it the LED's on the front did'nt show what was in the battery the 85% battery charge never lit up changed it for a mppt charger off ebey and works fine so i know the panel is working fine i also like to see the voltage of the battery on the display which you cant on the truma model
 
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The far right LED has the wording "Batt Full" If that's not lit then I woukd assume it isnt fully charged.
Do you get any LED's lighting up when it's daylight? If not clearly something is wrong.
First thing I checked battery showing 12.75 volts fully charged, checked in line fuse that's ok checked fuse on controller that's OK. Checked panel feed 21.5volts. Checked feed too battery 3.45 volts.
Battery fully charged from EHU when in Cornwall a fortnight ago, solar controller still showing battery discharged.

Awaiting for dealer to fit me in to check that and a gas burner on the cooker that will not stay alight.

I want to do some off grid vanning, haven't done any in years.
 

JTQ

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The 12.7 volts whilst could indicate a nearly full lead acid "12volt" battery, it does not necessarily indicate it is being charged, in fact the balance of odds is it probably is not being charged if you see 12.7 volts.

If being charged and showing just 12.7 volts, it would mean it's close to fully discharged.
A battery nearing fully charged should show a lot higher voltage; actual values vary with both battery detail technology and controller characteristics but typically will be approaching 14.3>14.5 volts. Note "whilst being charged", not off charge.

A quite telling easy check is put a load on the battery so it is definitely not fully charged. After removing that load, and with the panel exposed to the sunshine, if you don't see its voltage at least into the upper 13 volts, then the solar system is not charging it.

Using "volts" is at best only "indicative" of what could be happening, these to be of more use requires possession of the maker battery characteristic curves or tables, not things readily available to retail buyers.

Measuring the current going to or from the battery and solar controller is the really telling characteristic, after all that is what charging really is, stuffing current into the battery.

THESE little cheap current testers are ideal for our solar systems; they insert into a blade fuse holder in the positive wire between the controller and battery, with the fuse replaced into the probe.
Set up as so the system works unaffected; when you want to check the current flowing you simply switch it "on", and the value is displayed. Be that going the right or wrong way!
If left switched "on" then ultimately the tester's battery (replaceable) will run down, hence why it is best to switch it off over periods where you are not wanting reading. IMO a great tool to have in your DIY tool bag for many other tasks.
 
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JTQ

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12.7 volts and above. Is fully charged. you are quoteing charging rates and floating charge rates.

12,7 through to 12.9 volts is, depending on the particular technology of the battery, alloying of lead, physical build etc, the fully charged steady state value seen. ie. the battery well rested neither recently been charged or discharged.
It is "not" a charging voltage. If the system is supposedly on charge and showing those volts, then it is way from fully charged or not being charged.

Volts are not any sort of "charging rates".

Rates involve "quantities", whereas volts is just the "push" needed to move those "quantities". The "quantities" here being current, "amps".

"Rates" are the "speed" such "quantities" are shifted at.
 
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I see what you are saying sorry. When I first supected the the controller was not charging I did
First checked the battery , not connected. 12. 75v
Then the battery inline fuse, 20A ok
Then the contrller fuse, 20A ok
I then covered the panal for 15 or so minutes and then fitted battery then fuses.
Checked the batterwith the cover removed still 12.75 surely this sould be reading 13.8.
Went back to the controller and checked solor panal output 22.4V
Then checked the feed to the battery 3.451V.
Then I rang the stealer to book it in for repair, plus a gas ring that will not stay alight.
Have I missed something?

It was a bright sunny day.
 

JTQ

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Have I missed something?

The only one I think would help is that you have not ensured the battery was not somewhat discharged to be able for it to be recharged.
However, you are right to expect that even with a full battery most controllers will drop to circa 13.4 volts and a miniscule current, into a caretaker sort of role.
But some controllers do stop even sending a tiny current, in fact just draw the same that they use to monitor the battery till they detect the battery is into discharge, where they "wake up" and start recharging.

So, to be sure your system is working it is best to actually make it need to work, by giving it a battery known to be able to be topped up a little bit.
Then if you see into the upper 13 volts you will know it is working, as such volts can't come from a battery, say one drained to exhibit 12.6> 12.5 volts in your case.
As said earlier, a current tester would give you the real performance value, the actual current the system is stuffing into the battery. Way better to check what charging is actually doing, rather than what various volts could imply.
 
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Apologies if i've missed who the manufacturer of your caravan is.

But Swifts have an additional 10A fuse for the solar inside the Sargent PSU
 
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Apologies if i've missed who the manufacturer of your caravan is.

But Swifts have an additional 10A fuse for the solar inside the Sargent PSU
I'll go and have another look , you don't happen to know the number. I did look.

Van make is in my signature.
.
 
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The only one I think would help is that you have not ensured the battery was not somewhat discharged to be able for it to be recharged.
However, you are right to expect that even with a full battery most controllers will drop to circa 13.4 volts and a miniscule current, into a caretaker sort of role.
But some controllers do stop even sending a tiny current, in fact just draw the same that they use to monitor the battery till they detect the battery is into discharge, where they "wake up" and start recharging.

So, to be sure your system is working it is best to actually make it need to work, by giving it a battery known to be able to be topped up a little bit.
Then if you see into the upper 13 volts you will know it is working, as such volts can't come from a battery, say one drained to exhibit 12.6> 12.5 volts in your case.
As said earlier, a current tester would give you the real performance value, the actual current the system is stuffing into the battery. Way better to check what charging is actually doing, rather than what various volts could imply.
I have an old battery I've been threatening to take down to the tip think it might still be around 12.2 f I'll hook it up.
 
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I'll go and have another look , you don't happen to know the number. I did look.

Van make is in my signature.
.

Sorry, i probably should have seen that!

You have to remove the 4 screws and pull the PSU out of its box. Up inside near the myriad of connectors is a single 10A fuse sat all by itself, I believe its even marked as Solar on the PCB.

I was in there a few weeks ago while i was adding an additional 100W solar panel
 
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The 12.7 volts whilst could indicate a nearly full lead acid "12volt" battery, it does not necessarily indicate it is being charged, in fact the balance of odds is it probably is not being charged if you see 12.7 volts.

If being charged and showing just 12.7 volts, it would mean it's close to fully discharged.
A battery nearing fully charged should show a lot higher voltage; actual values vary with both battery detail technology and controller characteristics but typically will be approaching 14.3>14.5 volts. Note "whilst being charged", not off charge.

A quite telling easy check is put a load on the battery so it is definitely not fully charged. After removing that load, and with the panel exposed to the sunshine, if you don't see its voltage at least into the upper 13 volts, then the solar system is not charging it.

Using "volts" is at best only "indicative" of what could be happening, these to be of more use requires possession of the maker battery characteristic curves or tables, not things readily available to retail buyers.

Measuring the current going to or from the battery and solar controller is the really telling characteristic, after all that is what charging really is, stuffing current into the battery.

THESE little cheap current testers are ideal for our solar systems; they insert into a blade fuse holder in the positive wire between the controller and battery, with the fuse replaced into the probe.
Set up as so the system works unaffected; when you want to check the current flowing you simply switch it "on", and the value is displayed. Be that going the right or wrong way!
If left switched "on" then ultimately the tester's battery (replaceable) will run down, hence why it is best to switch it off over periods where you are not wanting reading. IMO a great tool to have in your DIY tool bag for many other tasks.
One current tester on order. Free postage, then they charge handling charge ?????
 

JTQ

May 7, 2005
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One current tester on order. Free postage, then they charge handling charge ?????

Sorry I lead you into that, I included it to identify these TENMA devices, though the cheapest vender of others I know. Better than say from HERE
I read their offer of Free delivery as "on all UK Mainland online orders over £20.00 (ex VAT)".
I suspect their computer server doing the online purchase transaction, does not recognise £6.95 as meeting that condition? ;)

Their free delivery used to be only about a £8 ex VAT transaction, times are changing.
I can generally find lots of "useful" electrical bits I "need" to group together from their extensive range when I order to meet whatever trigger value ruling, that I have never run into that issue.
 
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In the past I have been advised that a good battery should read a minimum of 12.8v to be healthy. I have just checked the status of our battery which is connected to a Truma controller and the average read over the past 4 days has been over 14v. Prior to that it was average of 12.9v. I can see my peak voltages as far back as the 7th March.
 

JTQ

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In the past I have been advised that a good battery should read a minimum of 12.8v to be healthy. I have just checked the status of our battery which is connected to a Truma controller and the average read over the past 4 days has been over 14v. Prior to that it was average of 12.9v. I can see my peak voltages as far back as the 7th March.

But remember that 12.8 or similar figure relates to a "rested" battery without any charging or loading, one rested some hours after last being charged; reading where conditions are otherwise, like one coupled to a solar system infer no such information on the battery's state of charge.
However seeing values into the 13 and more indicates it is or has been benefitting from a charge. A very good indicator a caravan's solar system is working if off EHU.
 
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Sorry, i probably should have seen that!

You have to remove the 4 screws and pull the PSU out of its box. Up inside near the myriad of connectors is a single 10A fuse sat all by itself, I believe its even marked as Solar on the PCB.

I was in there a few weeks ago while i was adding an additional 100W solar panel
Van only 4 months old I'll resist the temptation to look.
You Have an Elite. Did you bye from Grantham's how have you found them for service??

I'm a newish customer with them I'll leave it to them. to fix.
 
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Van only 4 months old I'll resist the temptation to look.
You Have an Elite. Did you bye from Grantham's how have you found them for service??

I'm a newish customer with them I'll leave it to them. to fix.

From Granthams yes, this one came from their Retford site where the two before that were bought from the Grantham site. Prefer Retford as its a lot closer to me !

No issues with their service on this or the previous caravan (so far!)

And yeah, if it doesn't work, let them sort it. Interestingly mine came with a Sargent solar controller rather than the Truma one you have (not that i use it, i use a Victron MPPT controller now as the Sargent one was garbage).
 
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From Granthams yes, this one came from their Retford site where the two before that were bought from the Grantham site. Prefer Retford as its a lot closer to me !

No issues with their service on this or the previous caravan (so far!)

And yeah, if it doesn't work, let them sort it. Interestingly mine came with a Sargent solar controller rather than the Truma one you have (not that i use it, i use a Victron MPPT controller now as the Sargent one was garbage).
Have you a link please.
 
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Have you a link please.

I use one of these


With the factory 100W panel and an additional 100W panel connected in parallel
 
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