New to solar

[gordoncbrown]

Hi, just picked up a motorhome. It has a solar panel fitted. The controller is a Truma SDC12 MPPT. Although it has been on hook up for 24 hours the Batt low light is illuminated all the time, amber. The MPP light next to it is flashing green. Took it off hook up and the battery health light dropped fro green to amber after a few hours , despite it being sunny. Does anyone have any knowledge of this controller and if it seems like it is working and I’m concerned over nothing. Thanks

 

[XxAnthxX]

Here’s the manual…….

https://www.baileyofbristol.co.uk/wp-content/uploads/2022/05/SDC1225-Truma-Manual-REV1-OK_2021-07-15.pdf

 

[monzer]

I would unplug from hook up and see how well the battery works. New van has maybe been sitting a while and the battery could be dead.

 

[DBK]

I would unplug from hook up and see how well the battery works. New van has maybe been sitting a while and the battery could be dead.

I agree, sound like a dead leisure battery or batteries.

 

[XxAnthxX]

With the MPP light flashing indicating it’s ready to charge…..I’m guessing it’s not connected to the battery, or I’d say it would be green if it was charging.

I’d check its connection to the hab battery, either physical connection or fuse.

The photo appears that there’s no cables on the two right hand connections? This is where both battery positives should be.

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[KarlKontiki]

Hi, just picked up a motorhome. It has a solar panel fitted. The controller is a Truma SDC12 MPPT. Although it has been on hook up for 24 hours the Batt low light is illuminated all the time, amber. The MPP light next to it is flashing green. Took it off hook up and the battery health light dropped fro green to amber after a few hours , despite it being sunny. Does anyone have any knowledge of this controller and if it seems like it is working and I’m concerned over nothing. Thanks

I have this same issue. Did you find a fix? Thanks

 

[Tremblers1980]

I have this same issue. Did you find a fix? Thanks

I have the same issue on a new Swift Carrera 194. I have a question back with Swift through the dealer (van was only picked up 5 days ago). The output from the solar panel to the controller is as expected. The output from the controller to the battery is only 2.6v and 0 amps. The vehicle benefits from being on hook up so batteries (2 leisure in parallel and vehicle battery) are with a good state of charge and all fuses are intact. I am guessing that the controller has a malfunction or I have a bad connection somewhere. Did the others with this problem get a fix?

 

[monzer]

I have the same issue on a new Swift Carrera 194. I have a question back with Swift through the dealer (van was only picked up 5 days ago). The output from the solar panel to the controller is as expected. The output from the controller to the battery is only 2.6v and 0 amps. The vehicle benefits from being on hook up so batteries (2 leisure in parallel and vehicle battery) are with a good state of charge and all fuses are intact. I am guessing that the controller has a malfunction or I have a bad connection somewhere. Did the others with this problem get a fix?

Have you checked what is happening when the batteries are low? If you are plugged in then batteries will be full and the controller will know not to send any charge to them.

 

[autorouter]

That output of 2.6V doesn't sound right at all. Is it possibly a typo and should be 12.6V?

You should start by measuring some voltages: the solar panel voltage (left two terminals), should be 18V to 20V or more when the sun is shining.

The leisure battery voltage should be 12.0V to 12.7V if it's not being charged, and anything from 13.0V to 14.6V if the solar is charging. Measure the voltage at the actual battery positive and negative terminals. Then measure where they output from the solar controller - that's between the centre (negative) terminal and the 4th terminal. The voltage should be identical to the leisure battery voltage. If it isn't, there's a bad connection/fuse blown somewhere along that wire.

Note that if the leisure battery is full, the voltage should still be high - 12.6 to maybe 14V - but the amps will be zero because the controller's job is to avoid overcharging an already full battery.

 

[Tremblers1980]

That output of 2.6V doesn't sound right at all. Is it possibly a typo and should be 12.6V?

You should start by measuring some voltages: the solar panel voltage (left two terminals), should be 18V to 20V or more when the sun is shining.

The leisure battery voltage should be 12.0V to 12.7V if it's not being charged, and anything from 13.0V to 14.6V if the solar is charging. Measure the voltage at the actual battery positive and negative terminals. Then measure where they output from the solar controller - that's between the centre (negative) terminal and the 4th terminal. The voltage should be identical to the leisure battery voltage. If it isn't, there's a bad connection/fuse blown somewhere along that wire.

Note that if the leisure battery is full, the voltage should still be high - 12.6 to maybe 14V - but the amps will be zero because the controller's job is to avoid overcharging an already full battery.

Thanks for the replies. The output voltage measured at the regulator is 2.6v and 0 amps. Input from the solar panel is 19.59v and 3.89 amps on a cloudy day so about 76 watts (it is a 100w system). When dark there is no activity on the regulator (battery low light extinguishes and MPP light stops flashing). The van has been off grid for a day with the fridge running and lights operating no problem, and I have checked the the condition of both leisure batteries and they are as expected (a good state of charge). When hook up is put back on the batteries start taking charge from the charger in the PSU. I am not sure if the solar charge regulator is connected via the charger in the PSU or not (i.e. not sure it is directly connected to the batteries - solar regulator can direct charge to either the leisure batteries or vehicle battery). I have read that the MPPT type regulator can lock out if it has experienced a spike (i.e. it clips to a low voltage and zero load). Completely removing power from the unit for a couple of minutes can act as a reset. I have tried this but it has not altered the situation. The dip switches on the regulator are set up for lead acid batteries. It is not clear in the specs what type of leisure batteries have been fitted, other than they are sealed units and fitted on their sides (one under each front seat). Having seen that others have had the exact same issue with this type of regulator on brand new vehicles I was interested to understand what was there eventual findings. I have not found Swift to be the most responsive of suppliers.

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[autorouter]

If the leisure batteries are at a good state of charge (12.0V or more) and the output of the MPPT is 2.6V and 0A, then there is no connection between the leisure batteries and the MPPT. Could be a blown fuse, bad connection or break in the wire. I can't imagine a scenario where a defective MPPT would cause that, without wires getting hot and maybe smoking. There is a fuse on the MPPT controller, and there should be a fuse near the leisure battery also.

 

[Tremblers1980]

I think the MPPT connects directly into the PSU. I have checked all of the fuses and they are good. One thing I have just discovered is that my leisure batteries are AGM not lead acid. I have read that the wrong DIP switch settings can cause a problem with the regulator, so this may be an avenue to explore (need to check the vehicle battery type before changing this).

 

[Tremblers1980]

The vehicle battery is lead acid and I think the only difference between the two types of battery from a charging point of view is the AGM can take a higher voltage so I will keep with the lead acid setting.

Given your consistent diagnosis, I pulled the PSU this morning (made sure the 240v was unhooked, 12v isolated and fuse pulled from the solar regulator) which is not easy as it is set back in a floor mounted cupboard. On removal I found a number of wires had been stretched across the metal carcass of the PSU. Movement of the PSU resulted in clicking of the 12v main switch and indicative of an intermittent short. Also buried at the back of the PSU (not easy to see) is a 10amp fuse. I removed the fuse and found it had blown. I replaced the 10amp fuse, refitted the fuse in the solar regulator and solar charge was restored. However when I went to move the PSU back into position the 10amp fuse blew again. I retraced my steps but before refitting the fuse spent some time making sure all of the cables were away from the carcass and it's sharp edges and not likely to be trapped. I believe the cause of the issue is a cable chafing on the sharp metal carcass of the PSU, causing a short circuit and the fuse to blow. Interestingly, the fuse also blew when I tried to read the current being output by the solar regulator, after I first restored the solar power (may just be a function of how my multi meter works).

Thanks for you comments and support, it is what I needed to see the task through to a logical conclusion. As an aside, the Dealer still has not had a response from Swift.