Solar Regulator

Submitted: Sunday, Sep 16, 2012 at 17:22
ThreadID: 98052 Views:2799 Replies:1 FollowUps:10
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I have a D250s and a smartpass. I have had the units for a couple of years but only recently decided to add two 90 watt unregulated Lorentz Solar panels connected via the D250s Dual to my service battery.. It had two cycles, green power on and solar and battery, After a couple of minutes it would be green power on solar alternator battery light on then power light off. It would repeat this over and over while the engine was not running.

To eliminate any wiring issues I disconnected everything such as alternator and smartpass so only the solar and power to battery and earth was connected but the problem still the problem persists.

I assume the alternator light should not come on when wired as above. The unit operates ok from the alternator when connected. I feel the unit has a fault.

I feel I have exhausted wiring issues as the alternator light comes on even though I have disconnected the alternator from the D250S. The system works fine when charged via the alternator. I am thinking of buying a solar regulator without LCD and using the D250S for alternator charging and a separate reg for the solar.

Can anyone recommend a good quality regulator without the LCD as I already have a battery monitor. Any information or suggestions appreciated.............
Cheers Peter Taylor

Can anyone recommend a solar regulator ,odel

Any advice appreciated
Peter Taylor
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Reply By: trains - Sunday, Sep 16, 2012 at 17:59

Sunday, Sep 16, 2012 at 17:59
Hi Peter,

Whilst I dont have a smart pass on my system, I have the 250s dual.

I find that whilst there is some surface charge on the starter battery, ie supply to the 250, the alt light stays on, and it shows charge heading to the 2nd batt.

When solar connected, it has a think and then charges away happily with solar input, sometimes the alt led stays on, other times not.
When 2nd batt fully charged, it shows it going back into the starter battery.

I assume the smart pass just enables bulk current from the alternator to go to your 2nd battery over and beyond the 20a ? that the 250 offers.
Not sure how that would affect the feed back to the starter battery when the 2nd bat is full.

either way, with a multimeter, can you determin if your getting full volts/ charge from the solar panels to the 250, and then from the 250 to the 2nd battery when solar connected with a 2nd battery that needs charging.

If thats all working, regardless of the led lights status, then you know your 250 is doing its job.



AnswerID: 495035

Follow Up By: Member - kwk56pt - Sunday, Sep 16, 2012 at 19:17

Sunday, Sep 16, 2012 at 19:17
Hi Trains,
thanks for the input. I was hoping to hear from a D250s dual owner. I have disconnected my smartpass. to simplify things I have only the solar connected, the earth and power going to the battery. I have 2 X Lorentz 90 watt panels hooked up. When I put the panel in the sun the green power light comes on and the solar light and the battery light. The alternator light his not on as the motor is not running and I have disconnected the alternator leas from the 250S dual.

After a few minutes, sometimes sooner the alternator light will come on and the green power light goes out.
Then the green power light comes on the solar the alternator and the battery and as the battery light comes on the green power light goes. It keeps cycling like this and then will revert to what I think is normal, that is green power on solar on and battery light on. My multimeter confirms the power is indeed being switched off.

Can you confirm that when on solar once it settles down only the green battery light the solar and battery lights stay on and they do not cycle on and off. So simply I am asking does your green power available light stay on or is it cycling on and off. My voltage is 12.6 or about 80%SOC Solar is delivering 19.9 volts. usually. I just checked it and its 18.volts from the solar and 12.88 into the battery. Its 5.00pm here and the panel are putting in only 3 amps. Interestingly its the most consistent it has ever charged without the power light going on and off.

Now I am not sure what it tells us but I will check it again at the same time tomorrow to see if it will work when the panels are delivering low amps.
FollowupID: 770693

Follow Up By: Bob Y. - Qld - Sunday, Sep 16, 2012 at 21:54

Sunday, Sep 16, 2012 at 21:54

There was a "problem" like yours, within the past few weeks on this site, concerning an apparent fault with the 250S, and am pretty sure some of the gurus were able to help the poster.

Do a check over the past 2-4 weeks, and am sure you'll find it, and the prognosis.


Seen it all, Done it all.
Can't remember most of it.

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FollowupID: 770711

Follow Up By: Member - kwk56pt - Sunday, Sep 16, 2012 at 23:14

Sunday, Sep 16, 2012 at 23:14
Thanks Bob Y for your reply.

I had made that post you talk about prior to going on holidays and now I have returned I have tried to resolve the issue. I established my solar panels are unregulated and are supplying 20v to the C Tek which is within their spec.

I have isolated my C Tek smartpass, all loads and the alternator feed to eliminate any possible wiring faults. I now have just the D250s with a solar feed and a lead to battery positive and another to earth. This is a very basic wiring setup.

I would like someone to confirm that the green power light stays on when on solar and doesnt cycle on and off. My alternator light comes on and the power green light goes out. Soilar is proving to be expensive and a hassel and I can see why generators are the go unless you are retired and doing this a lot of the time.

Cheers Peter
FollowupID: 770717

Follow Up By: trains - Monday, Sep 17, 2012 at 10:05

Monday, Sep 17, 2012 at 10:05
Hi Peter,
Regrarding the lights on the unit.

when I have the engine running, I get the alt led on showing charge going to the 2nd battery (ie 2nd batt led on) , and it stays on till the surface charge is gone from the charging source.

When I plug in the solar, the solar led goes on and shows charge to the 2nd batt, even if the alt led is on too.

Ive checked with a 100w panel the amps and volts in, and in lower light conditions have seen higher amps into the battery than from the solar panel input using a clamp meter.

During this time, my power indicator led is always on, or better described as flickering, not a true bright LED ON if you know what I mean.

A few questions just for clarification.
How are the two panels wired up, in series or in parallel ?
The 250 is a "12v" unit, not a "24v" unit, ie it will accept up to 20ish v from the panels.

Do you run an earth from the solar panels to the unit?
Do you run an earth from the alt/1st batt to the unit?

Does this issue with the solar charging alt light on, pwr light turns off happen with a fully charged or flat battery ?

Does this issue happen in low light or full sun conditions.

I have found the unit will start charging as soon as there is light on the panel first thing in the morning or at night, and when its decided the batt is fully charged will go into putting power back towards the alt/ 1st batt.

Running the fridge from the 2nd batt whilts its charging dosent seem to affect it and it can charge the battery in the mornings sun, then float it as it deems fit in the afternoon.

Are your batteries being charged at the end of the day, or are you having flat batteries ?.

When I first installed it, I noticed the lights went on and off a bit as you describe whilst it had a think about the batteries state of charge etc, but then went into charging mode soon after.

I also have a lcd display of battery voltage I keep an eye on, and it keeps the battery fully charged, or on float.

Hope this helps.


FollowupID: 770732

Follow Up By: trains - Monday, Sep 17, 2012 at 13:45

Monday, Sep 17, 2012 at 13:45
Just to add.
Just realised you have mentioned the panels inputting on 12v with around 20v.

Do the earth wires for that go to the battery, or the 250?

Ok so this morning, I thought I would go through the operation of my 250.
Power light dim, but on in the morning, start engine, and power light brighter, and alt led, and 2nd batt led on and shows charging.

Back from trip, battery charging at 14.7, engine off.
Alt led still on, and 2nd batt led still on, so using the surface charge off the main battery.

Plug in solar, and the solar led comes on too.
Bit later, the alt led goes out, but still have solar and aux batt leds on.

Power led still on and brighter than this morning.

Didnt blink on/ off like you mention yours did.

Are you using any earths that earth thru the chassis? or are all earths via good sized wire ?

Almost sounds like an earth issue causing the unit some confusion.
Or you may have a faulty unit.

Double/ tripple check all your wires/ crimps/ soldered joints and anderson connections, It could be something causing issues in that area.

If not what has the place that sold you the 250 said about the problems your encountering.



FollowupID: 770739

Follow Up By: Member - kwk56pt - Monday, Sep 17, 2012 at 19:24

Monday, Sep 17, 2012 at 19:24
I am immensely grateful for your informative reply. I am a bit embarrassed to say the light bulb moment was when you asked..........

Do you run an earth from the solar panels to the unit?
Do you run an earth from the alt/1st batt to the unit?

The answer was no but I quickly shifted the solar earth from the service battery earth to the D250S earth. The green power light remained on while the alternator, solar and battery lights were also on. Eventually the alternator light went out and its been running for several hours now with just the green power light on along with the solar and battery light on.

I have a smartpass as well. The manual says smartpass earth to battery, D250s earth to battery so I had assumed wrongly the solar earth was to go to the earth on the battery. I had a smartpass, the D250s, a fuse box and a BM1 battery monitor which included a shunt to count the amps used and produced. So it was a bit of a spaghetti junction but as often as I checked my wires sadly it just did not occur to me to earth the solar to the D250S as after all it was earthed to the battery anyway.

Suit least now I have a starting point and I suspect it should still work via the shunt to battery earth providing the solar remains earthed at the D250S and another lead is run to the battery via the shunt. It appears that it is important for the earth to go to the D250S but it is not shown in the C Tek installation instructions.

My alternator earth from the start battery goes to my service battery.
Should this be earthed to my Ctek unit ?

Once again many thanks, you have put a end to much stuffing about and grief in getting it repaired or replaced. I feel a bit dumb but I am pleased to have made some progress and its a lesson I will not forget in a hurry.

Cheers Peter
FollowupID: 770753

Follow Up By: trains - Tuesday, Sep 18, 2012 at 10:59

Tuesday, Sep 18, 2012 at 10:59
Hi Peter,
Great to hear you might have found the culprit to the problems you were having.

Might pay to double check that connection too, maybe its working because it was moved, and may just mask a poor connector crimp/solder or the wire size is a bit small etc.

I always like to know exactly why it didnt work, and thus what was needed to make it work, then you know you really did fix it :).

For others reading this thread.

In all my 2nd 3rd battery installs I always, ALWAYS ran good wire from the positive and the negative to the 2nd/ 3rd batt/ isolator/ dc dc device etc.
Also added good sized earths to the chassis on the starter too.

Ive seen many setups come undone with using the chassis as an earth, or issues with incorrect wire size or poor connectors.

Most people are more than capable of setting up their vehicle with 12v, but sometimes the finer points of the install is where they come unstuck.

Your not the first, and wont be the last to get caught out with fussy wiring requirements of electrical devices.
I certainly have over the years.

Lets face it those of you who are reading; its just as easy to run a seperate earth wire thru your vehicle when your running the positive.

Yes, its a bit more cost, but when your away from it all, its great to have a system you know you can rely on and not have to chase issues that come up after some corrugated travels even tho it worked fine when you first installed it.

Let us know how it all goes with the smart pass installed etc.


FollowupID: 770796

Follow Up By: trains - Tuesday, Sep 18, 2012 at 11:07

Tuesday, Sep 18, 2012 at 11:07
Just to add,
Yes, I would run the earth from the starter battery to the 250, then good earth to the aux battery, from the 250.
Then you have good wire from the alt/ starter to the 250, and then it can do its stuff from there.
I wonder if the shunt was the culprit?

FollowupID: 770798

Follow Up By: Member - kwk56pt - Tuesday, Sep 18, 2012 at 13:02

Tuesday, Sep 18, 2012 at 13:02
Just for those who may follow there is a diagram showing the earth's for the install at , click on battery chargers and scroll dowm. It shows the solar needs to be earthed to the D250S and that is then earthed to the battery. The alternator earth is supposed to go to the battery directly according to the diagram.

I did run a return earth to the starter battery from the service battery and not directly to the chassis. I will wire back in the smartpass and earth shunt for the battery monitor and see how it goes and post back.

FollowupID: 770809

Follow Up By: Member - kwk56pt - Wednesday, Sep 19, 2012 at 21:59

Wednesday, Sep 19, 2012 at 21:59
I can confirm that when I wired in the smartpass and ran a earth from the D250S to the service battery and earthed the solar to the D250S it all appeared to work.

However when I diconnected the earth to the service battery and ran it via a earth post and then to the shunt and back to the service battery the D250S fault light began to flash which evidently mean battery wiring fault.

So its probably a matter of running another lead from the d250s directly to the shunt to see if that works.. The end is nearly in sight. At least it works now so I just need to see if its possible to get it working when earthed via a shunt.

Many thanks again for the assistance offered. Pity I cant change the title of the post to C Tek solar Reg so that some other person may benefit if they read the installation instructions and believe that along with the alternator. smartpass and D250S the solar earth is returned to the service battery earth when in fact the solar earth needs to go to the D250S earth.

Thanks Peter
FollowupID: 770932

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