#172456  by mobiusnz
 Mon Apr 26, 2021 5:51 pm
Hi guys - I disconnected everything from my Solar Controller the other day. I follows instructions for order of disconnection.

I then installed a new AGM 120AH Battery which needed some new terminals on the cables as I was going from Post to Bolt connectors.

Afterward I reconnected everything and was surprised to be getting nothing from the panel - Not too surprised as late on an autumn day with the sun very low in the sky at 5pm.

I decided to put a meter on and was shocked to find the polarity from the panel was the wrong way round?? I though I was going mad and maybe reading it wrong so disconnected from the controller and tested again - Started wondering if a fault could cause a polarity flip but couldn't find anything to indicate that was possible. I then looked at the black leads from the panel and saw they were labelled + and - with colour coded stickers. I put markings where the cables entered the roof and then down below I got the red cable they'd joined to the panels black cable and pushed it up - Sure enough up above the roof the negative cable had moved an inch with confirmed what my meter was telling me - Red was negative and black positive.

So it appears when they joined red and black wires they got them backward - Probably realised and put them in the controller ignoring the colours.

I of course didn't take a lot of notice disconnecting as I had nice colour coded wires and labelled connectors on the controller so figured I couldn't go wrong.

So my question is - Now I've wired them the right way round I feel like I would have noticed if the coloured pairs side by side were different orientations but may not have - So

1) If they had the polarity wrong the whole time I'm picking either the controller would have shut off the input or it might have killed the controller?? Could the controller have handled it?? Its the basic red and black PWM TPS1230 sold as a Camec and has TopRaySolar on it - Its also used by Jayco a lot. It has worked well in summer charging phones, tablets, running lights and pumps so definitely was working.

2) Assuming they had it right (by reversing the colours) and then I connected it for a while wrong will it have damaged the controller??

I guess I'll see tomorrow when we get some sun what happens - If it registers solar input or if its dead.

My other question is - What is the legality - I know doing the wrong colouring with 240V could be deadly and would be highly illegal. I think I'll go back to them and point it out if the solar controller is blown and suggest they owe me a new one. I don't want to name the company at this point as I've always found them good to deal with up to now but this is a pretty questionable install.
 #172458  by mattn
 Mon Apr 26, 2021 6:26 pm
First up - on any planet this not your fault, the installation was about is an unprofessional and cowboy as it gets, and is far from a simple mistake. You were given a hospital pass, luckily its solar so not literally.

A quality controller will be protected from a reverse voltage input, and a cheap controller probably is as well, so not too much worries there, so expect to have been lucky.

The electrical wiring standards NZS3000 apply to ELV installations, as does NZS5033 (ref: https://www.worksafe.govt.nz/about-us/n ... pv-systems), however it is not PEW. Even though it is not PEW, it must still meet the standards, and in the unlikely event the screwup somehow meets the standards, its still pretty poor workmanship.

What to do - fix the faulty join, do it now and problem is solved forever. Don't do it, and potential for problems exists forever. An alternate (That may or may not meet the standards) would be to sleeve the incorrectly coloured wires with the correct colours (use heat shrink). Add a label the proverbial out of everything, from the solar panels and to the controller, warning of the screwup. Who pays - you can guess from my post, I would be interested to know how that conversation goes.
 #172460  by mobiusnz
 Mon Apr 26, 2021 7:45 pm
Thanks @mattn - I was pretty horrified. I think I’ll resleeve as that’s a good idea and they have done a really nice neat job with the joins which I’m picking is why they didn’t want to re-do it when they discovered their mistake. Hopefully I’ll see some charge tomorrow :)

If the controller is dead there is a new one from dometic that is the same price and a bit smarter. Ie you choose battery chemistry etc
 #172487  by mobiusnz
 Wed Apr 28, 2021 11:20 am
Ok - So got home yesterday - Unfortunately due to the time of year I got nothing when I left or when I got back on the current from the panel but the voltage had gone from 12.8 up to 13.1 so the panel and controller are working.

My question now is - Should I get a new controller? From what I can find that basic Red and Black TPS1230 controller really only does flooded and my new battery is AGM. It seems this one

https://www.rvsupercentre.co.nz/dometic ... 12-24v-30a

Does have selectable battery charge settings for the battery type - It is in general a lot more customisable and smart than the TPS1230 unit for the same price.

From the basic reading I've done I don't think I've likely to see any massive gains spending a lot more money on a MPPT controller with a single 140W panel and I don't think I'll reach a point where I need more power in this caravan. Maybe if I ever start touring the country for long periods I might want TV's etc but for me its lights, pump and charging phones and tablets only.

I guess what I'm asking is - How big a problem is the current charger with an AGM battery, I suspect it could actually do damage to the life of the battery - At present we're getting so little sun I don't think I'm going to have a large issue but given some decent sunlight hours I think it tries to raise the voltage too high?

Is that Dometic unit a good buy - Its very good value and I know there isn't a lot in a PWM controller but having a brand name behind it like Dometic who want to protect their brand gives me some confidence.
 #172489  by mattn
 Wed Apr 28, 2021 12:37 pm
My personal opinion is there is way too much over-complication around solar systems and battery settings. They are all lead acids, and in a motorhome the perfection demanding theory get blown out the water by the normal day to day (ab)use. You need a controller that is good enough, not perfect.

I would recommend changing to a better quality controller though, mainly because the data on that one means I am not certain it is doing a good enough job. While it probably is, a controller can destroy a battery just by being connected 365 days a year.

Cheapest option is to put a battery isolation switch in place, and let the battery sit when not being used. A quality AGM will be safe to leave for a a couple of months before connecting for a top up, some are rated for 6 or more months in storage.

I would not upgrade to that controller, while its probably better than what you have, its still a cheap controller and not $100 better. IMHO, you would be best to get a MPPT controller such as the Tracer 2210AN (About the same price off aliexpress) - not because of the gains in having the MMPT, but because of the much better control you have of settings, and higher quality control of the voltages to the battery the controller can. (I have not looked at controllers recently, other can chime in with the state of the market and good value for money models)
 #172493  by mobiusnz
 Wed Apr 28, 2021 4:31 pm
Thats good info thanks MattN

I've ordered that one anyway as I want to get rid of the potential for overcharging quickly before I kill my nice brand new battery. They have said I have 7 days right of return as they couldn't tell me what size the wire terminals were so it might be no good anyway. I will look to bring in an MPPT one - Its a tough game knowing how much to spend on an MPPT one as I was actually given one with the battery, he just threw it in and commented they are only $50. When I looked at it the wire terminals were too small for the wires used which stopped me putting it in, 5 minutes research and I found out why they are so cheap - They aren't MPPT at all, just PWN with MPPT printed on the case.

One of my big frustrations up to now with the controller I have now is when it was installed they didn't put the 12V load on the controller - I guess that's because currently the load is running off the 12V system that came with the caravan and charges the battery off mains etc so it would have been fiddly to leave the existing mains charger etc in place AND have load running off the controller.

What this has meant is the couple of overcast holidays where the battery dropped in voltage at night, the controller starts chirping non-stop and you can't shut it up so I end up going out in the rain and disconnecting the positive terminal from the battery. It was exacerbated by the fact the old battery was a flooded and the first time I didn't know it wasn't sealed so hadn't checked the water level (Got some demineralised water and topped it up) and other times it will inexplicably evaporate off a bunch of water. I'll check it on multiple trips and it won't drop a millimeter. Then the one time I'm leaving after work and short on time the battery will be low and when I check the level it was down 20mm-30mm

I'm not sure if the way its been wired - They just put the panel on the roof, straight down to the controller and then wired from the battery terminals directly into the post connectors on the battery - I'm wondering if somehow when we're on mains AND its sunny the controller / mains charger get confused about charge voltages and push too much into the battery??

I like the idea of a switch to cut the charge from the controller - Then the occasional time we camp on mains I can disconnect the solar controller from the battery so I don't end up with mains AND the controller trying to charge the battery. That now leaves me wondering if the onboard mains charger is ok charging the AGM battery??

Nothings ever as easy as it appears - Basically I was all but gifted a brand new 120AH Century AGM Deep cycle (And cheap MPT controller), A) the battery is too big for the box but its sealed so I'm putting it under the front seat. B) It has bolt terminals not the post terminals so had to find some connectors and crimp them onto the cable (Luckily my brother in law is a sparky and had a long handled adjustable crimper) and now I realise possibly both of my charged might be too thick to keep the battery health of an AGM battery ok.

I realise I just said my brother in law is a sparky but he literally only got qualified fairly recently and has little real world experience and specialises in fixing commercial kitchen appliances - Never worked with solar or ever really 12V systems.
 #172494  by mobiusnz
 Wed Apr 28, 2021 4:42 pm
PS - If I buy something like the EPEVER one the nerd in me won't let me stop at the controller and I'll have to buy the remote screen and wifi/app options etc :lol:
 #172500  by mattn
 Wed Apr 28, 2021 9:02 pm
Your setup is fairly typical, most don't tap the solar controller load for a number of reasons - usually its only rated the same as the controller and not enough for peak loads, retro fit means all sorts of rewiring for no real benefit etc.

Don't worry about the mains and solar competing. 'Its complicated', like really really complicated to model what is happening when a battery is being charged and you have multiple charge sources and loads. The good news is in practical terms its no more complicated than "it sorts itself out".

Having to top up the water in the battery is a sign something is not right - given the cost of the new AGMs, its wise to pull out the old controller nd replace it with something a bit better. The beeping should not be happening, the fact it was indicated the battery was being over discharged which is not good, but hopefully the new controller has not beeper. A tube of super glue and/or a small screwdriver will fix the beeping if needed :D

I am not a fan of solar controller battery monitors. To do a half decent job it has to be shunt based - for $50 you can get a shunt based dedicated monitor off aliexpress that will run rings around a solar controller display for the important information (State of charge of battery). Where they can be useful is seeing how much current the panels are producing, but unless the load is connected to the controller, the load and battery charge currents are useless,.
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