Built A tiny home, but it has solar issues

[The_realTW]

Your posts dont really come across as having it sorted so I thought I would have a look. Perhaps I may have a different perspective.

You posted a picture above showing max volts at 13.7. What is your bulk charge set at?

I WANT TO BE CLEAR I MEANT NO OFFENSE, EVERYONE is welcome and needed here. I did not mean for my post to sound short. Your "Different perspective" is completely welcome.

[chrisski]

If you could get the battery monitor working, that could get some good info also. I look at that quite a bit to when I turn a load on to see if it is draining the battery, or I'm producing enough solar to keep the device on. I use the monitor to decide when to turn my fridge from electric in the day to gas at night. At night, I will turn a devices on and off to see where my draws are coming from. I had about seven incandescent bulbs I found by seeing they had an unusually large draw. I also found my wife had snuck an electric food warmer that was pulling up to 1000 watts when in turned the heating element on. My 4 gold cart batteries could not sustain that overnight.

Some shunts are compatible with different battery monitors, and are plug and play. My Victron comes with instructions on how to connect a non-Victron Shunt. I'm sure other brands do the same. My shunt cable is a standard RJ12 cable.

Could also be as simple as the cable from the shunt to the battery monitor being shot. My cable came with something like 25' of wire, and I wish I could trim it down to about 5'. Could be if yours is the same, the installer messed the cable up and that could be why its not working. When I get around to making that interface cable shorter, I'm sure I'll mess it up also.

[The_realTW]

Your posts dont really come across as having it sorted so I thought I would have a look. Perhaps I may have a different perspective.

You posted a picture above showing max volts at 13.7. What is your bulk charge set at?

Oh it’s far from “sorted” lol , I’m just glad there is forward progress now

ill get your requested info in a few

[Bala]

Your posts dont really come across as having it sorted so I thought I would have a look. Perhaps I may have a different perspective.

You posted a picture above showing max volts at 13.7. What is your bulk charge set at?

[The_realTW]

I have not read every post in this thread but here is what I believe. Without that - wire connected in the charge controller the batteries were never charging off solar.

It is quite possible the batteries are no longer any good as they have been undercharged for so long. Sometimes when batteries are no good they will go to full charge voltage very quickly without drawing many amps.


You could run a test using just your one big panel connected at midday on a good day. Put more load on the system than your panel wattage. So of you have a 300w panel turn on lights etc until you have more than 300w load and see what your meters are reading. V, PVwatts in and amps

Turn everything off then disconnect the batteries and put in place another known good battery. It could be out of a car etc, it will only need to be in for a few minutes. Reconnect all the system and load it up the same as before and see what your meters are reading.

If there is no difference between the two batteries then you need an amp meter to do some tests. If the test battery shows good numbers then you battery bank is the cause.This will tell you if your panel and controller wiring are working

Thank you so much for your input, as you mentioned however your pretty late to the game. All the tests your talking about have already been done, I do own an Amp meter, and also the batteries themselves are healthy, there just is not enough of them. As for the load your referring to, aside from turning the AC on, which isnt used with solar anyway, I cannot come close to a 300 watt load. I guess most of this will be moot once I put the new system in and recoup my costs in court over the negligent first install.

Thanks so much for dropping by

[Bala]

I have not read every post in this thread but here is what I believe. Without that - wire connected in the charge controller the batteries were never charging off solar.

It is quite possible the batteries are no longer any good as they have been undercharged for so long. Sometimes when batteries are no good they will go to full charge voltage very quickly without drawing many amps.


You could run a test using just your one big panel connected at midday on a good day. Put more load on the system than your panel wattage. So of you have a 300w panel turn on lights etc until you have more than 300w load and see what your meters are reading. V, PVwatts in and amps

Turn everything off then disconnect the batteries and put in place another known good battery. It could be out of a car etc, it will only need to be in for a few minutes. Reconnect all the system and load it up the same as before and see what your meters are reading.

If there is no difference between the two batteries then you need an amp meter to do some tests. If the test battery shows good numbers then you battery bank is the cause.This will tell you if your panel and controller wiring are working

[The_realTW]

Hey everyone, this is just an update, real quickly even with the solar "working as it should" lots still remains a mystery. Like how did this thing ever work before at all?, were the batteries ever charged? , on top of the mysteries are the glaring obvious things like even with full sun I am not exceeding 115 watts generation, which even for the Trina seems like a huge amount of loss. I would like to be seeing somewhere around 250 watts going down that line. I think once I rerun all the wires, things might improve. Also I noticed in my present location everything with sun before 11am and after 3pm is very low charging rate. So if we were to run numbers and be very crucial, I am getting 4 hours MAX of "full" charge, I put full in quotes because I believe I am not getting all the juice I should. I can see playing the devils advocate for a minute, why solar is not embraced by everyone. Short of having a turret that follows the sun (And I know these exist) I will need far more panels to collect enough energy in the short time it is on them and of course the batteries to store it all for later collected use.

Don't get me wrong, I love the fact I can exist off of solar, but I am brought back to reality on nights like tonight. Today was cloudy for a good part of the day and my solar only reached 40%, as soon as the "sun" we did have went down I was faced with the dreaded alarms of LVDC. It amazes me that a simple fridge could literally drain it. I had no lights on and my laptop was charging, but sure enough, that fridge everytime.

I digress, I am sitting here with the generator running for the first time in awhile (mostly to give it some use) and I am backfeeding the batteries through the converter box. I know once I switch back to the inverter/batteries it will drop to like 35-40% again.

I know that adding panels and batteries will improve the system.

I have "stick up" lights (battery operated) everywhere and I am going to buy a charging system so I am not constantly spending money on batteries. The sad part is this system was supposed to allow me to use all the things that were installed in this tiny home, and I have actually had to go through the process of not using them and working around them (TV, Microwave, 110AC ceiling lights, fridge).

Its just frustrating that is all I guess.

Oh one more thing. I will be the first to tell you I am the biggest CHEAP@ss you will ever know, which is why I am ALWAYS downing the lithium battery chants. however in fairness of opening my eyes I have been doing some research on LIPO4 (The new Lithium Iron Phospate) and the strong claim is although these things are brutal with upfront costs, they swear that you pay less over their lifetime then you will for their lead acid counterparts. I paid Drew $331.68 for the two massive Interstate 6VDC batteries. The batteries I am now looking at are $1299.00 and are 300AH LIPO4 @ 12 Volts, so there is still calculation to do but if I got 3 of them (that is an incredible amount of dough) that would give me 900AH @ 12V, although I am not sure I can run 3 or if it has to be in pairs. If I have 900AH and a panel system that can charge it, I doubt ill ever hear the LVDC alarms again. Lots to think about and $3600 bucks for batteries is INSANE. They claim with LIPO4 you can run them all the way to 0% and they will still work fine. I imagine the SCC for LIPO4 must be different as well.

Anyway I am getting the list together, Ill keep you updated.

here are some photos of the SCC panels for you to look over.

[The_realTW]

Here's an idea for the helper panel.

You can hook your PWM charger to the "helper panel" and still use your MPPT charger. If you remove the 100 watt panel from the roof, it can become a portable system. When I tilt mine into the sun, I get about 40% more production. Also because I can aim these panels at the morning sun, it will start producing power a couple hours earlier until a couple hours later than the flat panel. You may even get more power out of this portable panel than the flat panel.

I have 400 watts of portable panels I aim into the sun three times a day, and these can make more charging amps than the 950 watts of flat panels on the roof.

For the cables not long enough, I've used butt connectors before to attach another cable to and make it longer.

All am going to say about all this is I am formulating a plan and a list, and when its complete ill be back. I will make it an Amazon shopping list so everyone can look it over, as for the mobilesetup I am way ahead of you!

Thanks

[chrisski]

Here's an idea for the helper panel.

You can hook your PWM charger to the "helper panel" and still use your MPPT charger. If you remove the 100 watt panel from the roof, it can become a portable system. When I tilt mine into the sun, I get about 40% more production. Also because I can aim these panels at the morning sun, it will start producing power a couple hours earlier until a couple hours later than the flat panel. You may even get more power out of this portable panel than the flat panel.

I have 400 watts of portable panels I aim into the sun three times a day, and these can make more charging amps than the 950 watts of flat panels on the roof.

For the cables not long enough, I've used butt connectors before to attach another cable to and make it longer.

[The_realTW]

First of all, I'm glad it's up and running.



Give it some time and see what happens. Percentage wise, Those results are not that far off from what I see for my flat panels on my roof.

When I come close to the rated power of the panel, its without a cloud in the sky, and then only an hour before and after high noon. The clouds shining through a break in the clouds still won't produce full energy. On top of that, that panel has to be facing into the sun, both tilted by angle to the ground and azimuth. There's a bit of loss because of this.

A 320 watt panel that's been stepped down to 14.6 charging volts is about 22 amps. With what you're seeing at 115 w at 14.6 charging volts is sending 7.9 amps to the battery.

My flat panels in theory based off wattage labels only. should push 41 amps, but at high noon, I get between 20 and 25 amps. Those amps only come between about 10:00 - 2:00.

All this really tells me is I will need a bigger system, probably in the neighborhood of 1000 watts or so, and some more batteries to carry the charge longer. The charge returned to like 10 watts once the sun moved off the direct exposure, so while I am still charging I am doing so at .11 A, which would take a lifetime to charge completely. I honestly expected more from the Trina, and I suspect if I rewire these things, Ill get some more out of it.

An MC4 Crimper and set of 6 connectors, male and female will run you $30. If there's any play in those cables, extra cable, you can snip the end off, strip the wire, and recrimp and slide on, and you may be able to call it a day. Usually you can cut a little bit off these cables without having to redo the whole thing.

I wish it was that easy, but he literally only ran ENOUGH wire to make the run, so it was pulling and that is eventually what separated it completely, I think running new connectors and new wire might honestly be in my best interest long term.

=========

May still be worth a call to Drew to figure out why he did not put the negative battery cable to MPPT out of the build.

Since we are currently on the opposite sides of a small claims lawsuit for negligence, and this new wrinkle will be added to the evidence, i do not think a phone call will yield much positive results. I sadly think he is just very elderly and he made some mistakes (negligently) and never bothered to correct them.

Actually, more for if the Bat- input on the MPPT supposed to be routed directly from the shunt. I'm unfamiliar with the Distribution system you have that does shore power, alternator charging, and PV Charging. The device may be a switch to choose one source at a time, and now the solar will be charging as long as there's sun up. That box could be a safety device to prevent too much from going into the battery from both solar and say shore power at the same time.

I thought I had explained this better in the video but Ill try in words as well. First off I have no idea if a negative cable should be on the shunt, or if it even matters what side its on, I suspect since we are seeing the rise in watts/amps it was supposed to be. I also suspect the reason the SCC appeared to be suspect the whole time is because it was doing its job to begin with, it was limiting current based on the conditions it had to work with.

As for the system, yes the box (The WFCO converter) IS DESIGNED to send voltage back to the batteries to charge them when in a shore power situation, the SWITCH you mentioned is placed in the system to avoid a feedback loop hitting the inverter. I cannot explain it much more then that but when on shore power the solar system is still active as it can send current to the battery, but the INVERTER system which powers the tiny home is shut down, so no current goes from the converter into the inverter itself, which as you know is tied to the converter already. We tried during testing to do it the natural way without the switch and drew blew the final stage capacitors right off the 1st inverter. So if I am on shore power (which is almost never) AND I am backfeeding the batteries WITH that shore power, the switch is thrown to avoid the inverter looping back (And the inverter is completely off as well) its confusing but it all works so who am i to say lol. Your pretty smart to figure most of it out I hope that explains the rest.

I have 458 AH of FLA batteries, and I can't charge at more than 13% if that, or 60 amps. If your two batteries are half that, then 30 amps is about the max.

I suspect that the system I have will need to be seriously upgraded for long term longevity.

==========

What are you going to do with all your free time now?

Catch up on sleep I dont know, I am still sitting at 49% after todays charging, my guess is tomorrow when the sun comes up ill get a true full day with the ONE panel, I disconnected the helper panel completely for now. I tucked all the cables under the panel and removed all the splitters.

==========

On that other website, I don't actually have the PV- from the array going directly to a busbar. That's probably the labeling I put on the wire to show that particular stud on the negative busbar is hooked to the Solar Charge Controller. Wouldn't surprise me if I mislabeled something. All those labels are for if I ever take the wires off and put them in a gigantic pile, I can pull the cables out one by one and know where they go without guessing.

=========

I did not ask that question but I do know what you mean by all the cables. Everytime I show someone my tiny home they are like "this is nice" and when I pull the curtain back and show them that wall the reactions are always wide eyed "wow what is all that". I hooked the PWM controller up as well but honestly it does not give much info and I didnt do any meter test, I am happy to know it works and I stored it in a bin under my bed, if that MPPT does fail someday, that extra controller could mean the difference between no charging capability and having some while awaiting a new MPPT controller replacement.


+++++++++++++++++++++

Thank you once again, I truly appreciate you guys sticking with me, I know some of you fell off this whole saga, but those who continued to contribute I really do appreciate it.

[chrisski]

First of all, I'm glad it's up and running.

Also why only 115 watts out of a 320 watt trina?????:

Give it some time and see what happens. Percentage wise, Those results are not that far off from what I see for my flat panels on my roof.

When I come close to the rated power of the panel, its without a cloud in the sky, and then only an hour before and after high noon. The clouds shining through a break in the clouds still won't produce full energy. On top of that, that panel has to be facing into the sun, both tilted by angle to the ground and azimuth. There's a bit of loss because of this.

A 320 watt panel that's been stepped down to 14.6 charging volts is about 22 amps. With what you're seeing at 115 w at 14.6 charging volts is sending 7.9 amps to the battery.

My flat panels in theory based off wattage labels only. should push 41 amps, but at high noon, I get between 20 and 25 amps. Those amps only come between about 10:00 - 2:00.

An MC4 Crimper and set of 6 connectors, male and female will run you $30. If there's any play in those cables, extra cable, you can snip the end off, strip the wire, and recrimp and slide on, and you may be able to call it a day. Usually you can cut a little bit off these cables without having to redo the whole thing.

=========

May still be worth a call to Drew to figure out why he did not put the negative battery cable to MPPT out of the build. Actually, more for if the Bat- input on the MPPT supposed to be routed directly from the shunt. I'm unfamiliar with the Distribution system you have that does shore power, alternator charging, and PV Charging. The device may be a switch to choose one source at a time, and now the solar will be charging as long as there's sun up. That box could be a safety device to prevent too much from going into the battery from both solar and say shore power at the same time.

I have 458 AH of FLA batteries, and I can't charge at more than 13% if that, or 60 amps. If your two batteries are half that, then 30 amps is about the max.

==========

What are you going to do with all your free time now?

==========

On that other website, I don't actually have the PV- from the array going directly to a busbar. That's probably the labeling I put on the wire to show that particular stud on the negative busbar is hooked to the Solar Charge Controller. Wouldn't surprise me if I mislabeled something. All those labels are for if I ever take the wires off and put them in a gigantic pile, I can pull the cables out one by one and know where they go without guessing.
=========

[The_realTW]

Ok here is the update, I powered down the solar and the inverter, and disconnected the battery + from the SCC, at the time of disconnection it was getting 1 watt and 18.7 volts DC with full sun on the panel. here is what happened next.

Action: I added a heavy gauge wire to the Battery - of the SCC, I then terminated that wire at the shunt that has the negative run from the outside batteries, I terminated it on the same side as the positive that goes to the Battery + on the SCC just for uniform sake. I powered the system back up, and replaced the main solar fuse.

Result: As soon as the solar panel came online i was seeing 30-40-50 all the way to 98 watts coming from the panel at 33 volts DC, the battery was also showing a charge output of 6.7-8.3 amps

Action: I went up top and unhooked the "helper panel" from the chain so just the 320 trina would be running, I went back down stairs.
Result: No change in the readings

Action: I unhooked the solar and the battery from the SCC for 10 minutes, and then hooked up first the battery and then the solar as soon as the system was reset
Result: as soon as the solar came online i was seeing a max of 115 watts and 36.0 volts coming from the panel, the charging amps had changed a little but not much

Action: I went up top and disconnected the splitters and had just the trina running directly from the panel to the SCC
Result: no real change in the readings, but a problem did develop (more on that later)

Action: I went up top and washed and dried the panels, they had scum on them, and then once they were shiny i came back downstairs
Result: no change in the reading

All throughout this process the controller has STAYED in MPPT and not moved to any other mode, Also while fiddling with the wires I noticed drew had put one on way to tight and it slipped outof its MC4 connector, I have rigged it for now, but that whole run will need to be redone, I am thinking of just ordering a 50 foot kit and redoing it myself, I can get a 50 foot kit of pos-neg MC4 preterminated cables for about 30 bucks at home depot (their not in stock go figure so ill have to order) or Amazon. This would require me reopening the roof grommet to run the new wires, but it might be an improvement.

I am going to hook the PWM controller just for giggles and I do not plan on returning it, for its obvious the issue was drews negligence in not hooking up the NEGATIVE CABLE in the very first place, and Ill never even know if those batteries ever charged at all, and if they did HOW????? I would love for someone to chime in on that.

Truth be told having an extra controller around as a spare is not that bad, and it was only 25 bucks,

Result: its obvious now the batteries are charging, maybe not at 30amps, but lets see what the PWM controller brings us.
Should I invest in an MC4 termination kit, since I may need it again in the future (about 150 bucks) or just get the pre terminated stuff now?

Also why only 115 watts out of a 320 watt trina????? I know I need to account for loss, but that is ridiculous

Ok ill await the replys, thanks again for your patience everyone, were sniffing this thing out finally!

[The_realTW]

I have news ill be back soon with an update!

[oregon_phil]

chrisski , I looked at your RV build on another site and I think you have the negative PV lead going straight to the Victron MPPT controller right? Not to a common 12VDC ground bus bar like The_realTW setup. I have a mechanical background, not electrical but I'm thinking that can't be good either.

[The_realTW]

Looks like you found the problem. A black wire from the shunt to the bat neg of the charge controller will give SCC what it needs to charge.

Whether that’s the MPPT or PWM, should not matter. Without that bat - attached, it should have never worked.

I don’t like the idea of multiple lugs to the shunt. I connect each lug to its own stud on a busbar to split at a busbar. The only thing that would change that for me would be if the documentation on the shunt said four lugs connected there is fine.

Really sounds as if you know your system.

im flattered but I only know it as setup, I do not understand how it ever charged in the first place. I will run a black wire from the existing controller today, and to the shunt to start. What I’m curious is why the MPPT never sent the current out, did it “sense” the black wire missing and therefore scale it back? Also if I have 33-36 volts of solar coming in, why am I only seeing 18V at .2 amp, I really think there is more to the issue. I’ll report back once the black wire has been rigged to the shunt.