Wiring & Add Ons Chat

[Bossrox]

Got an itch to sophisticate your system with some automation?

If you're doing more than a basic system, there's a lot of gadgets that can be incorporated to sophisticate a system super tricked out, so this thread is mostly about covering any slick add-ons you or I have schemed up.

But 1st, it's most important to use the proper wiring size for the heavy amps of charging & inverter loads & here's a chart you can go by.

1 AWG 50 amps @ 37.7 ft, 100 amps @ 18.9 ft, 150 amps @ 12.6 ft, 200 amps a@ 9.4 ft, 300 amps @ 6.3 ft.	2 AWG 50 amps @ 29.8 ft, 100 amps @ 14.9 ft, 150 amps @ 9.9 ft. 200 amps @ 7.4 ft, 300 amps @ 4.9 ft.	4 AWG 50 amps @ 18.8 ft, 100 amps @ 9.4 ft. 150 amps @ 6.3 ft, 200 amps @ 4.7 ft, 300 amps @ 3.1 ft.	6 AWG 50 amps @ 11.8 ft, 100 amps @ 5.9 ft, 150 amps @ 4.4 ft, 200 amps @ 2.9 ft, 300 amps @ 2.2 ft.
1/0 AWG 50 amps @ 47.5 ft, 100 amps @ 23.8 ft, 150 amps @ 15.9 ft, 200 amps @ 11.9 ft, 300 amps @ 7.9 ft.	2/0 AWG 50 amps @ 60 ft, 100 amps @ 30 ft, 150 amps @ 20 ft, 200 amps @ 15 ft, 300 amps @ 10 ft.	3/0 AWG 50 amps @ 75.6 ft, 100 amps @ 37.8 ft, 150 amps @ 25.2 ft, 200 amps @ 18.9 ft, 300 amps @ 12.6 ft.	4/0 AWG 50 amps @ 95.2 ft, 100 amps @ 47.6 ft, 150 amps @ 31.7 ft, 200 amps @ 23.8 ft, 300 amps @ 15.8 ft.

[Bossrox]

An inline kilowatt meter

My charge controller can't give me a total of the power I'm generating off the inverter or how much solar went to charge the batteries except what it's doing at the moment so wanting to know what I'm sending out of the inverter to the house, I ordered a digital kilowatt meter to put between the inverter & the house. Now I'll know for sure what I'm shaving off the power bill.

A bi-directional amp in & out monitor

With my Victron charger, I can see how many amps it's kickin' out @ 24v but my inverter reads amps it's putting out @ 120v. Altho It's pretty easy to figure out the conversion where you know how much the batteries are losing or taking, it's kind of a nuisance always calculating, so along comes a cool solution.

Well I found a meter, that at a glance gives you the stats on what direction the flow of energy is coming from, solar or batteries, where you can see how much is going to the inverter vs. what's going in or out of the batteries. Now I can easily keep an eye on state everything is running under so I can make faster changes as needed without having to decipher the old way.

[Bossrox]

A dual purpose sun intensity automation switch

With a good sunny day my panels can put out 100 amps that can run 2 window A/C's along with everything else & still have some power to spare to send to the batteries but other than that, if it's going to be a sketchy day of getting much sunlight, I needed to find a way to divert 1 of the A/C's off solar to utility power to avoid over taxing the batteries.

What I came up with is a temperature sensing switch I use a lot thruout my system & replaced the thermal sensor with photo resistors. It's still in refinement stages but right now it will send a signal to a power relay to switch my shed A/C over to utility power if the sun goes away & switch it back to solar when it returns.

Once I get it refined to where I get it working like I'd like it to, I'll post the materials you'll need if you need something like that.




Well here's the switch & to turn it into a sun intensity switch you'll need a 100k & 10k "ten turn pot", don't use a common pot, then 10 photo sensors. the photo sensors have a very tight resistance range so it takes 10 of them in series to widen it's range. Just get a blank electrical box & a cover, drill 10 sets of tiny holes in the cover, put a dab of silicone caulk under each chip where it sits on the plate, let the caulk set stiff, then on the back side of the plate, tie them all together in series, mount it outside where it'll be exposed to the sun all day & run some thin 2 strand wire to the control switch.

I mounted the control switch in a double ganger electrical box, carved a slot in the double sized plate to slide in the switch & 2 holes for the 10 turn pots. On the 100k pot, both leads go to the sensor input, the 10k pot you'll hook in series with 1 of the 2 incoming photo sensor wires, then combine those wires with the 100k pot wires into the sensor input & it's good to go.

1st adjust the 100k pot at night or covered up so there's no light, so the readout says 0, then the 10k pot you'll adjust during peak sun, about noon to 3pm, or put a strong flashlight on it if you do it at night & set it for 100. Then from the switch functions, you set the switch to how much sun intensity you want it to trip the built in relay to kill or turn on whatever device you want to control. in my case it's switching an A/C over to utility power when sun intensity is low & back to solar when appropriate. That's how I made my sun intensity switch & here's a schematic of it. You can find all the parts on ebay.



I recently added 12 more panels that I'm also utilizing this for. If you have your charge controller already maxed out like I have with 12 panels but have more panels you could tie in, this can switch in extra panels to feed the charger more power during less sunny conditions, however I've found that tying in another 12 panels is too much current to let just 1 of these switches handle, so I'm dividing them up on 2 switches & staggering when they kick in to keep the current input from fluctuating so dramatically.

1 thing to beware of is if the threshold is set too high when the relay disconnects the extra panels, you'll get a continuous arcing across the contacts that'll eventually fry the contacts but that can be remedied with some nosparc brand DC suppressors if needed.

Getting another charger would be the ideal thing to do & will eventually but for the time being this switch will accomplish near the same goal & a cheap way to put off buying another charger when I can get the parts to make a switch for about $35.

A current sensing switch incorporated in my system also.

The sun switch above is a great tool to conserve your batteries on unpredictable days but then I came up with an extra measure to better conserve battery drain with another of my novel automating gadgets.

I added a current sensing switch to monitor the inverter output current, which when engaged, is looking for the high current draw of the cabin A/C or the frig going into defrost cycle to do the job it's intended for.

Even tho the sun intensity switch is controlling the shed A/C, overall there may not be enough sun for the day for both A/C's to run at the same time & send adequate charging to the batteries to keep them topped off.

So even if my sun switch is running the shed A/C on solar, when the current sensing switch detects my cabin A/C running or frig defrosting, it will switch the shed A/C over to utility until the cabin A/C shuts down. A nifty double back up when needed.

[Bossrox]

A low battery voltage inverter kill switch

If you're trying to integrate 1 of the many cheap chinese inverters into your solar system, there's a major flaw with them!

Every 1 of them I've seen has a low voltage cut-off on a 12v system at around 10.5 volts or times 2 if on a 24v system. That'll drain a battery near dead & if you know anything about proper battery ethics, draining any battery that low will destroy it in no time.

Batteries are a major expense in a system & you sure as hell don't want to let these crap inverters keep you poor replacing batteries, so I did some huntin' to find an outboard battery voltage sensor that would kill an inverter to keep it from draining batteries to low & here's what I came up with but I've yet to gather the components & build it but I had an electrical engineer look at this & he said the circuit is looks good but the zener diode value has to be changed depending on the voltage you're working with. This schematic is for 12 volts.



As written by the author......

Here is a very useful project for a low battery voltage cutoff or disconnect circuit. Rechargeable batteries deliver very good performance and lifespan if taken care of. There are many things which can be done to take proper care and protect your rechargeable batteries which are, not over charging them, don't charge them in fast mode & don't let them get fully discharged.

When batteries are deeply discharged frequently, their life will get shorten drastically and be toast in no time. Therefore it is better to disconnect your battery from the load when your battery gets weak. But it is very difficult to check and disconnect from the load every time they require charging so the circuit shown here will do this job very efficiently by automatically monitoring the voltage of the battery and disconnect the battery from the load on an adjustable preset low voltage level of the battery.

The circuit is very simple to build and using few components. The heart of the circuit is a TL071 operational amplifier IC that is connected in comparative mode here. The 10K variable resistor is used to adjust the desired voltage level on which you want to deactivate the relay or disconnect the load from the battery. A 2N3904 transistor is connected at the output of the IC to drive the relay. The 5.1V zener is used as a voltage reference.

The circuit can be used with any type of batteries for example 12V, 9V, 6V, 5V etc. Only you have to change the 5.1V zener diode value according to the battery voltage type. For example if you want to use the circuit with 6V battery then simply change the zener diode value to 3.1V.

End of authors article.

My guessing here is from this info, the zener diode looks to be about half the volts of the system so a 24v system will likely be around 12v, will find out soon if I'm right.... Well now my source tells me everything should work ok but for a 24 volt system, to use a 16 volt zener diode. Might try out both just in case 1 works better than the other.

Of course this gadget requires your inverter has a remote switch connection. Will build this after everything is set up & get back to y'all. It would seem something like this premade would be a good seller but I've not run across any.

It looks like someone else will have to report on if this works 'cuz I was fortunate enough that the guys who make the Solinba inverter I ordered, offered to modify my inverter to cut-off @ 22.7 which would kill the inverter when the battery discharged about 50%. It's not ideal for me to allow them to go that low but that was the best they could do & I can live with.

[Bossrox]

A way to defeat peak hour rate increases

I'm on 1 of those utility companies that has a peak usage charge during a 3 hour period each day. The way their system works is they look at your usage for the month during peak hours & the day of that month you used the most energy in a 1 hour period is the point they pick to charge those rates.

Normally, a kilowatt costs 5 cents for off peak hours but during peak will now be $12, the equivalent of paying for 240 kw for every kw you tally up, So here's my solution to defeat that charge.

For late fall, winter & early spring it's 6 to 9am & late spring thru fall it's 4 to 7pm, so I set my system up on a timer that if It's on utility power, it will kill the utility power during that time & switch over to solar. Pretty simple solution, 'ey?

To do something like that tho, you'll need to have an inverter with a remote switch hookup or modify the one you got if it doesn't & an adequate battery bank to carry the house for 3 hours, as during the 6-9 am time of the morning there won't be much significant solar & during middle season 4-7pm peak you'll likely have have a heavy load running A/C's & waning solar power being near the end of the day plus many days of sparse sun.

The problem with middle season peak tho is, without a pretty beefy battery bank, during the last couple hours the sun is waning & won't be charging strong, then late afternoon summer showers or just plain cloudy are common, so those without beefy battery banks will have to use some utility power during peak but with some of the power saving gadgets I've incorporated in my system with a less than beefy battery bank, I've been able to keep it under a kilowatt. Next year I should have a big enough bank to kill that problem.

Water heaters are the biggest guzzlers of power & while I could run it on my inverter, it would tax it heavily which I elected not to do until I get a beefier inverter so it's solely on utility power & that's 1 appliance you sure don't want to be firing up during peak.

I only flip on the breaker when I need it but for others I'd put a timer on it so it won't come on during peak. Just as an example, a typical heater draws 3500 watts, if it fires up during peak, you could face about a $40 peak charge just for that 1 tank of hot water, that should hurt your wallet enough to give it priority in your energy saving strategy.

[Bossrox]

Another snafu to deal with on automated systems

If you're supplementing your power with solar using an automated system like I'm doing, something I've run into & you likely will as well, is most inverters don't fire up lickidy split, they either soft start or take a few seconds to to engage fully.

So the problem I found is, it causes the transfer relays to chatter violently which could cause heavy arcing across the contacts especially if it's switching on heavier loads which could feedback utility power to the inverter that might damage it,

So my cure for that is to add a timer delay to the main transfer switch so the inverter can come up to full power before switching over to solar which then eliminates the relay chatter.

[Bossrox]

2nd inverter added with some slick gadgetry

On good sunny days with the current equipment I have, my batteries are nearly charged up around 1 or 2pm leaving an excess of power from the panels at peak sun hours not getting utilized. So far, I've been running my shed A/C on utility power only & tho my original inverter is rated to handle that much extra load along with everything else, it would have pushed into it's upper power output range which I'd like to avoid in fear it would shorten it's lifespan being a chinese unit, so I limit the output to no more than half it's rating, but with a new 4kw inverter I can now take on more of a load with some peace of mind.

Well on days when sun exposure is good, I got maybe 4 or 5 hours where I have excess panel power not getting utilized & could likely squeeze another 3 or 4 kw out of the system per day. So I employed a somewhat complicated scheme to automate when the shed A/C gets access to solar & sensor switches determine if there's enough sun to run it without draining the batteries heavily.

So here's what I did...... 1st I took a digital thermostat switch & swapped the thermistor sensor with photo sensor, then that switch feeds a delay timer that feeds a DPDT relay to switch the A/C between solar & utility power. But I also only need the inverter on in a 4 hr window each day so another programmable timer turns it on & off, then the photo sensor switch does the rest on deciding when to switch it between solar & utility power, then shuts down the inverter & switches back to utility power after the sun weakens on it's way to setting.

The delay timers purpose is to keep the relay from switching as much, saving wear & tear on the contacts. As a pretty normal occurrence, there are sometimes patches of clouds the sun will dive in & out of & the relay would be chattering away so I put a 45 second delay inline to allow such instances to go unnoticed till a more steady stream of sun happens.

Update: It's now been tested on a full sun day & the shed A/C ran non stop for 4 hours without much depletion of battery reserve, shaving 4kw off my utility power use so if I get a pretty sunny month I could cut my utility power use down around 100kw, pretty good idea, 'ey.

I plan on doing a video on this sometime soon & will add it to this post when it's done. It should be fascinating.

[Bossrox]

System is now fully automated

With what I got now, I'm generating less than half of what I'm consuming during the summer months so to best ration the power for the best balance of usable power generated while limiting excessive battery drainage & since I can't be around all day to babysit it & manually ration out power, I had to come up with a scheme to automate everything that was flexible under varying solar conditions & here's what I came up with.

Still waiting a few components to arrive to totally automate the system but here's what it will do when completed.

I had been switching power manual with a transfer switch until I found a cheap high amp DPDT relay to transfer power from solar to utility which was required to design an automated system. With that, I could now move on to do the following.

A timer turns on the main inverter in the morning & switches off utility power over to solar then shuts down at 7pm & switches back to utility power.

My 2nd inverter, dedicated to only the shed A/C is also on a timer but starts at 1130am when the panels are nearing full power, at the same time a photo sensor is monitoring the solar intensity & if it falls below a set threshold, it switches the A/C back to utility power until the sun comes back in full force.

Many times there may be an abundance of scattered clouds the sun dodges in & out of frequently & would cause the photo switch to go into convulsions, so to limit excessive cycling, both a delay on & delay off switch was incorporated to ignore switching to utility power if only short spurts between full sun & fast passing clouds is going on & if it looks like it's going to be a strong solar day, I can hit a switch to override auto mode to full solar power.

Paranoid that either the shed A/C could die or the inverter running it do the same, a fail safe circuit was employed to monitor the shed temp. If it goes above 90 degrees it shuts down both inverters & switches over to utility power. The shed could easily get 120 degrees or more without the A/C running & roasting my inverters would surely do 'em in.

Then if my main inverter fails which the fridge, freezer & everything else is on, another relay switches everything over to utility power.

On days when it will be fairly cloudy & the panels can't deliver enough to run everything & keep the batteries near topped off, I'll have a current sensing relay I can engage to monitor the main inverter & if it sees the current from my cabin A/C running, it'll take the shed A/C off solar & switch it to utility power then back when the cabin A/C quits to save the batteries from excessive drainage.

Extended periods of low sun can be pretty tough on the battery drainage when 2 A/C's are running along with all the other stuff that will pull over 100 amps off the batteries & the best output I can get from the panels right now is a 100 amps max.

For the winter, 4 heating pads totaling 70 watts will be under my battery bank & the bank wrapped in insulation with a temp sensing thermal switch to keep them at around 70 degrees so they don't lose the efficiency of charging & discharging that occurs in real cold temps.

I have a kilowatt meter coming off each inverter so I can see what usable power I made each day compared to what my panels did & I'm finding, for every 10kw of usable power the inverters put out, the panels put out about 3kw more which looks to be about a 30% loss to inverter & battery charging inefficiency.

Except for making some minor adjustments for the type of solar day that's expected, It'll pretty much run itself without very much intervention & with peace of mind every possible fail safe was addressed to protect the system & keep power up no matter what happens.

There's a bit more to the gadgetry involved in this set up but it would get long & drawn out to explain it all so sometime in the near future after everything is completed & been tested, I plan on doing a video of it all in better detail. It's quite a complex union of electronics & was a wiring brain twister to figure out as you'll soon see, the control center looks like a plate of spaghetti was thrown on the wall & here's a glimpse to see what I mean.

[Bossrox]

Arc suppression circuit formula for power switching relays

If you want to transfer your house load between the inverter & power company with a DIY relay system, switching during heavy current loads will cause arcing contacts that'll shorten the relays lifespan & could possibly send damaging feedback to the inverter you certainly need to avoid so if you're building your own transfer system, this info is pretty important.

I don't understand the formula below to get the component values & got someone looking into it for me shortly but if someone has an answer for what the component values would be for a 120 & or 220 volt relay, share it if you will.

This info came from Illinois Capacitor.

ARC SUPPRESSION (relays)

Arc suppression is when a capacitor and resistor are connected across the contacts of a relay to absorb (suppress) the electrical arc that occurs when the contacts open. The resistor is utilized to current limit the added energy that could be stored in the capacitor when the contacts were opened.



The following are used to determine the capacitance and resistance values needed to suppress the arc.

C=I^2/10
R=V/ [10+ (1+ (50/V)]

The main characteristics are:

• capacitance
• dv/dt
• Voltage rating

Update: after finding several sites with similar component values, it looks like a disc capacitor of .1uf rated to at least the voltage of the circuit, I doubled it, & a 100 ohm 5 watt resistor for 110v or double that for 220v. Follow the orientation of the components shown in the diagram, I believe it's important. I'll do a high load bench test of this before adding it to my system & get back to y'all how that turns out.

Test was a failure, I didn't notice any significant arc suppression. I wonder if it makes a difference if the capacitor is electrolytic or not? Anyways, I ordered some new stuff to experiment more with but I may ultimately end up having to spend about $30 a pop for the NoSpark brand arc suppressors, that times 8 contact points with 2 DPDT relays that'll bongo jack up the cost of this project, about $240 to protect 2 $30 relays..... ouch!

[Bossrox]

DIY schemes for combining solar with line power

If you've decided to add solar supplementation, how are you going to tie it in to your house. This thread is for your ideas of how best to get it done for the do it yourselfer.


My 1st hairbrain idea was to hook a double pole double throw relay between the inverter & house power so that when the inverter was running, it would auto switch to the inverter.

Here's the problem with that tho, on paper it works flawlessly but thinking it out some more I could see it would be possible for 1 set of contacts sticking while the other switches. If that were to happen, there would be feedback from the house power going into the inverter & that most likely would fry the inverter so without being able to locate a relay that could prevent that from happening, I'm shying away from this idea now.

Another thing to look out for is when your tapping into the house panel box using a 120 volt inverter with a contactor is NEVER EVER make the mistake of feeding into both hot legs. Be sure all the house circuits you'll tie into are on the same power leg, switch your breakers around if needed to make it happen or if you make the mistake I first did not thinking of it, found out the hard way & fried a relay. Be absolutely certain to double check you got it right, take a volt meter reading off each breakers hot to hot output that you'll tie into which should read 0 & repeat that test on each breaker against the others. If you get 220 on any, fix it so it's right.

Also, contact arcing will be an issue too, it's not critical but if you want to get the most lifespan from your relay it's best to put arc suppression on each relays contacts. Unfortunately I haven't found a cheap source for accomplishing this so far. I found & ordered some cheap so called suppressors off ebay with crap results & the only other place I found for a reliable suppressor wants $30 apiece. Well on my 4 DPDT contactor, that will require 8 of them. At that price tag It would be cheaper just to replace the relay as needed every so often. If any knows of an effective cheap solution, I'd like more info on it.

Another idea is if you have enough power to supply a certain circuit in your house, disconnect that circuit from the breaker & tie it into the inverter or get a manual transfer switch if you want to alternate. I got a nice 60 amp switch off ebay for about 50 bux I use to switch my entire house load to either inverter or utility power, nice gadget.

So those curious on my experimental relay transfer switch here's a video of my 1st relay transfer box, I have the parts to do a stronger transfer relay but because of the reason imparted earlier, I'm shying away from this method now?

[Bossrox]

A cheap beefy relay to transfer loads from solar to utility & essential to have if automating your system

This 80 amp DPDT relay is the ticket to building a sophisticated automated system or as a simple transfer switch & the best part is the price tag of $30 & can be found on amazon. Beats the hell out of a manual transfer switch!

[Bossrox]

Trimetric battery monitor, a most useful measuring tool for just about everything you'd want to know going on with your batteries

.

Got my Trimetric battery monitor hooked up today. Tells you all you need to know going on with the batts. Amps or watts + or - going in or out, voltage & much more but mostly what I got it for is I can see how many a/hrs have been used & it can pretty accurately calculate the % state of charge using a built in algorithm that takes into account the battery turnaround efficiency.

Another cool measurement it does, it displays the difference between the last discharge amount vs the amount returned back to fully charged in %, that shows exactly how efficient the turn around is & can do all that on a battery bank up to 10,000 a/hrs. Not many metering tools can display as much info as this & not cheap either, about $200

[Bossrox]

Here's the latest covering my solar panel switching sensors.

[Bossrox]

In this video, I demonstrate a high temperature fail safe circuit to protect my inverters from overheating in case of an A/C failure.

[Bossrox]

In this video I cover how to heat, cool & flush hydrogen gases from an outside battery cabinet.