Suggestions Please!

johnmckay1969

I am new to solar and over the past two weeks, I have read so much that my eyes hurt. Some of the information I understand and some, not too sure. I'm looking for some suggestions, based on the following info.

I had a cheap harbor freight 45W solar kit that worked fine for about 6 months. Now the panels are barely charging. I got this kit based on a friends recommendation. His still works after 3yrs, mine does not. I should have used that money for some quality components, which is what I want to do now.

I have two deep cycle Exide batteries, with 105Ah rating and 182 reserve capacity. I use them to run a 65w mobile radio, charge hand held radios, flashlights, cell phones, and cordless tool battery chargers. The mobile radio uses little to no power, unless transmitting. The cordless tool chargers are 7amp. All the other chargers are half this amperage or less. The mobile radio and a 12V, 1500W inverter, are connected directly to the batteries. The rechargeable items all run off the inverter. The batteries will be about 8' from the controller and the panels about 12'. From what I have read, I need the panel wattage to be equal to the Ah of the batteries. I did extensive reading on batteries. From what I gather, the RC is the most important rating to consider? The above items are my priority but I have been considering the possibility of running a freezer, just in case of an extended power outage.

I'm now looking at something in the 200-250W range, like this.
http://www.solar-electric.com/kyocera-kd245gx-lfb-245-watt-polycrystalline-solar-panel.html

And a MPPT controller like this.
http://www.solar-electric.com/mosumpsochco.html

And MC4 cables
http://www.solar-electric.com/30fomc4so2ex.html

Any suggestions that may be better than these items?
Thanks!

niel

Re: Suggestions Please!

it may not work because the 45w in pv you had was insufficient to recharge those 2 batteries and you are running a deficit as well as the items being powered draw huge amounts of power from those batteries. odds are the batteries are either dead or diminished in their capacity now. you need a more detailed summary of the loads and their times.

johnmckay1969

Re: Suggestions Please!

niel wrote: »

it may not work because the 45w in pv you had was insufficient to recharge those 2 batteries and you are running a deficit as well as the items being powered draw huge amounts of power from those batteries. odds are the batteries are either dead or diminished in their capacity now. you need a more detailed summary of the loads and their times.

Ok, I will try to gather this information, when I get home tonight.

Slappy

Re: Suggestions Please!

U can also check the panels with a amp meter. Just unhook panel wire then check with you amp/volt meter. But as mentioned already probly batteries being under charged. I have 2 of those sets and they don't put out much power. I just use those as "toys".

johnmckay1969

Re: Suggestions Please!

Slappy wrote: »

U can also check the panels with a amp meter. Just unhook panel wire then check with you amp/volt meter. But as mentioned already probly batteries being under charged. I have 2 of those sets and they don't put out much power. I just use those as "toys".

The batteries were shot. Thankfully, I was able to swap them out. I will check the panels with a meter, when I get a chance. Right now my priority is to replace them with quality units.

Here is the load specs. The mobile radio, flashlight charger, radio chargers, and phone chargers, are the only loads that will be daily. The amount of time will vary, depending on use of the items being charged. The larger loads (tool chargers) would never be daily and unless I was working on a big project, would never be more than once a week.


Mobile Radio: 65W max (only while transmitting few seconds at a time throughout the day) I have no idea how much power it uses when not transmitting but it is likely to be on for 5-12 hours a day.

Drill/Driver Charger: 840W 30-90 minutes maybe? Depends on the amount of time the tools are used. It is highly unlikely this would ever be daily.

Drill/Driver Charger: 420W 30-60 minutes maybe? Depends on the amount of time the tools are used. It is highly unlikely this would ever be daily.

Flashlight Charger: 21.6W 30-120 minutes daily at most.

Radio Chargers X2: 16W for both 30-60 minutes daily at most.

Phone Chargers X2: 5W for both 30-60 minutes daily at most.

niel

Re: Suggestions Please!

before we go any further i have to ask if you have grid power where these items are at? i am assuming you don't otherwise why would you put these items up to a battery, but i have to be sure of this.

johnmckay1969

Re: Suggestions Please!

niel wrote: »

before we go any further i have to ask if you have grid power where these items are at? i am assuming you don't otherwise why would you put these items up to a battery, but i have to be sure of this.

You are correct. No grid power.

niel

Re: Suggestions Please!

i'm not ignoring you, but i've got some stuff to do now so i'll go over your loads with you later and after that discuss a solution to your charging dilemma.

BB.

Re: Suggestions Please!

Will you be powering everything from 12 VDC (really 10.5 to ~15.5 VDC for a deep cycle battery bank--Which has its own issues), or will you be OK with a good quality (for example) 300 Watt 12 VDC TSW AC inverter?

If you will be doing DC, then look at a DC Amp*Hour / Watt*Hour meter.

If you will be using 120 VAC, then look at using a Kill-a-Watt type power meter.

Long term, I would suggest a good Battery Monitor as a good way to keep track of your Battery State of Charge (may be hard to justify for a small off grid power system).

For flooded cell batteries, the Hydrometer (with a thermometer for temperture correction) to measure/log the temperature corrected specific gravity for each cell.

-Bill

niel

Re: Suggestions Please!

ok in going over what you've said here there are some concerns. the first concern is the power for the radio. you state it is 65w, but is that the dc power rating or the rf power rating? this is important as there can be a significant difference between the 2.

my next concern is the 1st drill as i'm wondering why it is nearly double the consumption of that of the 2nd drill and both of these are quite high of draws. i understand these 2 will not be used every day, but i suspect when they are used that they would both be on the same day and this kind of stress on the entire system in that day cannot be ignored or averaged.

bb. is right that a meter to monitor consumption can narrow down these loads more accurately and even after you've bought all you need for the system it would help in keeping it well.

johnmckay1969

Re: Suggestions Please!

niel wrote: »

ok in going over what you've said here there are some concerns. the first concern is the power for the radio. you state it is 65w, but is that the dc power rating or the rf power rating? this is important as there can be a significant difference between the 2.

my next concern is the 1st drill as i'm wondering why it is nearly double the consumption of that of the 2nd drill and both of these are quite high of draws. i understand these 2 will not be used every day, but i suspect when they are used that they would both be on the same day and this kind of stress on the entire system in that day cannot be ignored or averaged.

bb. is right that a meter to monitor consumption can narrow down these loads more accurately and even after you've bought all you need for the system it would help in keeping it well.

Sorry it took so long to respond. I had computer problems over the weekend.

65W is the rf output power rating. It is a 12v mobile radio, which is why it was connected directly to the batteries. All other loads were run from the inverter.

The larger drill/driver charger is 7A (x) 120V (=) 840W
The smaller drill charger is 3.4A (X) 120V (=) 408W Are these calculations correct?

I previously had a 350W inverter, that would not run the drill/driver chargers. After I noticed the amperage of the chargers, I made the calculations above and determined I needed to use a larger inverter. I already had the 1500W inverter, so that is what I used. Before connecting to my solar system, I connected the 1500W inverter to a car battery, that sits idle, more than it is used. It always charged the tool batteries and start the car, with no problem. I know the alternator will charge the battery quicker than solar but the car is seldom driven. That is why I thought it would not be too much of a load, for the solar system.

niel

Re: Suggestions Please!

glad you made it back to clear that up some. i have to point out that power isn't as easy to come by or as cheap as one might think. how much do you think the gasoline costs to run the car's alternator and let's not forget the car and its maintenance and costs of ownership are not free either. now a generator is a smaller version of a gas engine unlike that used in a car specifically designed to generate electricity and not movement, but again, it is still an expense to buy and run it. solar can do it too, but it won't be as cheap as you are thinking.

now as far as those loads go i am figuring for worst case conditions and not the average because if you go by the average then it will fail on the high power draw points. i also see that in operating a 2 way radio that to generate a clean 65w rf modulated signal that it will be much higher than the 65w of power to be inputted. in going by some radios i've had and some out there the input amps on a 50w radio can be 12a-13a. i'm not sure of your radio's full power requirement, but i'm going to guesstimate that at 15a. i will also guesstimate the tx/rx times at max and typically 2hrs tx and 10hrs rx. that tx would be 10minutes for every hour on and even if it is higher than the norm it is insignificant compared to the other items you wish powered.

load requirements-
radio total

---

50ah, 30ah tx and 20ah rx
drill/ch 1

---

105ah
drill/ch 2

---

35ah
flashlight

---

3.6ah
phone charger--0.42ah
total ah

---

194.02ah

at 12v this is 2,328.24wh in the day and your 45w kit will not even come close to working with this. if over a narrower 3hr insolation period say for winter this is 776.08w. what is needed in pv is much higher due to ratings being in stc and other losses. now i'm not including the losses for the inverter to operate and individual charger losses, but only going hypothetically all 12v power items that it would be about 77% efficiency meaning you need 776w/.77=1,008w stc in pvs or a charging current of about 84a for that 3hr period.

this is quite a large requirement and the batteries must be drawn down no more than half to help preserve battery life so it will need to be 2 x 194.02ah = 388.04ah battery capacity at a minimum. that explains your quick failure and i'm surprised it lasted as long as you said it did given the loads you cited. odds are it wasn't at the high end often and was able to reach some level of nearly charged at some points (maybe weekends?) overall it was draining the batteries too far with not enough full recharges that made your system fail. the other guy's system must not have as high of loads and/or load times as well as possibly having another charge source available at some time he may not have mentioned.

Vic

Re: Suggestions Please!

johnmckay1969 wrote: »

Sorry it took so long to respond. I had computer problems over the weekend.

The larger drill/driver charger is 7A (x) 120V (=) 840W
The smaller drill charger is 3.4A (X) 120V (=) 408W Are these calculations correct?

Hi John,

The charger current requirements simply MUST not be steady state numbers, if they are chargers for cordless hand tools. This may well be a PEAK current rating.

EDIT:
An Icom 65 W 2M FM XCRV requires 15A on TX @ 65W, 1.0 A at Max Audio and 0.8A Squelched on RX
A Yaesu 2800M 65W 2M FM XCVR requires 10A @ 65W, 0.7A at Max Audio, and 0.3A Squelched on RX.

Other similar 2 M XCVRs should be similar.
End EDIT...

A Kill-A-Watt might be a good idea to tabulate the total power required to recharge a completely depleted battery in each of these chargers.

Just my opinions, 73, GL, Vic

niel

Re: Suggestions Please!

vic,
thanks for those examples. we also don't know what service these radios are being pressed for, but are probably similar. again, i would go with the higher numbers until he can know for sure otherwise.

Vic

Re: Suggestions Please!

Hi niel,

YES, perhaps made too many assumptions, especially on the radios. Vic

johnmckay1969

Re: Suggestions Please!

niel wrote: »

glad you made it back to clear that up some. i have to point out that power isn't as easy to come by or as cheap as one might think. how much do you think the gasoline costs to run the car's alternator and let's not forget the car and its maintenance and costs of ownership are not free either. now a generator is a smaller version of a gas engine unlike that used in a car specifically designed to generate electricity and not movement, but again, it is still an expense to buy and run it. solar can do it too, but it won't be as cheap as you are thinking.

now as far as those loads go i am figuring for worst case conditions and not the average because if you go by the average then it will fail on the high power draw points. i also see that in operating a 2 way radio that to generate a clean 65w rf modulated signal that it will be much higher than the 65w of power to be inputted. in going by some radios i've had and some out there the input amps on a 50w radio can be 12a-13a. i'm not sure of your radio's full power requirement, but i'm going to guesstimate that at 15a. i will also guesstimate the tx/rx times at max and typically 2hrs tx and 10hrs rx. that tx would be 10minutes for every hour on and even if it is higher than the norm it is insignificant compared to the other items you wish powered.

load requirements-
radio total

---

50ah, 30ah tx and 20ah rx
drill/ch 1

---

105ah
drill/ch 2

---

35ah
flashlight

---

3.6ah
phone charger--0.42ah
total ah

---

194.02ah

at 12v this is 2,328.24wh in the day and your 45w kit will not even come close to working with this. if over a narrower 3hr insolation period say for winter this is 776.08w. what is needed in pv is much higher due to ratings being in stc and other losses. now i'm not including the losses for the inverter to operate and individual charger losses, but only going hypothetically all 12v power items that it would be about 77% efficiency meaning you need 776w/.77=1,008w stc in pvs or a charging current of about 84a for that 3hr period.

this is quite a large requirement and the batteries must be drawn down no more than half to help preserve battery life so it will need to be 2 x 194.02ah = 388.04ah battery capacity at a minimum. that explains your quick failure and i'm surprised it lasted as long as you said it did given the loads you cited. odds are it wasn't at the high end often and was able to reach some level of nearly charged at some points (maybe weekends?) overall it was draining the batteries too far with not enough full recharges that made your system fail. the other guy's system must not have as high of loads and/or load times as well as possibly having another charge source available at some time he may not have mentioned.

Ok, If I had four batteries instead of two, that would have got me a little above the 388.04ah. That part, I think I understand.

Now for the panels. Sorry if I seem ignorant about all this but I am. The more I read, the more complicated it seems to get. Does this mean I need 1008w of charging per day or 1008w of panels?

niel

Re: Suggestions Please!

sorry i wasn't clear enough, but it would be 1000w in pvs.

zoneblue

Re: Suggestions Please!

And so you see thats about 7m2 and 80kgs of panels.

So this is why its so very important to accurately assess your loads. For a couple hours work it saves you megabucks.

Go out buy one of each of the meters that bill refered to, run each of your loads off it for 24 hours, and it will tell you exactly how many Wh that appliance , whther its ac or dc used in that period. Then you wont be guesssing.

The alternative is to get a cheap dc clamp meter and work it out like Niel or vic did below.

ie: It draws, 240ma at idle for an average of 8 hours each day,but it also draws 2.1 amps for 20 mins in transmit, so thats:
(8 * 0.24A * 12.8V) + (0.3 * 2.1A * 12.8V) = 32Wh. Add them all up, add 20% for a comfort margin and bobs your uncle.

johnmckay1969

Re: Suggestions Please!

zoneblue wrote: »

And so you see thats about 7m2 and 80kgs of panels.

So this is why its so very important to accurately assess your loads. For a couple hours work it saves you megabucks.

Go out buy one of each of the meters that bill refered to, run each of your loads off it for 24 hours, and it will tell you exactly how many Wh that appliance , whther its ac or dc used in that period. Then you wont be guesssing.

The alternative is to get a cheap dc clamp meter and work it out like Niel or vic did below.

ie: It draws, 240ma at idle for an average of 8 hours each day,but it also draws 2.1 amps for 20 mins in transmit, so thats:
(8 * 0.24A * 12.8V) + (0.3 * 2.1A * 12.8V) = 32Wh. Add them all up, add 20% for a comfort margin and bobs your uncle.

OK, I'll see what I can do. I definitely don't have the money for 1000W of panels.

johnmckay1969

Re: Suggestions Please!

I know it has been a year since this post was started but I thought I would give an update. I had other projects to complete and most of the information was over my head, so I took a break from the solar project.

I finally decided to just try something and below is what I got.

Solartech 85 Watt Multicrystalline Solar Module
SunSaver 6 Amp 12 Volt Solar Charge Controller
MC4 Extender Cables

Since my two batteries were replaced under warranty, I used the same as my original system. I also retained the 1500W inverter. I also added a volt meter. The mobile radio and inverter are run directly from the batteries. Everything else is run from the inverter. I have been using this for around 6 months. So far so good. I will update if anything changes.

Thanks for all the information!