Solar charge confusion

[kj4oll]

Based on what I have learned from the fine folks on this DIY solar forum:
https://diysolarforum.com/
Seems like lead-acid technology is not ideal for daily deep cycling.
(battery will need replacing often)
There is a battery technology that is designed for constant cycling, very deep discharge.
Lithium batteries.
The only issue w/ Lithium batteries is that they are damaged if allowed to freeze.
I lived in your area (El Cajon) back in the 1950's, don't recall ever having to break out the snow shovel.....
The DIY forum has vast amounts of information on this technology.

[RMinMN]

The camera specs state 1A but doubt it actually takes that .. but that is the spec.

That is the spec for the charger, not the camera itself. You'll have to diagnose what it really requires. The other part to be concerned about is will the WIFI reach to where you want the camera and do so reliably. If you have a phone power bank you can check this out. The powerbank may be able to power the camera for quite some time. There are powerbanks with solar chargers built in that may do the job for you without all the calculations. Here's an example: https://www.amazon.com/20000mAh-Port...53457174&psc=1

[J Tiers]

With the drain being so much lower (0.3A not 1.0A), take my estimates and cut to 1/3. The battery can be 1/3 the capacity, the panel and charger 1/3 the capacity.

The 1.8A panel is then credible to cover it.

If the camera is motion sensing, that cuts the actual drain on average to much less even that the 1/3.

Based on what I have learned from the fine folks on this DIY solar forum:
https://diysolarforum.com/
Seems like lead-acid technology is not ideal for daily deep cycling.
(battery will need replacing often)
There is a battery technology that is designed for constant cycling, very deep discharge.
Lithium batteries.
The only issue w/ Lithium batteries is that they are damaged if allowed to freeze.
I lived in your area (El Cajon) back in the 1950's, don't recall ever having to break out the snow shovel.....
The DIY forum has vast amounts of information on this technology.

Now, for a camera, with a very low drain, the cost of the battery is low regardless. So the OP can use whatever at approximately the same cost. For larger systems, the cost of sufficient lithium cells becomes hugely expensive, almost prohibitively so. Several L-A replacements can be made for less cost.

I, and others I know, use lead-acid batteries in solar setups, and have done for 25 years. My usage is lighter, but the others use them for off-grid houses that they live in all the time, and their only power source is solar (or backup genset).

NONE of us have experienced the problem you mention: "(battery will need replacing often)". We find the life to be 7 to 10 years, unless there have been unusual occurrences, like someone going away after heavy usage and leaving a light on (battery was below the charge controller cut-off point for 3 weeks). That did kill one set of batteries the second time it happened.

Now, your statement has many unquantified variables: What is "daily deep cycling"? What batteries are used for this cycling? How "deep" do you cycle them? What do you consider "often"; once a year, once every 3 years, once every 10 years?

It is reasonably well accepted that lead batteries which are typically cycled no more than about 25% of capacity will be long-lived. That means regular discharges to where they have 75% to 80% of their charge remaining.

The thing of it is, that when you use a battery as your sole power, for a house or for a camera, you need, as several of us have mentioned, to provide capacity for more than one day of use. Most will allow for 2 to 4 days use with minimal to no charging (due to weather conditions of overcast. rain, etc).

When you allow for that, then you automatically dramatically drop the discharge "depth". Obviously, if you can use the battery 4 days, then you cannot use more than 25% of capacity per day. And you do not generally design for an absolutely dead battery at the end of the time.

[Lee Cordochorea]

One important thing that gets overlooked by many folk: If 10% of the PV array is shaded, you loose about 90% of PV output. The gizmo is a "solar system", not a "shade system." Keep ALL of it in the sun for as long as possible.

Another bit of advise which may or may not help: PV works better in the cold and not so well in the extreme heat.

[BCRider]

Mike, that panel 50000 watt panel you posted might or might not be useable. It's only about 11x18 inches. So it's impossible to output they are using in their psychobabble advertising splash... Unless that's total lifespan power delivered over many years..... So that's some really shady specification right there. It may or may not be enough to charge up your battery to make up for the power the camera uses due to the size and the fact that you won't be out there to aim it at the sun all day.

The guys mentioning lithium batteries are right. But the simple fact is that those require a whole other charge management setup. The commonly and easily bought panels that come with charge managers are aimed at lead acid RV batteries. So you might as well go with the flow on that front. Plus you'd want to be sitting down when you hear the price for the lithium RV coach batteries.....

[Mike Amick]

Yea, that is a pretty ridiculous claim on that small solar panel, huh. I think what I will do is hook up the cam to a battery and see how long it lasts. I have a couple sealed lead acid (sla) laying around and also have some 18650 lithium that I can make a power bank out of. For output to the camera I usually tear apart a car phone charger to do the 12 to 5v thing which includes the usb connector. Then I'll find a cheap panel and see if it can keep the battery full while powering the cam. Pretty sure it will turn out to be close to the calculations in these posts.

As far as motion detection goes, it doesn't matter, I have the camera set to record to a micro sd 24/7. I am just wondering how the cameras that come with a solar panel do it. They must not be set up to do constant recording, and their batteries are contained in the camera meaning they are not that big nor are the solar panels.

I am really glad I asked the question though, I had some misconceptions that you guys straightened out real quick, along with some points that i never thought of..

[PStechPaul]

Make sure you read the current when it is dark to see if the IR LEDs draw more current in those conditions. And when testing to see how long the camera will run on various batteries, it would be a good idea to rig up a low voltage cut-off and a timer. Here is a 555 circuit that can be adapted to drive a cutoff relay or timer. In fact, you could use an opto-relay in place of the opto-isolator shown, to disconnect the battery when the voltage drops too low. The components shown operate at a battery voltage of 10 volts.

[Lee Cordochorea]

Unless that's total lifespan power delivered over many years..... So that's some really shady specification right there.

Power is a rate, not something we can pile up. I'd go with "shady."

The better quality arrays top out at 150 watts per square meter.

[Mike Amick]

Make sure you read the current when it is dark to see if the IR LEDs draw more current in those conditions. And when testing to see how long the camera will run on various batteries, it would be a good idea to rig up a low voltage cut-off and a timer. Here is a 555 circuit that can be adapted to drive a cutoff relay or timer. In fact, you could use an opto-relay in place of the opto-isolator shown, to disconnect the battery when the voltage drops too low. The components shown operate at a battery voltage of 10 volts.

ahhh ... that's right Paul, those IR led's, good thought. And not sure but I think I can take a SLA down to nothing without destroying it. It would be like leaving the head lights on my car for a week type thing. I have done that and just charged it back up, I may have unknowingly hurt it but it seemed ok after charging.

[PStechPaul]

It may not be destroyed but it will certainly shorten its useful life. SLAs use the same chemistry as wet cells, and are subject to the same limitations. The battery in my rarely used truck has run down several times due to a 40 mA drain, and has usually charged up OK, but after about 3-5 years it needs replacing. If kept properly charged it would probably last 7-10 years.

[rdfeil]

PStechPaul is absolutely right about allowing a SLA battery to discharge completely. It WILL damage the battery. How much life will be reduced has been argued for years, but the more it happens the worse the damage. As you are looking at solar charge controllers, look for one with low battery protection. The good ones will shut down the load output if the battery discharges below a safe level. Another possible way to do this is with a Lithium battery system. Properly designed Li batteries have internal circuitry to shut down the battery pack before excessive discharge occurs. Li batteries will be DESTROYED if they discharge to low even one time. Because of this good Li battery packs protect themselves. Li batteries are also temperature sensitive, so if this is an option, check the temp specs closely and think about your weather and remember a closed box in the sun is much hotter that outside temp.

[J Tiers]

lead acid cells do not like being discharged to below about 10.5V for a 12V nominal system. The discharge itself does not kill them, but rather the time spent in a discharged condition does. Any time spent at a low state of charge tends to allow formation of the "bad kind" of sulfate (known as "sulfation").

The battery cannot operate without lead sulfate being formed, but the structure of the material is such as to allow the battery to be charged, that is, the lead sulfate being dissociated into lead and sulfuric acid (and a form of lead oxide at the other plate). But, allowed to sit discharged, the sulfate changes in such a way as to be difficult or impossible to dissociate, so not possible to recharge completely. At low states of charge, the change occurs faster, so deep discharge on a regular basis tends to "wear out" the battery more than lesser discharges.

The "deep discharge" types can take more such cycles than starting batteries. If you drain a starting battery to a low voltage 4 times, it is generally toast. For some it may be 6 or 8 times, but for sure not many. Deep discharge types will take many more deep cycles, but that depends on a fast recharge to minimize the time that the sulfate is allowed to sit in the discharged electrolyte. Many solar systems are set up with less charge capacity than ideal, especially backup systems. Those are susceptible to "sulfation", and the loss of sulfate from falling off the plates.

As for low cost chargers, the ones from WindyNation can handle LI cells, and most have low voltage protection on at least one of the outputs.

[Mike Amick]

Ok, Uncle Uncle ... I knew I shouldn't have said that. But thanks for letting me know it hurts the battery way more than I thought.

Also, I have a couple older batteries from some computer UPS's so i wasn't too worried. i wouldn't do it to a new battery.

lead acid cells do not like being discharged to below about 10.5V for a 12V nominal system. The discharge itself does not kill them, but rather the time spent in a discharged condition does. Any time spent at a low state of charge tends to allow formation of the "bad kind" of sulfate (known as "sulfation").
.

thanks for this, I always wondered what actual harm was being done draining a battery flat, this I understand.