Any gurus on solar panels for charging batteries?

**ExFlyinguy** · January 4th, 2022, 01:48 PM

Solar sucks compared to generators except that genny's need gas and gas storage is a royal pain in the ass (IMHO)

For what GL is looking for- I humbly opine that ~100 watt solar panel will accomplish his needs.

I purchased a folding portable 100 watt do-it-all (controller built in) unit that I throw on my RV when boondocking. It supplements the RV batteries well enough that I haven't felt the need for more.

I am math stupid. It doesn't help when they advertise some crap in Watts, and other stuff in amps...FFS

**GunLawyer001** · January 4th, 2022, 01:51 PM

OK, any thoughts on this panel (200 W) being able to work with this 1000 WH battery?

https://www.amazon.com/ROCKPALS-Port...n%2C76&sr=1-18

https://www.lowes.com/pd/Jackery-Jac...Use/5001885531

I'd expect to charge the battery up with house current, let it sit around until the power fails, then try to top it off with the solar panels as we use the power.

We also have generators to run the fridge & freezer, but the gasoline is finite. Solar should be sustainable.

I could be wrong about this.

**streaker69** · January 4th, 2022, 02:05 PM

Something that I didn't explain earlier, a 1000WH battery in perfect conditions is able to supply 1000W for 1 Hour. If you draw 500W from it, you'll get 2 Hours of run time. So on and so forth. If you plug in 1500W (like a hair dryer, cause we know GL likes to look good), you'll get 45 minutes out of it.

Don't be surprised when these devices don't even come close to their advertised ratings. That 1000W device looks small. That panel looks decent enough. You won't get 200w out of it, you might get 150 to 180. Those ratings are always under perfect conditions.

**streaker69** · January 4th, 2022, 02:07 PM

Originally Posted by ExFlyinguy

Solar sucks compared to generators except that genny's need gas and gas storage is a royal pain in the ass (IMHO)

For what GL is looking for- I humbly opine that ~100 watt solar panel will accomplish his needs.

I purchased a folding portable 100 watt do-it-all (controller built in) unit that I throw on my RV when boondocking. It supplements the RV batteries well enough that I haven't felt the need for more.

I am math stupid. It doesn't help when they advertise some crap in Watts, and other stuff in amps...FFS

Watts = Volts X Amps

Amps = Watts / Volts

It's all part of Ohm's Law, learn it, love it, live it.

**GunLawyer001** · January 4th, 2022, 02:10 PM

Originally Posted by streaker69

Something that I didn't explain earlier, a 1000WH battery in perfect conditions is able to supply 1000W for 1 Hour. If you draw 500W from it, you'll get 2 Hours of run time. So on and so forth. If you plug in 1500W (like a hair dryer, cause we know GL likes to look good), you'll get 45 minutes out of it.

Don't be surprised when these devices don't even come close to their advertised ratings. That 1000W device looks small. That panel looks decent enough. You won't get 200w out of it, you might get 150 to 180. Those ratings are always under perfect conditions.

Am I likely to be able to get a fridge down to cold with this 500W unit? That's how we rolled the last power outage that lasted several days, I used a gas generator to run the fridge for 30-60 minutes, then shut down. Kept the door closed. Did that a couple times a day, also had to run the sump pump, which is a power hog with the constant startups.

Any thoughts on this one? I know it's enough to charge up every AA and D-cell I could want, and plug in a radio, maybe a TV (not that anyone broadcasts much if the cable is out).

https://www.jackery.com/products/exp...tm_content=All

**streaker69** · January 4th, 2022, 02:20 PM

You'd need to find the specs for your fridge, what's the operating current and what's the inrush current when the compressor starts. If the inrush is too high, chances are you're blow out the unit. For charging batteries, or running a TV or other smaller electronics, it shoud work just fine, just avoid anything that needs to run a motor.

A generator is more capable of riding out inrush due to motor starts, you can normally hear a generator load up when it's trying to start a motor, but then it runs normally once it's started.

You are correct in how to keep your fridge cold by cycling it, I just don't think that device is going to have enough output to do it.

**streaker69** · January 4th, 2022, 02:32 PM

If I were building something for myself, I'd probably go with 2 to 4 deep cycle marine batteries hooked up in parallel with a 1500W inverter, and here's why.

If a battery goes bad, I can replace it, for about $120 with another one from a common source. I won't need to go out and try to find a specially built battery for a device such as that Jackery. Who knows where they're going to be 6 months from now. That's the problem with many of these chinese products.

You can use any solar panel with a charge controller to maintain those batteries. A 1500W inverter would be enough to run a fridge for a while, considering that the output of a normal 120VAC15A outlet is around 1800W. But normally you're only supposed to draw around 80% of the max or 1440W. If I recall correctly.

Putting batteries in parallel means that the voltage (12V) remains the same, but the current is additive.

Four 12V1000Wh batteries in parallel gives you 12V@4000Wh.

Putting batteries in series means the voltage is additive, but the current remains the same.

Four 12V1000Wh batteries in series gives you 48V@1000Wh which isn't really useful in the home environment.

All of that could be easily built and configured for much less than $1000.

**GunLawyer001** · January 4th, 2022, 02:50 PM

Originally Posted by streaker69

If I were building something for myself, I'd probably go with 2 to 4 deep cycle marine batteries hooked up in parallel with a 1500W inverter, and here's why.

If a battery goes bad, I can replace it, for about $120 with another one from a common source. I won't need to go out and try to find a specially built battery for a device such as that Jackery. Who knows where they're going to be 6 months from now. That's the problem with many of these chinese products.

You can use any solar panel with a charge controller to maintain those batteries. A 1500W inverter would be enough to run a fridge for a while, considering that the output of a normal 120VAC15A outlet is around 1800W. But normally you're only supposed to draw around 80% of the max or 1440W. If I recall correctly.

Putting batteries in parallel means that the voltage (12V) remains the same, but the current is additive.

Four 12V1000Wh batteries in parallel gives you 12V@4000Wh.

Putting batteries in series means the voltage is additive, but the current remains the same.

Four 12V1000Wh batteries in series gives you 48V@1000Wh which isn't really useful in the home environment.

All of that could be easily built and configured for much less than $1000.

Is there a substantive difference between "marine" and "marine and RV" deep cycle batteries? I'm seeing both on the websites.

**streaker69** · January 4th, 2022, 02:59 PM

Originally Posted by GunLawyer001

Is there a substantive difference between "marine" and "marine and RV" deep cycle batteries? I'm seeing both on the websites.

Off the top of my head, I believe the Marine/RV batteries are little different as they are able to supply higher CCA (Cold Cranking Amps) for starting an engine vs a marine battery that's not meant to start an engine. Someone correct me if I'm wrong.

**85MikeTPI** · January 4th, 2022, 03:22 PM

Originally Posted by streaker69

Off the top of my head, I believe the Marine/RV batteries are little different as they are able to supply higher CCA (Cold Cranking Amps) for starting an engine vs a marine battery that's not meant to start an engine. Someone correct me if I'm wrong.

I thought it was strictly about long-term usage patterns not destroying the battery. These batts still for long periods and can hold their charges longer. The RV rating usually just equates to the batteries being larger capacity.