Solar Show and Tell

[rmkrum]

Lithium batteries live longer when not brought to 100% SOC all the time. For example, the Toyota Prius holds its traction battery pack between about 80% and 50% all the time IIRC. Makes for less stress and longer life.

[SilverHouseDreams]

Originally Posted by rmkrum

Lithium batteries live longer when not brought to 100% SOC all the time. For example, the Toyota Prius holds its traction battery pack between about 80% and 50% all the time IIRC. Makes for less stress and longer life.

You are comparing quite different uses, EVs (electric vehicle) and even PHEVs (plugin-hybrid electric vehicle) are far more abusive to the batteries than an RV type environment. The Prius is pushing energy at 23kW or 42kW rate during regenerative braking, some EVs push >100kW. In the case of the Prius, they allow regenerative braking to function even when the battery is "full" as it has this buffer in the SOC...however my i3 wouldn't, if the SOC was >90% regenerative braking was not predictable, and at >95% it entirely used the mechanical brakes.

We aren't charging our batteries at anywhere close to the charge rates that EVs see, nor PHEVs during regen braking. EVs also have significantly higher discharge rates, so they must do more to maintain the battery life cycle. This is also why things like PowerWalls exist, it is the 2nd life for perfectly functional battery packs that can no longer serve the abusive life cycle of a EV.

You are right in that you could probably see 2X the number of full cycles if you don't charge to 100% SOC all of the time...a Prius can easily see many cycles during a single drive, times multiple drives a day, every day of the year for 10 years. I doubt any of us are pushing 10-cycles per day.

[wulfraat]

Originally Posted by mythbuster88

Why do you do that?
Whats wrong with 100% SOC all the time?

Service life of Victron Lithiums slightly improve in the case of partial charge instead of a full charge.

Service life of Victron Lithiums also improve with lower current for charging vs. higher current.

[thiel]

Originally Posted by rmkrum

Lithium batteries live longer when not brought to 100% SOC all the time. For example, the Toyota Prius holds its traction battery pack between about 80% and 50% all the time IIRC. Makes for less stress and longer life.

But what if I'm just rocking flooded lead acids? Not even AGMs.

I know, it's sacrilege!

[rmkrum]

Meh. All I can afford are flooded lead acid batteries. Pair of 6 volt GC2 from Sam’s club...

[ROBERT CROSS]

Originally Posted by rmkrum

Meh. All I can afford are flooded lead acid batteries. Pair of 6 volt GC2 from Sam’s club...

Yep...KISS, here too.😏
Where we camp, it's 120w Zamp that moves around while connected to the 7way.
Keeps the 7yr old Lifelines happy. 🤗

Bob
🇺🇸

[rmkrum]

Originally Posted by SilverHouseDreams

You are comparing quite different uses, EVs (electric vehicle) and even PHEVs (plugin-hybrid electric vehicle) are far more abusive to the batteries than an RV type environment. The Prius is pushing energy at 23kW or 42kW rate during regenerative braking, some EVs push >100kW. In the case of the Prius, they allow regenerative braking to function even when the battery is "full" as it has this buffer in the SOC...however my i3 wouldn't, if the SOC was >90% regenerative braking was not predictable, and at >95% it entirely used the mechanical brakes.

We aren't charging our batteries at anywhere close to the charge rates that EVs see, nor PHEVs during regen braking. EVs also have significantly higher discharge rates, so they must do more to maintain the battery life cycle. This is also why things like PowerWalls exist, it is the 2nd life for perfectly functional battery packs that can no longer serve the abusive life cycle of a EV.

You are right in that you could probably see 2X the number of full cycles if you don't charge to 100% SOC all of the time...a Prius can easily see many cycles during a single drive, times multiple drives a day, every day of the year for 10 years. I doubt any of us are pushing 10-cycles per day.

A little off subject, but there is Prius experience locally that shows their battery pack and hybrid system is quite capable of severe service. One of the ones I am aware of is an older Prius with over 500,000 miles on the original system--the owner is obsessive about doing the factory-recommended service on time and to this date, has had no issues. My 2012 is used for daily commutes, and has over 168,000 on it.

This is why I suspect that RV use of appropriate Lithium-based technology will be quite effective. When it gets a bit cheaper, or I get to head out more often, I plan to seriously look into, and probably get a massively upgraded solar/Lithium system into my AS.

[rmkrum]

Originally Posted by thiel

Hey folks... silly question: should I be shutting off my solar panels when I'm plugged in for an extended period?

My question would be "why?" If you have a decent MPPT solar controller, and a decent multi-stage converter/charger, they may argue a little bit about who gets to put the most charge on the batteries, but when the batteries are fully charged (assuming lead-acid batteries) both charge systems should back off and be happy...I don't turn my solar system off when I'm connected. I actually use the MPPT controller's voltmeter to see what's going on with the batteries...I just make sure it is not set to "Dry Camp" as that setting boosts the battery float voltage a bit too much.

[AirMiles]

Good posts on this thread since my last WiFi availablity. Colorado is not very “connected” and that’s a good thing. Wuulf, nice report on your five day boondocking performance.

On the question “should I shut off solar”, I did the opposite. I’ve disconnected my shorepower charger and only use solar for battery charging. I think I’ve had my solar for about 60 days now with 30 days of actual usage and I haven’t needed anything but solar. I prefer to use solar for charging my batteries over the shore power charger.

[thiel]

Originally Posted by AirMiles

Good posts on this thread since my last WiFi availablity. Colorado is not very “connected” and that’s a good thing. Wuulf, nice report on your five day boondocking performance.



On the question “should I shut off solar”, I did the opposite. I’ve disconnected my shorepower charger and only use solar for battery charging. I think I’ve had my solar for about 60 days now with 30 days of actual usage and I haven’t needed anything but solar. I prefer to use solar for charging my batteries over the shore power charger.

I like to keep my fridge running while it’s parked in the driveway. I suppose it uses so little propane that I should actually just unplug ...better for the batteries anyway.

[uncle_bob]

Hi

Some math:

If you run a charge cycle a week, and are out for 6 months a year, that's only 24 cycles a year. Take it up to one a day and you are at 182 cycles a year.

If you are running at a charge / discharge rate that gives you 5,000 cycles to 80% capacity:

Once a week / 6 months will last for 208 years
Once a day / 6 months will last for 27 years
Once a day / every day will last for a bit over 13 years

If you are a pessimist (or really run a big charge or discharge rate) cut all those time periods in half. If you have a 600AH bank, getting up to or over 600A charge and 600A discharge is what puts you in that category.

Next up is that this is the 80% point. Is that time to toss the batteries? I'm not at all convinced it is. It would be nice to have a bit more data ( how many cycles to failure, how many to 50% ....).

Since this is an "average" sort of thing, what you do mostly is what likely is the key. I'd bet that most of us are running pretty big battery stacks. That puts us closer to the first case (200 years) than anything else.

If anybody believes that the data really shows a 200 year life ... I have a bridge I'd like to sell you . I suspect that any answer that comes out over 30 years is suspect. We just don't know what all the variables are ... yet. With a 5K cycle number, you have to get to once a day for 6 months to be pushing this. At 2.5K cycles 3 months of once a day gets you just below 30 years.

Personally, I'm quite happy with a 20 or 30 year life on the batteries. I very much doubt they will still be in service at that point. *Something* better will come along. They will get swapped out because of the features of the new gizmo. Welcome to the reality of any techno-gizmo. What could those features be .... without a Tardis, we'll have to wait and see

====

By comparison, run a lead acid on any of the higher cycle rates and it's not going to very happy at all. One full cycle a day is a "one year life" sort of scenario for lead acid. They would be very much into a "high charge / discharge rate" environment at that point. Even the six month / once a day scenario is likely to be a one year sort of thing for most lead acid's. You will spend way more money on the lead acid's than on the lithiums if that's what you are doing ....

Bob

[Paprika]

"On the question 'should I shut off solar,' I did the opposite. I’ve disconnected my shorepower charger and only use solar for battery charging."

Ditto. I almost never use shore power charging; with ample solar capacity I just don't have the need. When I'm plugged in, shore power supplies my 120 VAC appliances, and solar power takes care of everything that uses 12 VDC. I've been doing it this way for years.

[thiel]

Originally Posted by Paprika

"On the question 'should I shut off solar,' I did the opposite. I’ve disconnected my shorepower charger and only use solar for battery charging."

Ditto. I almost never use shore power charging; with ample solar capacity I just don't have the need. When I'm plugged in, shore power supplies my 120 VAC appliances, and solar power takes care of everything that uses 12 VDC. I've been doing it this way for years.

How do I do that? Is there a circuit dedicated just to the charger?

[uncle_bob]

Originally Posted by thiel

How do I do that? Is there a circuit dedicated just to the charger?

Hi

On most rigs, there is a breaker that can turn the charger / converter off. With some charger / converters you can flip a switch to disable them or shut them down via WiFi or Bluetooth. It's very much a "that depends" sort of thing.

For shutting down solar, the stock AS configuration really does not have a way to do that short of pulling a fuse. With fancier controllers, you can get into the same sort of remote switch / WiFI / Blutetooth sort of thing.

Bob

[AirMiles]

How to do that? My shore power battery charger is on a jumper wire which goes to the bedroom 120V circuit. I just turn off the bedroom 120V circuit breaker to disable shore power charging. I haven’t needed the bedroom 120V plug-ins because I use the factory USB 12v plugs and added a second USB/Cigarette lighter plugs on the other side of the bed. I could just disconnect the jumper wire and have use of the bedroom 120V plugs if desired. By using the breaker disconnect method, I could just turn the breaker on if I ever do want shore power charging.

[uncle_bob]

Originally Posted by AirMiles

How to do that? My shore power battery charger is on a jumper wire which goes to the bedroom 120V circuit. I just turn off the bedroom 120V circuit breaker to disable shore power charging. I haven’t needed the bedroom 120V plug-ins because I use the factory USB 12v plugs and added a second USB/Cigarette lighter plugs on the other side of the bed. I could just disconnect the jumper wire and have use of the bedroom 120V plugs if desired. By using the breaker disconnect method, I could just turn the breaker on if I ever do want shore power charging.

Hi

Using a breaker as a switch is not a real good idea. They have a *very* limited number rated cycles. It is not at all uncommon to wear them out ....

Bob

[AirMiles]

Today in Montrose CO I had the opportunity to help out a new Airstream owner with a Gopower portable solar panel. His batteries were so discharged that we first had to go buy new batteries. The only ones available locally were Walmart deep cycles. So we dropped those in and connected the portable solar power panel. I now have a happy camper next door to me with fully charged batteries. I guess every new Airstream owner needs to murder a pair of batteries before they figure out how to manage their batteries. I too murdered my first set of batteries. The portable unit quickly charged up his new batteries to float mode!

[Paprika]

"Using a breaker as a switch is not a real good idea. They have a *very* limited number rated cycles."

I've heard this before, but a little research suggest that it may not be true. For example, in this discussion thread referring to a Square D 50A Homeline breaker, the moderator says:

“On a small molded case circuit breaker like the 50A mentioned above, the criteria is: 6000 full load amp operations and 4000 zero amp operations for a total of 10,000 operations. So unless you have a very poorly manufactured breaker, that is well outside the UL operations parameters - most breakers will not wear out due to switching. Its overload performance is: 50 operations at 6x rated current (or 150A which ever is lower) so it is possible for a breaker to wear out electrically if it is subject to regular ‘instantaneous’ tripping.”

A quick check of Schneider/Square D's specs turns up this statement:

"Regarding switches and circuit breakers there are guidelines for mechanical operation that the devices must pass to be UL Listed or Component Recognized. For switches UL98 standard calls for a 30-100 ampere switch to be cycled for 6,000 operations with current and 4,000 operations without current for a total of 10,000 cycles. UL489 standard has this same requirement for 100 ampere circuit breakers. Typically Square D / Schneider Electric will test beyond those requirements." (emphasis mine)

Maybe I'm overlooking something, but it sounds as if the typical household circuit breakers we're talking about here are good for thousands of switching operations, (although perhaps only a handful of full-fault trips). In the application we're talking about here--switching on a converter on rare occasions--it seems unlikely that anyone would wear out a breaker.

[mythbuster88]

Originally Posted by Paprika

"Using a breaker as a switch is not a real good idea. They have a *very* limited number rated cycles."

I've heard this before, but a little research suggest that it may not be true. For example, in this discussion thread referring to a Square D 50A Homeline breaker, the moderator says:

“On a small molded case circuit breaker like the 50A mentioned above, the criteria is: 6000 full load amp operations and 4000 zero amp operations for a total of 10,000 operations. So unless you have a very poorly manufactured breaker, that is well outside the UL operations parameters - most breakers will not wear out due to switching. Its overload performance is: 50 operations at 6x rated current (or 150A which ever is lower) so it is possible for a breaker to wear out electrically if it is subject to regular ‘instantaneous’ tripping.”

A quick check of Schneider/Square D's specs turns up this statement:

"Regarding switches and circuit breakers there are guidelines for mechanical operation that the devices must pass to be UL Listed or Component Recognized. For switches UL98 standard calls for a 30-100 ampere switch to be cycled for 6,000 operations with current and 4,000 operations without current for a total of 10,000 cycles. UL489 standard has this same requirement for 100 ampere circuit breakers. Typically Square D / Schneider Electric will test beyond those requirements." (emphasis mine)

Maybe I'm overlooking something, but it sounds as if the typical household circuit breakers we're talking about here are good for thousands of switching operations, (although perhaps only a handful of full-fault trips). In the application we're talking about here--switching on a converter on rare occasions--it seems unlikely that anyone would wear out a breaker.

Wow thats interesting.
I use my breaker as a switch all the time.
No doubt there should be switch but the entire system is sort of a prototype for now.
I keep discovering more things to do.
This Airstream thing is really keeping me busy between upgrades and all the factory screw ups!

[uncle_bob]

Originally Posted by Paprika

"Using a breaker as a switch is not a real good idea. They have a *very* limited number rated cycles."

I've heard this before, but a little research suggest that it may not be true. For example, in this discussion thread referring to a Square D 50A Homeline breaker, the moderator says:

“On a small molded case circuit breaker like the 50A mentioned above, the criteria is: 6000 full load amp operations and 4000 zero amp operations for a total of 10,000 operations. So unless you have a very poorly manufactured breaker, that is well outside the UL operations parameters - most breakers will not wear out due to switching. Its overload performance is: 50 operations at 6x rated current (or 150A which ever is lower) so it is possible for a breaker to wear out electrically if it is subject to regular ‘instantaneous’ tripping.”

A quick check of Schneider/Square D's specs turns up this statement:

"Regarding switches and circuit breakers there are guidelines for mechanical operation that the devices must pass to be UL Listed or Component Recognized. For switches UL98 standard calls for a 30-100 ampere switch to be cycled for 6,000 operations with current and 4,000 operations without current for a total of 10,000 cycles. UL489 standard has this same requirement for 100 ampere circuit breakers. Typically Square D / Schneider Electric will test beyond those requirements." (emphasis mine)

Maybe I'm overlooking something, but it sounds as if the typical household circuit breakers we're talking about here are good for thousands of switching operations, (although perhaps only a handful of full-fault trips). In the application we're talking about here--switching on a converter on rare occasions--it seems unlikely that anyone would wear out a breaker.

Hi

The key there is the exact specific sub category those breakers are in. There are indeed sub categories that get down into the "125 cycles" range.

Bob