It's Power

[Davydd]

Originally Posted by Winston

We were waiting for the Davydd Team to chime-in before adding our 'standard fare': "we use lots of power".

Seems this topic surfaces every couple of months and the comments reflect that most pride themselves on maintaining low electrical consumption. We chose to spend a bit more 'up-front' in order to fully enjoy our toys and gadgets while on the road. We just returned from a trip in which we camped 106 days without shore power - - and having a competent electrical system that allowed us to do what we wanted to do was a pleasure.

We tent camped for close to 40 years before we bought our first Class B. I didn't buy one so we could rough it out with pride. I successively sought the most comfort that could be put in a Class B. Why Class Bs? Probably for my professional challenge instincts in design and undoubtably the best RV to tour which I mostly like to do. Those two reasons are merging in the design of Mies - "Less is more" and could be, at my age, the last Class B I might own. Of course I said that four RVs ago.

[hbn7hj]

It looks to me that to have a compressor fridge a B needs 300 watts of solar or a generator you can use in a campground be it Onan or UHG.

If you choose generator you need lithium for fast charge rate and short run time.

For me, 100 watts of solar, 100ah of AGM because it is there, and 200ah of lithium would do it. I would have a lithium charger capable of a 100 amp charge rate. Both battery banks to 100% every evening.

All you need is one 100ah lithium battery and one 80 amp AC lithium charger and a battery bank switch. $1500

It could be done on one lithium but the generator run time would increase.

[MsNomer]

Originally Posted by hbn7hj

It looks to me that to have a compressor fridge a B needs 300 watts of solar or a generator you can use in a campground be it Onan or UHG.

If you choose generator you need lithium for fast charge rate and short run time.

For me, 100 watts of solar, 100ah of AGM because it is there, and 200ah of lithium would do it. I would have a lithium charger capable of a 100 amp charge rate. Both battery banks to 100% every evening.

All you need is one 100ah lithium battery and one 80 amp AC lithium charger and a battery bank switch. $1500

It could be done on one lithium but the generator run time would increase.

I ran a compressor fridge just fine for a year on 100Ah AGM. Only needed more, and added solar, when I added MW, etc.

[themexicandoctor]

I did discover today as my RV Guy was doing his preliminary work on configuring a new vattery bank set up that I did in fact have a loose ground/negative connection deep underneath the rig.

As it is, since then charging has improved about 15-25%.

My two panels 80 & 170 are not wired 100% effective but I do get pmax highs of 240watts, etc. And there is presently a deficit by having the two batteries presently separated by a 3 feet/6 feet of wire plus being stuck far away from the battery bank, etc.

Next week there will be just a 4.5 feet run from the mew batteries to the box, the only way to get it closer is to move the inverter, etc & put them right under me - they are Lifeline AGM's so I will be fine - in the new set up I merely open the rear cargo doors and they are right there.

Having said that, maybe you could get away witha smaller set up & less money but I woukd budget for 25-45 amp hours draw.

If you were using a Engel MT45 Combination Chest Freezer, much lesss.

[GeorgeRa]

Originally Posted by MsNomer

Our 200Ah AGM and 300W solar are normally more than adequate for fridge, MW, Instapot, etc., but this smoke is playing havoc with the system and cramping our lifestyle. Even in Laramie, WY, the panels collect a layer of soot and function at less than half capacity. Since we are stationary and boondocked, this means limited cooking. Really makes me appreciate what I don’t have at the moment.

Almost the same set, we have 230Ah vs 200Ah. After evening movie we are back to full by noon next day with reasonably good harvesting conditions. In a good campsite fresh water tend to be our limit.

I am planning to pass on the current Li trend and wait for Silicon/Lead acid batteries.

[Davydd]

When do you think Silicon/Lead acid batteries will be a feasible choice in an RV?

And what is the performance characteristics of them in regard to charging, weight and temperature range?

[jakegw2]

My 200ah of LiFePO4 is not far from the same usable capacity as your 440ah AGM. I can and do discharge down to as low as 5% (~190 ah usage) of the rated ah (I can do this safely because a Battleborn 100 ah battery actually has about 108 ah of capacity, so even discharging the full rated capacity does not create the damage that a true full discharge would). With AGM you are probably trying to extend the useful lifespan of your battery bank, which would limit you to somewhere in the 220 - 265 ah range.

[booster]

Originally Posted by jakegw2

My 200ah of LiFePO4 is not far from the same usable capacity as your 440ah AGM. I can and do discharge down to as low as 5% (~190 ah usage) of the rated ah (I can do this safely because a Battleborn 100 ah battery actually has about 108 ah of capacity, so even discharging the full rated capacity does not create the damage that a true full discharge would). With AGM you are probably trying to extend the useful lifespan of your battery bank, which would limit you to somewhere in the 220 - 265 ah range.

Nope, our 440ah bank has usable capacity of 352ah when taken to 20%, which in reality only has a minor shorting in of life no matter how much the lithium battery folks distort the specs for life. Most of the data I have seen actually shows lithium losing life faster than AGM with deep dicharges.


Both types of batteries have advantages and disadvantages, and neither covers it all the best.



The drop in lithium sellers tend to highly manipulate and often distort the specs and data to make their products look superior, IMO.

[avanti]

Originally Posted by jakegw2

My 200ah of LiFePO4 is not far from the same usable capacity as your 440ah AGM. I can and do discharge down to as low as 5% (~190 ah usage) of the rated ah (I can do this safely because a Battleborn 100 ah battery actually has about 108 ah of capacity, so even discharging the full rated capacity does not create the damage that a true full discharge would). With AGM you are probably trying to extend the useful lifespan of your battery bank, which would limit you to somewhere in the 220 - 265 ah range.

...and if I ever DID have to replace my batteries, I could do it, what, maybe 3 times before you break even financially.
...and when we get a cold spell, I lock the door and walk away.
...and my solar panel will keep my AGM charged up, healthy, and ready to go, regardless of the temperature.
...and I need no fancy battery management system telling me per/cell voltage and temperature and doing mysterious things that I can never keep straight in my head.

Lithium isn't BETTER, it is just DIFFERENT. Depends totally on what you need and what you value.

Pick your poison.

[Bud]

Originally Posted by booster

Nope, our 440ah bank has usable capacity of 352ah when taken to 20%, which in reality only has a minor shorting in of life no matter how much the lithium battery folks distort the specs for life. Most of the data I have seen actually shows lithium losing life faster than AGM with deep dicharges.


Both types of batteries have advantages and disadvantages, and neither covers it all the best.



The drop in lithium sellers tend to highly manipulate and often distort the specs and data to make their products look superior, IMO.

Tesla vehicles have plenty of power, so The Issue is Longevity. Tesla controls the charging without full charging or too low discharging. The exception is catastrophic events like the present hurricane, they allow more charging and discharging.

My 35 mph ebike is the same. Initial full charges maybe 5 times for equalization, then 80 or 90% charges for longevity, same with discharges. The owners choice. But full charges later for equalization of cells with the question being, how often. I assume Tesla does the same.

If I purchase a li3 or volta, I will not charge, discharge for longevity as I will not outlive the batteries, or maybe I will.

Oh booster, I really really enjoyed your 'keg' post And the flowers. Fun post, thanks.

Bud

[booster]

Originally Posted by Bud

Tesla vehicles have plenty of power, so The Issue is Longevity. Tesla controls the charging without full charging or too low discharging. The exception is catastrophic events like the present hurricane, they allow more charging and discharging.

My 35 mph ebike is the same. Initial full charges maybe 5 times for equalization, then 80 or 90% charges for longevity, same with discharges. The owners choice. But full charges later for equalization of cells with the question being, how often. I assume Tesla does the same.

If I purchase a li3 or volta, I will not charge, discharge for longevity as I will not outlive the batteries, or maybe I will.

Oh booster, I really really enjoyed your 'keg' post And the flowers. Fun post, thanks.

Bud

Absolutely, all of the battery types have their quirks and Achilles heals. I think with a lot of the lithium batteries, they figure (probably correctly) that the longer inherent life will have the batteries lasting long enough that the unit will have been sold or scrapped before the number of cycles ever got to claimed range.



What I think the big difference in a lot of the discussions about particular batteries by particular manufacturers is that they tend to revert away from being a singular product and go to the overall type.


I just can't believe in any way that a "drop in" battery that claims 14.7v full charge and 95% discharge, without much for controls and possibly using old school charging stuff is in the same category as a fully designed lithium system that has limits on full charger and discharge, auto balancing, etc through a sophisticated control system.



This isn't just lithium batteries or batteries in general as over claiming capability seems to be very pervasive in many RV products. Shore chargers and solar controllers are near the top of the list. Remember when the "smart" chargers first came out, and even to now, they were claimed to make the batteries last way longer and always be perfectly charged?

[GeorgeRa]

Originally Posted by Davydd

When do you think Silicon/Lead acid batteries will be a feasible choice in an RV?

And what is the performance characteristics of them in regard to charging, weight and temperature range?

I know the Silicon wafer / lead acid batteries is coupling two well known technologies into one. The mechanical and electrical backbone will be via silicon wafer likely doped/coated to right parameters, and lead/lead oxide layers will contain minimum lead to function as a battery. Recently they entered evaluation with a large German industrial battery manufacturer – Hoppecke.
https://www.prnewswire.com/news-rele...300961035.html

Back to your questions, their literature claims high current density for charging and discharging. Weight is low, price lower than Lithium.
Based in testing company choice their focus is on industrial 24/48V applications, when will they trickle down to RV business, I don’t know but likely sooner than my appetite for Li.

[Davydd]

Originally Posted by GeorgeRa

I know the Silicon wafer / lead acid batteries is coupling two well known technologies into one. The mechanical and electrical backbone will be via silicon wafer likely doped/coated to right parameters, and lead/lead oxide layers will contain minimum lead to function as a battery. Recently they entered evaluation with a large German industrial battery manufacturer – Hoppecke.
https://www.prnewswire.com/news-rele...300961035.html

Back to your questions, their literature claims high current density for charging and discharging. Weight is low, price lower than Lithium.
Based in testing company choice their focus is on industrial 24/48V applications, when will they trickle down to RV business, I don’t know but likely sooner than my appetite for Li.

Seems like a lot of vague on the come information with no concrete information and probably not in my RV lifetime span to worry about it.

I have benefitted from lithium ion batteries that far exceed what you can get in a van over AGM for 4-1/2 years so far. I'm an early adopter in most things and seldom wait because there may be something better in the future.

[themexicandoctor]

I was adopted but not an early adopter of technology unless its on the battlefield.

But that is the beauty of this site, those oof us who have skills in other areas get to walk amongst the Technology Giants among us.

As for batteries, when my contacts at Lifeline say "No, we won't touch Lithium for large or small RV Banks ..." along with my contacts at FullRiver & Battleborn*, I have to listen.

*he is a passenger on a boat that has already sailed versus the two above who are family & top executives.

At the same time, I own my Dream Bike, a Kawasaki Z1000 & I purchased a Shorai Lithium Battery for install before the bike arrived 39 days later even though it had a perfectly fine AGM Battery installed.

For me, as an end user I was amazed at both the size of the lithium in comparison but gobsmacked at the difference in weight - almost four times as light!

[GeorgeRa]

Originally Posted by Davydd

Seems like a lot of vague on the come information with no concrete information and probably not in my RV lifetime span to worry about it.

I have benefitted from lithium ion batteries that far exceed what you can get in a van over AGM for 4-1/2 years so far. I'm an early adopter in most things and seldom wait because there may be something better in the future.

I agree, their information is still vague, but they don’t have product on the market yet. Contract with the US Battery Company with decent deep cycle technology will likely expose advantages and disadvantages of this new technology and time to market time-frame, it could be a few years, good enough for my needs.

In regards being an early adapter, I am in but only if I need it.

https://www.prnewswire.com/news-rele...301101485.html

[Davydd]

I designed and built my timber frame home in 1982 with a roof at the optimum angle and orientation for solar in Minnesota but never put it in. Had I done so, in hindsight, it would have had to be a liquid system (no photovoltaics back then) that would not have a payback because of the cost and longevity. Fortunately, I learned that while in construction the first winter when I realized my passive solar design would not let the temperature go below 50 deg. with no heat when it was -20 degrees outside. So that was the first thing to go when I ran out of money during construction. I was experimenting in passive energy design back in the early 70s before the energy crisis hit the pubic's awareness in 1973. That was really short lived. I see few homes designed today for energy efficiency other than equipment.

[MsNomer]

Originally Posted by GeorgeRa

Almost the same set, we have 230Ah vs 200Ah. After evening movie we are back to full by noon next day with reasonably good harvesting conditions. In a good campsite fresh water tend to be our limit.

George, what is your approximate daily draw?

[GeorgeRa]

Originally Posted by MsNomer

George, what is your approximate daily draw?

Depends on weather, low 25Ah/24 hours and high 45Ah/24 hours for the fridge, 15Ah for evening max.

[GallenH]

GeorgeRA: What's your brand/capacity of the fridge? Thx.

[GeorgeRa]

Originally Posted by GallenH

GeorgeRA: What's your brand/capacity of the fridge? Thx.

Isotherm Cruise 85l / 3 cu.ft. with Isotherm Smart Energy Controller (SEC). I changed the original fan to a very quiet one, and added some Styrofoam insulation. Back side is fully open and air can be drawn from the bottom, back and drawer sides. Never had issues up with temperatures up to 105F in Arizona.