Re: 48 VOLT SOLAR LITHIUM SYSTEM Reply #75 – February 16, 2018, 11:42:31 pm When demand calls for it, firmware might be upgraded to higher charge voltage, depending on mfg. Might be a good question before buying a new inverter/charger. Quote Selected
Re: 48 VOLT SOLAR LITHIUM SYSTEM Reply #76 – February 17, 2018, 10:27:54 pm Used Nissan Leaf and Chevy Volt packs cost $3,000. However, they need to be reconfigured for the appropriate voltage for a charger and inverter. This would be a challenging and innovative project.That said, I believe all motorhome makers should spend the professional engineering time to create a high capacity (20 KWH +) and high-voltage battery and solar panel system design to bring us into the 21st century.The technology has already been developed and is safe and reliable using EV (Electric Vehicle) and solar industries. The motorhome makers just need the guts to make the change from 100 year-old technology.The other technology I recommend is replacing the generator with propane fuel cells. This would back up the solar panels when the sun don't shine. Fuel cells are expensive but may be cheaper in bulk.Imagine a totally silent rig that can boondock anywhere, anytime. Quote Selected 1 Likes
Re: 48 VOLT SOLAR LITHIUM SYSTEM Reply #77 – February 18, 2018, 08:24:42 am Quote from: Tim – February 17, 2018, 10:27:54 pmImagine a totally silent rig that can boondock anywhere, anytime.Now, imagine what it would cost. Quote Selected 1 Likes
Re: 48 VOLT SOLAR LITHIUM SYSTEM Reply #78 – February 18, 2018, 08:47:02 am With new rigs costing $1M, the additional cost would be minimal. The performance gain would be maximal. An all-electric boondocking rig would now be practical. The return on investment would be based on:- Free power from the sun- No generator or battery maintenance- No campground fees if boondocking- 10 year battery life- Better human health because there are no generator fumes, vibration, nor noise to disrupt the natural soundscape Quote Selected
Re: 48 VOLT SOLAR LITHIUM SYSTEM Reply #79 – February 18, 2018, 09:16:01 am Quote from: Tim – February 18, 2018, 08:47:02 amWith new rigs costing $1M...See, that's where you lost me.I'm not disputing any of your technical points, or questioning the "goodness" of a all-electric, environmentally friendly, totally self sufficient RV. Sadly, the DW and I do not have $1M to spend on a coach. Being charter members of the lower middle class totally sucks. Quote Selected 4 Likes
Re: 48 VOLT SOLAR LITHIUM SYSTEM Reply #80 – February 18, 2018, 09:38:13 am Quote from: Tim – February 18, 2018, 08:47:02 amWith new rigs costing $1M, the additional cost would be minimal. The performance gain would be maximal. An all-electric boondocking rig would now be practical. The return on investment would be based on:- Free power from the sun- No generator or battery maintenance - No campground fees if boondocking- 10 year battery life- Better human health because there are no generator fumes, vibration, nor noise to disrupt the natural soundscapeTim, granting you have the battery bank to run say a 250 kw electric motor in your coach for 4 or 500 miles a day, what do you use to recharge that bank overnight before travelling the next day if you do not have a generator or shore power to recharge your propulsion batteries? Quote Selected 1 Likes
Re: 48 VOLT SOLAR LITHIUM SYSTEM Reply #81 – February 18, 2018, 09:56:15 am Quote from: Tim – February 17, 2018, 10:27:54 pmUsed Nissan Leaf and Chevy Volt packs cost $3,000. However, they need to be reconfigured for the appropriate voltage for a charger and inverter. This would be a challenging and innovative project.That said, I believe all motorhome makers should spend the professional engineering time to create a high capacity (20 KWH +) and high-voltage battery and solar panel system design to bring us into the 21st century.The technology has already been developed and is safe and reliable using EV (Electric Vehicle) and solar industries. The motorhome makers just need the guts to make the change from 100 year-old technology.The other technology I recommend is replacing the generator with propane fuel cells. This would back up the solar panels when the sun don't shine. Fuel cells are expensive but may be cheaper in bulk.Imagine a totally silent rig that can boondock anywhere, anytime.All fine and dandy, untill you get a week of overcast, shaded site, a hailstorm that destroys the solar panels etc. Utopia only exists in theory, only to be awoken by reality. Wise people never put all of there eggs in one basket. And economic feasibility SHOULD severely impact a rational persons decisions. Do what makes YOU happy. Trust me, you do not have all the answers, nor do I. Quote Selected
Re: 48 VOLT SOLAR LITHIUM SYSTEM Reply #82 – February 18, 2018, 02:15:59 pm On the Chevy volt battery packs.. can't you use the bms that goes to the Battery pack and just hook into the inverter/charger and the bms will do it's thing? Quote Selected
Re: 48 VOLT SOLAR LITHIUM SYSTEM Reply #83 – February 18, 2018, 02:39:04 pm Quote from: DavidS – February 18, 2018, 02:15:59 pmOn the Chevy volt battery packs.. can't you use the bms that goes to the Battery pack and just hook into the inverter/charger and the bms will do it's thing?You can probably use the volt bms, but the battery pack is 300+ volts. So now we need an inverter from 300 volts dc to 120 ac for house use, and a converter down to 12 volt dc for your coach systems, if you want to, or you could keep your present 12 v system . And 120 or 240 volt ac input to run the bms and charge the batteries. Quote Selected
Re: 48 VOLT SOLAR LITHIUM SYSTEM Reply #84 – February 18, 2018, 02:43:32 pm I had a customer long ago who outfit his old FTX with 2,000 nicads he had access to for free. Elon musk's megafactory is going to build 2170 new dimension li ion cells. Should be less than a dollar per cell sometime coming up.Requires a temp controlled area and a complicated BTMS. If we live long enough Dr goodenough's latest breakthrough cells (li ion inventor) using silicone will change the world. Fraction of the price. Three times more energy density. Multiple times faster recharging. Imagine a 750 mile range electric car that could be recharged in 30 minutes? Or power a coach easily. Electric hub motors? Quote Selected
Re: 48 VOLT SOLAR LITHIUM SYSTEM Reply #85 – February 18, 2018, 09:39:03 pm The solar panels keep the battery 48V lithium charged quite well. However, at Mammoth Cave National Park, we camped in a partially shaded site for six days. No hookups. We reduced the load by running the icemaker one day during the day and putting the ice cubes in the propane fridge.A modern engineered system would predict power usage and generation and recommend how to shed the load to maintain the battery. A good user interface could show exactly what is happening with the engine and house batteries.In my case, there are three batteries in a redundant system:- Primary house battery, 48V lithium- Engine battery, 12V lead acid- Toad battery, 12V lead acidMy RC (Radio Control) charger could theoretically recharge the 48 volt pack from the 12V batteries. Quote Selected
Re: 48 VOLT SOLAR LITHIUM SYSTEM Reply #86 – February 18, 2018, 10:54:32 pm Quote from: Tim – February 18, 2018, 08:47:02 amWith new rigs costing $1M, the additional cost would be minimal. The performance gain would be maximal. An all-electric boondocking rig would now be practical. The return on investment would be based on:- Free power from the sun- No generator or battery maintenance- No campground fees if boondocking- 10 year battery life- Better human health because there are no generator fumes, vibration, nor noise to disrupt the natural soundscapeSorry Tim, thought you were talking about an "all electric ", electric propelled coach, which is far, far in the future. For electric only with no generator, think you are pretty close to getting there. But I think like Old Phart, plenty of electrical capacity, BUT, also backup propane for heat, hot water, cooking and refrigerator. Or, in my case, diesel for heat and hot water. [aqua-hot]. As for ac, Parliament, [before they closed] had a design coach that used 48 volt ac's and could run 2 ac's on battery for 20 hours without generator or solar charging. If they had made that coach, would have been $1.5m +..... Quote Selected
Re: 48 VOLT SOLAR LITHIUM SYSTEM Reply #87 – February 19, 2018, 02:15:55 am Reduce the A/C load in half by dumping the early 70's technology roof mounted units results in greater run time on any given system=and less $ for install. Standby losses and conversion losses also drop. I was hoping to build an modern A/C unit this winter that inrush current is essentially eqaul to running current, but I am running out of time. Shop building is still 5-8 weeks out. On my coach I think I can get by comfortably on an ultra efficient 9000 btuh unit for the bedroom, further extending run times by beefing up the insulation of the engine compartment and running the bedroom unit off of the alternator and a invertor while traveling. $900-1000 per unit. Economic replacement of my new last summer 1200 watt front A/C is non existent unless I can resell it for $400-500. Quote Selected
Re: 48 VOLT SOLAR LITHIUM SYSTEM Reply #88 – February 19, 2018, 06:49:55 am Agreed, our 90's era equipment can be redesigned for better efficiency. Heat pumps have come a long way. Or better yet, do propane-powered ACs exist? Wish I had a regular propane oven.The problem with running AC or other power hog during the day is that the battery is depleated by nightfall. This causes anxiety. That said, we do a lot of microwave and convection oven cooking during for lunch so the batteries have a chance to charge before nightfall. Quote Selected
Follow-ups Camp Chef oven Re: 48 VOLT SOLAR LITHIUM SYSTEM Reply #89 – February 19, 2018, 08:35:14 am Quote from: Tim – February 19, 2018, 06:49:55 amWish I had a regular propane oven.We have been considering one of these:Amazon.com : Camp Chef Camping Outdoor Oven with 2 Burner Camping Stove :... Quote Selected 1 Likes As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.
Re: 48 VOLT SOLAR LITHIUM SYSTEM Reply #90 – February 25, 2018, 11:10:57 am Need to clear up a couple of previous statement I made previously in this thread.The new Tesla Gigafactory will be producing a new battery not the existing 18650. The new cell will be a 21700 or 2170 for short. The 18650 is 18mm long and 65mm in diameter. The new 2170 will be 21mm x 70mm. Slightly longer and fatter. Elon claims the highest energy density and cheapest cost. Tesla's (TSLA) cheaper, more powerful 2170 battery cell is the perfect...Also I found this table of the different chemistry for lithium batteries. LiCoO2 3.7 V 140 mA·h/g 0.518 kW·h/kgLiMn2O4 4.0 V 100 mA·h/g 0.400 kW·h/kgLiNiO2 3.5 V 180 mA·h/g 0.630 kW·h/kgLiFePO4 3.3 V 150 mA·h/g 0.495 kW·h/kgLi2FePO4F 3.6 V 115 mA·h/g 0.414 kW·h/kgLiCo1/3Ni1/3Mn1/3O2 3.6 V 160 mA·h/g 0.576 kW·h/kgLi(LiaNixMnyCoz)O2 4.2 V 220 mA·h/g 0.920 kW·h/kgIt looks like LiFePO4 at 3.3v (4 * 3.3 = 13.2v) would work with current 12v systems without new components. I don't think the current charge profiles in our systems would be optimal for the these but worst case it would take slightly longer to charge as the charger would back off sooner than required.I leave it as an exercise for the reader to figure out if that will work for you.see yaken Quote Selected
Re: 48 VOLT SOLAR LITHIUM SYSTEM Reply #91 – February 25, 2018, 06:10:50 pm Two threads here:1. Battery FormatI have yet to be convinced that having 1000's of small cells is better than four large prismatic or pouch cells, The Nissan Leaf or Chevy Volt batteries make more sense to me, being composed of moderately large-format size. The higher number of cells, the more complicated the BMS (Battery Management System) becomes.2. Battery ChemistryI am biased toward LiFePo4 because they are relatively cheap and available. I have yet to see Large pure lithium batteries for sale.Although my 48Volt system is doing well and I will be getting about $3,000 back on my taxes. However, for a limited budget, four large (180 to 400 Amp-Hours) cells could be used with no BMS. I mean, there is a human BMS who monitors for over and under voltage.In fact, four 400 Amp-Hour LiFePo4 batteries could not only be the house battery, but the starting battery as well. They can put out 4000 amps for 10 seconds. This would save another 100+ pounds of lead engine / starting batteries.The only caveat is that the LiFePo4 batteries would have to be temperature-controlled to be from 40F to 90F to prolong their life. Quote Selected
Topic: 48 VOLT SOLAR LITHIUM SYSTEM