How much power do you use?

[yaakbus]

Thats what I love about the bus community. I've been an entrepreneur for 18+ years, i love how crafty people like you are to make things work for you.

Originally Posted by o1marc

I can use scrap engineered wood, just not cut log fire wood that may still carry pests.
As effective as they are you can usually find enough "firewood" where ever you go to use for one night.

[PNW_Steve]

Originally Posted by weboughtabus

If you understood that diagram, please look at this.

That configuration is likely to cause the premature failure of the 1st bank. Parallel banks should be approached with caution due to equalization issues.

The ideal solution for a 400ah/48v battery bank would be to use an appropriate number of 400ah batteries in series.

Example: 8x6volt=48v or 6x8v=48v

That will give you a total capacity of 19.2kwh and a usable capacity (@50%DOD) will be 9.6kwh.

The 6v/400ah batteries cost $300-$500 each and weigh about 120lbs each. So 8 of them, in total, will be approximately:

Cost - $3200 (apx)
Weight - 960lbs
Usable capacity - 200ah@48v or 9.6kwh.

You want to charge that bank at C/8-C/12 to avoid damaging your batteries. Assuming real world output is around 80% of rated capacity you will need 2kw of panels or more. However, with only 2000 watts of panels you may have trouble getting a full charge from solar if you are using it daily in the winter. Depends considerably on location. Nogales vs Seattle....

That is some system for a mobile application. I have seen & serviced systems notably smaller that supported an off grid house.

Please post pics of your battery install. I am really anxious to see how it goes together.

[ThePimentals]

The answers won’t be all over the place. It’s easy. If you plan to use 2 computers, a fridge etc for 3-5 days. There is not enough room for how many batteries that would take to power that stuff. You’ll need to be on shore power

[Doktari]

I read a article about a bus where they rewired an entire Nissan Leaf battery pack to 48 volts. I don’t remember where I read it. But if I was thinking about a half ton or more of lead and 2-5 kWh per day I would consider it.
They needed to add one extra Leaf module to make it a balanced 48 volt bank. I think it was nearly 20 kWh which is a lot of watt hours. And didn’t take much space.
To answer your question I have 400 Ah at 24 volts and 2400 watts of solar. My batteries are on the outside and very cold which reduces the capacity by about 20% down to 320 AH. So there is only about 160 useable AH. It runs low pretty quickly.
I need to fine tune the system this year. Meter my fridge and I’m considering getting a Magnum Energy 300 watt inverter so I can put the 2500 watt Outback inverter to sleep mode a lot of the time. It uses 480 watt hours to be on for 24 hours. And is about 90% efficient when used for small loads. Around 95% efficient for bigger loads.
If I doubled my lead batttery I think I’d be fine.

[Smokey's pipe dream]

BUY 3 TIMES BIGGER THAN THEY TELL YOU COMPARE IT TO CUTTING YOURSELF RATHER HAVE A SCRATCH TO HEAL UP OR A DEEP SLICE IN OTHER WORDS IF YOU BARELY TOUCH YOUR CAPACITY AND YOU HAVE A MASSIVE SOLAR PANEL SET UP IT WILL CHARGE UP QUICK IN THE MORNING SUN BUT IF YOU NEED DAYS OF POWER WITHOUT SUN YOU DONT HAVE ANY WORRIES EITHER AND IT WILL STILL CHARGE QUICKLY ALSO PUT A SOLENOID IN YOUR CHARGE LINE FROM YOUR ALTERNATOR SO YOUR RUN BATTERIES ARE SEPARATE FROM YOUR SOLAR BATTERIES BUT YOUR BUSSES ALTERNATOR WILL CHARGE THEM ALL UP GET A REALLY GOOD MPPT SOLAR CHARGER AND SEPARATE POWER METER! MORE IS REALLY CHEAPER AND IF YOU GO REDICULAS BIG YOU DONT HAVE TO WORRY ABOUT KILLING YOUR BATTERIES FROM DRAINING THEM BELOW 50% UNLESS YOU GET LITHIUM THEN YOU CAN GO DOWN TO LIKE 30% AND IT won't HURT THEM GOOD LUCK NO OFFENCE TO THE GUY ABOVE ME'S COMMENT BUT FINE TUNING TO GET A TINY BIT MORE POWER AND A FEW AMP HOURS WHY??? WHY STRAIN YOUR SYSTEM LIKE THAT???? GET'ER DONE! ONE TIME NO WORRIES

[PNW_Steve]

Doktari,

A couple of members here have lithium battery banks.

The setup you are describing requires a somewhat complicated battery management system and a fair bit of tech savvy to make it play.

I looked at commercially produced battery/bms setups and found them to be way beyond my budget.

[Smokey's pipe dream]

MY SONS AND I ARE STARTING A FULL SERVICE SKOOLIE AND TINY HOUSE BUISINESS WE DO IT ALL IN HOUSE FROM PALLET REPURPOSING TO THE FINEST OF YACHT WOOD BRIGHT WORK CABINETS FURNITURE VENEERS YOU NAME IT IF ITS CHEAPER AND THE QUALITY AND FIT ARE GOOD WE'LL BUY IT AND USE IT BUT IF NOT WE'LL BUILD IT CUSTOM WE DO ALL TYPES OF METAL AND FIBERGLASS FABRICATION INCLUDING ONE OFF MOLDING FOR REALLY CUSTOM SCHOOLIES WE OFFER POP UP FULL OR PARTIAL SECOND FLOORS AND SLIDE OUTS, AS WELL AS SUNKEN FLOORS AND SLIDE OUTS, CUSTOM
MADE SPIRAL STAIRCASES WE OFFER ELEVATOR BEDS AS WELL AS MURPHY STYLE BEDS THE SKY TRUELY IS THE LIMIT WE WORK FAST BUT WE DONT LOSE QUALITY! SATISFACTION WITHIN REASON GUARANTEED! JUST IMADGINE
500 SQFT FROM A SKOOLIE!!!! maybe a hot tub on the upper deck between a pop up bed room on each end give me an email lilman772@gmail.com

[Dirtdoctor]

i live off grid- servicing two dwellings and we run 3 refrigerators and 5 freezers. My suggestion is to contact OUTBACKPOWER.com. Talk with their techie folks. They produce a great system and I’ve seen some diy stuff that is a disaster waiting to happen. Storing power is important- but with busses we have a PTO capability and with properly designed gearing you can run a generator with the engine. Storing power is another great thing- wrecked electric cars have batteries that when properly set up can provide power (compact design vs lead acid batteries). But engineering it properly is key. I’ve seen battery banks in enclosed spaces wo venting- it burned one boat to the waterline. I’ve seen too small of gage wires being utilized and melt insulationing. So properly spec’d And installed is the way to go.Cheers

[Doktari]

I live near Arlington, WA and have done a few workshops with the Trace Engineering, Outback, Midnite, Home Power magazine, Solar Energy International, and other folks. Magnum is near here too. It seems to be a RE hub. Could be a lot better however. All that talk about a green economy when Obama came in. Reality set back in.
I agree, starting with a robust well engineered system and then delve into DIY made sense for me. And respect the laws of physics. Poor connections concern me. I bought a good crimper but the lugs didn’t fit correctly sometimes. So have to adjust it. I think I’ll start crimping and soldering both.
On big buses and coaches it makes sense to tap into or improve the powerful mainframe engine driven charging system. There’s more to that than meets the eye also however. Grounding straps, voltage drops, isolation, regulation, adjustability, belts, pulleys, alternator temperature, etc. There is no plug and play turnkey system that is optimized. They all require tweaking.
I’m thinking I can build a system that does what I want better than the mainframe alternator. Because it works more seamlessly with the solar. And it might be more than I can use anyway. But I’ll probably hack into the mainframe alternator eventually if I keep this vehicle.
For those who want to learn to fine tune a system there’s a lot of potential. Conversly, One can toss money and energy at it. Then it’s like a house on wheels.
I’m striving to learn how to optimize small systems. For anyone interested in a very informative sticky thread on fine tuning alternator charging read the sticky by Sternwake on the vandweller forum. He managed to customize his existing Dodge alternator charging system so it is adjustable without spendibg gobs of money. I’d like to figure out how to do it for Chevy.
As far as parallel batteries are concerned I was told to keep the parallel strings to a maximum of three. When the time comes for new batteries I’ll study that. It would be great if there was an easy way to isolate each battery for testing and balance charging without disconnecting a bunch of stuff and getting a sore back. I guess this is why sone people like Lion technology. They are taking it to the individual cell level. Whereas with FLA there is still a lot of estimating. But I still like FLA for my needs.

[PNW_Steve]

Originally Posted by Doktari

I live near Arlington, WA and have done a few workshops with the Trace Engineering, Outback, Midnite, Home Power magazine, Solar Energy International, and other folks. Magnum is near here too. It seems to be a RE hub. Could be a lot better however. All that talk about a green economy when Obama came in. Reality set back in.
I agree, starting with a robust well engineered system and then delve into DIY made sense for me. And respect the laws of physics. Poor connections concern me. I bought a good crimper but the lugs didn’t fit correctly sometimes. So have to adjust it. I think I’ll start crimping and soldering both.
On big buses and coaches it makes sense to tap into or improve the powerful mainframe engine driven charging system. There’s more to that than meets the eye also however. Grounding straps, voltage drops, isolation, regulation, adjustability, belts, pulleys, alternator temperature, etc. There is no plug and play turnkey system that is optimized. They all require tweaking.
I’m thinking I can build a system that does what I want better than the mainframe alternator. Because it works more seamlessly with the solar. And it might be more than I can use anyway. But I’ll probably hack into the mainframe alternator eventually if I keep this vehicle.
For those who want to learn to fine tune a system there’s a lot of potential. Conversly, One can toss money and energy at it. Then it’s like a house on wheels.
I’m striving to learn how to optimize small systems. For anyone interested in a very informative sticky thread on fine tuning alternator charging read the sticky by Sternwake on the vandweller forum. He managed to customize his existing Dodge alternator charging system so it is adjustable without spendibg gobs of money. I’d like to figure out how to do it for Chevy.
As far as parallel batteries are concerned I was told to keep the parallel strings to a maximum of three. When the time comes for new batteries I’ll study that. It would be great if there was an easy way to isolate each battery for testing and balance charging without disconnecting a bunch of stuff and getting a sore back. I guess this is why sone people like Lion technology. They are taking it to the individual cell level. Whereas with FLA there is still a lot of estimating. But I still like FLA for my needs.

Definitely agree with the idea of starting with a "well engineered" system.

I cringe when I see folks start throwing good money after bad trying to get a poorly designed system to perform. Or simply give up.

It's a small world I used to fly out of Arlington airport. Lived I'm Marysville, Everett and, most recently, Granite Falls.