Lithium Batteries, who has them?

[campingnut]

Thanks Terry and Bob. If I used a Morningstar pwm 45 controller and used the custom mode (computer interface) to turn off equilization and float and then used the Victron BMV 600 to monitor % state of discharge and votage cut offs it should be ok? If I manually check the cell differences?

Cut off charge at 14v and cut off load at 12? Conservative levels?

Maybe the dingo would be better?

[T1 Terry]

Thanks Terry and Bob. If I used a Morningstar pwm 45 controller and used the custom mode (computer interface) to turn off equilization and float and then used the Victron BMV 600 to monitor % state of discharge and votage cut offs it should be ok? If I manually check the cell differences?

Cut off charge at 14v and cut off load at 12? Conservative levels?

Maybe the dingo would be better?

All round the Dingo is a better unit so that would be my first choice. The charging capacity (solar and mains) is virtually unlimited using the Dingo 20/20 as a base controller. The Victron would be a good choice for battery monitor as it has many great features at a great price.
You still need active cell voltage monitoring if you want to keep the cells safe from over/under voltage damage. This is part of a secondary control kit that integrates with Plasmatronics Dingo that is custom designed around the equipment you already and any you plan to add in the future. They are not expensive, around the $400 mark depending just what custom features you need and it forms a secondary control of all the charging sources so the cells can't be accidentally damaged by over voltage.
This isn't a sales pitch, I only mentioned it so you have an idea regarding the price of this type of gear so you don't get catch by someone trying to cash in and charging crazy $$ for something that quite likely doesn't really perform the task required.
I'm looking forward to seeing this unit Slowhand is getting manufactured, the sooner manufacturers understand what is really required and gear up, and skill up to this new technology the better, most of what's out there at the moment just doesn't stack up as far as doing the job required and doing it at a sensible price.

T1 Terry

[slowhand]

G'day Terry, I'm not getting one made, just trying to get them to make one which suits lifepo4 and does individual cell charging. The cost of R&d and engineering would huge, so wont be getting anything out of it other than a good system for everyone hopefully.

Tried a number of manufacturers and none have a clue and I don't have the knowledge to design a dedicated charge controller which will charge individual cell lines. There may be problems of doing it that way, but as there are many chargers which can do multiple LA batteries, I can't see a problem and wish I had got past the maths block years ago when I attempted an electronics technology course. Sadly my lack of education put a block on that.

Their engineers are working on it I'm told, but that could mean anything. Trying to explain via email to non english speaking people what you want, is sometimes very confusing for both parties. But will keep at them until something gives, or find an electronics engineer that can design one here in Tas.

[campingnut]

So for now if a cell is down a little I could isolate it and give it a boost with a small charger(eg 4 volts) until it measures the same as the others on my fluke -OR put a load on a high cell and bring it back to the others OR put them all in parallel for a few days and clean all the contacts in the process.

Keep trying Bob. I believe in you. Both you and Terry and Martin have helped me lots.

This might sound like oversimplifying it but all we need is four mini chargers (one for each cell or group of cells) that charge till say 4 volts then switch off when each gets to exactly 4 (or whatever you choose) Some might be on a little more time than others. As long as they all cut off at exactly the same voltage then shouldnt they all be balanced? This might be thrown out somewhat if a load was on while your charging. Or the one charger could go around the four cells swtching off and moving to the next cell when it reaches the exact preset level.

Or better still have two lithium sets -one is charging while the other takes the load. When the one is full and is switched off from charging it takes over the load while the other charges in peace. That way each cell can turn off in the charging battery when it reaches the right voltage without any interference from a load. Does this make sense or am I just raving lol

[T1 Terry]

So for now if a cell is down a little I could isolate it and give it a boost with a small charger(eg 4 volts) until it measures the same as the others on my fluke -OR put a load on a high cell and bring it back to the others OR put them all in parallel for a few days and clean all the contacts in the process.

Keep trying Bob. I believe in you. Both you and Terry and Martin have helped me lots.

This might sound like oversimplifying it but all we need is four mini chargers (one for each cell or group of cells) that charge till say 4 volts then switch off when each gets to exactly 4 (or whatever you choose) Some might be on a little more time than others. As long as they all cut off at exactly the same voltage then shouldnt they all be balanced? This might be thrown out somewhat if a load was on while your charging. Or the one charger could go around the four cells swtching off and moving to the next cell when it reaches the exact preset level.

Or better still have two lithium sets -one is charging while the other takes the load. When the one is full and is switched off from charging it takes over the load while the other charges in peace. That way each cell can turn off in the charging battery when it reaches the right voltage without any interference from a load. Does this make sense or am I just raving lol

All those ideas have been tried and were a dismal failure resulting is severely damaged cells, and that was only charging to 3.6v, not 4v Once you fully understand the requirements of these cells, in a house battery application and that is quite a bit different to an electric vehicle application, the system to achieve the required result is quite simple.

T1 Terry

[cvtripper]

Here's a good laugh from a facebook page.

"To run an airconditioner for 2 hours you would need 40 100ah batteries.
Then to recharge those batteries you would need about 80 200watt solar panels."

Holy cow! lol

No sure if I should let them down lightly or throw in something like 10,000 batteries would be needed!
What do you think?

Hi , does any one use an inverter to run their air conditioner? If so what type of air con and what type of inverter/ set up to you have?
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Macca Macca likes this.

Nikki Perry W
45 mins · Like

Lyn Dutch F
44 mins · Like · 1

Paul Athens f
41 mins · Like

Liz Molnar ? Hubby's electrical engineer... Anyone done this?
40 mins · Like · 1

Macca Macca f
39 mins · Like

Paul Athens I doubt it would possible
39 mins · Like

Mark Lawry I don't think so...
38 mins · Like

Diane Douglas No it cant be done .Hubby said if you had a big enough inverter it would flatten the batteries within
Minutes. ..use a generator. .
37 mins · Like · 1

Liz Molnar Thx Diane. He not done the sums yet but mumbling all sorts of stuff
35 mins · Like

Alan Jennison our aircon is inbuilt (Motorhome is ex tour bus - any problems running it at idle for several hours? it is a diesel
33 mins · Like

Diane Douglas Lol thats okay. ...we used our genni. Up near Georgetown recently 44% no problems @ all.honda 2kva..(nothing less.)
32 mins · Like · 2

Jill Simmons I think you can only run them form 240v or if no power a gene. We bought a gene to use the AC when no power, but it is Honda, and very quiet; I tested it out at our National.
32 mins · Like · 2

Troy Helbers As Diane Douglas has said it can't really be done.
For it to work you would need something like 20 batteries, 2000 watts of solar panels and around a 3000 watt inverter.
All of this would cost around $10,000.
The only real option is a 12volt water cooled airconditioner. Even this would use a reasonable amount of power and won't cool a caravan/motorhome down. It will give a little relief if you are standing in front of it.
31 mins · Like · 1

John Raban Anything is possible, but definatly not viable or portable. Around 100 x 120 amp batteries & 100 x 200watt solar panels might work lol
27 mins · Like

Liz Molnar Thx we are newbies
25 mins · Like

David Lee Believe troy helbers as diane douglas I have a 5000/10000w inverter it runs air con till compressor cuts in drops battery instantly below 10.5 inverter shuts down need shit load of batteries I connected up 500 ahs of batteries together and still not enough speaking from experience
24 mins · Like · 1

Jill Simmons So are we, but I learned a lot by camping at KKC by my self, and with the help of friends.
24 mins · Like · 1

Troy Helbers When we all first started we all thought the same thing then with a little knowledge that comes from experience, asking questions and investigating we realize it can't be done.
23 mins · Like · 1

Liz Molnar We thought running the air con for a few hours when going to bed through inverter . If batteries flat can be charged next day using Generator ... Any experience /thoughts ?
21 mins · Like

John Raban May be one day someone will come up with a high powered low voltage consumption motor to run air con
19 mins · Like

David Lee Liz Molnar it cant be done sorry to disappoint you but if you get far enough away from people you can run your generator
19 mins · Like · 1

Trent Trent You would be looking at around 180amps at 12v. A surge of maybe 250amps at start up.
Possible but very expensive, roof space needed for solar massive and the weight of the batteries needed to setup a sustainable system to run this. No one does it for these reasons. It would be good though having a low current draw air conditioner.
17 mins · Like · 1

Troy Helbers To run an airconditioner for 2 hours you would need 40 100ah batteries.
Then to recharge those batteries you would need about 80 200watt solar panels.
16 mins · Like · 2

[campingnut]

Thanks T1 -I'm slowly putting the picture together. Your input is appreciated

[dapope]

They would be gobsmacked to see ours then. Not to mention quite a few others. Was nice being cool today when it was mid 30s outside. No generator run.

[T1 Terry]

Wombat (Eddie) is now concerned he will have too much solar and not enough load to use it, even with the air con 80 x 200w solar panels and 40 x 100Ah batteries, I'm guessing this was calculated by the engineer....... he isn't on that other motorhome forum and a book writer as well is he

T1 Terry

[dapope]

I reckon its the solar has saved my alternator from flogging itself to death.