12 Volt or 24 Volt?

[native pepper]

After reading the blog posted by Terry, I'm really pleased I've had some one who worked out the problems others are and have faced many year ago and believe got a system and set up parameters to get long lives out of lifepo4. It's good to see someone admit the true situation with their system, so others can learn from their misadventures.

The most important things are addressed in the blog, like bulk charge, but still people use some form of float and that's why the charge controller we use are just bulk to 14v with nothing else.

Same with temps, slowhand worked out many years ago lifepo4 only likes temps between 18-23deg C, beyond those problems arise. That's why in some of their systems they use peltiers to control pack enclosure temps and try to make sure as many installations are internal within areas of constant livable temps. In the bus, the pack is under under the lounge and away from anything creating heat. The inverter and other bits are no where near the pack, so it stays at a constant temp.

Same with balancing, gone from using a torch bulb, hobby charge balancer, to BMS with active balancers, to now just a bulk charge controller to 14v and 8amp cell equaliser. Since this last setup, have been extremely happy to see my packs nicely balanced no matter what SOC or DOD they are. Even with a number of charge controllers connected and pumping in 80+amps, everything works fine, the equaliser handles it excellently.

Did notice one thing when first using both the bulk charger and equaliser, it took a couple of cycles for the packs to become stable. The first time I used the bulk charger, almost became paranoid because the cells were all over the place and needed constant balancing attention, because the active balancers couldn't cope. After a couple of charges with the equaliser, they settled down, but the balancers still couldn't handle the fast charge to 14v. As soon as the equaliser was put on one pack, it took one charge to settle and from there, every cell charges at virtually the same rate and the differences are so minimal as to not be a worry at all. When the pack hits 14v, every cell is at 3.5v and along with charging and taking energy from the 4 points of the pack, finally am extremely happy with lifepo4.

My 120amp x 12v portable pack has had the most work, which when at home is every day and after the years I've had it, it still produces 121amps. Had thought as it was my experimental pack, it would have suffered with all the changes and tests I've done and so far no indication of any problems. So nice to see the reality of lifepo4 coming out, to remove the secrecy and intrigue some have put around them.

[T1 Terry]

There is more to setting up lithium house batteries than first meets the eye, some are about to find that out the hard way

Agree. And, unfortunately, they will give Lithium a bad name in the process and the doomsayers will be out in full force.

Sadly there will be quite a few with holes burnt in their wallets, but those than set up their packs correctly will still be going strong, only the sellers who didn't have a clue and those that had their batteries for 12mths or less or don't have lithium batteries at all yet pumping out heaps of incorrect information will be the ones with the bad name.
You would agree I'm sure that once the system is set up correctly they are very easy to work with, far less work than the AGM batteries they replaced and I'm guessing your cells would have already outlasted 2 sets of AGM batteries and still going strong.

T1 Terry

[T1 Terry]

Same with temps, slowhand worked out many years ago lifepo4 only likes temps between 18-23deg C, beyond those problems arise.

That is a very narrow temp range NP, I'm afraid mine suffer anything from minus a few *C to 50*C plus and haven't shown any ill effects, leaving them connected direct to the solar for 6 weeks did though, but at least half of them are still alive and kicking 2 yrs later. As far as I can tell it's all to do with the pack assembly and initial condition charging, get that right and they are as tough as old boots, miss these vital parts and the pack suffers a shortened life

T1 Terry

[triptracks]

There is more to setting up lithium house batteries than first meets the eye, some are about to find that out the hard way

Agree. And, unfortunately, they will give Lithium a bad name in the process and the doomsayers will be out in full force.

Sadly there will be quite a few with holes burnt in their wallets, but those than set up their packs correctly will still be going strong, only the sellers who didn't have a clue and those that had their batteries for 12mths or less or don't have lithium batteries at all yet pumping out heaps of incorrect information will be the ones with the bad name.
You would agree I'm sure that once the system is set up correctly they are very easy to work with, far less work than the AGM batteries they replaced and I'm guessing your cells would have already outlasted 2 sets of AGM batteries and still going strong.

T1 Terry

Terry,

The way I have flogged my cells over the past 2.5 years, if I had AGM I would have been thru at least 2 sets!
There is no way I could do what I am doing with AGM.

Free hot water morning and night, plus running a fridge and a separate freezer. And the kettle and the coffee maker. Then the full size washing machine (hot washes). Oh, and the 5kW air conditioner.... phew!

Today, I only harvested 575AH. I feel disappointed as there are some large holes in the graph as I didn't need the power. I thought the 608AH I harvested recently was good, but I suspect there is another 100AH in there, so maybe around 670AH, which is very close to my battery capacity. And no cloud today - so no scattered cloud "interference".

We weren't achieving this up north in the heat, but now we are in SA on the Yorke Pensinsular, that is something else. It'd be nice if it was a bit warmer though - we aren't use to 9C at night and 20C during the day (although, today was a bit nicer at 24C).

[native pepper]

I agree Terry, it is a narrow range and doubt many situations would provide that without the use of peltiers or other forms of temp control. Mine certainly don't sit within that range, but knowing that gives me a guide to keeping the pack in as stable and within as small a range of temperatures as possible. My old friend was one of those who wanted things right on the spot, rather than good enough, which is me. I do understand the logic, everything works much better in stable constant environments, so having lifepo4 in a stable small range of temps would certainly not harm them and may help them live longer.

I've experienced what dramatic high and low temps can do when using a lifepo4 starter battery. It worked wonderfully well for about 2 years, then you had to give it a few goes before it summoned up the energy to start the Sahara diesel. Which got worse and worse until after 3 years, it was bulging and wouldn't turn the engine over. It still fully charges, but doesn't have the amps. It would have experienced temp changes from below zero to 70-80deg in the engine bay. Now it's used to power a security camera and light on the workshop. So far after nearly 2 years, it still works ok and shows no signs of failing. I'm about to get another one for the backhoe and will site that in the cabin in an insulated box, to see if that makes any difference to it's life. Even thought of doing that with the Sahara, but haven't got past thinking about it.

Having your pack as close as possible to 18-23deg, may only relate to certain uses of the pack, like using lots of amps when the air temp is near zero, or over 30deg or some other magical number above that. As I don't know how to work that out or test it, I avoid using big draw on the pack during those times. Luckily the bus rarely gets cold or to hot and with the advent of a/c to it in the next few weeks, that will be the case hopefully. Don't know it that approach is the right one, but it can't hurt to make the effort.

Off subject, I've read in the last couple of days they have invented a capacity with a massive capacity and is very small. The claim is these will replace batteries in everything and will be rechargeable in minutes. By 2020 or so, we may end up with energy storage to run your home in a shoebox. Maybe that's what slowhand was working on, when you look at how our universe operates and how far we've come with miniaturisation of technology. It's only logical to see energy storage is going the same way, because of rapid and growing take up of solar, solar system exploration and coming travel, the next step would be storage. I'm beginning to feel, lifepo4 will only be a transitional storage system and we may see within 5 years enough storage to push a car 1000klms, in the size of a suitcase.

[bagmaker]

lots of energy in small spaces when you thing about it

boom.jpg

[native pepper]

Yep, look at the voyager probes still going after many decades running on a small nuclear power plant, just a few problems with that form of energy production though. Its not illogical to see the future where energy storage is so small, yet so capable and there are so many working on this problem, we may see a number of very reliable nano energy storage systems in smaller and smaller sizes. Our understanding of physics is far from the reality and every day they discover their understanding is minuscule. With a universe so large and diverse, who knows what is ahead, we may see small electrical wiring which can carry 12v without loss for klms, as an extension of fibre optics. All very exciting if we live that long to see it and don't blow ourselves up in the process.

[T1 Terry]

Is this the battery you are refering to NP? http://www.smh.com.au/technology/innova ... r=Mjk3NjE4
I do love these great leaps of imagination reporters possess. The jump from (could offer longer phone life after a few seconds charging to powering electric vehicles. They haven't even developed a proto type large enough to power a phone yet the imagination says it would power an electric vehicle. Sadly, the reality of most of these things is they are nothing more than vapourware. The idea is to generate funding for further research from any source possible, after a few yrs and millions of $$ it proves not to be compatible with scaling up to a useable size or not commercially viable or the magic get out of jail free, while doing this research we came up with an even better lab sized marvel, so no point in carrying on with this one, let's pour funding into the next wonder..... and so one it goes. It is the result of science having to come up with solid ground breaking achievements to attract funding so very highly paid professors get to keep their grants and their research staff. Fortunately, every so often a real breakthrough emerges or this whole thing would fall over. Things like 3D printing, salt water batteries, the flow battery that first made an appearance back in 1973 I think it was, it has been rebirthed so many times the list of attempts is as long as your arm, the latest is the RedFlow battery as a commercially available house storage battery.
Even after 43 yrs of development it is more expensive and less efficient than LiFeP04 and has far more down sides than LYP batteries so something appearing in the lab today would be very unlikely to reach the sales counter in under 10yrs. Even Aquion and there salt water battery with the brains of Jay Whitacre and billion dollar backing from some of the biggest names in finance it took 9 yrs from the lab to the first prototypes out in the real world and 10 yrs till they will be available for purchase by the general public, that will be next yr some time all going well, but they are still more expensive in Aust than LYP batteries. I think the LYP battery still has further development potential but I think it will still be viable in 10 yrs time.
The new generation of electric vehicle batteries will be the one to watch, double the range for the same size/weight and expect to be out in the market place late 2017 or 2018 and the norm by 2020. 400km recharge in 20 mins, so the 10 min break every 2 hrs driving means no range anxiety for those sticking to the unwritten rules, add autonomous drive and the car will stop for a recharge whether you like it or not

T1 Terry

[native pepper]

Yep that's the one and agree with you, most claims never get beyond the experimental stage. However from all these claims, we ended up with lifepo4 and many other innovations. As capacitors are a proven application, development of them to be able to store and power large things, is an open door. Whether someone enters that door and attains a viable outcome, is yet to be seen, especially with all the vested interests involved desperate to protect their primitive honey pot. I've had a capacity driven torch for a long time, all you do is shake it and it charges, have to give it lots of shakes to get a long use out of it, but it's easy to just shake a few time when you need light. Now have dummy "d" cells, which you slide a AA lifepo4 into and that gives you the required voltage, also use AA & AAA dummies in my camera's, which has extended their usage dramatically. So we are slowly moving to lifepo4 in many ways, pus AA and AAA cells are so cheap now. Bit like linux computing, everyone runs it down and they still can't believe linux runs over 95% of all computing on the planet and is state of the art.

Could be wrong, but the non roll out of dedicated lifepo4 chargers may be a ploy by vested manufacturers to maintain their lead acid products and market control, probably the reason they continue to claim their chargers and parameters are fine for lifepo4. All those I run into on the road with lifepo4, use lead acid chargers and claim they are fine with the float settings, yet seem to have trouble keeping them in balance and from over charging. The link l you provided shows hat to be the case in many situation, when i read how they used their lifepo4, it didn't surprise me they didn't last. It surprises me there are no bulk chargers with parameters that really suit lifepo4, other than the ones we have and those the Stones use in off grid.

When you look at the parameters they use for phone batteries and even the lifepo4 big batteries they sell, all seem to have charge and discharge parameters which to my mind are designed to reduce their life spans. I never charge my phones beyond 80-85%, or let them get below 20%, so far one has lasted at least 7-8 years and the big one more than 3 years without any problems. The old one is used for our band dealings and the new one for private calls and the net, neither shows any inclination to lose their power capacity and they are li-ion. My old mate made a charge station for phones, which uses his li-ion parameters, thought it may be left for me, but his son took it, so have to resort to watching the charging regime to control it.

Once my mate passed, getting dedicated chargers became impossible and it took negotiations with many manufacturers before we found one that was prepared to provide what we wanted at a reasonable price. After all, making a bulk charger without float, equalisation and temp controls, to my mind would be much cheaper than one with all the bells and whistles needed to control lead acid. Even tried to get them to install cell equalisers in the charger, but that went down like a lead balloon. Just happy we have what seems to work well, only time will tell whether we are right or not.

[T1 Terry]

After much frustration we went down the other path, rather than trying to get manufacturers to build what we wanted we built an interface to make any charger lithium compatible by monitoring cell voltages and turning the charger off if a cell reached undesirable voltage levels. Once the cell voltage settled the system reset and waited for another high voltage call but generally during the stop charging cycle the charger either dropped into absorption mode by itself, or if it completely shut down it would restart in float mode so the over cell voltage was no longer a problem, but the interface still keeps a look out just in case. After 5 1/2yrs the system has been tweaked a few times to get it into a smaller package but proven reliable and negated a need for auto cell balancing for 12v batteries. 24v and 48v are another matter, a bit like using a dog to herd cats, so the research is aimed in the direction of developing a capacitor balancing system aimed at moving the over charge from the high cell to the low cell but only while the over cell voltage is actually occurring, that way any problem that may actually be simple to fix in the early stages are not hidden by the balancing system until the problem is so serious damage has occurred.
At the same time we are looking into high output inverters with a very low standby and low percentage loss related to load, for instance an inverter that can power the microwave and air con at the same time yet charge a phone with minimal overhead losses, no inverter does that yet as far as I have seen and I've seen quite a few.

T1 Terry