I'm sorry Boeing screwed up, but I just recalled that i got this idea from the Tesla Motor Model S sedan car... so... someone got it right...

http://www.breitbart.com/Big-Government/2014/02/14/Fifth-Tesla-Car-Fire-In-Five-Months


http://www.bloomberg.com/news/2014-...ause-of-toronto-garage-fire-with-model-s.html

 

If you would like a demonstration of how much energy a small battery can deliver under fault conditions, put a 9V battery in your pocket with a couple of dollars worth of coins.

It's a lot like Zippo rash, if you know what that means.

 

@ Bountyhunter:

both articles say this text, I quote:
http://www.breitbart.com/Big-Government/2014/02/14/Fifth-Tesla-Car-Fire-In-Five-Months
"We don't yet know the precise cause, but have definitively determined that it did not originate in the battery, the charging system, the adapter or the electrical receptacle, as these components were untouched by the fire," said Tesla spokeswoman Liz Jarvis-Shean. "

http://www.bloomberg.com/news/2014-...ause-of-toronto-garage-fire-with-model-s.html
“The Model S continues to have the best safety track record of any vehicle in the world,” Tesla said in a statement. “In this particular case, we don’t yet know the precise cause, but have definitively determined that it did not originate in the battery, the charging system, the adapter or the electrical receptacle, as these components were untouched by the fire.”

So... it kind of made my point: Tesla figured out how to do it. Until counter argument I keep my point.
_____________
Also we can keep in mind the already heard of Cell phone explosions... does that mean that we will ban them? Although these cases mostly the cause was the Li-Ion battery.

To make one single point clear: I opened this subject to get an idea what to look at.

Thank you all for pointing the safety concerns of this project and sorry that all stood on exactly this argument.

Can we move on, i found a website talking of lifepo4 batteries, it is specialized in electric Bikes (mainly).

I am not 100% sure of the specs, here are a few links. Actually they offer a charger to go with the battery banks...

About the safety reasons, are there any concerning LFP batteries? In a brief search i did not find anything more exact than:

"Lithium iron phosphate has no known carcinogenicity whereas lithium cobalt oxide does because it contains cobalt, which is listed as a possible human carcinogen by the IARC. LiCoO2 can lead to problems with runaway overheating and outgassing, particularly in the form of lithium polymer battery packs, making batteries that use it more susceptible to fire than LFP batteries. This advantage means that LFP batteries don't need as intense charge monitoring as traditional li-ion. However, LFP batteries tend to have lower (~60%) energy density in comparison to traditional li-ion."
Source Wikipedia:
https://en.wikipedia.org/wiki/Lithium_iron_phosphate

40152 headway battery, phosphate, lifepo4, 15AH
http://www.greenbikekit.com/battery-cell/40152-headway-cell.html

1 cell of 15AH at 19.99Eur??? is it me or this is a barging...

A 360W charger at 39.19 Eur?
http://www.greenbikekit.com/battery-charger/360w-e-bike-battery-chargers.html


Is this worth changing the title from UPS with LI-Ion to UPS with LiFePO4 ?

thank you for this imput

P.S.: my intention to build this still rests.

Thank you all for your ideas! keep them coming...

 

@ Bountyhunter:


“The Model S continues to have the best safety track record of any vehicle in the world,” Tesla said in a statement. “In this particular case, we don’t yet know the precise cause, but have definitively determined that it did not originate in the battery, the charging system, the adapter or the electrical receptacle, as these components were untouched by the fire.”

So... it kind of made my point: Tesla figured out how to do it. Until counter argument I keep my point.

Since you are inclined to get your failure analysis data from the maker who stands to lose billions when the fires cause are determined...... just like asking the fox to find the missing chickens.

BTW: it has already been admitted that ruptures to the battery compartment on Teslas causes fires if the battery is ruptured. PERIOD. Their claim is that by looking at miles driven, their cars are no more likely to catch fire than other cars.... which may be true considering how many "conventional" cars also catch fire from other electrical problems.

We were trying to illustrate to you that Li batteries have an inherent risk of fire. You seem intent on using them regardless.

So, good luck.

A Tesla Model S electric car caught fire this week after hitting road debris on a Tennessee freeway, the third fire in a Model S in the past five weeks.

The blaze on Wednesday afternoon near Smyrna, Tennessee, engulfed the front of the car. A spokeswoman for the Tennessee Highway Patrol says the Model S ran over a tow hitch, which hit the undercarriage of the car, causing an electrical fire.
It's the second Model S blaze involving road debris.

http://phys.org/news/2013-11-tesla.html

The smell of car batteries roasting in the flickering flames has reached the nose of he National Highway Traffic Safety Administration, which aid it’s opened a formal probe into the safety of the Tesla Model S electric car after reports of two fires caused by cars hitting debris in the road. In other words, Elon Musk is probably not happy right now.
The “undercarriage strikes” are the reason for the safety investigation, reports USA Today, as both cases involved fires in the battery compartment when cars hit stuff in the road that pierced those compartments.
This morning before the NHTSA announced the probe, CEO Musk rolled out three steps the company would take because of the fires but said in the lengthy blog post that he still thinks the cars are safe. The steps as summarized by USA Today:

•Higher ground clearance to make them less likely to strike road debris that can potentially penetrate the battery pack and ignite a blaze.
•Asking federal safety regulators to “conduct a full investigation as soon as possible into the fires.” Musk gave no hint that NHTSA was about to open an investigation.
•Amending the cars’ warranty to cover damage due to fire.


http://consumerist.com/2013/11/19/c...-official-probe-into-safety-of-tesla-model-s/

​

 

I have seen a lot of car fires over the years, not all were blamed on batteries as gasoline burns better than batteries. However we did not give up using gasoline just because of the risk of fires neither.

 

I have seen a lot of car fires over the years, not all were blamed on batteries as gasoline burns better than batteries. However we did not give up using gasoline just because of the risk of fires neither.

This is really a study in defective design reasoning. I spent 30 years as a designer of various types....

First: yes, many cars have gone flambe with gasoline even from simple rear end collisions. We did not abandon gas for a simple reason: the motor needs it to run and there is no commercially viable substitute (even today, the EV is a financial disaster which only exists at all because of government subsidies). So, yes, we accept the risk of gas and try to improve safety to contain it. If there was any better way, we would use it.

That leads us to Li batteries: they have a significant fire risk. When is it justified? In cases where the lighter weight is so attractive/essential it must be taken on. Portable electronics and, yes, even electric cars must have Li. The latter have no choice: their #1 design shortcoming is short range and they must squeeze every pound out of the massive battery pack. They have integrated a massive amount of expensive protection and monitoring circuitry as well as physical protection.... which has not proven to be fully adequate so far since several Teslas have burst into flames after they drove over a piece of metal which spun up and punctured the battery pack. They will certainly have to be redesigned to fix this flaw.

But when designing any product, balance risk/reward: why would the risk and cost of Li be justified in a UPS system?

IMHO, it would never be.

proof?

Count all the UPS products on the market that are using Li batteries.

Wow.... that didn't take long.

Edit to add: another place Li are being sold is for starting batteries for motorcycles. As stated before, the size/weight savings is the litmus test, and for bike's it is enough to make them viable as a product for that application.... although they cost about 7X what a comparable lead-acid does and so far, have had very mixed reliability results. The jury is still out as to whether they will ever catch on. A bike's battery is under the seat, about three inches under where the family jewels reside when riding. The pictures of Li battery fires I saw are enough to make me not want to sit on an Li battery.....

 

You guys made me remember a safety concern on the Bugatti Veyron: At the full speed of 407 kmph ... the tires will explode after 15 minutes, that is all ok: The fuel lasts only 12 seconds...

Same here: the Li-Ion batts in my UPS will be on wheels, castor wheels that is... do you see a piece of metal coming from underneath to pierce them to cause fire???

)

Ok guys, let's leave the Li-Ion Apples and move our discussion onto Cherries:

THE LIFEPO4 Batteries, they are still Lithium based and... firework-free (apparently)

Do you have any data on them? still lighter than the LA and with just half the charge of the LI-Ion weight-wise, and i quote from wiki:

"The major advantages are that the LFP batteries do not have such safety concerns as overheating and explosion, have 4 to 5 times longer cycle lifetimes than the lithium batteries, have 8 to 10 times higher discharge power (which can produce an instant high current) than the other lithium batteries, and have a wider operating temperature range than the other lithium batteries."

This makes an interesting bet for me.

P.s.: To answer the question about shops and delivery: I live in Paris, FRANCE.

 

Ultimately it's your project so build it how ever you want for what ever reasons you feel justify it.

Just don't expect that any battery type that is not LA based will directly drop right in and work with the systems present charging and monitoring circuits.

 

Ultimately it's your project so build it how ever you want for what ever reasons you feel justify it.

Just don't expect that any battery type that is not LA based will directly drop right in and work with the systems present charging and monitoring circuits.

Exactly my point. That is why I am asking for the heads-up, Thanks for your guidance I stumbled across an article that talked about a 1% rule on the Li-ion: overcharged 1% and they will explode, undercharged 1% they deteriorate.

So... let's leave this chapter behind and move on to LIFEPO4 Batteries.

 

You have to ask a question to get the conversation away from, "You'll shoot your eye out, kid". Which part do you want to design first and how far have you gotten with your schematic?

 

In big, this is my idea:

https://www.dropbox.com/s/cjfz3crtcgos8a3/PC Project.jpg

Note that i do not know the requirements of the LCD. I think it's a 12V too... not 100%.

I built a 12v Stabilizer, or voltage regulator, a few years back in high-school.

For now I am concentrating on the UPS:

I wish to keep it as simple as possible and I am looking at alternatives for the battery bank.

Has anyone got some experience or worked with LIFEPO4 cells?

I have seen on the website greenbike (see previous posts) a 360w charger, will it suffice to charge my battery bank, for starters I would probably go with a 160 Ah.

I have a hunch that if I use the pc at the same time as charging the batteries from the wall plug, i think that the 360w won't suffice. I still need a second power supply to convert 220v to 12v while no sun shines or i'm not running on batteries.

 

In big, this is my idea see picture.

Note that i do not know the requirements of the LCD. CHecked after and transformer says: output 19v 2.1 Amps

I built a 12v Stabilizer, or voltage regulator, a few years back in high-school.

For now I am concentrating on the UPS:

I wish to keep it as simple as possible and I am looking at alternatives for the battery bank.

Has anyone got some experience or worked with LIFEPO4 cells?

I have seen on the website greenbike (see previous posts) a 360w charger, will it suffice to charge my battery bank, for starters I would probably go with a 160 Ah.

I have a hunch that if I use the pc at the same time as charging the batteries from the wall plug, i think that the 360w won't suffice. I still need a second power supply to convert 220v to 12v while no sun shines or i'm not running on batteries.

Note that i do not know the requirements of the LCD. I think it's a 12V too... not 100%.

I built a 12v Stabilizer, or voltage regulator, a few years back in high-school.

For now I am concentrating on the UPS:

I wish to keep it as simple as possible and I am looking at alternatives for the battery bank.

Has anyone got some experience or worked with LIFEPO4 cells?

I have seen on the website greenbike (see previous posts) a 360w charger, will it suffice to charge my battery bank, for starters I would probably go with a 160 Ah.

I have a hunch that if I use the pc at the same time as charging the batteries from the wall plug, i think that the 360w won't suffice. I still need a second power supply to convert 220v to 12v while no sun shines or i'm not running on batteries.

 

You guys made me remember a safety concern on the Bugatti Veyron: At the full speed of 407 kmph ... the tires will explode after 15 minutes, that is all ok: The fuel lasts only 12 seconds...

Same here: the Li-Ion batts in my UPS will be on wheels, castor wheels that is... do you see a piece of metal coming from underneath to pierce them to cause fire???

No, I see a miniscule battery cell imbalance causing some cells to be overcharged possibly causing the fire.

 

No refrigerator? What kind of blackout party is that?

 

@SergS: did you ever get it to work?

I stumbled across your post while looking for a similar solution. I have a camera that i need to keep turned on for a robotic EOAT. The camera requires 24VDC and 2A. I am currently using a siemens LA batt and it weighs 10lbs; I am researching ups for li-ion batt (which weighs 3lbs).

Thanks
Karan

Hello,

I am thinking of building an UPS that uses a few banks of 18650, 3.7 Li-Ion batteries.

Mainly i need 12v so, wiring them in sets of 4 (4x3.7v= 14.8v), should give me a lot of juice, and considering the price is somewhat lower than the old lead boxy ones, it should be a viable option.

The only concern is the charging circuit that must have good protections and at least 350W at about 2.5 Amps to run sensitive electronics.

This is the first step.

If any details, please ask. I have limited knowledge in electronics.

Thank you!

 

I'm also wondering what happened with this thread.

I ended up here by googling the exact same question SergS asked here... and decided not to go ahead with this project as I want my house and me to survive.

I just hope SergS dissapearance was not caused by a homemade Li-ion powered UPS...

Cheers! And very neat forum, I didn't know about it!