Answers about fast charging lead acid battery.

[scottsAI]

VRLA battery 9C charging rate is possible! Wow.

Covers the concerns, efficiency of fast charging, etc.

http://www.evdl.org/docs/hawker-fastcharge.pdf

Have fun,

Scott Beversdorf.

[dnix71]

Yeah it works, but you have to monitor battery temp carefully and not go above 75-80% SOC. They also say 9c was possible but 5c was the practical standard. That still means you need 1/4 tp 1/3 larger battery pack for that type of charge cycling.

If businesses/malls put fast charge stations on their property for electric cars, then electric cars would be a lot more practical. But that would add to the grid load during the day, instead of shifting it to night when demand is lower.

For mobile quick charging to work, cars would need to have onboard converters with a normal 120vac outlet adapter.

[zap]

Interesting... thanks Scott.

The only wording I could find in the document about battery life was:

"Field testing, to date has shown good operation battery life employing rapid recharging up to 5C."

I wonder how it effects battery life.

[scottsAI]

If staying on context of battery life for automotive.

1,000 cycles is required. Problem earlier vehicles had trouble past 500-800.

For latest Chevy Volt, OB Gov said the battery must last 10 years...

That is like 2500 cycles.

May delay introduction, No battery has demonstrated it can do it.

The Volt Battery has not been around 10 years.

Scott.

[commanda]

That is like 2500 cycles.

May delay introduction, No battery has demonstrated it can do it.

From the THundersky website, Chinese mfg of Lithium Iron Phosphate batteries;

http://www.thunder-sky.com/pdf/TS-LFP40.pdf

80. % DOD (depth of discharge) > 2000 times
    
70. % DOD > 3000 times
    
    

Guess what batteries I've got in my scooter? My average daily DOD is about 25%, so they should just about last forever.

Amanda

[zap]

Amanda, it looks like you are still running the same thundersky's?

If so, how have they been holding up and are you happy with them?  Any regrets or problems?  How many miles on your scooter now?

Did you end up building your own BMS?

[dnix71]

Those are LiFeP04 not PbSO4 batteries. Lithium Iron Phosphate are the best available and don't go thermal if you overcharge them. The downside is they are very heavy and expensive. Tesla uses a proprietary version of them because they are the only battery that will last 10 years in normal use. Tesla also includes battery replacement/disposal in the cost of the car, which is the only responsible way to do it.

http://www.teslamotors.com/efficiency/charging_and_batteries.php

The conspiracy nuts who claim big oil is against the electric car ignore the fact that there is no common battery for electric cars that works for long in real life and doesn't have major environmental problems with recycling.

1,000 cycles isn't even 3 years. Existing hybrids need battery replacements 2-3 years and it costs big bucks.

http://books.google.com/books?id=5Rwryml3YMEC&pg=PA394&lpg=PA394&dq=ev+battery+replaceme
nt+schedule&source=bl&ots=kKCdJjCqsM&sig=DYCwe_HWBGieg7blO1BkUFHSdbs&hl=en&ei=he
vlSeflH5fKtgepreSXAg&sa=X&oi=book_result&ct=result&resnum=3

20% of the vehicle cost is lead acid batteries or 55% for NiMH. What you save in fuel is more than lost in battery replacement.

[spinningmagnets]

I am skeptical of all conspiracy theories, but after reading documentation of Texaco/Chevron control of "large format" NiMH battery patents (found in current hybrids) and their refusal to sell to anyone unless it is for large volume contract (huge PR opportunity wasted, could help "green-wash" oil company, but...)

Govt may "demand" 10 year life before replacement, batteries improving fast these days, big near-term market. Assuming 14-yr lifecycle for car, couldn't initial battery last 7 years? Govt will cave in, here's why:

Volt is a great car in most recent configuration, but best estimates are near $39K. Hummer, Saab, Saturn, Pontiac slated for closing down. G8 and smallest Hummer slated for re-badgeing as a Chevy. UAW and Michigan will demand additional bail-outs.

China BYD worlds biggest manufacturer of Lithium batteries, building factory in Mexico for hybrid car and electric car. Things change, but current estimate is $24K for cheapest model to compete with $39K Volt. (Buffett bought lots of BYD stock)

Ford Escape hybrid sold over 100K units, doubling production now. Also introducing hybrid that looks just like 2010 Toyota Prius/Honda Insight.

Will Obama/congress allow Volt to sink because current battery only lasts 7 years under harsh use?

Govt's job is to establish standards to help consumer (and in the end this also helps companies) Battery unit format should be a package that can be swapped in to Ford/Toyota/Honda/Volt. (OSHA says one worker should not lift more than 60 lbs, so Lithium cell should be 59lb each)

When I buy a flashlight, it MUST take "C" or "D" cells, no funky new format I can't find unless special order. Printers are cheap! unbelieveable! but ink cartridges are expensive and brand-specific.

Sorry if too OT...

[commanda]

Zap,

Of course I'm still running the same ThunderSkys. I fully expect to still be running them 10 years from now.

Very happy with them. All the cells reach full charge within 3 minutes of each other. So the BMS is doing what it is supposed to do; keeping the cells balanced.

The odometer has just passed 5000 (EVT) Kms, which is about 4350 real kilometers. I've now done about 1200 Kms on the ThunderSkys.

Only problem I had with the BMS was the first one failed due to being a little too alpha prototypish. Cooling fan wire vibrated off and the whole thing tried to impersonate a big lump of carbon. The Mk2 beta prototype has been going for over 5 months now. Might be time to actually finish screwing it together.

My one regret is that I didn't buy a second set when the Aussie dollar was so good against the greenback. Would love to put the same setup in my caravan which I'm refurbishing to put on my block of land. The original set cost AU$1200, the same now will be closer to AU$2K.  Looks like the caravan will have to manage on the used SLA's that came out of the scooter.

Amanda

[Bruce S]

Amanda;

 Pardon the jump in here. I was given a bunch of the HP battery sticks intact.

These little gems weigh 1/3 what one of my rebuilt NiCd packs do for the same v/Ah.

While looking into the correct charging circuits for the Li-Ion cells that are each 3.7@2600mA, the notes say to stay @0.5C and end charging time at 3hrs, using CV/CC.

Your BMS is homebuilt and I plan on doing something similar for the 48V 550watt e-scooter we have.

Are there any gotcha's I should be looking to avoid?

There seem to be a great number of SMD chips available for both types out there now for either the 3.6/3.7 cells. Not that hard to proto one up just looking to make sure it doesn't flame my office

Thanks in Advance

Bruce S

 

[commanda]

Bruce,

Start here;

http://www.endless-sphere.com/forums/viewforum.php?f=14

Best source of info available anywhere.  My unit is in there somewhere under "Commanda's BMS".

The dedicated chips are really designed for small applications. Daisy chaining them together for a 48 volt pack is generally unworkable. Unless you're real hard core (like me) easiest solution is to buy the kit from GGoodrum (long post near the top).

Amanda

[Bruce S]

Amanda;

 Thanks for the info. As BT would tell you, because of teenage daughter being hard core would be nice, but not for now:)

I am more inclined to make use of 12V cell packs and Series them together.

Thanks for the link, I will certainly read as much from it as possible.

Queensland Nurses are telling me the rain finally finished after a rainy Easter.

Cheers

Bruce S

[wdyasq]

"Govt's job is to establish standards to help consumer (and in the end this also helps companies) Battery unit format should be a package that can be swapped in to Ford/Toyota/Honda/Volt. (OSHA says one worker should not lift more than 60 lbs, so Lithium cell should be 59lb each)"

Where does it say that in the copy of the Constitution you have, I can't find it in mine .....

After you find that .... show me something the government does well. Don't give the military as they do things IN SPITE of the government!

They protect the border..... uh ... they educate better than .... oops....

Oh, I did find one .... the FBI was successful in burning down a lot of things combating criminal things like folks not wanting to play like they wanted them to...

Well, waiting for the change ...

Ron

[zap]

Thanks for the info Amanda... nice to know you're that pleased with them.

They're still a bit to rich for my blood.

Nice score Bruce.  That ought to get the scoot scootin.

[zap]

"Govt's job is to establish standards to help consumer..."

That stuck in my craw also Ron! (sigh)

I think most people don't even realize how much more freedom they the keep giving up every day... so how can they care if they don't even realize it?

I'm not waiting for the change... I'm fearing it.

[commanda]

Guvernments job is to get itself re-elected.

Consumerism wasn't even invented when the constitution was framed.

What's that Latin expression that translates to "Buyer beware" ?

Amanda

[TomW]

caveat emptor...

Yeah we had paradise here and we foolishly sold / gave it to the likes of GM and WalMart who are slowly destroying it and selling it back to us.

Sorry thats politics and I can't go there.

Tom

[Bruce S]

Zap;

  I am thinking they will be a good fit, but after reading the link, I am sure it will also be a learning experience for building a BMS.

We have the wonderful battery tester I use for the NiCds before sending them out, and I will be using it to test/keep these alive while I learn.

Biggest issue I think I'll have is the max current drain being much lower than NiCds. The energy density is so much better I'll learn to live with it.

I did a quick rebuild of the packs I have. These are the HP Laptop unit that use the Samsung (ICR18650) packs. Strung them in a 4s4p set x4 gave me 48V@5Ahr. the pack came in at less than 5lbs! and the e-scooter loved it! With the battery box sized for 12VSLAs I think I could fit a good 50Ahr worth in there and still have lots of room for the BMS and a coffee cup :/ "I'm hooked"

Amanda's BMS looks very promising, work's getting in the way of my online reading :]. BUT I'll get there.

As a nod to the original poster, thanks for letting this drift in 10 directions!

Cheers

Bruce S

 

[Bruce S]

SPOT ON!!

Only in the very 1st elections, when they really did not even want the job was it NOT to get re-elected.

NOW it doesn't matter which side left,right so-called middle, once elected it OH did "I" say that? What I meant to say is ""...

My fun during elections is to show up and actually ask logical questions to see/hear how they answer and then ask the question in a different way to see if they're paying attention.

Haven't had one answer the same way twice in 30 years of voting

Bruce S