LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

[goboatingnow]

Originally Posted by deckofficer

Because I still don't have a good balance. The charger only sees pack voltage. That is why I'm following Maine Sail's advice and getting the variable power supply to finally get them in balance. Check my resting voltages vs topping voltages.

Ogh I see I taught you were already using that.

Dave

[goboatingnow]

Originally Posted by daddle

So you guys would buy your halyards with the requirement that they "might function" vs. "rated for the load"?

So when used at currents less than C the cells will not need regular[\B] balancing. What is regular? Seconds, days, years, N cycles? Greatly less than C or arithmetically?

It appears that getting the system wrong could be expensive and dangerous.

I don't quite see what point you are making. If you charge a series string, you do need to monitor individual cell voltage. I stop charging ( in this setup ) when any cell reaches the target voltage. ( this is after a few initial balancing cycles ) I don't bother to implement charge bleed off ( top balancing ) . Yes this means I have slightly different SOCs across the strings. I measure imbalances around .1v. Since Li ferrous doesn't care about percent charged, I just use the batteries at that point. I estimate the loss of SoC at around 5%. I really couldn't care. Over time at the discharge rates I'm using I don't see the balance getting any worse and usually I find the cells converge rather then diverge.

Once you monitor HVC, nothing gets expensive and dangerous

Dave

[deckofficer]

Originally Posted by hellosailor

Many cars, fully electric? Better odds for electric boats, because docks usually have power posts these days.

Cars? Nuh-uh. Cities are not going to put power posts on street parking, too expensive, can't exclude the gassers either. Condos and coops with parling lots and assigned parking aren't going to install them, can't afford to break up the concrete and invest themajor money. Homeowners? OK, some will spend a couple of grand to do it in their garage, if they have one. Apartment dwellers? Can't do it.

Sure, it is nice to see a burger or coffee chain install a couple of charging posts but a couple of posts won't do it. I don't see how "pure" EVs are going to get past the infrastructure problem.

OTOH most boats are docked more than eight hours at a clip, making them a way better market for EVs. Just pull out the stinking diesel, drop in the...oh, wait, we're still waiting on electric propulsion motors with warranties, aren't we?

I have 3 EVs and love the plug and play nature. One is a truck and the other a China knock off of the Smart Car. I've driven the Tesla Roadster from Roseville, California, over Donner Summit to North Shore Tahoe on a charge it got in Palo Alto. A great car, tons of power without needing a transmission, and their new Model S sedan has a 300 mile range.

[Maine Sail]

Originally Posted by Kettlewell

Lithium batteries are considered hazardous, which changes the shipping equation. You can't ship even small ones via the US Postal Service.

But they can ship UPS and FedEX. A friend of mine, also in Maine, orders CALB cells from CO and pays a LOT less that what I did from Balquon.

[hellosailor]

UPS ground beats motor freight? Good lord, the apocalypse has come!

[deckofficer]

Originally Posted by hellosailor

Bob-
"The same purchase from Balqon on their clearance sale is $1032, and at their regular price (and probably newer cells) $1520,"
Batteries aren't like day-old bread or last week's sushi, batteries have a radically longer shelf life. And business inventory (etc) taxes are usually assessed on the first of the year, or the first of a fiscal period of some kind. Battery clearance, 1/3 off?? I never heard anyone in the battery business saying there was that much margin between retail and net net in the first place. What, you can't hear Robbie saying DANGER WILL ROBINSON! right about now? There's a significant part of this picture missing. Maybe Balqon was severly mismanaged and needs to hold the fire sale to pay off loan sharks. Maybe not. But I'm betting there's a huge backstory we're not hearing.

I've tried to find a back story but no mud found. Their main business is selling electric yard tractors to the Southern California ports to help them meet emission standards. The ports like these tractors and today for $925,000 ordered (3) regular cargo trucks for highway use. 100 mile range on a 500 kw-hr battery bank. Besides them being the main distributor for Winston cells here in the states, I think their electric truck and tractor business will keep them viable.

[hellosailor]

Maybe someone put two and two together, and figured out that if you can sell a truck for $300k, it doesn't pay to screw around selling a thousand dollars worth of batteries to some consumer who's gonna take up just as much of your time. That would probably be a best-case scenario. And here I was thinking I don't need batteries, but at those prices...gee, they SHOULD be able to sit on the shelf five years, right? <G>

[daddle]

Originally Posted by goboatingnow

I don't quite see what point you are making. If you charge a series string, you do need to monitor individual cell voltage. I stop charging ( in this setup ) when any cell reaches the target voltage.

Monitoring individual cells with a voltmeter? Or is there an hands-free method of accomplishing this.

My point is trying to determine if this technology remains in the fanboy stage or is ready for cruisers that have better things to do than monitor batteries.

[deckofficer]

Originally Posted by hellosailor

Maybe someone put two and two together, and figured out that if you can sell a truck for $300k, it doesn't pay to screw around selling a thousand dollars worth of batteries to some consumer who's gonna take up just as much of your time. That would probably be a best-case scenario. And here I was thinking I don't need batteries, but at those prices...gee, they SHOULD be able to sit on the shelf five years, right? <G>

Quite the contrary. They appreciate the sailor's business, and other than my 3 1/2 month wait, everyone else has gotten their cells in a timely fashion. Here is what they did extra for me, shipping-no charge, banding-no charge, jumper buss bars-no charge, and then they refunded me $280 on the order via PayPal. Upon trying to convert the PayPal money into a credit to my VISA card, I somehow sent it back to Balqon. I emailed them to my mistake but the funds haven't been re-submitted. I'm not a fan of PayPal, and would be fine with a store credit.

[senormechanico]

Originally Posted by diugo

Hehe, I always enjoyed firing those engineers who were so certain they were right all the time and could never admit that they might be wrong---until they were

Good engineers collaborate in teams, where all "mights" and "probablies" are welcomed and evaluated. That's why I'm here.

A little off topic, but funny none the less.
I read a quote the other day which went something like this:

"I CAN'T STAND people who are ALWAYS SURE they are ALWAYS RIGHT!"

"Are you certain about this?"

"ABSOLUTELY!"

[witzgall]

You cannot group all lithium batteries into the same HAZMAT category. I do not believe LIFEPO4 are considered hazmat at all.

Chris

Originally Posted by Kettlewell

Lithium batteries are considered hazardous, which changes the shipping equation. You can't ship even small ones via the US Postal Service.

[mcarling]

Originally Posted by deckofficer

10 years from now so many cars will be fully electric and large format lithium cells will be a mass merchandise item.

I don't think fully electric vehicles will be the driving force behind mass adoption of lithium phosphate batteries. I believe that most automobile manufacturers (starting with Ferrari, Porsche, etc.) will switch from lead-acid to lithium phosphate for starter batteries within the next five years, as Harley Davidson have already done.

[downunder]

Originally Posted by daddle

Monitoring individual cells with a voltmeter? Or is there an hands-free method of accomplishing this.

My point is trying to determine if this technology remains in the fanboy stage or is ready for cruisers that have better things to do than monitor batteries.

This unit for $33.00 looks the go and can handle up to 8 cells.

EV-Power | Cell Logger 8 cells / 1 battery (USB port)

From the mob Lagoon4US is getting his batteries.



Measurement Unit for 8 cells (3V) or 1 battery (up to 43V). Data recording, alarm triggering in overcharging or discharging and a USB connection for reading and further processing.
Battery Voltage Monitor, Logger and Recorger

* Small size with multiple functions, backlight 128*64 lattices LCD and Buzzer Tone Reminder; the interface can be operated smoothly.

* It can not only measure 2-8S Li battery individual voltage, but also measure NiMH, NiCd, Pb battery pack voltage.

* It can be set Individual Voltage Alarm and Pack Voltage Alarm, Overvoltage Alarm, Low Voltage Alarm, Differential Voltage Alarm and Time Over Alarm. What’s more, the extra alarm output can be linkage controlled by the users.

* It has 8 sets default monitor alarm settings, which can be selected for different battery packs.

CellLog8 information on GWL blog

[Lagoon4us]

Fairly sure these are or are similar to the JUNSIE that Terry advocates, i think they are cheaper on Ebay and as Terry says you need to get the connector plugs when purchasing..

Cheers

[daddle]

Okay. Thanks Downunder. Very interesting.