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Old 26-01-2013, 09:07   #1486

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

senormechanico-
I have some old application guides from Eveready and GE, for their NiCad and lead batteries, and both actually do remark on what we now call balancing. Except, their point is that when cells are in series, if you allow the battery to go dead OR discharged very low, any one of those cells may in fact be reversed and then subsequently be damaged or fail completely. IIRC they never mentioned it as a fire risk, but those chemistries are unlikely to burst into flames. More likely is that they will simply explode (as many do every year) from overcharging, but one reversed cell didn't mean an explosion or fire, it just meant "ruined".

So in this aspect lithium-C4 [sic] batteries are differnent only in that they are explosive due to the higher energy density. Hey, before starships had warp drives, we never worried about warp core explosion either, did we?

Dockhead-
The fact that Balqon had to take apart a Winston battery scares me. The more I hear about Balqon the more I wonder wtf these guys are doing and how they expect to stay in a commercial business. Balqon are partly OWNED by two Winston companies, so they should be able to pick up a phone and say "Can you send us the info on..." without having to take it apart. Balqon also advertise their batteries on their web site with a "five year warranty". Well, here in the US, if you didn't publish that warranty openly, didn't use the specific terms required by law, and didn't make it available before the purchase (online web purchase included) that substantially changes your legal obligations under warranty laws and under our Uniform Commercial Code. Balqon? You guessed it, no warranty available online. No statement that it is full or limited. So an online purchase may legally get a 4-year unconditional warranty, as opposed to the five year limited pro-rata warranty that Balqon intends to sell with them. [Note to anyone who has a problem within four years...remember that!]

In the US, this is just basic business skills. Clearance on three year old stock...three month order lag...taking apart batteries instead of asking what's inside (or maybe, not having any faith in what the answer might be?)...

I sure hope I'm just the pessimist in the room, but these guys REALLY could clean up their act. I know, their battery is perfectly safe, it isn't lithium-C4, and the clearances were a damned good price. I'd still feel like I was experimenting, and to me, trying a new grind of coffee is experimenting enough.<G>
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Old 26-01-2013, 09:16   #1487
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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Then you are operating recklessly.
That would only be true if there were safety-of-life dependencies on my batteries, which there are not. If there were safety-of-life dependencies, then I would check cell balance more often, but not any more often for LiFePO4 than for lead acid. I would check lead acid batteries for balance every time setting out if there were safety-of-life dependencies.

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Cells could easily go out of balance (and then out of range), especially near full charge and near full discharge.
That is no more true for LiFePO4 than for lead acid.

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The critical difference, of course, is that lead acid cells are much more tolerant of voltage excursions. That "opinion" should not be overlooked.
I haven't seen any evidence to support that opinion.
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Old 26-01-2013, 09:17   #1488
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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These guys are a distributer is the Czech Republic...isn't that Eastern Europe? I've never done business with them....

EV-Power | Your Complete Power Solutions
Bingo!

That's inside the EU so much simpler. And the have something similar except with some kind of control system:

EV-Power | LiFePO4 Battery Pack (12V/17Ah PCM)

If you download the spec sheet, you see that there is a 42 amp version.

What do y'all think?
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Old 26-01-2013, 09:17   #1489
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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The more I hear about Balqon the more I wonder wtf these guys are doing and how they expect to stay in a commercial business. Clearance on three year old stock...three month order lag...taking apart batteries instead of asking what's inside...These guys REALLY could clean up their act.
I agree. The only thing Balqon had going for it was price. However, price/value was the most important element for me.
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Old 26-01-2013, 09:20   #1490
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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Bingo!

That's inside the EU so much simpler. And the have something similar except with some kind of control system:

EV-Power | LiFePO4 Battery Pack (12V/17Ah PCM)

If you download the spec sheet, you see that there is a 42 amp version.

What do y'all think?
I don't know anything about the company, but you should save expensive hassles over VAT and duties. I would buy from within the EU.
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Old 26-01-2013, 09:29   #1491
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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I haven't seen any evidence to support that opinion.
The evidence [that LFPs are sensitive to voltage] is overwhelming. Keep your hydrometer---you'll soon be needing it again.
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Old 26-01-2013, 09:32   #1492
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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The evidence [that LFPs are sensitive to voltage] is overwhelming.
All batteries are sensitive to voltage. I have not seen any evidence that LiFePO4 batteries are more sensitive to voltage than lead acid batteries.
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Old 26-01-2013, 09:38   #1493
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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All batteries are sensitive to voltage. I have not seen any evidence that LiFePO4 batteries are more sensitive to voltage than lead acid batteries.
Then you apparently haven't ever driven a car and left the lights on. After a quick jump start, lead acid batteries generally rebound. Now, try doing the same thing with your LFPs.
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Old 26-01-2013, 09:42   #1494
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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Keep your hydrometer---you'll soon be needing it again.
I will absolutely never, ever buy another lead acid battery for any application.

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Originally Posted by diugo View Post
Then you apparently haven't ever driven a car and left the lights on. After a quick jump start, lead acid batteries generally rebound. Now, try doing the same thing with your LFPs.
I've given other people jump starts, so I know what you mean. It's bad for lead acid batteries to discharge them like that. Extreme discharge is also more likely with lead acid batteries than with LiFePO4 because of the self-discharge rates.
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Old 26-01-2013, 09:49   #1495
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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It's bad for lead acid batteries to discharge them like that.
It's even worse for LFPs.
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Old 26-01-2013, 10:02   #1496
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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Bingo!

That's inside the EU so much simpler. And the have something similar except with some kind of control system:

EV-Power | LiFePO4 Battery Pack (12V/17Ah PCM)

If you download the spec sheet, you see that there is a 42 amp version.

What do y'all think?
For the radio I would still go with the Winston non-BMS 40 a-hr 12 volt battery. This is what they say for it........

Information:
Concerning the 12V LP batteries: The monolithic batteries do not have any PCM (any electronics) inside. They consist of finely balanced cells with identical perfomace at the standard operating range of 11V to 16V. The battery must be managed as a single monolithic 12V block.


My assumption (and that is all it is) is cells are checked for internal resistance and then 4 are selected to make a 12 volt battery that won't be warranty headaches. What I base this assumption on is the de-rated C for the 12 volt battery vs individual cells. What I am seeing is if cells are balanced well, not subject to greater than 1 C loads and charges, not over charged or run flat, they stay balanced.

EV-Power | Lithium Battery 12V/40Ah (WB-LP12V40AH)

The 17 a-hr 12 volt battery as this warning......

Note: Due to the limitations of the protection circuit module (PCM), these LiFePO4 block 12V batteries may not be suitable for high current traction applications. They cannot be used as starting batteries. Check with us for more details. These batteries have PCM (protection circuit module) electronics inside. The PCM manages the internal cells and provides overcharge and discharge protection.

At 17 a-hr, your SSB voice peaks could draw 2C, if they made the same battery with BMS built in at a 40 a-hr rating, your voice peaks would never reach 1C.
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Old 26-01-2013, 10:06   #1497
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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Following up on Deck Officers recommendation on a LiFePO4 battery for me to use as a power supply for a HF radio, I wrote to Balqon for information. My questions, and their answers follow:

I am interested in your 40 amp/hour 12 volt battery to use as a power supply for a marine HF radio on board a sailboat. Can you tell me:

1. Does this battery have an on-board BMS, and if so, can you please describe the functionality of it?

2. Can you ship to the UK, post code SO31 1ZL? Cost and time?

Thanks very much, Dockhead




Hi: These batteries do not have a BMS, they were made for a direct replacement. Balqon does not feel safe selling these batteries without some sort of minor BMS though. We opened up a 12v90ah battery and realized there was (4)-90ah batteries inside, no resistors or anything. So I would suggest a BMS or one of my options is to call China direct and ask one of their technicians.

Yes we can ship to the UK. How many were you looking for? I will set up a quote to show costs for this shipment, and to get approval from you to confirm purchase. Regards, Balqon."




So it looks like Balqon are just flogging something they get from China.


Is it worth messing with something like, do you think? The price is right.
Are you sure that you have a problem using the house bank ?
Thousands of boats do it that way. Voltage sag might cause some distortion, but SSB transmissions are distorted at the best of times.
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Old 26-01-2013, 10:12   #1498
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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It's even worse for LFPs.
Regardless of the battery technology, leaving the lights on is a bad idea. However, I plan to have enough solar capacity and battery capacity that I could leave most everything except the propulsion motor on and never fully discharge the batteries.

Over the next few years, LiFePO4 starter batteries will replace lead acid starter batteries in new cars. I'm willing to bet that the auto manufacturers will equip LiFePO4 starter batteries with the same BMSes with which they now equip lead acid starter batteries -- none at all.
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Old 26-01-2013, 10:16   #1499
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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For the radio I would still go with the Winston non-BMS 40 a-hr 12 volt battery. This is what they say for it........

Information:
Concerning the 12V LP batteries: The monolithic batteries do not have any PCM (any electronics) inside. They consist of finely balanced cells with identical perfomace at the standard operating range of 11V to 16V. The battery must be managed as a single monolithic 12V block.


My assumption (and that is all it is) is cells are checked for internal resistance and then 4 are selected to make a 12 volt battery that won't be warranty headaches. What I base this assumption on is the de-rated C for the 12 volt battery vs individual cells. What I am seeing is if cells are balanced well, not subject to greater than 1 C loads and charges, not over charged or run flat, they stay balanced.

EV-Power | Lithium Battery 12V/40Ah (WB-LP12V40AH)
And no control device of any kind at all? Even the Balqon guy was warning against that.

I will write to him and ask what kind of control device he recommends.

Or why don't you like the model with the built-in control thingie? It's almost the same price per amp/hour.

In any case, we're homing in on a solution!! Thanks to Deck Officer and the rest of you, who unlike me have done the hard work figuring out this technology and doing the alpha testing at your own expense.

I am not retired and have to ration my time among the hundreds of different boat jobs, and I just can't afford to be playing with this technology at this stage of its development. So pardon me for mooching off your development time!

I am totally convinced that lead-acid is history. I have 8 one-year old Trojans which I hope will give me 3 or 4 years yet of service. By the time they're gone, I hope there will be a fully developed plug and play LiFePO solution -- I'm sure there will be! I can't wait. It's really so much not a trivial issue -- managing power on board is a huge headache while cruising -- one of the biggest and messiest jobs. When as part of that you have to do 19th century chemistry with specific gravity and acids and all this Dr. Frankenstein-like technology, worrying about sulphated plates, equalizing, all this crap we do. I can't wait until it is merely a quaint memory sitting cross-legged on the salon sole checking the specific gravity of 8 * 6 = 48 cells with a 19th century squeeze bulb hydrometer.
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Old 26-01-2013, 10:24   #1500
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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I'm willing to bet that the auto manufacturers will equip LiFePO4 starter batteries with the same BMSes with which they now equip lead acid starter batteries -- none at all.
The only way that's going to happen is to somehow inhibit the irreversible reverse reactions that plague the chemistry in all lithium ion cells when they are overdischarged. I hope there's a future for lithium under the hood---but it won't be found with the current set of cell ingredients.
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