New Lithium-Ion Batteries

[OceanPlanet]

I'll take a guess (base loosely on some experience and also on what I've heard), that at 1C you'd get some voltage-regulated current tapering at 95-96%. But I'm just guessing.

To do real tests on when the tapering starts vs. charge rates (on large lithium banks) you'd need a pretty hefty charging system at your disposal...;-)

[FlyingCloud1937]

Originally Posted by OceanPlanet

Yeah, I sat in on the early ABYC meetings on standards for OCP, AIC, etc. on lithium (and large AGM) banks.

Early suggested level for AIC rating (in lieu of a mfg recommendation) is 100 x the AH capacity of the bank.

Note: Re the Corvus stuff mention in that article...They seem to have been targeted more for higher-voltage propulsion applications. In fact, I'm delivering a 1080Ah x 24V house bank system next week to a client in BC that was looking at Corvus however it turned out that Corvus didn't yet have applicable BMS for the 24V house system.

Is that 1080ah 24v a lith... bat?

If so what is the charge source, and OCP?

Have you any info on what and how Insurance companies deal with the added risk?

What about marine Surveyor's any of them up to speed on this technology?

How about the UL, CG requirements?

Lloyd

[FlyingCloud1937]

Originally Posted by T1 Terry

I don't think anyone in their right mind would use lithium polymer batteries when lithium iron batteries are so much safer and better suit the purpose. Lithium polymer is what the model plane people use, special bags to put them in case they explode or burst into flame. Lithium iron batteries don't do that, the Chinese manufactured prismatic cells are military spec tested to insane levels to prove they won't explode or catch fire. Don't make the mistake of comparing Lipo cells with Li cells, chalk and cheese. The worst thing an Li cell will do is vent gas similar to petrol fumes but far less dangerous than the fumes from lead acid batteries and a much smaller volume per cell. Abuse an Li cell and you will shorten it's life, but only the one cell, savagely over charge them and they inflate like a balloon and then vent out the cap, same if you reverse charge them but this can only happen in a long string high voltage pack like in an electric vehicle.
Personally, I see adding a BMS unit is adding a failure point, not a safe guard, they are as reliable as the toy you get in a Christmas cracker and have lead to far more battery failures than they have prevented. Long string high voltage battery packs may need them (jury is still out on the EV forums regarding that one) but in a 4 cell series pack? Waste of time and money. A simple cell logger from the hobby shop, I like the Junsi cell log 8, around $14 for a non data logging model and $28 for a data logger. These have an audible alarm for low and high cell voltage and an alarm port that can be used to drive a relay to shut down the charging system is a cell goes into high voltage. A few minutes maybe monthly is all that would be needed to balance any wayward cells but I haven't had to do that at all since I condition charged my battery pack and that was over 3 mths ago. my batteries work 24/7, over 200Ah flow in and out every 24hr period. They only need balance at the very top of the charge anyway so the 100% charge and balance can be done at the operators convenience. Even if a cell starts to fail for some reason it's only a loss of capacity, not a total failure unless the cell has been driven into a reverse charge condition, virtually impossible in a 4 series cell pack.
Don't get conned and ripped off buying stuff you don't need just because you don't realise you don't need it.

T1 Terry

T1,

What you're advocating is a DIY solution, I would not recommend this to anyone that is not EE informed.

Near as I can tell consumer rated systems, have a much larger requirement then a DIY system...it's great you're doing the beta...but I don't see it going mainstream, as you propose...just to much liability.

Lloyd

[T1 Terry]

Reading through that link Loyd, it had to be lithium polymer batteries that burnt through the hull of that boat, lithium iron are not self combusting so an underwater fire is impossible. The only flammable part of a lithium iron battery is the solvent used in the electrolyte, this can only be got out by overheating the battery and then it comes out as vapour. Drill a hole in the case and nothing comes out, the electrolyte is vacuum impregnated into the active material and that is only micros thick on each side of aluminium plates and copper plates. It's only nano particles of lithium iron phosphate in a binder sprayed on to the aluminium plate, the copper plate is coated with graphite. Neither copper, aluminium or graphite will self combust, lithium iron phosphate will not combust in water no matter what the armchair professors tell you, check out all the You Tube videos of people putting hole in these prismatic cells and dumping them in water, nothing happens.
I liked this bit

I can get wet cell batteries anywhere. Maybe not T105's but the same chemistry and a workable temporary solution when the chips are down.

I agree with Maine and Bill -it'll be a long time before I move away from Trojan.

I bet they don't sing that tune about their Trojans much longer, since the company was taken over a while back the quality has dropped alarmingly, the lead acid EV boys are screaming.
I doubt you would have trouble getting lithium iron cells anywhere in the world now days, may take a week or so at the most but you can still get them, even in the Australian Northern Territory. Their famous line is “NT stands for, not to today, not tomorrow, nor Tuesday or Thursday.
If absolute worst came to worst, it's not like the two battery types are completely incompatible, a lead acid could be married up to get you through a tight spot till you got to more friendly waters but as I said before, they don't just die, they loose capacity so more frequent recharges would be needed on the crook cells till they were replaced. A 3.5v charger could be a handy thing to carry in the tool kit just in case, plugged into a small inverter and connected across the dodgy cell so the rest of the pack can carry it home.

T1 Terry

[OceanPlanet]

Originally Posted by FlyingCloud1937

Is that 1080ah 24v a lith... bat?

If so what is the charge source, and OCP?

Have you any info on what and how Insurance companies deal with the added risk?

What about marine Surveyor's any of them up to speed on this technology?

How about the UL, CG requirements?

Lloyd

Yes, the 1080Ah x 24V house bank is a custom Genasun system, made up of 3 x 360Ah x 24V banks. The three banks are running in parallel however each has it's own BMS and charge/load relays so each bank can isolate itself from either the charge or load busses. Each 360Ah x 24V bank is 2 x 360Ah 12V packs in series.

Charge source? Wasn't discussed at the meetings I was at. Not sure what you're asking about there. Of course we are often asked to come up with improved charging systems to take advantage of the LiFePo4 capabilities.

OCP? Also not discussed in the early meetings, however as always should be based on conductor ampacity. In addition to the fusing en route to the positive relay bus(obviously a good idea, aside from the ABYC reqs!), I know that Genasun also includes a simple ANL fuse in series (between a couple of the in-series cells) in each individual pack. If you short a tool while installing an external fuse/breaker, the internal fuse is your friend.

Surveyors? Good question. Some have been at the IBEX seminars, etc. but by no means do I think much Li knowledge has filtered to the average Joe Surveyor (yet).

UL & CG reqs? Beats me.

[T1 Terry]

Originally Posted by Jorma

T1 Terry,

Still one for clarification of the charging curve:

If I get it right, one of the greatest things with LiFePO4 batteries is, that there will be no absorption phase of reduced charge acceptance as with LA’s when hitting SOC 80-85%. See the picture.

What is your experience? If you charge LiFePO4 cell with 1C current, when will it slow down and how much? At SOC 95% or 99%?

Jorma

Between 98% and 99%. I'm not real good at the pictures on graphs thing so don't take this literally but it's a rough guide

This is only correct for cells in good condition that haven't been abused and had coatings form on the active plate surfaces. The coating slows the charge acceptance rate because less area is available, this would cause the fast charge section to drop back to 95% or even 90% in a badly affected cell, the remainder would need to be fed inat a reduced rate

[FlyingCloud1937]

Originally Posted by OceanPlanet

Yes, the 1080Ah x 24V house bank is a custom Genasun system, made up of 3 x 360Ah x 24V banks. The three banks are running in parallel however each has it's own BMS and charge/load relays so each bank can isolate itself from either the charge or load busses. Each 360Ah x 24V bank is 2 x 360Ah 12V packs in series.

Charge source? Wasn't discussed at the meetings I was at. Not sure what you're asking about there. Of course we are often asked to come up with improved charging systems to take advantage of the LiFePo4 capabilities.

OCP? Also not discussed in the early meetings, however as always should be based on conductor ampacity. In addition to the fusing en route to the positive relay bus(obviously a good idea, aside from the ABYC reqs!), I know that Genasun also includes a simple ANL fuse in series (between a couple of the in-series cells) in each individual pack. If you short a tool while installing an external fuse/breaker, the internal fuse is your friend.

Surveyors? Good question. Some have been at the IBEX seminars, etc. but by no means do I think much Li knowledge has filtered to the average Joe Surveyor (yet).

UL & CG reqs? Beats me.

Hi Bruce,

I want to take a stab at developing total costs for the above system.
I visited your site and see your system costs for bats and BMS are $27,000.00. does that include the required 750 amp Class T fusing, and relays? Are there any other cost associated with the install, above a typical bat install.

Warranty:
Genasun solar charge controllers carry a limited lifetime warranty on materials and workmanship. Genasun batteries and battery management systems (BMS) carry a two-year warranty on materials and workmanship. Genasun’s warranty does not cover damage due to abuse, operation beyond the rated specifications, or use without a properly installed and configured battery management system (BMS). An on-site system inspection by a Genasun technician or representative is required to activate the warranty on batteries and battery management systems (not required for the 2x100Ah 12V low-current system). Installation is not included. Normal decrease in battery capacity resulting from use is not covered under this warranty.

It appears that there would be a cost to activate the warranty?

I am sure that the Yacht Policy Insurer, is going to tack on a premium to policy to cover their added risk, what's your experience/knowledge of this?

Charging costs I assume will be equal to LA's except for the charge premium for time of LA's over 80% SOC. I also see that the alternator regulator is $400.00 for LI, maybe a premium of $125.00 over a Balmar MC614. I am assuming that a good quality large frame alternator in the 250 plus amp range will be the same for both LA and LI.

What about shore side chargers is there a premium?

What do think the real fire risk is with the Genasun bats, does it warrant increased fire protection?

Life expectancy, what's your real experience? I read your Li-vs-LA.pdf, but I'm not sure that represents real life. First it looks at worst case scenario for AGM's, and best case for LI's. My experience with flooded LA cells is considerably better than your AGM proforma. And purchase costs for the AGM bank seems about twice what I know they cost for the same size bank, at least here on the west coast.

I also know that I have vast experience with Trojan bats. They have a 7 yr warranty, and they do stand behind their warranty. I have installed at least a couple dozen Trojan banks over the last ten years, all have performed, or are still performing well past five years. None have had to be warrantied, but I do know of at least a couple of installers that have made claims that were covered even though the early demise was a result of poor charge regime.

My own Trojan bat bank, of 6 T-125's turns 9 years old this year and will have to be replaced. But I can say they have been as good an investment as any I've made on my own boat

My biggest worry is the LI bank replacement cost for a onetime error be it mistake or negligence on the part of the owner operator, or caused by an associated system failure.

I'm in hopes for this technology, especially as it matures and price point starts to drop as the manufacturing cycle matures.

I have had a lot of customer interest, but price point is certainly an issue today. Before I can tell my customers that they can expect a long term value comparable to existing technology, I need to feel confident in the numbers.

I certainly see where my CCG would be a good fit for on-board axillary charging.

Thanks for your post, I look forward to learning more from your early developed knowledge.

Lloyd

[T1 Terry]

Hi Loyd,
My issue with BMS systems is they are micro processor controlled and don't fail to safe mode. If the program has a glitch it doesn't shut everything down, it just stops controlling at that point. If it was charging then the charging continues until one of the back up systems takes over. Most BMS systems don't have a back up plan, how could a computer fail . If all BMS systems were mandatory complete system shut down in the case of a program glitch and loss of control they would be safer to a degree, maybe and emergency power supply remains to operate radios and nav gear would be a good addition. Even if the batteries were driven into the ground the most important part is safety, the failed batteries can always be replaced. I agree with the fuseable link mid pack, I use link plates made from copper sheet with a hump halfway between the bolt holes to allow flex but also a section clear of the battery cases so if a dead short at battery level occurs the link will fuse but not burn into the battery cases. I put a piece of heat shrink over that part as well so any molten material will be contained.

T1 Terry

[FlyingCloud1937]

Originally Posted by T1 Terry

Hi Loyd,
My issue with BMS systems is they are micro processor controlled and don't fail to safe mode. If the program has a glitch it doesn't shut everything down, it just stops controlling at that point. If it was charging then the charging continues until one of the back up systems takes over. Most BMS systems don't have a back up plan, how could a computer fail . If all BMS systems were mandatory complete system shut down in the case of a program glitch and loss of control they would be safer to a degree, maybe and emergency power supply remains to operate radios and nav gear would be a good addition. Even if the batteries were driven into the ground the most important part is safety, the failed batteries can always be replaced. I agree with the fuseable link mid pack, I use link plates made from copper sheet with a hump halfway between the bolt holes to allow flex but also a section clear of the battery cases so if a dead short at battery level occurs the link will fuse but not burn into the battery cases. I put a piece of heat shrink over that part as well so any molten material will be contained.

T1 Terry

T1,

That's good to know.

What is your motivation for being an Early Adopter DIY'r?

Based on the the bat's that you use, and the lack of the BMS, how does that reconcile with the bat manufactures recommendations?

IIRC you are at about 5 months with this system, and you appear to be well informed in re the issues, and EE. How can we translate that to a consumer friendly system. Especially for my customers that are technology challenged, not to mention a little challenged for proper maintenance?

I also want to say thanks, for your posting and sharing of knowledge.

lloyd

[OceanPlanet]

T1,
Yes, OFF should absolutely be the default mode for a safe BMS. That is the way Genasun is set up. Any cell module fails to report, you get a com alarm and the system will not drive the relays. Any cell goes overvoltage, the charge bus relay is turned off for that bank. Any cell goes undervoltage, then the load relay for that bank is turned off. Good old heavy-duty coil relays are used (non-latching type) since they cannot fail "on".

If after a long period of time after a LVC there is no charge source, and voltage continues to drop (as the BMS itself draws a little bit so it can kill the battery itself eventually), then the BMS cuts the charge relay also and turns itself (the BMS) off. This leaves no load on the bank at all.

There are BMS power switches (Off, Run, and Start) for each bank so you can restart an isolated bank when a charging source is available. Conversely if after a HVC, for any reason any cell continues up in voltage, then the load bus relay will be cut also. The default mode, unless everything is ok is that a bank (usually there are two) is completely isolated from charge and loads.

Genasun is pretty adamant about using dual parallel banks, with independent BMS and relays. Just in case you DO have the type of electrical mishap that you fear could happen.

This may all seem rather obsessive, however I've learned the hard way that if there is a way for the user (no matter how well-intentioned) to screw up the batteries, they will. So even though some may prefer to depend on themselves to monitor the cells, charging, balancing, etc. those are not the systems I sell (anymore).

I keep my ears & eyes open for any new brands/systems that could be better, but for now the Genasun is the system I provide to professional installers for house banks. The founder of Genasun started creating lithium systems for boats (and yes, the first systems were Li-Co) in 2006.

For high-voltage propulsion applications there are other options; and some new ones for that coming down the pipe.

[downunder]

At the prices given for the Lithium batteries listed on this website below ($200 for 200AH) and given that a 600AH lithium bank would be equilivant to 900/100AH LA system seem to me even with extra cost of BMS they are almost ready price wise for prime time. For a catamaran the weight saving looks good to me.
As Ocean Planet indicated there are video’s on U-tube testing the flammability of Thundersky batteries and than does not seem to be an issue.
Now the high end products such as GENASUN, Mastervolt etc are still charging a small fortune to wealthy consumers.
Seems like LP battery banks are nearly ready for mainstream.
http://currentevtech.com/Lithium-Batteries/Thundersky-c11/
CALB (Formerly Sky Energy) Lithium Iron Phosphate (LiFePo4) 3.2V 180AH

With high energy density and made from the LiFePo4 chemistry these batteries are both capable and safe. CALB batteries offer a slightly higher continues output compared to Thundersky allowing for smaller battery packs that have a higher continuous current rating than larger Thundersky cells. These cells are recommended for people that still like the cost effectiveness of large format prismatic cells but need higher continuous output compared to Thundersky.
$247.50

Thundersky Lithium Iron Phosphate (LiFeYPo4) 3.2v 200AH
With high energy density and made from the LiFeYPo4 chemistry these batteries are both capable and safe. Thundersky offers a very good price/capacity ratio making it very good for standard EV Conversions or bulk energy storage where price is a concern. They also offer very high cycle life, which is nice when considering your return on investment.

Was: $250.00
Now: $220.00

The EV enthuisiates have been playing around with LiPo batterise for 5 years or more

[OceanPlanet]

Flying Cloud,

Ok for me to PM you?

[FlyingCloud1937]

Originally Posted by OceanPlanet

Flying Cloud,

Ok for me to PM you?

Yes, as a matter of fact my-email is also available.

Thanks,
Lloyd

[goboatingnow]

Today , right now LiFePO4 is not applicable to run of the mill boating domestic applications. However its not far away. The advantages are simply enormous, no need for 100% charging( the major source of LA failure) , high weight energy density,, constant discharge terminal voltage, very low internal resistance( quieter electrical systems), easy recharge , ie constant voltage. Ease of end of charge monitoring, easy SOC determination, no peukert effect. Right now the primary downside is cost. ( thats easy to fix over time). Secondary problems mainly focus around the enormous short circuit currents and hence fusing is more necessary ( This however is equally arguable in high power AGM installations)


In fact in factional C charging regimes typical of most boats, BMS's arnt even strictly necessary. The current charging sources actually cant generate HVCs and LVCs can be handled by simple alarms and manual intervention, At fractional C, cell balancing,( other then possible initial balance) is not a requirement.

There is no doubt in my mind that we will see this technology adopted in time in boat domestic systems, the advantages are too good to ignore.

[downunder]

Originally Posted by goboatingnow

Today , right now LiFePO4 is not applicable to run of the mill boating domestic applications. However its not far away.

Right now the primary downside is cost. ( thats easy to fix over time).

Secondary problems mainly focus around the enormous short circuit currents and hence fusing is more necessary ( This however is equally arguable in high power AGM installations)

There is no doubt in my mind that we will see this technology adopted in time in boat domestic systems, the advantages are too good to ignore.

When you look at the prices here looks to me that price has been sorted. By the time my vessel is finished in late 2013 there is no doubt they will be cost effective.

At a cost of around $600 for 600ah LiPo from this site doesn't that solve the cost issue now.

http://currentevtech.com/Lithium-Batteries/Thundersky-c11/