LiFeP04 Batteries for Solar & BMS

[Sunking]

PN EMI shielding is there to guard against the EV's motor controller, not external sources. External sources is chump change compared to what the motor controller can generate. Most DIY Ev builders uses a different battery to power the Controller to combat the problem. What Orion is done is allow you to use a DC-DC converter to run the controller off the HV Traction Battery.

Stop and think about it. A EV can draw up to 1000 Amps and uses PWM operating at 10 to 20Khz. That much current pulsed rings like Hell's Bell.

[PNjunction]

I think either one is a reasonable approach with some flexibility.

Just went to the Orion site and saw that it promotes their EMI protection - something sorely needed in today's environment. I wonder how many EV'ers may have had their bms go askew driving into areas of heavy FM Broadcast, NOAA, radio transmissions of every kind, and having the antennas, er balance leads picking all that up. Even in a fixed location environment, a neighbors plasma-TV may be a problem. I suppose you'd have to test for it before blaming it on this though.

I'm glad they are highlighting that since I think that's very important.

[Living Large]

I believe the House Power BMS from CleanPowerAuto LLC has similar options. LVC, HVC, and passive top balancing that can be disabled I think. While the first thing I think of is top-balancing, being able to turn off the passive balancers and perhaps utilize the HVC to fire on the weakest cell after you do a bottom balance manually, might be something to look into.

Not for me, but maybe for others...

I was looking at both House Power and Orion Jr for use with LFP and a bottom balancing approach. I believe I was considering the Orion for its added (at a small cost) ability to report the individual cell voltages via a CANBUS interface - but I don't honestly remember.

The House Power has a simple series loop where if any board goes open on charge or discharge it can trigger a HV or LV detect at the cell level of the first cell to hit the threshold, IIRC. I haven't looked at them for 3 months - this is from memory. I don't recall how that threshold would be programmed on each board though. There was a version with individual cell boards, and another with the electronics on a one board for multiple cells.

[PNjunction]

Orion is a centralized BMS with some smarts, but it does not have to be used as a BMS in the traditional sense. I use it as a battery monitor to turn off my battery charger. I Bottom Balance.

I believe the House Power BMS from CleanPowerAuto LLC has similar options. LVC, HVC, and passive top balancing that can be disabled I think. While the first thing I think of is top-balancing, being able to turn off the passive balancers and perhaps utilize the HVC to fire on the weakest cell after you do a bottom balance manually, might be something to look into.

Not for me, but maybe for others...

[PNjunction]

Does this mean my plan to use a window of 20%SOC to 90%SOC on a LFP bank, bottom balancing and a BMS, was all wet? We had discussed staying away from the knees. What am I missing, forgot, or never knew? Is my plan to use 70% of the capacity not realistic?

You CAN, but man, you had better have your power-budget calculations down to a tee if you plan to go there with an unstable source like solar only. One bad week or unexpected heavy emergency load means lights out.

I mean the sliding window of SOC that I talk about is cool and all, but is it practical for *you* ? Maybe so, but like taking lead to only 50% DOD many would argue not to go that far and shoot for maybe 35% max - it all depends on your power budget.

[PNjunction]

Well PN the irony of this whole thread and LFP batteries is it is only people like you and I who can work with them because we have the knowledge and skills to pull it off as long as we ignore cost. As for the public cannot be done because they do not have the knowledge or skills, not is there any automated equipment out there to work around that. Only thing out there now is Top Balance and it is expensive and is the root cause of battery failures.

Can't argue with that - realizing that American companies for the most part gave up on lithium-based batteries early on not so much from a technical standpoint, but from an inability to deal with the simplicity of lead that, um, just works even if THAT is often misunderstood. I think most who look into lifepo4 just realize it is not plug-n-play, or farm it out to others (or sharks) to do the job.

Well many folks with year old 3rd generation LFP cells are now starting to report capacity loss and failures. New package same ole line of crap. Failures are still being traced to over discharge using Top Balance, but capacity loss is a huge disappointment and set back. No matter what the manufactures say or do, calendar life still remains at 2 to 4 years regardless of cycles.

Yeah I've read those reports too, but only 100 messages later in the threads do we find out that they are using very old stock, abused their batteries early on testing and learning the right way .. and most importantly, using them in EV applications, not in a "Sub-C" solar storage application that I always harp about.

[Living Large]

No LL everything still applies.

Good, I'll go back to sleep now, and rest easy - even though there is a high level conversation the wheels are having about moving windows that are over my head

My best guess is restricting oneself to 50% will extend the number of cycles beyond what could be expected utilizing 70%, but also requires increased cost.

[Living Large]

Many this for the detailed reply, my next question is, how much maintance is required on the FLA battery, and what sort of maintance is required to maximise the life cycles out of the FLA battery?

Equalization periodically, checking the electrolyte level regularly, not discharging beyond a certain depth of discharge (which varies depending on which expert is telling you), charging at the right rate, storing them charged.
Here are a few sources of many on the internet:

http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery

http://rollsbattery.com/public/docs/user_manual/Rolls_Battery_Manual.pdf

[Legit]

Well I use GBS rather than Sinopoly with a Orion Jr as a smart battery monitor in my NEV (neighborhood electric vehicle) my racing golf cart so to speak. CALB, Sinopoly, GBS and a handfull of others are all Chi-Com LFP battery manufactures from the failed Thundersky Batteries. Same crap different package and name.

Orion is a centralized BMS with some smarts, but it does not have to be used as a BMS in the traditional sense. I use it as a battery monitor to turn off my battery charger. I Bottom Balance.

Anyway from an economic POV using Chi-Com LiFeP04 batteries is really the only option because they cost around 40 to 50-cents per watt hour. By a brand like A123, LG, Enerdel and others and you are looking at $2 to $4 per watt hour. Additionally LiFeP04 is really the only choice one has for solar because they do have the longest cycle life. Ironically LiFeP04 is the worse choice for electric vehicles because they have the lowest energy density and lowest charge/discharge rates and thus why no EV manufactures use them. Well A123 cylindrical cells can be used in EV's as they have high charge/discharge rates butt still poor energy density (low range), but they cost $2/wh.

So to answer your question LiFeP04 aka LFP batteries are the only logical selection for solar applications. And Chi-Com large format prismatic cells are about the only option at 45-cents per watt hour. Think what a nightmare and expense of using A123 cylidirical cells would be having say 8000 cells for a 48 volt 200 AH battery. You can do the same thing with 16 Chi-Com 200 AH cells for 1/5 the cost. Even at 45-cents per watt hour is way too much to be feasible when you can get a FLA that last just as long or longer for 15 to 20 cents per watt hour.

Even at 15 cents per watt hour is a looser compared to commercial power. Batter systems are no where close to competing with commercial power.

Many this for the detailed reply, my next question is, how much maintance is required on the FLA battery, and what sort of maintance is required to maximise the life cycles out of the FLA battery?

[Sunking]

That's the info I need,thks, there is this chap in our neck of the woods who converts petrol vehicles to electric www.freedomwon.co.za he seems suitably qualified in the field and uses Sinopoly LifeP04 batteries with a Orion BMS battery monitoring system, says the same setup can be used for a solar system - what do you reckon SunKing? does the Orion BMS also do this "over discharge using Top Balance"

Well I use GBS rather than Sinopoly with a Orion Jr as a smart battery monitor in my NEV (neighborhood electric vehicle) my racing golf cart so to speak. CALB, Sinopoly, GBS and a handfull of others are all Chi-Com LFP battery manufactures from the failed Thundersky Batteries. Same crap different package and name.

Orion is a centralized BMS with some smarts, but it does not have to be used as a BMS in the traditional sense. I use it as a battery monitor to turn off my battery charger. I Bottom Balance.

Anyway from an economic POV using Chi-Com LiFeP04 batteries is really the only option because they cost around 40 to 50-cents per watt hour. By a brand like A123, LG, Enerdel and others and you are looking at $2 to $4 per watt hour. Additionally LiFeP04 is really the only choice one has for solar because they do have the longest cycle life. Ironically LiFeP04 is the worse choice for electric vehicles because they have the lowest energy density and lowest charge/discharge rates and thus why no EV manufactures use them. Well A123 cylindrical cells can be used in EV's as they have high charge/discharge rates butt still poor energy density (low range), but they cost $2/wh.

So to answer your question LiFeP04 aka LFP batteries are the only logical selection for solar applications. And Chi-Com large format prismatic cells are about the only option at 45-cents per watt hour. Think what a nightmare and expense of using A123 cylidirical cells would be having say 8000 cells for a 48 volt 200 AH battery. You can do the same thing with 16 Chi-Com 200 AH cells for 1/5 the cost. Even at 45-cents per watt hour is way too much to be feasible when you can get a FLA that last just as long or longer for 15 to 20 cents per watt hour.

Even at 15 cents per watt hour is a looser compared to commercial power. Batter systems are no where close to competing with commercial power.

[Sunking]

Does this mean my plan to use a window of 20%SOC to 90%SOC on a LFP bank, bottom balancing and a BMS, was all wet? We had discussed staying away from the knees. What am I missing, forgot, or never knew? Is my plan to use 70% of the capacity not realistic?

No LL everything still applies.

[Living Large]

{snip}

Strangely, we're almost back to the 50% capacity rule like with lead, but with far less um, autonomy-anxiety!

{snip}

Does this mean my plan to use a window of 20%SOC to 90%SOC on a LFP bank, bottom balancing and a BMS, was all wet? We had discussed staying away from the knees. What am I missing, forgot, or never knew? Is my plan to use 70% of the capacity not realistic?

[Legit]

Well PN the irony of this whole thread and LFP batteries is it is only people like you and I who can work with them because we have the knowledge and skills to pull it off as long as we ignore cost. As for the public cannot be done because they do not have the knowledge or skills, not is there any automated equipment out there to work around that. Only thing out there now is Top Balance and it is expensive and is the root cause of battery failures.

Something else is coming to the surface. Chi-Com LFP batteries are on their 3rd generation, and the 3rd generation has been out now for just over a year now. Each generation claimed 1000 to 2000 cycles. Well many folks with year old 3rd generation LFP cells are now starting to report capacity loss and failures. New package same ole line of crap. Failures are still being traced to over discharge using Top Balance, but capacity loss is a huge disappointment and set back. No matter what the manufactures say or do, calendar life still remains at 2 to 4 years regardless of cycles.

That's the info I need,thks, there is this chap in our neck of the woods who converts petrol vehicles to electric www.freedomwon.co.za he seems suitably qualified in the field and uses Sinopoly LifeP04 batteries with a Orion BMS battery monitoring system, says the same setup can be used for a solar system - what do you reckon SunKing? does the Orion BMS also do this "over discharge using Top Balance"

[Sunking]

Additional capacity to account for unforeseen extra loads, inclement weather, minor mistakes in the power budget, etc. Can't charge it back up to 90% SOC? No problem as long as you design to allow for a sliding window, which ordinarily would damage Pb pretty quickly. Not to mention being able to totally unhook and leave your battery for a year or more as long as you have 40% or so in it and no parasitic loads.

Well PN the irony of this whole thread and LFP batteries is it is only people like you and I who can work with them because we have the knowledge and skills to pull it off as long as we ignore cost. As for the public cannot be done because they do not have the knowledge or skills, not is there any automated equipment out there to work around that. Only thing out there now is Top Balance and it is expensive and is the root cause of battery failures.

Something else is coming to the surface. Chi-Com LFP batteries are on their 3rd generation, and the 3rd generation has been out now for just over a year now. Each generation claimed 1000 to 2000 cycles. Well many folks with year old 3rd generation LFP cells are now starting to report capacity loss and failures. New package same ole line of crap. Failures are still being traced to over discharge using Top Balance, but capacity loss is a huge disappointment and set back. No matter what the manufactures say or do, calendar life still remains at 2 to 4 years regardless of cycles.

[PNjunction]

This is what I find so attractive about lifepo4 in a solar storage application - that sliding window of SOC / DOD under irregular solar conditions without incurring battery damage long term. But that means de-rating and oversizing your bank a little bit to do so. Once again though, this costs more up front.

Strangely, we're almost back to the 50% capacity rule like with lead, but with far less um, autonomy-anxiety!

Additional capacity to account for unforeseen extra loads, inclement weather, minor mistakes in the power budget, etc. Can't charge it back up to 90% SOC? No problem as long as you design to allow for a sliding window, which ordinarily would damage Pb pretty quickly. Not to mention being able to totally unhook and leave your battery for a year or more as long as you have 40% or so in it and no parasitic loads.

Aside from the fun we're having dealing with top / bottom balance, voltages, etc, I find the practical ability to have sliding windows, and being able to just walk away from a partial discharge for a year or more so liberating. And I'm just a 12v geek - someday I'll be 24 or 48v with some REAL loads. This practical aspect is what excites me so much, even though my wallet might complain in the beginning. But being able to treat my battery poorly if it were lead, (within reason of course) and have lifepo4 just shrug it off and even reward me for doing so is what blows my mind.