Lithium battery BMS Question with Flexmax80

[jflorey2]

You guys keep telling me that Lithium batteries are not as good as the FLA.. and yet, everywhere else I'm reading says the opposite and that the only drawbacks to the Lithium are price and the fire hazard. Something doesn't add up.

Lithium batteries are far better than FLA for electric vehicles. Do you have an electric vehicle you want to power with them? No? Then different criteria apply.

If you said "I want to build an off grid power system, cost is no object, and it has to be as small and light as possible" then LiFePO4 would be a great option. If safety isn't important either, then consider standard lithium ion. But you keep bringing up cost and longevity, and you haven't said you want light weight. In the light of those criteria, FLAs will work better for you.

If Lithium isn't as good as FLA, whey are people buying them for Solar storage?

Because they are easier to install (lighter) because Tesla is selling them (and Tesla is "sexy") and with the orders-of-magnitude increase in battery production for EV's they are getting cheaper. In some cases it's because manufacturers want to harness economies of scale - for example the BMW home battery uses exactly the same battery as they use in their car.

Why would companies like Simpliphi even exist

Because as every marketer knows, you don't sell the steak - you sell the sizzle.

That being said, if you want lithium and cost is no object, then Simpliphi (and monolithic battery systems like it) would be a good choice for you.

[john95]

For a 20 kWh usage:

I paid $1,200 for my 8x 6 volt FLA 225 Ah each (10.8 kWh), I'd would need 4 times more of what I have (43.2 kWh) to accommodate my 20 kWh (50% discharge). I need to spend $4,800 for 32x 6 volt batteries 225 Ah, 18 months warranty, maybe 3 years of lucky use, then another $5K for another 3 years.
with $4,800 I can only buy 5 LiFePO4 100 Ah, 5 years warranty, but I can buy a used Nissan Leaf 24 kWh battery for like $3,000 that still may have 5 or 7 years left of use.

How is using FLA or LiFePO4 batteries cheaper or better than using Li batteries you smart people?
Tesla PowerWall even has the inverter already incorporated, just add millions of more panels!

[Sunking]

You obviously missed the "put in storage" and "I'm a prepper" part eh?

That explains it, you are nucking futs.

[Sunking]

You also seem to be conflating self-discharge (quite low in a Li battery) with battery life. 2 years on a shelf, and a lead acid battery has lost it's charge completely and is ready for recycle. Li batteries would only loose a couple %

A little higher than that Mike. Depending on chemistry 1 to 4% per month, so at two years it is possible to have completely self discharged and destroy itself. However is a completely moot point when on solar or any charger which negates any self discharge issue.

[Sunking]

You guys keep telling me that Lithium batteries are not as good as the FLA.. and yet, everywhere else I'm reading says the opposite and that the only drawbacks to the Lithium are price and the fire hazard.
Something doesn't add up.

Because you believe in hype, sales pitches, gloom, and doom.

[jflorey2]

For a 20 kWh usage:

I paid $1,200 for my 8x 6 volt FLA 225 Ah each (10.8 kWh), I'd would need 4 times more of what I have (43.2 kWh) to accommodate my 20 kWh (50% discharge). I need to spend $4,800 for 32x 6 volt batteries 225 Ah, 18 months warranty, maybe 3 years of lucky use, then another $5K for another 3 years.
with $4,800 I can only buy 5 LiFePO4 100 Ah, 5 years warranty, but I can buy a used Nissan Leaf 24 kWh battery for like $3,000 that still may have 5 or 7 years left of use.

Right. That Leaf battery will have ~16kwhr left. It will also need either an external CAN spoofer (to get it to turn on) or you'll have to gut the battery and add your own BMS. It will also not work with your system - it's a 400 volt battery, so you will have to replace your inverter.

And in 5 years it will be down to 8kwhr and you'll be longing for those lead acid cells.

But if you are comparing used to used, used forklift batteries are dirt cheap.

Tesla PowerWall even has the inverter already incorporated . . .

Sure it does.

Now try to buy one.

[Murby]

Because you believe in hype, sales pitches, gloom, and doom.

No, actually I have no beliefs at all.. and I'm one of the few people in this country who have none.

But I do believe in evidence, data, and research as well as rational deduction... and my rational deduction is telling me that if Lithium batteries where the greatest thing since sliced bread, you'd still try to discourage people from them so you have a supply of cheap batteries for your toys.

I'm here doing research and you're over there launching insulting remarks because I showed interest in acquiring one of your cherished salvaged batteries.

And now that I see how childish you act because of it, if I do go ahead with the project, I might just put up a nice youtube video to show others how to follow along, where to find the batteries, and how to put them to work...

Sometimes its better to play nice than to be a jerk.

[ButchDeal]

But I do believe in evidence, data, and research as well as rational deduction... and my rational deduction is telling me that if Lithium batteries where the greatest thing since sliced bread, you'd still try to discourage people from them so you have a supply of cheap batteries for your toys.

So your evidence, data, and research is telling you that SunKing purposefully trying to miss lead you for his own interests?

I'm here doing research

but disregarding any information you get that you do not like?

And now that I see how childish you act because of it, if I do go ahead with the project, I might just put up a nice youtube video to show others how to follow along,

you would not be the first to put up miss-leading youtube video

Sometimes its better to play nice than to be a jerk.

don't like your own advise I take it.

[Sunking]

So you now have 4 very experienced people telling you do not know what you are talking about and incapable of learning. Count them up. 1, 2, 3, and me makes 4. I win that argument and you loose.

FWIW you I live in Panama and cannot take your batteries. If you had really done any research and want batteries that last a long time and can be stored completely discharged for decades then you would know wet NiCd is what you are looking for.

As for Pb batteries hate to tell you but warranty speaks loud and clear. Rolls, Hup, Trojan, C&D all offer 10 year warranty product lines at half the price of cheap POS 1 year chi-com warranties.s. Not one lithium battery manufacture comes close.

Bu there is a tidbit of info that is factual. A123 Systems makes the hands down best longest lasting LiFeP04 battery. They come with a 1 year warranty and good for a claimed 1000 cycles. Compare that with a Trojan Industrial battery that comes with a 10 year warranty with 3000 cycles to 80% DOD at 1/4 the price of A123 smart guy.

My last comments before I exit this thread is any members that have been here for a while will say this about me. I care more about your money and safety then you do. They may call me a jerk or ass which is OK by me, but l have no vested or personal interest in any outcome. I just do not have any patience or tolerance for stupidity.

[jflorey2]

But I do believe in evidence, data, and research as well as rational deduction... and my rational deduction is telling me that if Lithium batteries where the greatest thing since sliced bread, you'd still try to discourage people from them so you have a supply of cheap batteries for your toys.

Hey, if you have money to waste, go with SimpliPhi. They are very easy to use, and are designed in part for applications like yours (i.e. lots of money, doesn't want to do a lot of work.) They're not too reliable yet from what I have heard (the Gudgels have seen several failures in the field) but they have a warranty, so they must be fine.

[Murby]

My last comments before I exit this thread is any members that have been here for a while will say this about me. I care more about your money and safety then you do. They may call me a jerk or ass which is OK by me, but l have no vested or personal interest in any outcome. I just do not have any patience or tolerance for stupidity.

A bit of a revelation,

I think the issue here is that you're not recognizing the difference between someone just seeking instruction, and someone doing research to learn. People seeking information for these kinds of projects are going to come in two flavors.. 1) Tell me what to do, and 2) Tell me what you know.

You seem to be putting everyone in the "Tell me what to do" category and when they question your statements or challenge them, you get angry, short, and arrogant. Some of us just want to find the information and make our own decisions, and of course, we are responsible for those decisions.

The number 1 ("tell me what to do") folks are foolish because when some forum groupie tells them what to do and they are wrong, the groupie just walks away and the person who followed their advice is left holding the bag.

Thank you for your contribution, your advice is appreciated, I may follow it, I may not... I won't know until I learn more and have completed my research.

By the way, I'm also an RC Pilot (or maybe I should say I was).. but I'm old old school. I've own cars, built boats, gliders, planes and several helicopters (my fist helicopter was a Cricket back in the 80's),

[Gianbriela]

Why would you want to disconnect the charger for.? That is silly. If your batteries are charged by noon, you would go on batteries until the next day and all that power that could be utilized from the panels is never used. All that does is wear out your batteries faster. Not a good idea. There is no reason to ever turn off the charger. If done correctly you do not even need a BMS. You just set up the Charge Controller to operate as CC/CV Float charger and set the voltage to 54.4 volts and call it done.

Hi Sunking: I am a newbie in the solar system universe. I recently installed a system with the following:15 - 320w GCL panels, a Sigineer 6048 inverter, Outback FM80 CC and LiFePO4 batteries. The Battery bank is a 48V - 16s1p 300Ah from China and a built in BMS. After, almost two months of good operation, the system shutted down during the night, I do not know the reason. I confirmed that the reason for the shut down is a BMS failure, because the voltage readings directly at the battery poles are ok (50V), but the reading after the BMS is low (14V). My question is, based on your post above: Can I Iive without the BMS? (I mean bypass it). I know something caused the BMS to malfunction and I plan to reinstall everything, but I have doubts about "dropping" the BMS. What would be the correct settings on my Outback? Thanks.

[Mike90250]

Hi Sunking: I am a newbie in the solar system universe. I recently installed a system with the following:15 - 320w GCL panels, a Sigineer 6048 inverter, Outback FM80 CC and LiFePO4 batteries. The Battery bank is a 48V - 16s1p 300Ah from China and a built in BMS. After, almost two months of good operation, the system shutted down during the night, I do not know the reason. I confirmed that the reason for the shut down is a BMS failure, because the voltage readings directly at the battery poles are ok (50V), but the reading after the BMS is low (14V). My question is, based on your post above: Can I Iive without the BMS? (I mean bypass it). I know something caused the BMS to malfunction and I plan to reinstall everything, but I have doubts about "dropping" the BMS. What would be the correct settings on my Outback? Thanks.

Your system engineer/Installer has to look at it and fix it. Being new, it should all be covered under warranty. Do not tinker with things, the batteries, without a working BMS can easily start a fire.

[tom rickard]

You got your answer early in this thread. Set the Flexmax voltage right at the balance point of the REC, and use the REC relay trigger to switch a contactor between the PV and the flexmax in case the REC balancers need to disconnect.

Another way is to ditch the flexmax and use SMA or Victron gear that will talk directly to the REC

For my system i use a combination of SMA AC coupled and a Flexmax80 DC coupled, i set the voltage setpoint of the Flexmax below the balance point of the REC.

Don't worry about the lithium knockers on here, they were saying the same thing in 2013 when i installed my lithium system, and when it's still going in another 10 years they will likely still be saying the same!

Fortunately, there are enough people that have been using Lithium off grid systems for 7 years + that the voices of the naysayers are getting fainter..

The REC will look after your Leaf batts. Just install them in a climate controlled enclosure, that is where people go wrong.

[jflorey2]

I confirmed that the reason for the shut down is a BMS failure, because the voltage readings directly at the battery poles are ok (50V), but the reading after the BMS is low (14V).

Have you checked the cell voltages? If most of the cells are at 3.3 volts and one is at .2 volts, then that cell is dead (even though the pack reads 50V) and the BMS did you a big favor by disconnecting the battery.

My question is, based on your post above: Can I Iive without the BMS? (I mean bypass it).

No. With what you've told us so far, the BMS is critical for your safety.

I know something caused the BMS to malfunction and I plan to reinstall everything, but I have doubts about "dropping" the BMS. What would be the correct settings on my Outback? Thanks.

Outback settings would not change. Normally a BMS doesn't affect a battery's operation.