Tesla battery pack?

[SunEagle]

I saw a post on diyelectriccar forum that indicated that the cause of the fire was major over charging of the Tesla modules. They did not spontaneously catch on fire. They were being charged by a FLA forklift charger.

Look. We understand that you and a few other members know the technology for lithium batteries. The problem is the vast majority of people that come hear are nu-bees when it comes to this technology and if they make a bad decision (like over charging) the end result is a fire or worse.

The Forum can't have a few people make posts that Lithium is not dangerous when we have to protect the majority that could get hurt if they play with the stuff.

When it comes to electricity or any battery technology if you become complacent or careless the end result can be bad.

So please stop being overly defensive when it comes to Lithium technology and the dangers associated with it.

[Ampster]

............................
So please stop being overly defensive when it comes to Lithium technology and the dangers associated with it.

My attempt was to show a cause and effect relationship between careless action and the fire. In my mind that was knowledge that could benefit the uninformed. One of the benefits of forums like this is to share knowledge for the greater good.
I have spent a good part of my career doing risk management and a close friend specializes in risk management with regard to chemical reactions. One of the first things that is done in risk management is to assess the risk and understand the causes and effects.
Charging every battery chemistry causes heat. Heat causes most chemical reactions to proceed faster. I guess it depends on ones point of view whether my comment was intended to increase knowledge or defend the Lithium battery industry. I will note your comments and try to choose my words more carefully.

[SunEagle]

My attempt was to show a cause and effect relationship between careless action and the fire. In my mind that was knowledge that could benefit the uninformed. One of the benefits of forums like this is to share knowledge for the greater good.
I have spent a good part of my career doing risk management and a close friend specializes in risk management with regard to chemical reactions. One of the first things that is done in risk management is to assess the risk and understand the causes and effects.
Charging every battery chemistry causes heat. Heat causes most chemical reactions to proceed faster. I guess it depend on ones point of view whether my comment was intended to increase knowledge or defend the Lithium battery industry. I will note your comments and try to choose my words more carefully.

Thank you. I appreciate your knowledge and input concerning Li technology.

I am hoping a better and safer energy storage system will eventually be invented.

[J.P.M.]

My attempt was to show a cause and effect relationship between careless action and the fire. In my mind that was knowledge that could benefit the uninformed. One of the benefits of forums like this is to share knowledge for the greater good.
I have spent a good part of my career doing risk management and a close friend specializes in risk management with regard to chemical reactions. One of the first things that is done in risk management is to assess the risk and understand the causes and effects.
Charging every battery chemistry causes heat. Heat causes most chemical reactions to proceed faster. I guess it depend on ones point of view whether my comment was intended to increase knowledge or defend the Lithium battery industry. I will note your comments and try to choose my words more carefully.

Why not just stop ignoring/soft peddling the need for a lot of caution and instead approach the subject from the direction of something like "DON'T GET INVOLVED IN LITHIUM OR ANY SYSTEM UNLESS YOU REALLY KNOW WHAT YOU'RE DOING " Then, state your case addressing how the dangers and inconveniences and unknows might be addressed.

Advocates of new/different technologies often soft peddle the drawbacks of anything they think is great.

Spend more time practicing what you just wrote rather than as an apostle for things that can be unsafe and a waste of money to the uninformed.

Think of who will read what you write and never underestimate their gullibility or lack of understanding of what you communicate.

[jflorey2]

Some issues have been
they dont work off grid as in we cant get them to work nicely with generators, we have tried a few and they just dont like them
software glitches, we are on I think the 3rd software upgrade

Yeah, I've spoken to several installers who have said that SW compatibility is the #1 problem when trying to integrate these batteries. Strange that we've made so much progress with the cells themselves - and the problem is now that we can't get all the computers to talk to each other.

[Ampster]

..................

Think of who will read what you write and never underestimate their gullibility or lack of understanding of what you communicate.

That is good input. There are probably a lot more lurkers than registered users. Therefore I may have missjudged the audience. I looked for some statistics but couldn't find any. Is there any data about the number of users and the hits on this forum? Those numbers must be available somewhere and are important for driving ad revenue.

[SunEagle]

That is good input. There are probably a lot more lurkers than registered users. Therefore I may have missjudged the audience. I looked for some statistics but couldn't find any. Is there any data about the number of users and the hits on this forum? Those numbers must be available somewhere and are important for driving ad revenue.

A daily average of visitors to this forum is 440 people with maybe a dozen being registered members. So yes you have a very big and probably uneducated audience reading these posts.

[J.P.M.]

That is good input. There are probably a lot more lurkers than registered users. Therefore I may have missjudged the audience. I looked for some statistics but couldn't find any. Is there any data about the number of users and the hits on this forum? Those numbers must be available somewhere and are important for driving ad revenue.

So, I believe, was the rest of the input of the post you quoted.

[AaronTSchultz]

I appreciate all the comments in this post, However, being new to this board, and new to lithium (but doing my research), my 2 cents are this. If we over criticize new technology we do it a disservice and scare people off, therefore acting as the "King of Knowledge" on the new technology. Just as the person reasoned that usually new tech adopters minimize the risk of the technology, it is equally as destructive to the populous to misstate facts about the discharging rates or over exaggerate the consequences. The new technology should be presented with a fair critique of the benefits and consequences and allow people to make up their own mind on whether they are qualified enough to undertake a project. Its as though you are making the decision that if someone makes the dumb choice to not wear a helmet while on a motorcycle you are not even going to talk to them about a motorcycle... It is quite controlling.

That being said. I have been researching lithium batteries and have purchased 4 of the tesla battery modules for my Off grid School bus to RV conversion. Since my wife wants everything run off electricity we are going to need an 8000W hybrid inverter charger. My question is this. l have been able to find the safe charging parameters for 24V system, but if I run 2 in series and 2 pair in parallel for a 48V system, does anybody know what the safe charging parameters would be for the Charge Controller, the Safety Switches, and the hybrid inverter Charger, so as not to over/under charge the battery? The reason I ask is if I have to run in 24V @ 8000W It will be a constant 333Amps which is ok for the 4 batteries, but it is quite a bit for the wire as the only wire I have seen is rated up to about 200Amps.

Please let me know if I am missing something and will be able to run from the 24V batteries to the hybrid inverter/charger, or ideally let me know what the settings are for the 48V system or at least what the 100-0% are and I can do the math to get to 90%-30% for the safety settings. I would prefer the 48v system as most of the hardware is more compatible with the 2400W of solar I will have at the 48V, specifically the charger, and the hybrid inverter/charger. Thanks for helping someone learn more about this technology and get a solution to a problem.

[AaronTSchultz]

I would also not underestimate the people that "look" at this site without registering. There are a lot of smart people, and to be honest they are not going to find this page without a bit of digging and knowledge of the tesla batteries (believe me).

I would also ask those that are requesting a member state "Do not get involved without knowing what you are doing" and then state their solution to overcome this problems, follow their own advice and maybe put in their comments "TESLA IS A GREAT SOLUTION" And then state their case on why it's beneficial, but then what the warnings of such a product might be. Again, a person will not have the ability to judge for themselves if they have the correct capabilities unless both positive and negatives are addressed.

[inetdog]

I would also not underestimate the people that "look" at this site without registering. There are a lot of smart people, and to be honest they are not going to find this page without a bit of digging and knowledge of the tesla batteries (believe me).

I would also ask those that are requesting a member state "Do not get involved without knowing what you are doing" and then state their solution to overcome this problems, follow their own advice and maybe put in their comments "TESLA IS A GREAT SOLUTION" And then state their case on why it's beneficial, but then what the warnings of such a product might be. Again, a person will not have the ability to judge for themselves if they have the correct capabilities unless both positive and negatives are addressed.

When the actual and purported positives are amply represented in the advertising of a product, it seems more important to deliver opposing claims or advice than to agree with the self-promotion. Those who can, from experience, support any of the marketing claims are more than welcome to do so.

[AaronTSchultz]

I guess sometimes we are talking about 2 different things, If a system is sized correctly and being used in an off-grid situation where the amp draws on the battery are very low compared to the capabilities of the battery, This unit will reduce the risks significantly. However if the unit is being used for a vehicle and is drawing a very large amperage for short bursts that can heat up the batteries, then it is very important to overstate the risks as the probability of causing a runaway is much higher.

I was simply stating that there is no marketing for the 2nd hand batteries that were used in vehicles, just people stating opinions based on video's or experiences... and if those that are detracting the viability of the batteries ask another to state both sides equally, they should be willing to do the same.

[Ampster]

.........
That being said. I have been researching lithium batteries and have purchased 4 of the tesla battery modules for my Off grid School bus to RV conversion. Since my wife wants everything run off electricity we are going to need an 8000W hybrid inverter charger. My question is this. l have been able to find the safe charging parameters for 24V system, but if I run 2 in series and 2 pair in parallel for a 48V system, does anybody know what the safe charging parameters would be..........

Essentially the safe charging parameters are 4.1v per cell and a charging Amperage of less than 1C. That way you should not experience the heat buildup that can be dangerous. You seem to understandsome of the basic concepts. What I don't know is what voltage and amperage setting are available on your hybrid inverter charger. Tell me the name and model of the inverter. Tell me how many cell groups are in parallel in a 24v Tesla module and I can walk you through the math. The information is readily available. Most modules contain about 5kWhrs of energy so your 8kW inverter would run every thing for about two hours at a safe discharge rate of less than .5C.

Charging Lithium can be very simple because you do not need to think about Bulk, Absorb, Float or Equalize. You just need a charger that gives you control over voltage and amperage. Tesla uses a Battery management system and you can be the BMS or you can use one of the many BMS devices designed for after market Tesla modules.

I have been charging and discharging various Lithium Chemitries for over ten years and drive a Tesla so you can consider me a fan of the technology. I promised the Mods to explain the safety procedures so that you will not have to experience some of the "disastrous" results that some on this forum will warn you about. You clearly understand the sentiment on this thread.

[Ampster]

When the actual and purported positives are amply represented in the advertising of a product, it seems more important to deliver opposing claims or advice than to agree with the self-promotion. Those who can, from experience, support any of the marketing claims are more than welcome to do so.

Marketing and self promotion? Shouldnt we focus on the science to properly understand the benefits of one technology over another? It is afterall, just physics and chemistry and the language of physics is math. Ohms law is an important part of the toolkit one must have to safely charge and discharge a battery. Sunking has left us with many good examples where Ohms law applies.

[AaronTSchultz]

• Tesla's "85" kWh pack consists of 16 modules of 444 cells for 7,104 total cells. So I am to gather in a 24V pack we are going to have 444 total cells, 6 of which are in series to give us 24.6 (if my math is correct) and 74 series of 6 in parallel. If the continuous discharge current at about 1c is 233A / battery and I have 4 batteries this would be close to 900A @ 24V. Currently I am going to be running an 8000W inverter which will equal 333A between all batteries at 24V. (maybe a bit more with DC AMPs, max of 40A @ 12V). My charge watts is 2400W of solar max and at 24V it will be approximately 25amps/HR/Battery which will be well below any charge threshold. I want to do a 48V charger, and 48V batteries (2 pairs of 2) which will also allow me to get a 48/8000 hybrid inverter charger. Lower the output amps to 170ish or 85 per 48V set. Is this the best design, or is there wire out there that will handle the 333A coming out of the batteries into the hybrid inverter charger? (close proximity probably 5 feet max.)?

I have a decent understanding of what is going on in the batteries, however, I just want to make sure I'm getting a second opinion on when I put the packs in series the voltage doubles for the safety charging, or if something that I am missing happens to make the proper charging voltages (High/Low cutoffs) different than double the 24V setup. (I hope this makes sense). I also have 4 individual BMS, 1 for each battery with a new circuit board that was attached at the re-seller 057Tech.com . I will have the high/low charging settings set on the mppt charger, and on the hybrid inverter/charger, and I will also have battery monitors with high/low shunts that can disconnect the batteries. On top of all that I am going to have a thermostatically controlled heating blanket for cold weather, and I shouldn't have any problem with heat in the batteries.

Let me know if I am missing something. Please, I am all about learning and most of the time I am wrong, until I learn what I'm missing.