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IOTA Engineering IQ4 LiFePO4 Module Discussion

Hi. Thank you for the post and sharing of all the information.

1.Have you tested the voltage at the battery bank while charging? My guess is you might end up with a 14.6v reading, depending on cable length, etc.

2. Most LiFePO batteries I've seen have an overvoltage protection of around 15v, so 14.7 wouldn't trip the BMS anyway. I wouldn't think that + or - .1v would be life threatening. Not ideal, but you are only using the charger sparringly i wouldnt see it as issue.

Again, thanks for the plethora of info.
 
Hi. Thank you for the post and sharing of all the information.

1.Have you tested the voltage at the battery bank while charging? My guess is you might end up with a 14.6v reading, depending on cable length, etc.

2. Most LiFePO batteries I've seen have an overvoltage protection of around 15v, so 14.7 wouldn't trip the BMS anyway. I wouldn't think that + or - .1v would be life threatening. Not ideal, but you are only using the charger sparringly i wouldnt see it as issue.

Again, thanks for the plethora of info.

My cable length is fairly short, made up of 6 awg and 2/0 awg. I did test the voltage at the common bus bars where the charger and battery leads all meet up. I also tested at the terminals on the charger. Same voltage.

My BMS has the high voltage disconnect set at 14.7v I believe. I would have to check on that however. It might be 14.6v. It certainly isn't 15v.

My concern with the charger now is that it isn't doing much. For a charger rated at 55 amps, it wasn't even over 30 amps of actual charge.
 
My cable length is fairly short, made up of 6 awg and 2/0 awg. I did test the voltage at the common bus bars where the charger and battery leads all meet up. I also tested at the terminals on the charger. Same voltage.

My BMS has the high voltage disconnect set at 14.7v I believe. I would have to check on that however. It might be 14.6v. It certainly isn't 15v.

My concern with the charger now is that it isn't doing much. For a charger rated at 55 amps, it wasn't even over 30 amps of actual charge.
Interesting...what brand batteries do you have? They should have came with a manual that stipulates the high voltage cutoff. 14.7 seems incredibly low. That would be like an inverter shutting off below 12v. Doesn't seem practical. At any rate even if you have 14.69v going into the bank it might not trip thr BMS.

Also did you ever use the Iota Charger with SLA batteries? I have two of the same charger hooked up in parallel. When charging SLA/AGM they both put out 55 amps and then slowly dwindle as they reach the absorption stage. Just got my LiFePO batteries and ordered the IQ LiFePO. When i do an amperage test i can let you know my results.

I have tested the efficiency of the Iota Battery Chargers as well with an Amp Clamp. Not what they claim to be in the documentation. They say greater than 80 percent but i have consistently gotten around 65 percent efficiency. Around 2400 AC watts going into the two 55 amp chargers and 1600 watts or less going into the battery bank.
 
This entire thread is about charging LiFePO4 batteries using the IQ4 LiFePO4 module.

14.7v is really bad for a LiFePO4 battery.
 
This entire thread is about charging LiFePO4 batteries using the IQ4 LiFePO4 module.

14.7v is really bad for a LiFePO4 battery
With all due respect sir you mentioned the inefficiency of your charger so I replied. I'm sorry if the information I provided wasn't helpful.

Also your statement about 14.7 being bad for Lithium Batteries is simply false. For one thing that would mean the engineers at Iota are incompetent and you know better than they do. Also here is an article which explains in detail how charging voltage for lithium batteries varies depending on how they are manufactured.


Again, consult the documentation provided from your battery manufacturer to get clarity on what the overcharge protection voltage is.

Have a good day, sir.
 
With all due respect sir you mentioned the inefficiency of your charger so I replied. I'm sorry if the information I provided wasn't helpful.

Also your statement about 14.7 being bad for Lithium Batteries is simply false. For one thing that would mean the engineers at Iota are incompetent and you know better than they do. Also here is an article which explains in detail how charging voltage for lithium batteries varies depending on how they are manufactured.


Again, consult the documentation provided from your battery manufacturer to get clarity on what the overcharge protection voltage is.

Have a good day, sir.

The link you provided is not relevant to Lithium-Iron Phosphate (LFP or LiFePO4) cells. 3.650 is the well-known well-established maximum voltage per cell in an LFP battery. Therefore, 14.7 volts is incorrect for this chemistry. Vendors are not fault-free.

Edit: Read the "Lithium Iron Phosphate(LiFePO4) — LFP" portion from that website here: https://batteryuniversity.com/learn/article/types_of_lithium_ion

It's pretty clear that 14.7 is way too high.
 
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14.7 volts at the charger ports = Less at the battery due to loss of the cable?

So the actual voltage could be less?
 
14.7 volts at the charger ports = Less at the battery due to loss of the cable?

So the actual voltage could be less?

The charger can't assume you have small cables. What if the amperage is low but voltage is high because the cells are full? Even 14.6 is too high. 14.2 is a reasonable maximum charging voltage for LFP.
 
The link you provided is not relevant to Lithium-Iron Phosphate (LFP or LiFePO4) cells. 3.650 is the well-known well-established maximum voltage per cell in an LFP battery. Therefore, 14.7 volts is incorrect for this chemistry. Vendors are not fault-free.

Edit: Read the "Lithium Iron Phosphate(LiFePO4) — LFP" portion from that website here: https://batteryuniversity.com/learn/article/types_of_lithium_ion

It's pretty clear that 14.7 is way too high.
Interesting article. Thanks for the info. Here is another article from another battery charging company which claims that 14.7 is safe for lithium ion phosphate.


My battery manufacturer recommended 14.6 and I noticed that battle born recommends 14.4 they're all different. I think it is a non sequitur to just claim 14.7 is "dangerous" for lithium iron phosphate batteries Especially in instances where it is not being used all the time But that is just my opinion And the opinion of several different engineers you are free to have yours :)
 
Look, you will decrease the life of your LFP above 3.65 volts per cell. This is a fact. Can you get away with charging to 14.7? Yes, but you're not going to get 3500 cycles out of the cell. The article you provide says 15.2v! That is absolutely insane. Can you do that once? Yes. Do not do it on a regular basis. I mean, it's your money, but do not advocate it here, please. Most batteries will disconnect at those voltages anyway (gee, why do you think they'd do that?)

Point me at a battery cell spec sheet that > 3.650 is OK. It doesn't exist. For a reason.

This is not opinion. It's fact. There's a lot of misinformation out there.

Do not charge your battery to these voltages on a regular basis. And for goodness' sake, don't spread this misinformation.
 
Look, you will decrease the life of your LFP above 3.65 volts per cell. This is a fact. Can you get away with charging to 14.7? Yes, but you're not going to get 3500 cycles out of the cell. The article you provide says 15.2v! That is absolutely insane. Can you do that once? Yes. Do not do it on a regular basis. I mean, it's your money, but do not advocate it here, please. Most batteries will disconnect at those voltages anyway (gee, why do you think they'd do that?)

Point me at a battery cell spec sheet that > 3.650 is OK. It doesn't exist. For a reason.

This is not opinion.
Look, you will decrease the life of your LFP above 3.65 volts per cell. This is a fact. Can you get away with charging to 14.7? Yes, but you're not going to get 3500 cycles out of the cell. The article you provide says 15.2v! That is absolutely insane. Can you do that once? Yes. Do not do it on a regular basis. I mean, it's your money, but do not advocate it here, please. Most batteries will disconnect at those voltages anyway (gee, why do you think they'd do that?)

Point me at a battery cell spec sheet that > 3.650 is OK. It doesn't exist. For a reason.

This is not opinion. It's fact. There's a lot of misinformation out there.

Do not charge your battery to these voltages on a regular basis. And for goodness' sake, don't spread this misinformation.
Hey man I'm not here to get into a heated argument and all riled up. Life is too short for that! I just think its funny that Iota Engineers who make BATTERY CHARGERS FOR A LIVING insist that 14.7 volts is safe for most LiFePO batteries and we've got random people on the internet claiming Krakatoa will erupt if we dare go above 14.6. Lol for crying out loud listen to yourself man. And I never suggested to stray from your battery manufacturer's suggestions. What I'm going to do when I get my IQ LIFePO is test the voltage that is going into the bank as well as contact my battery manufacturer and ask them for their advice, as any sane person should. Lol have a good day man.
 
Hey man I'm not here to get into a heated argument and all riled up. Life is too short for that! I just think its funny that Iota Engineers who make BATTERY CHARGERS FOR A LIVING insist that 14.7 volts is safe for most LiFePO batteries and we've got random people on the internet claiming Krakatoa will erupt if we dare go above 14.6. Lol for crying out loud listen to yourself man. And I never suggested to stray from your battery manufacturer's suggestions. What I'm going to do when I get my IQ LIFePO is test the voltage that is going into the bank as well as contact my battery manufacturer and ask them for their advice, as any sane person should. Lol have a good day man.

I'm not heated or riled up. If you use that charger to charge most LFP batteries, those batteries will *disconnect* and leave you without a battery!

This vendor is publishing dangerous information. Vendors have faults.
 
I'm not heated or riled up. If you use that charger to charge most LFP batteries, those batteries will *disconnect* and leave you without a battery!

This vendor is publishing dangerous information. Vendors have faults.

I wonder if we could adjust the internal voltage pots on the converter to fine tune the bulk charge rate to our desired value? (change the max output down a little...)

Or if there is any tweaking that could be made in the IQ4 to help on this... (Like a pot in there to tweak with or a resistor that could be changed...)


Here is some references to IOTA converters having pots in them:

 
I'm not heated or riled up. If you use that charger to charge most LFP batteries, those batteries will *disconnect* and leave you without a battery!

This vendor is publishing dangerous information. Vendors have faults.
Hi. Can you show me an example of a battery that disconnects at 14.7 volts? I would be interested to see a chart from the battery manufacturer. Also, one thing we are neglecting is C rating. According to what I've read, HEAT is what causes premature failure in Lithium Iron Phosphate batteries. I agree that 14.7 is not ideal at a typical C rating. But what about 14.7 volts at, say, .1C or even .2C. Do you really think it would generate that much heat on the lithium cells? For example, 14.7 volts and 10 amps charging a LiFePO battery would generate less heat than 14.6 volts and 20 amps. I agree that lower voltage charge increases life span, but it also decreases capacity. The opposite is also true. Higher voltage charge increases capacity and decreases lifespan. It is important to note that the cycle data assumes the same C rating applied to the batteries. Take care!

 
Technically a BMS doesn't cut off at a certain pack voltage. It cuts off when one of the cells reaches maximum. Since all LFP cells are spec'ed to 3.65 volts max, multiplied by 4, that's 14.6 volts with perfectly-balanced cells. However, you will have some imbalance between cells at those voltages. If your cells are absolutely amazing, you might have only (for example) 12mv of difference between min and max which means 14.6v can be 3.62, 3.62, 3.62, 3.74 - and the BMS will disconnect because 3.74 is obviously way higher than 3.65. Daly is a popular BMS. https://dalyelec.en.made-in-china.c...BMS-with-Canbus-Communication-Canbus-BMS.html -- the disconnect voltage is 3.65 +- .025. That BMS will disconnect in this circumstance.

LFP can be damaged in many ways. This is one of them. Heat, as you say, is another. But it's not the combination of heat and voltage that I'm pointing out. All things being equal, it's safe to say that you shouldn't charge to 14.6 on a regular basis at any current or temperature. That will reduce the life of the cell.

Lower voltage (e.g. 3.5 volts per cell) doesn't translate into any real-world capacity difference. You might get another 0.3% capacity between 3.5 and 3.65. That's not worth the long-term damage and reduced lifespan.
 
I wonder if the IQ4 module has any pots inside it or anything which could allow for any tweaking..
The DLS itself does. Credit to @halfwave: You can internally adjust the voltage of the DLS-30. See their post in another thread.

 
Is there a 220-240v version of the IOTA ? Or an alternative other than the mean well style options ?
 
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