What Wattage is too expensive?

[mat3833 10+ year member]

Slight continuation to the power discussion. Batteries only hold so much power. That is usually measured in AH or Amp Hours. I'm too lazy to convert that to watt hours, but you just multiply by the batteries voltage to get watt hours.

Starting a car would use very high currents for a very short duration. Ex:
14v X 300a X 5 seconds = 350ish watt/minutes or 5.8 watt/hours.

14v X 100a X 30 minutes = 700 watt/hours.

Even if I'm only using 50a of current to play my system for the half hour, it's still 7 times more energy than starting the car.

Matt

 

[Water Bear]

Anyway, the only thing I'd take exception to that has been posted here is claims of charging 6s banks up over 15.5V. The Russian dudes and my source in China did not suggest this and I can say charging at normal car voltage (14.4-14.8) seems to provide ample performance for those of us doing so.

This is the thing I don't follow. You're just talking about the particular cells you mentioned above, right? Consider the XS titan 8s. They have s5, s6, and s7 branded batteries which I assume literally refers to the number of cells in series. Whatever cells they're using, s5 is their 12v compatible line, s6 is 14, s7 is 16.

"12v batteries" are the ones that charge at 14.4-14.8, as I understand it. So an s6 of their particular brand is a 14v battery and should charge at 15.5-17.6 according to their spec sheet (link here) with 100% charge at 16.4v standing. So the statement that an s6 has to charge in the 14's is only true for the particular battery you were mentioning (if all the assumptions I've made to get here are correct, and some of them may not be).

This matters to me because my Mechman charges in the 15's during winter and almost never gets "warm enough" to be below 15, so I have to be super mindful of lithium ion charge specs.

 

[mat3833 10+ year member]

This is the thing I don't follow. You're just talking about the particular cells you mentioned above, right? Consider the XS titan 8s. They have s5, s6, and s7 branded batteries which I assume literally refers to the number of cells in series. Whatever cells they're using, s5 is their 12v compatible line, s6 is 14, s7 is 16.

"12v batteries" are the ones that charge at 14.4-14.8, as I understand it. So an s6 of their particular brand is a 14v battery and should charge at 15.5-17.6 according to their spec sheet (link here) with 100% charge at 16.4v standing. So the statement that an s6 has to charge in the 14's is only true for the particular battery you were mentioning (if all the assumptions I've made to get here are correct, and some of them may not be).

This matters to me because my Mechman charges in the 15's during winter and almost never gets "warm enough" to be below 15, so I have to be super mindful of lithium ion charge specs.

That's the issue we all have. Companies like XS power are rating their packs at voltages much higher than recommended by spec sheets for known cells. 2.7v is the max cell charge on almost every spec sheet I've seen. Some say 2.8v for brief periods, and others say 2.5v. based on that you have the following ranges for max charging voltage:
5s - 12.5-14v
6s - 15-16.8v
7s - 17.5-19.6v

These are max charge voltages I have seen. I don't like running anything at max of anything. 2.7v per cell is the majority of LTO spec sheet max cell voltage recommendations. I went with a 6s bank so I could run a factory alt charging at 14.1-14.3.

A 5s bank should never see 14.8v let alone over 14v. A 6s bank should not see over 16.8v

LTO cells are happy between 2.1-2.5v low voltage Cutoff is 1.9v. Staying in the 2.1-2.5 range is going to give you best results.

Matt

 

[Water Bear]

That's the issue we all have. Companies like XS power are rating their packs at voltages much higher than recommended by spec sheets for known cells. 2.7v is the max cell charge on almost every spec sheet I've seen. Some say 2.8v for brief periods, and others say 2.5v. based on that you have the following ranges for max charging voltage:
5s - 12.5-14v
6s - 15-16.8v
7s - 17.5-19.6v

These are max charge voltages I have seen. I don't like running anything at max of anything. 2.7v per cell is the majority of LTO spec sheet max cell voltage recommendations. I went with a 6s bank so I could run a factory alt charging at 14.1-14.3.

A 5s bank should never see 14.8v let alone over 14v. A 6s bank should not see over 16.8v

LTO cells are happy between 2.1-2.5v low voltage Cutoff is 1.9v. Staying in the 2.1-2.5 range is going to give you best results.

Matt

Thanks for explaining that, it makes more sense. Do you think the big brand companies are using cells not available to the public or...?

 

[winkychevelle 10+ year member]

Thanks for explaining that, it makes more sense. Do you think the big brand companies are using cells not available to the public or...?

6s lto is the right answer for the majority of people

big brands are using cells you can buy everyday.

And what he said is exactly right xs and d4s rate their batts incorrectly to take advantage of ignorant customers

 

[Water Bear]

It's an issue for me because the Mechman charges anywhere from 14.8-15.5, most of the time 15-15.5. So for example a 2.7v max cell in 6s works for me - that's 16.2 max charging volts - but a 2.5v max cell would not - that's 15v. 7s would be "safe", but then I'm so far below the max voltage that the battery wouldn't even be at half charge. At that point you're paying for a lot of product that you're not using and running closer to the redline, so to speak. The issue is that the mfg's probably aren't going to disclose the true spec...this explains why people build their own. That way you know for sure.

 

[Water Bear]

XS appears to sell 66160 Yinlong LTO cells. XS part no is "34-66160-40". I'm no detective, but that matches exactly the description of the 3.4v 40 AH 66160 Yinlong cell. I don't know if this is "official enough" as far as spec sheets go, but it says 2.9v max charging voltage which works out to 17.4v max.

 

[mat3833 10+ year member]

XS appears to sell 66160 Yinlong LTO cells. XS part no is "34-66160-40". I'm no detective, but that matches exactly the description of the 3.4v 40 AH 66160 Yinlong cell. I don't know if this is "official enough" as far as spec sheets go, but it says 2.9v max charging voltage which works out to 17.4v max.

I would be much happier staying at 2.6v charge 2.7v for short periods. 2.9v is way too high for anything I've seen. I don't trust XS power or any distributor. Yinlong has their own spec sheets, that's what I would trust.

The main thing here is longevity. These cells have a crazy long life. It seems these companies are banking on being able to abuse cells and get away with it because of their durability/longevity.

Personally, I plan to move my bank from car to car as I change. None of my amps like anything over 15v and my Jetta's ECU doesn't like anything over 14.8v, so for me it's a non-issue. 14.4v charge voltage, damn near zero voltage drop on a factory alt.

Matt

 

[Water Bear]

Wish I'd done this research before pulling the trigger on the Mechman. Funny how times have changed.

On the other hand if I can figure out how to make LTO work with 15 - 15.5v then the electrical in this here Tahoe is going to be like Thor pissed on a Chevy.

Well, maybe one day. 2x d3400s and a Mechman is going to be more then enough for 5k and that's what I plan to run for the foreseeable future.

 

[Water Bear]

Yinlong has their own spec sheets, that's what I would trust.

Any idea where I might get my hands on the Yinlong sheet?

 

[Original wis]

Sad thing is, for the $800 that I'm going to spend on cells I could get a taramps smart 3 and 4 12" CT Sounds 800 RMS Ozone. And it'll run on my current electrical, 250 alt and 100 ah AGM. Be ridiculously loud with just that in an 01 Sentra.

I've been a year without music and right now that's looking really good. I might have to save up and do the bigger system later. Choices...

 

[hispls 5,000+ posts]

Consider the XS titan 8s. They have s5, s6, and s7 branded batteries which I assume literally refers to the number of cells in series. Whatever cells they're using, s5 is their 12v compatible line, s6 is 14, s7 is 16.

I guess ask XS power what cells they use and check the manufacturer specs on those cells. They don't even tell you C rating or amp hours so just do whatever they say and at least they'll probably honor your warranty if something fails prematurely.

 

[mat3833 10+ year member]

Wish I'd done this research before pulling the trigger on the Mechman. Funny how times have changed.

On the other hand if I can figure out how to make LTO work with 15 - 15.5v then the electrical in this here Tahoe is going to be like Thor pissed on a Chevy.

Well, maybe one day. 2x d3400s and a Mechman is going to be more then enough for 5k and that's what I plan to run for the foreseeable future.

Mechman can regulate the alt down or up to whatever you want. I think the range is 12v-18v nominal?

Hey @hispls can you give this guy the spec sheet you sent me or post it in here for your 40ah cells. I can't find it anywhere.

Matt

 

[Water Bear]

Mechman can regulate the alt down or up to whatever you want. I think the range is 12v-18v nominal?

Hey @hispls can you give this guy the spec sheet you sent me or post it in here for your 40ah cells. I can't find it anywhere.

Matt

Mechman actually said there was nothing he could do reduce the voltage - he could only turn it up, for whatever reason. He might have meant "nothing I can do without rebuilding your alt", which is essentially what I was asking.

What I am really curious about is finding the spec sheet for the 66160 Yinlong cells XS sells, mostly out of curiosity. Might have to e-mail the Chinese distributor that @hispls used for his big order. I don't doubt that you and spls have the specs correct for the cells he's already got.

 

[winkychevelle 10+ year member]

Mechman actually said there was nothing he could do reduce the voltage - he could only turn it up, for whatever reason. He might have meant "nothing I can do without rebuilding your alt", which is essentially what I was asking.

What I am really curious about is finding the spec sheet for the 66160 Yinlong cells XS sells, mostly out of curiosity. Might have to e-mail the Chinese distributor that @hispls used for his big order. I don't doubt that you and spls have the specs correct for the cells he's already got.

Xs is using the same yinlong cells as everyone else. Literally just a wrapper.