LTO bank vs LiFeP04 for daily system

[HondaCRV03]

Yes. I added it since my next build will be about 12kw in bass. Also the 80ah has lifepo4 cells. So I figured why not add more lifepo4 cells to what I already have for more reserve.

The 80ah has like 12 spots per side (positive and negative) so I just ran 1 1/0 run per terminal to add it to the battery

 

[mat3833 10+ year member]

Yes. I added it since my next build will be about 12kw in bass. Also the 80ah has lifepo4 cells. So I figured why not add more lifepo4 cells to what I already have for more reserve.

The 80ah has like 12 spots per side (positive and negative) so I just ran 1 1/0 run per terminal to add it to the battery

Ahhh, OK so you are running a total of 120ah of LiFeP04 then. I was wondering about charging current.

 

[HondaCRV03]

I have a 320a currently. No issues with the set-up. I do have the cells on a balancer as well. I'm not sure if that makes a difference

 

[mrj858 10+ year member]

I run 260ah of yin long LTO with 8banks of Maxwell ultracaps…charging comes from 2 370 amp alts….I have roughly 8k on mids and tweets from 2 crescendo skyway 3ks for mids and a crossfire 2000.4 for tweets…. Bass amps are 4 Crossfire XT8ks ….I charge at 16 cold and 15.6-15.8 hot and have been for alittle over 2 years

 

[hispls 5,000+ posts]

So you are just leaving a little on the table then only charging at 14.4. I'm guessing your vtage stays right at 14.2 or so under heavy load?

Yes, leaving a fair bit of storage capacity unused and voltage takes a while to dip much more than a couple tenths even when going hard. Either will melt subs before you get below 14V

 

[mat3833 10+ year member]

Yes, leaving a fair bit of storage capacity unused and voltage takes a while to dip much more than a couple tenths even when going hard. Either will melt subs before you get below 14V

Huh, I was unaware that you could do that. Isn't the low voltage on the 6s packs something like 13.6-13.8?

 

[winkychevelle 10+ year member]

Huh, I was unaware that you could do that. Isn't the low voltage on the 6s packs something like 13.6-13.8?

Technically at 14.4v he only has 25% capacity and 14.8v would be 50%, 15.6v is 92%

His bank is huge at 240ah so even 25% of that is 60ah×10c= 600amp
600amp×14.4v=8640w
320amp alt×14.4=4608

He has 13248w capacity before dropping .1v and that's on a sinewave music is transient.

.1v increase is alot on a lithium cell. The yinglong cell would go from 25% soc to 31.35% just buy going up to 14.5

240ah × 31.25%=75sh
75ah× 10c=750amp
750amp×14.5=10875
320amp alt× 14.5=4640
15515w before dropping .1v

A 2267w increase over a .1v increase

 

[Bobbytwonames 5,000+ posts]

Just in case this helps anybody. This is why most people only need a 5s system.

 

[winkychevelle 10+ year member]

Just in case this helps anybody. This is why most people only need a 5s system.

View attachment 40777

Except that 5s is 100% charged at 13.6v and will be damaged above 14v

Idk how the chart for a 6s pack does you any good to support your 5s claim

 

[mat3833 10+ year member]

Except that 5s is 100% charged at 13.6v and will be damaged above 14v

Idk how the chart for a 6s pack does you any good to support your 5s claim

I'm not sure what 5s claim you are talking about?

Your chart is actually quite helpful. I was aware that lithium has a mostly flat discharge curve but I wasn't aware of how such a little voltage increase adds such a large percentage of capacity.

Unfortunately I would need a big bank to really use 6s LTO without testing what my ecu will actually tolerate or pulling the front battery and running some kind of Regulator to feed the cars electrical.

That's possibly an option, but I really have no idea how to implement something like that or how reliable it is.

Matt

 

[HondaCRV03]

Technically at 14.4v he only has 25% capacity and 14.8v would be 50%, 15.6v is 92%

His bank is huge at 240ah so even 25% of that is 60ah×10c= 600amp
600amp×14.4v=8640w
320amp alt×14.4=4608

He has 13248w capacity before dropping .1v and that's on a sinewave music is transient.

.1v increase is alot on a lithium cell. The yinglong cell would go from 25% soc to 31.35% just buy going up to 14.5

240ah × 31.25%=75sh
75ah× 10c=750amp
750amp×14.5=10875
320amp alt× 14.5=4640
15515w before dropping .1v

A 2267w increase over a .1v increase

No lie with your math it made me want to buy more cells lol. But also realize I won't be playing full tilt all day in traffic. Sounds like I'll be good for a few songs I think

 

[winkychevelle 10+ year member]

I'm not sure what 5s claim you are talking about?

Your chart is actually quite helpful. I was aware that lithium has a mostly flat discharge curve but I wasn't aware of how such a little voltage increase adds such a large percentage of capacity.

Unfortunately I would need a big bank to really use 6s LTO without testing what my ecu will actually tolerate or pulling the front battery and running some kind of Regulator to feed the cars electrical.

That's possibly an option, but I really have no idea how to implement something like that or how reliable it is.

Matt

He was saying 5s was good for most people. It isn't not at all. Unless the vehicle charges exclusively below 14v 5s lto will fail.

The chart is fine.

You could run a step down module to charge a 12v agm under the hood for the cars factory electric and have the alt charge to what ever voltage. Same way they run 16v agm without dual alts. Problem is the step down modules don't handle much current since they are simple big resistors inside of heat sinks. So you would need to parallel them till you had enough current to support the factory electrical systems likely 15-20amp

 

[Bobbytwonames 5,000+ posts]

Except that 5s is 100% charged at 13.6v and will be damaged above 14v

Idk how the chart for a 6s pack does you any good to support your 5s claim

Each cell can actually hold 2.9v. You will be good up to 14.5. Are you running a 5s bank? Have you ever ran one? I'm running one 40ah 5s bank of XS Power in my truck.

 

[Bobbytwonames 5,000+ posts]

I'm not sure what 5s claim you are talking about?

Your chart is actually quite helpful. I was aware that lithium has a mostly flat discharge curve but I wasn't aware of how such a little voltage increase adds such a large percentage of capacity.

Unfortunately I would need a big bank to really use 6s LTO without testing what my ecu will actually tolerate or pulling the front battery and running some kind of Regulator to feed the cars electrical.

That's possibly an option, but I really have no idea how to implement something like that or how reliable it is.

Matt

It was my chart. No worries.

 

[Bobbytwonames 5,000+ posts]

Except that 5s is 100% charged at 13.6v and will be damaged above 14v

Idk how the chart for a 6s pack does you any good to support your 5s claim

Unless you are running a high voltage system, which most people aren't, there is no reason to run a 6s. You can believe whatever you want. I've seen a boat load of 5s that did perfectly fine up to 14.4v - 14.6v.