LTO Starter Battery

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Conditions- LTO is a lithium based technology, but really differs in chemistry and design. It’s why the low voltage per cell. It seems to have very little potential for destruction.
Ruggedness- way better than SLA, which isn’t saying much. Similar temperature ranges. Again, the cycle count is very high; should give years of service under most any use paradigm. The C rates it’ll see in auto use are very minimal compared to capability.
 
sdnative said:
Based on the discharge curve of LTO cells, it seems a 5S configuration may work the best. Fully charged you will be at ~14.25V, and at the lower knee of the curve you will be at 10.5 to 11V.

As far as capacity, maybe size the discharge current to the CCA rating of a group 24 or 27 lead acid battery which is between 500-750A. At 10C that is 50-75 Ah for a 5S pack. If the cells are only 30-40Ah, you may need to consider 10 cells in a 2P5S arrangement.

BMS capable of handing those currents can get cost prohibitive, especially MOSFET (solid state) based BMS. May need to consider contactor based BMS or not using a BMS.

Do you have a link to the cells and BMS you are considering?
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Yes, 5s seems to be used by some vendors selling prepacked 12v starting batts as well as BMW. Trouble is the discharge curve is very steep initially, then steady but decreasing, then steep again. Not flat like LFP.
Am thinking 6 cells idling at mid charge is better than 5 cells running full tilt. It’s not a perfect fit for 12v for sure, which Is one of the issues to solve.
 
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sdnative said:
Based on the discharge curve of LTO cells, it seems a 5S configuration may work the best. Fully charged you will be at ~14.25V, and at the lower knee of the curve you will be at 10.5 to 11V.

As far as capacity, maybe size the discharge current to the CCA rating of a group 24 or 27 lead acid battery which is between 500-750A. At 10C that is 50-75 Ah for a 5S pack. If the cells are only 30-40Ah, you may need to consider 10 cells in a 2P5S arrangement.

BMS capable of handing those currents can get cost prohibitive, especially MOSFET (solid state) based BMS. May need to consider contactor based BMS or not using a BMS.

Do you have a link to the cells and BMS you are considering?
Click to expand...
The 10c rating is sustained, not burst. LTO can get to 50C burst. I’d love to do a 2p pack but I think it’s just a hair big to fit, will know more when cells come in. If the 1p pack works, I’ll be incented to add on more cells and have the house /starter battery combo.
 
grinchy said:
The 10c rating is sustained, not burst. LTO can get to 50C burst. I’d love to do a 2p pack but I think it’s just a hair big to fit, will know more when cells come in. If the 1p pack works, I’ll be incented to add on more cells and have the house /starter battery combo.
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I’m not convinced the bms is proving much value in this scenario, but I’ve linked it here:
www.aliexpress.com

49.96€ |2.4V Lto Bms 4S 5S 6S 7S 8S 9S 10S 80A 100A lithium Titanate Batterij Bescherming Boord Voor Auto Start Piek 1000A|Batterij accesoires| - AliExpress

Smarter Shopping, Better Living! Aliexpress.com
www.aliexpress.com www.aliexpress.com
 
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Thanks for all the input @sdnative
 
Regarding the Victron video link, guess what other product they sell . . . Balmar alternators. It’s an infomercial.
 
Alternator appears to be temperature sensing, but it’s external air temperature. Not alternator over temp, for example.
discussing the 2008 tundra which has the 5.7l engine. It may have a different alternator, but the article speaks in general on toyota design.

i think the upshot is that it’s cheaper to buy a $60 to $100 dc dc charger than it is to buy a new alternator.

victron orion non smart 9a is 65$
renogy 20a is $95
 
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A more realistic full power alternator test. The alternator (90A Bosch) is running full tilt for around 15 min+. It gets very hot (180C+ at the windings), but continues to work fine.



Now how long would it run 100% on a 40Ah LTO battery from flat to full at full tilt (140A effective charge out of a 180A alternator -> 3.5C) - roughly 17 min. Probably would burn out the alternator after doing this a few times . . .
 
This is definitely an interesting experiment I'll call it. Maybe questionable how much real world utility there is in such an upgrade as I'm not seeing it expand any use cases, and may even compromise some. Weight is a good advantage. Some real integration hurdles to work through. Application can be a bigger dictator of battery type than it may seem. Funny thing is that even most EVs in the last decade, has used standard FLAs for accessory support.

The low internal resistance of lithium's is one to watch. The RV forums has seen reliability issues with alternators when charging lithium batt's. Charge time is one way to look at it but brush and regulator life can be compromised even with shorter durations of heavy current. I'm not sure how much capacity margin is in the alternator charging system in extreme uses like cold weather where electrical loads can be high with all the heating and electrical accessories that the LX has.

Already some great consideration items @sdnative has pointed out. Few other things
- Safety of such a high current source underhood. Lead acids are somewhat self limiting in shorts because of their higher internal resistance. Lithiums may be a greater liability and risk to fire as you know it's unfused, at least to the starter
- Capacity: While lead acids have recommended discharge levels to maximize service life, the reality is they have built in useful emergency reserves which can be almost the full rated capacity.
- Jumping: May be difficult to jump if it goes dead, as the drained battery itself becomes a large load. If using a BMS, will want to understand the workflow necessary to get the car jumped and battery/BMS re-engaged

Not to discourage you and I'm all for pushing the envelope. Just some integration things to watch.
 
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Yep, it appears that the reason a lead acid is unfused is the high internal resistance. We'll need to calculate what the starter 1.5KW means in amps and fuse the starter line for this draw (150A?). The biggest other draw I can imagine is the 2000W/4000W pk inverter I was given for Christmas two years back that is sitting on a shelf. So a 300a fuse would cover both. . .
 
I have a supercapacitor I use for jumping. I think it'll do just fine. Now whether it needs a battery disconnect so the LTO doesn't suck it dry before the starter is an interesting thought. Maybe jumping will require some terminal shenanigans.
 
I was completely unaware of the LTO battery chemistry prior to this thread and from what I can find it seems their cold weather capacity retention and discharge charactistics are excellent compared to other Lithium battery chemistries. What I could not quickly find solid data on however is what their minimum charge temperature is? I ran into this quickly after outfitting my RV with a large solar array and LiFEPO4 battery bank. I had to add battery heaters or there was no charging possible in cold weather.
 
Yeah, I'm following this thread with interest of LTOs for my camper! Big inverters is a great reason for lithium's as even AGMs come up short at about 600 watts because of limited c-rates and peukert effects.
 
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RyanR said:
I was completely unaware of the LTO battery chemistry prior to this thread and from what I can find it seems their cold weather capacity retention and discharge charactistics are excellent compared to other Lithium battery chemistries. What I could not quickly find solid data on however is what their minimum charge temperature is? I ran into this quickly after outfitting my RV with a large solar array and LiFEPO4 battery bank. I had to add battery heaters or there was no charging possible in cold weather.
Click to expand...
-40C if I recall correctly
www.yinlong.energy

Yinlong LTO Batteries | Lithium-Titanate-Oxide Batteries

The fast-charging Yinlong LTO battery cells can operate under extreme temperature conditions safely. These Lithium-Titanate-Oxide batteries have an operational life-span of up to 30 years thereby making it a very cost-effective energy solution.
www.yinlong.energy www.yinlong.energy
 
grinchy said:
-40C if I recall correctly
www.yinlong.energy

Yinlong LTO Batteries | Lithium-Titanate-Oxide Batteries

The fast-charging Yinlong LTO battery cells can operate under extreme temperature conditions safely. These Lithium-Titanate-Oxide batteries have an operational life-span of up to 30 years thereby making it a very cost-effective energy solution.
www.yinlong.energy www.yinlong.energy
Click to expand...
I would double check and ensure "operating temperature" includes charging. The batteries I were using listed a -30C operating temperature, and would indeed hold a charge and discharge at very low temperatures, but would not accept a charge at all below freezing.

EDIT: Just read through the detailed spec sheet. Looks like they can take 80% charge all the way down to -20C. Very cool!!
 
www.yinlong.energy

Yinlong LTO Batteries | Lithium-Titanate-Oxide Batteries

The fast-charging Yinlong LTO battery cells can operate under extreme temperature conditions safely. These Lithium-Titanate-Oxide batteries have an operational life-span of up to 30 years thereby making it a very cost-effective energy solution.
www.yinlong.energy www.yinlong.energy
RyanR said:
I would double check and ensure "operating temperature" includes charging. The batteries I were using listed a -30C operating temperature, and would indeed hold a charge and discharge at very low temperatures, but would not accept a charge at all below freezing.

EDIT: Just read through the detailed spec sheet. Looks like they can take 80% charge all the way down to -20C. Very cool!!
Click to expand...
Great find!
The other cool thing is they can be 'dead' / full flat and then reawakened with no appreciable impact on capacity or cycle life.
 
Looks like yinlong rates 66160 as 6C sustained 10C burst.

Also their graphic for 30 yrs -> 10 years transport + 20 years energy storage cracks me up. 'new' cells -> done with 10 years as a vehicle battery, ready for 'new' 2nd life as energy storage.
 
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