LTO (Lithium Titanate Oxide) – The Ultimate Battery for Dash-Cam parking mode (DIY)

viciouslancer said:
How fast does your car charge the pack? If I'm only driving 30-45mins twice daily, can it keep up to running 24/7? I have a 2016 Honda Civic, so ~135A alternator output (which of course also needs to power/charge the rest of the car first)
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For 24 hour parking, assuming a 3-channel dash cam, the power consumption could be around 7W x 24h = 168Wh
For the 6S LTO to replenish this energy in 1 hour of driving, you will need to charge the LTO battery with around 12A, which is around 14-15A from the car including the dash cam consumption.
Your 135A alternator should be fine.
 
viciouslancer said:
I saw them there yesterday, but gone again! However, this looks good for you and @GPak experimenting so much https://batteryhookup.com/products/27-6v-40ah-lto-toshiba-scib-20-000-cycles-24x-20ah-cells

I really want to pull the trigger, but trying to find all the other parts is scary (no experience building anything like this) and looking pricey, especially being in Canada 🙁
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Just realized, although the price per cell is fantastic, the busbars appear to be welded, without threaded posts, so more DIY work due to disassembling the busbars, and then they will probably need to be welded into a 6S configuration.
This is not an easy task and requires special equipment.
 
GPak said:
the busbars appear to be welded, without threaded posts, so more DIY work
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I'd really like to see the top of those batteries with the balance board removed from the battery pack. There are threaded posts that pop up through the PCB, but it doesn't look like they are located where the battery terminals are. I'm wondering about the shape of the welded busbars under the PCB. I'm wondering how easily the busbars could be cut, bent, and drilled to add your own screw post (machine screw with a few nuts). That would avoid the need for extra equipment to do tack welding.

With a 12A charge rate, you're DEFINITELY looking at a direct-to-battery connection to your battery pack, with an inline ACC-triggered heavy duty relay. A wiring diagram and parts list is here: https://dashcamtalk.com/forum/threa...reliable-for-battery-hookup.52539/post-635048

My son leaves his BMS powered up all of the time, but the camera only runs while he is at work (8 hrs), at home in the driveway, he turns the camera off. He has a 30-35 min drive 2x per day and I think his charge rate is 6-7A, but I haven't checked it in a while, so I'm not sure.
 
Here's a crazy idea for an LTO battery on steroids!! :joyful:

The easiest way to use this pack is to use it essentially as is!
Simply remove (unscrew) the existing balance board and using the existing balance screws, add the BMS in its place, and Charge Controller and Relay in a separate small box.
And we have a perfect 24V 1104Wh LTO battery that can last for about a week of LBR parking!!!
An LTO battery with 10 times the capacity of a standard dedicated LFP battery at about the same price!!!

Most dash cam hardwire kits, and the HK4 in particular, work well with the 24V option.
(The ACC signal on HK4 input may require a small 12V to 24V step-up converter)
 
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GPak said:
Here's a crazy idea for an LTO battery on steroids!! :joyful:

The easiest way to use this pack is to use it essentially as is!
Simply remove (unscrew) the existing balance board and using the existing balance screws, add the BMS in its place, and Charge Controller and Relay in a separate small box.
And we have a perfect 24V 1104Wh LTO battery that can last for about a week of LBR parking!!!
An LTO battery with 10 times the capacity of a standard dedicated LFP battery at about the same price!!!

Most dash cam hardwire kits, and the HK4 in particular, work well with the 24V option.
(The ACC signal on HK4 input may require a small 12V to 24V step-up converter)
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I was thinking about this actually - maybe cut one connection so it's only 12v, but am not sure how to keep it charged up with 0.5-2hrs daily driving.
 
I asked BatteryHookup if they will have individual LTO cells for sale and if they have pictures of the 24 cells without the balance board, and how to connect without terminals.

This was their reply:
Individual cells will not be for sale until likely the end of the summer.

We don't have any photos without the balance board, however, it is definitely possible to convert them into 6s packs. You likely will have to carefully Dremel the busbars between series connection 6 and 7.

You want to keep them in the case they are in ideally.

To connect BMS leads, you'll have to solder to the terminals
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Based on the BatteryHookup images and suggestion to Dremel the bus-bar between series connection 6 and 7, and the image from the Global Toshiba site I posted earlier, I'm pretty sure how the cells are assembled.
It would be relatively easy to split the 24V 40A 1104Wh battery into two 12V 40A 552Wh batteries each by simply cutting one long bus-bar as shown in the attached sketch.

Charging it according to your driving-parking schedule is no problem, you can adjust the charge rate as needed.
However, it still requires quite a bit of DIY work to assemble the 12V battery in a custom box and set it up.
 

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Nice find for the product link on Toshiba webpage with the illustration of cell layout, GPak! Great drawing, too! I was just starting to sketch one up as well to see what various configurations might be easiest to create - your drawing is neater than mine 😉

Looking at the datasheet that they provide on the Toshiba page, it looks like the maximum rated temp is 55c. Though, I'm presuming those temp limits are more important as you approach the upper current limits of 160A (6.6A per cell) for charging and 350A (14.5A per cell) for discharging. With our 6S batteries, we're barely looking at about 1.0-1.5A per cell (give or take a little) charge rate and ~1w per cell power draw for the camera. Given this, it seems that it's likely to be a bit safer to discharge than to charge at "hot car" temps of 55-65c. With this data, it might be safer to change the BMS "Over Temp Protection" to closer to 55c for better battery longevity

The only difference I would recommend with your diagram is to position the new solder tab terminal in the center of existing busbar, between the two battery terminals rather than directly on top of one of the cell terminals. This will protect the internals of the anode/cathode terminals from excess temps if soldered quickly with a hot iron.
 
EricSan said:
.........
Looking at the datasheet that they provide on the Toshiba page, it looks like the maximum rated temp is 55c. Though, I'm presuming those temp limits are more important as you approach the upper current limits of 160A (6.6A per cell) for charging and 350A (14.5A per cell) for discharging. With our 6S batteries, we're barely looking at about 1.0-1.5A per cell (give or take a little) charge rate and ~1w per cell power draw for the camera. Given this, it seems that it's likely to be a bit safer to discharge than to charge at "hot car" temps of 55-65c. With this data, it might be safer to change the BMS "Over Temp Protection" to closer to 55c for better battery longevity
..........
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The current is divided only for parallel connected cells, for series connected cells the current is not divided, each cell receives the full current.
So when charging a pack at 160A, each cell gets 80A (2 parallel per series).
This is a 4C C-rate (for 20Ah cells) with a temperature limit of 55°C.

Interestingly, according to the datasheet, 23Ah cells are limited to 60°C, I think including because at the same 160A, the C rate is less, at 80/23=3.48C
So, 0.5 less C-rate => 5°C temp limit increase.

We are nowhere near these charge rates.
We charge up to 10A (and that goes to each cell), which is only 10/20=0.5C rate.
So the temperature of 60–65°C should be fine.

The voltage is opposite, divided if the cells are connected in series, and unchanged if the cells are connected in parallel.

EricSan said:
.....
The only difference I would recommend with your diagram is to position the new solder tab terminal in the center of existing busbar, between the two battery terminals rather than directly on top of one of the cell terminals. This will protect the internals of the anode/cathode terminals from excess temps if soldered quickly with a hot iron.
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I agree, that's a good point, I was worried about this.
 
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EricSan said:
Alternatively to soldering, I'm wondering if a battery tack welder might work for $30. I've never used one before...

https://www.amazon.com/gp/B0C4NJWM6F
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I think this could work depending on thickness/material of the terminal/bus bar you're trying to attach. Given the high current we're looking for, I'm assuming we need thicker material so this won't work well.
 
EricSan said:
And here it is in its new home! The velcro strap actually passed through the side of the trunk liner as shown in the first image. I cut slits with my dremel tool and then pushed the strap through the slits. These straps go through plastic clips so additional straps that go around the battery pack can be connected to the anchor points. It's held pretty securely in place. Have to see how the charge rate works out over the next few weeks and if it needs to be adjusted.

View attachment 80797

In the final install, there is only one input cable in (12v charge from the switched utility outlet also in the trunk) and only one output cable that goes to the camera (3 conductors: 5v power, ground, and 5v parking mode trigger).

View attachment 73658
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How are you supplying enough current to the trunk? Just long low gauge wire? I was thinking I should maybe keep it closer to engine bay - so I don't need a power cable to the trunk, and closer to power the dashcam as well.
 
My trunk has both a utility outlet and the main start battery for the car. A temporary and lower current connection to the utility port is just two feet away, and the battery is also right there for a high current hardwire connection. I think I posted a few images of the hardwire connection earlier in this thread. I used 11g wire controlled with an inline relay that is powered from the fusebox which is also in the trunk. My son’s battery pack sits on the rear passenger floor and is directly connected to the start battery under the hood. We had to push that same 11g wire through the firewall for that install.
 
Here is the parts list and wiring diagram for a direct to battery install on a parking battery:

EricSan

Post in thread 'Is the 12V socket in the trunk of my SUV reliable for battery hookup?'

Just be careful with how much current you pull from the utility outlet. I would not attempt to pull more than about 70-80w (no more than half of its rated capacity) from that type of port. Although fused with a 15A fuse, those utility ports are often wired with pretty thin wire that is really not meant to carry that much juice for an extended period of time. I melted a utility port plug-in adapter by charging a parking battery at 8A. I don't know if it wiggled loose or not, but the tip melted due to excess heat. The fuse was still intact. This could have caused a fire...

EcoFlow Plug.webp
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viciouslancer said:
12x10Ah in 2P6S for 20Ah? for ~CAD$150 or ~CAD$200 for 24x10Ah
https://www.aliexpress.com/item/1005008713240125.html
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Your battery link doesn’t open for me. It flashes an image of the cylindrical batteries with screw terminals on the ends, then wipes the page and says it can’t find that item. I think AliExpress is hiding Chinese products from US shopper because of the big beautiful import taxes that drive prices up 😉

Your bms link works fine. I purchased this model: JK BD4A8S4P, the link that I saved says it can’t ship to the US right now, but the price is $22:

https://www.aliexpress.us/item/3256807166629452.html
 
EricSan said:
Your battery link doesn’t open for me. It flashes an image of the cylindrical batteries with screw terminals on the ends, then wipes the page and says it can’t find that item. I think AliExpress is hiding Chinese products from US shopper because of the big beautiful import taxes that drive prices up 😉

Your bms link works fine. I purchased this model: JK BD4A8S4P, the link that I saved says it can’t ship to the US right now, but the price is $22:

https://www.aliexpress.us/item/3256807166629452.html
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Here's a screenshot from Chrome DevTools

High Power Grade a 10C 20000 Cycles+ 32145 Cylindrical Lithium Titanate 2.3v 10ah LTO Electrified Monorail System Battery
6pc - C$99.85
12pc - C$151.23
18pc - C$175.81
24pc - C$200.40

Your BMS link won't ship to me, and is C$47.81.
 

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That’s a nice deal to get 24 batteries for twice the cost of only 6 cells! I’d go for 24 and find something to do with the rest. It’s a shame that global shipping is so screwed up, it doesn’t need to be that way…. I’m contemplating a battery power supply for my turn table and turn table preamp.
 
viciouslancer said:
I wonder if these are any good. Seems like it can be (slightly) smaller in size compared to the prismatic?

12x10Ah in 2P6S for 20Ah? for ~CAD$150 or ~CAD$200 for 24x10Ah

along with this cheap BMS https://www.aliexpress.com/item/1005008884898400.html
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Your BMS link works and has the JK-BD4A8S4P model (that's 40A, for a 4S-8S configuration) for $35 with free shipping.
This is what EricSan and I use for 6S and 5S configurations respectively.

Your Battery link doesn't work, however there are plenty of other sellers of these batteries on AliExpress.
Here's a link that works with 6 cells for $66 including bas-bars and nuts, and with free shipping.
LTO-32145 10Ah Cell

It is the same size as My LFP DIY Battery cells except terminals are M4 vs M5.
Relatively small M4 terminals can be difficult to work with and easy to break when tightening the nuts.

GPak

Thread 'LFP (LiFePo4) Battery for Parking, 192Wh (DIY)'

This thread is the third one in a series of alternative parking batteries for dash cams.
Coming from these two threads, on ‘Power Stations for Parking’ and ‘LTO Battery for Parking’.
https://dashcamtalk.com/forum/threa...-dedicated-options-extra-functionality.49972/
https://dashcamtalk.com/forum/threads/lto-lithium-titanate-oxide-–-the-ultimate-battery-for-dash-cam-parking-recording-diy.50484/

I believe, we should not rely on car's starter battery to power dash cam in parking mode, stressing it with a constantly...
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