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

[viciouslancer]

I bought some of these to use for hardwire connection

. https://www.aliexpress.com/item/1005004386911405.htm

Maybe I'll just get a grommet to allow this to hang out of the enclosure, and I can also add a single wire butt connector for ACC through the grommet.

 

[EricSan]

Maybe someone else can share their experience cutting metal?

I do this the same way, either I drill holes that never seem to line up exactly where I want them to, or I use my dremel with a cutting wheel (or a combination of the two).

Added a handy feature for the battery:
Two brass tubes 2.4 mm ID and 3.2 mm OD, are pressed into the front panel, protruding about 1.5 mm, about the same as the display next to them.

Hey, now THAT’S a clever design feature! I always have to open the case to make those adjustments, and it’s a bit of a hassle. This is a nice and clean solution!

 

[GPak]

Since I experiment a lot, I wanted to be able to easily adjust the charging current from the very beginning.

On the original 7S pack, I added a second CC resistor in parallel with the existing one and a switch, as shown in attachments.
By adjusting these two resistors, I could set any two CC values and switch between them.

However, on the latest charger, the CC resistor is not so easily accessible, and I was constantly wondering how to get to it.
Then it hit me, and now I can easily adjust the CC over the entire range.

 

[GPak]

Also just received a spare JK-BMS from AliExpress.
Same model as my original and the one I bought on Amazon.
It has a Chinese label but no manual, 10G wires soldered and no ears.
The Amazon version came with an English label, detailed printed manual in English, screw terminals with bolts, 10G wires with ring terminals and ears, and is 10mm longer than the Chinese version.
Both versions have exactly the same model number and specs, go figure.

@wilsch - could you please check the Bluetooth range of your JK-BMS in a closed case?

Recently I noticed that the JK-BMS version with P- and B- wires bolted on, (from Amazon, and similar to yours) has a very short Bluetooth range of about 8 ft in a closed case.
Also, the power switch stopped working.
So I removed it and replaced it with a spare JK-BMS with P- and B- wires soldered on (from China and similar to my original BMS that I used on a 5S battery).
Now the Bluetooth range is about 20+ ft (plenty for car use), which is comparable to the range of my original JK-BMS for a 5S battery.

 

[EricSan]

Curious discovery about blutooth range. Inside the blue box really limits range for me as well. I have to be within 8-10ft. I used to be able to reach the EcoFlow with blutooth from the living room couch. I’m assuming the powder coated panels are thin gauge steel?

 

[GPak]

Curious discovery about blutooth range. Inside the blue box really limits range for me as well. I have to be within 8-10ft. I used to be able to reach the EcoFlow with blutooth from the living room couch. I’m assuming the powder coated panels are thing gauge steel?

Yes, steel plates but with venting slots and plastic frame helping with BT signal.
Using the same/similar case for a 7S battery with ANT-BMS, I got good range (never measured it though).
10 ft is not much, but probably good enough for a car.

Beside very good BT signal, at home, the Ecoflow switches to Wi-Fi, and I can access it from anywhere in the house, at work, and anywhere else I have a mobile connection.

To check the BT signal:
I removed the top cover of the case to see if there was a difference, and the range did increase to about 15ft, but still not as good as the original BMS for a 5S battery in a closed case.
Then I compared the Bluetooth signal strength (%) using BT inspector app, and it was about half that of the original BMS (both with open cases).
So I replaced the “new-style” BMS on 6S battery with a spare “old-style” BMS with a soldered P-/B- cables and now the BT signal is as good as the original one. (about 20ft with closed case)
Therefore I thought maybe the limited BT range was a shortcoming of the “new-style” bolted P-/B- wires version BMS.

Thanks to @Chuck McCoy for the post linked here (right on time):

Post in thread 'VIOFO HK6 Hardwire Cable - Test & Review'

Aug 26, 2025

@SafeDriveSolutions
Q: How do you test / confirm Bluetooth Signal if you suspect a defective HK6, or malfunction?
A:

1.) Download your favorite Bluetooth Signal finder from the APP Store;

‎Bluetooth Inspector

‎Discover nearby Bluetooth peripherals and inspect their services for information and characteristics. • View information and signal strength for all peripherals and devices, updating in real time as you move around. • Get battery level for your own Apple devices (signed into the same primary...

apps.apple.com

2.) Power Up HK6
3.) Confirm Red Status LED
4.) Open APP
5.) Start Scanning
6.) Click on HK6 for device info & Signal Strength

• Chuck McCoy

• 

 

[wilsch]

@wilsch - could you please check the Bluetooth range of your JK-BMS in a closed case?

Recently I noticed that the JK-BMS version with P- and B- wires bolted on, (from Amazon, and similar to yours) has a very short Bluetooth range of about 8 ft in a closed case.
Also, the power switch stopped working.
So I removed it and replaced it with a spare JK-BMS with P- and B- wires soldered on (from China and similar to my original BMS that I used on a 5S battery).
Now the Bluetooth range is about 20+ ft (plenty for car use), which is comparable to the range of my original JK-BMS for a 5S battery.

I can confirm that my bluetooth range is rather abysmal with the newer hw version of the bms. With the case closed I get about 6ft of range provided there's no other obstructions. So with the battery in my car's trunk, I cannot connect to it unless I pop the trunk and hold a line of sight between the phone and battery.

Though, I dont often find a need to check on the battery status now that I have everything set up and running, so this limited range isn't too much of a hindrance for me.

Sorry for the late reply, I've been rather busy since finishing up the battery and installing it in my car. Soon I'll share an update on my completed battery and car installation 🙂

 

[GPak]

I can confirm that my bluetooth range is rather abysmal with the newer hw version of the bms. With the case closed I get about 6ft of range provided there's no other obstructions. So with the battery in my car's trunk, I cannot connect to it unless I pop the trunk and hold a line of sight between the phone and battery.

Though, I dont often find a need to check on the battery status now that I have everything set up and running, so this limited range isn't too much of a hindrance for me.

Sorry for the late reply, I've been rather busy since finishing up the battery and installing it in my car. Soon I'll share an update on my completed battery and car installation 🙂

Thanks for the reply.
So we have two identical new versions of the JK-BMS, both with very short Bluetooth range - apparently a shortcoming of this particular model.

Today, I have sent a request to SUPPORT-JK BMS regarding the very short Bluetooth range.
I have provided them with links to my orders for the new and old BMS as well as a link to this forum.
I hope they will respond.

It will be interesting to see your complete battery and car installation.

 

[EricSan]

I'm curious to see another DIY LTO battery myself! I was just looking at the website for BattyerHookUp.Com and they have three varieties of LTO cells available, including some new, individual "naked" cells with tabs large enough for drilling for screw.

LTO 2.3v 20ah Toshiba SCiB 20,000 cycles

These cells have tabs sticking up which you can make holes in for bolted connections. They were recovered in working condition from a larger battery that was used for backup starting power only and these cells likely test near full capacity. Just $10 per cell for unused Toshiba 2.3v 20ah LTO...

batteryhookup.com

 

[EricSan]

Ha - I just discovered for myself the reason that you included a UPS relay, @GPak 🙂. I now have three cameras tied to my LTO battery and when I opened the app to see what the charge rate was while waiting to pick up my daughter and saw that the charge rate was only about 3.5A. This was strange, I remember setting to somewhere north of 5.0A, but that's not what I was seeing. I've also been noticing lately that the battery seemed to be charging more slowly that I was expecting. I knew I was drawing more from it, but I started wondering what was wrong. Is it the charger board? What was going on now? Sigh... Then I realized it was the impact of having multiple cameras running. As I turned them off one by one, my charge rate returned to 5.5A, just as I expected.

The 20w that were powering three cameras was being subtracted off of the 70w that was going to the batteries... I just have the cameras pulling directly from the batteries and the batteries are being charged by the charger/bms combo. I never put the UPS board in place because the draw of a single camera (when I built the box) wasn't really a concern... until now... 😉

 

[GPak]

Ha - I just discovered for myself the reason that you included a UPS relay, @GPak 🙂. I now have three cameras tied to my LTO battery and when I opened the app to see what the charge rate was while waiting to pick up my daughter and saw that the charge rate was only about 3.5A. This was strange, I remember setting to somewhere north of 5.0A, but that's not what I was seeing. I've also been noticing lately that the battery seemed to be charging more slowly that I was expecting. I knew I was drawing more from it, but I started wondering what was wrong. Is it the charger board? What was going on now? Sigh... Then I realized it was the impact of having multiple cameras running. As I turned them off one by one, my charge rate returned to 5.5A, just as I expected.

The 20w that were powering three cameras was being subtracted off of the 70w that was going to the batteries... I just have the cameras pulling directly from the batteries and the batteries are being charged by the charger/bms combo. I never put the UPS board in place because the draw of a single camera (when I built the box) wasn't really a concern... until now... 😉

The bypass function using a UPS module has many advantages, but like everything else, there are also a few minor cons.
Connecting additional loads to the battery won't affect the charging current and charging rate, as displayed in the app, which is good, but it will increase the current draw from the vehicle's electrical system.
If it's an alternator, as in your case (the right way to install the parking battery), then this isn't even a real con.
However, in my case with the CLA, I have to be careful not to exceed the CLA's rated current, I am planing to replace my old jeep soon, so I don't want to bother with running wires through a firewall.
I think it's a good feature to have, and its benefits far outweigh the cons.

 

[EricSan]

Yep, just reinstalled my hardwire connection to the battery and set the charge rate to about 9.3A. This tops out at about 145w of charging and with the ~20w draw of a few cameras, still leaves ~100-110w of power to charge the battery, depending on its state of charge.

Also, I think I discovered the "mystery" around that infuriating little orange LED indicator on the smaller 20A charger board that we both played with. Earlier, we were operating under the premise that it was some sort of "error" light, telling us something was wrong. After adjusting the charging current back up and watching things in the app as it was charging, I'm now thinking that the orange LED means that the charger is bucking the charge voltage (voltage delivered to the batteries is less than the input voltage to the board) and the LED goes out when the charger board starts boosting the charging voltage (voltage delivered to the batteries is greater than the input voltage to the board).

At my higher charge rate, I don't think I'm going to play with adding the UPS module. There isn't a practical benefit now. For a short time, I was back to using the utility outlet and I was being careful to keep the current draw below 50% of the power rating for the socket.

 

[GPak]

....
Also, I think I discovered the "mystery" around that infuriating little orange LED indicator on the smaller 20A charger board that we both played with. Earlier, we were operating under the premise that it was some sort of "error" light, telling us something was wrong. After adjusting the charging current back up and watching things in the app as it was charging, I'm now thinking that the orange LED means that the charger is bucking the charge voltage (voltage delivered to the batteries is less than the input voltage to the board) and the LED goes out when the charger board starts boosting the charging voltage (voltage delivered to the batteries is greater than the input voltage to the board).
.....

I noticed this too, but I wasn't sure because the LED switching from orange to green wasn't presisly synchronized with transition from buck to boost. In my case, as far as I remember, it would switch to green a little earlier, while still in buck mode.
At the time, I couldn't find anything about this in the product description.

Meanwhile, I finished working on a 6S LTO extended battery to test the extension concept, and it works.
I'll post the details soon.