Testing an Aux batt solution...

[Shane150]

I have the Bluetooth voltometer on my Powerboost.
I have been monitoring the 24/7 voltage on this truck for many months. Especially when I let the truck sit for days at a time.

Once I swapped for the little LFP Auxiliary, everything changed.
Note that the underhood battery is 1000 days old (original factory)

Here's 5 days of the truck sitting

WOW! Is there a viable LFP option for my location? I see frigid temperatures 3 months and sometimes it deeps down to -13F!

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[Snakebitten]

WOW! Is there a viable LFP option for my location? I see frigid temperatures 3 months and sometimes it deeps down to -13F!

I'm a follower, rather than a pioneer. But I think it's not recommended to go LFP at some low temperature threshold. I'm not sure what that threshold is exactly either.
If it were a sophisticated LFP battery, it would have a BMS with thermal management as well. Some sort of heating element, for example.

 

[FaaWrenchBndr]

I have toyed with the idea of mounting two Motorcraft batteries. One could get 15ah with the dual auxiliary batteries.

I had not even considered the idea of using a lithium unit.

 

[Shane150]

I'm a follower, rather than a pioneer. But I think it's not recommended to go LFP at some low temperature threshold. I'm not sure what that threshold is exactly either.
If it were a sophisticated LFP battery, it would have a BMS with thermal management as well. Some sort of heating element, for example.

Was that a straight swap or modifications to the tray and cable ends are necessary?
Can you share some pics please.

 

[Snakebitten]

Was that a straight swap or modifications to the tray and cable ends are necessary?
Can you share some pics please.

I purchased a red and a black 12" 4AWG battery cable. (extensions, if you will)
Then bolt/washers/nuts to attach one end of the battery cable extensions to the existing OEM auxiliary battery cables.

I then set the LFP into the small passenger side under seat storage that came with my truck. Drilled 2 holes in the back wall of the underseat storage to fish the battery cable extensions through.

This was a temporary location to make sure I was happy with the results. I didn't want to cut-modify the factory auxiliary battery compartment up to fit the LFP in, and then want to go back to a 7AH AGM.

I doubt seriously that I will go back. But I'm also not in a hurry to relocate the LFP from where I put it. It's not bouncing around or being molested in any way.

Can you see it in your minds eye?

Note that the back wall of the underseat storage is taller than the top of auxiliary battery tray. So the holes I drilled for the battery cable extensions are only in the underseat storage wall. I did that so the seat bottom wasn't on top of the cables.

 

[Shane150]

I purchased a red and a black 12" 4AWG battery cable. (extensions, if you will)
Then bolt/washers/nuts to attach one end of the battery cable extensions to the existing OEM auxiliary battery cables.

I then set the LFP into the small passenger side under seat storage that came with my truck. Drilled 2 holes in the back wall of the underseat storage to fish the battery cable extensions through.

This was a temporary location to make sure I was happy with the results. I didn't want to cut-modify the factory auxiliary battery compartment up to fit the LFP in, and then want to go back to a 7AH AGM.

I doubt seriously that I will go back. But I'm also not in a hurry to relocate the LFP from where I put it. It's not bouncing around or being molested in any way.

Can you see it in your minds eye?

Note that the back wall of the underseat storage is taller than the top of auxiliary battery tray. So the holes I drilled for the battery cable extensions are only in the underseat storage wall. I did that so the seat bottom wasn't on top of the cables.

Thank you! I can picture it. Was resetting the BMS necessary when swapping this aux battery?

 

[Jmitchelltfo]

I’ll probably use a technique similar to @Snakebitten on this one. I’ll take some pictures for those of you that don’t have an imagination……..like myself.

Great description of the work though sir!

https://www.batteriesplus.com/productdetails/slil12=20dcm=bt?variationCode=VI1387680

 

[Snakebitten]

Thank you! I can picture it. Was resetting the BMS necessary when swapping this aux battery?

I did not reset the BMS. I don't want to restart my underhood AGM counter for "days in service".

 

[Snakebitten]

I’ll probably use a technique similar to @Snakebitten on this one. I’ll take some pictures for those of you that don’t have an imagination……..like myself.

Great description of the work though sir!

https://www.batteriesplus.com/productdetails/slil12=20dcm=bt?variationCode=VI1387680

I know nothing about quality on these small LFP batteries. What would you say is the reason that 20AH example would be so much more expensive?

 

[KTM753]

X2 brand is regarded as premium quality for AGM batteries. I would imagine their LFP is also. USA engineered in Springfield, Missouri. Founder is a battery expert. Some good podcasts on the web where he is interviewed. Interesting listening.

 

[Jmitchelltfo]

I know nothing about quality on these small LFP batteries. What would you say is the reason that 20AH example would be so much more expensive?

The 10 year warranty is my best guess.

I figured that if I bought one of the Amazon sourced lithium batteries and a Bluetooth monitor that I’d be $90 in and if either of those items crapped out after a year, I’d be on the hook for the replacement cost. Also…..I had store credit that I didn’t have a use for unless I bought a starting battery. This seemed like the best way to burn up that credit.

 

[Snakebitten]

The 10 year warranty is my best guess.

I figured that if I bought one of the Amazon sourced lithium batteries and a Bluetooth monitor that I’d be $90 in and if either of those items crapped out after a year, I’d be on the hook for the replacement cost. Also…..I had store credit that I didn’t have a use for unless I bought a starting battery. This seemed like the best way to burn up that credit.

Out of curiosity, I'd love to hear what the maximum voltage is on that battery when you charge it the first time. And I mean before you put it in the truck.

I'm curious how balanced the manufacturer gets it before shipping.
The cheap Chinese examples on Amazon are shipped with little/no effort to balance the 4 cells. It took 3 nights of charging at 0.025 amps to get the LFP resistors to bleed/balance the battery.

I could have installed it unbalanced, of course, but I wanted it to be capable of being charged all the way to 14.6V

 

[Jmitchelltfo]

Out of curiosity, I'd love to hear what the maximum voltage is on that battery when you charge it the first time. And I mean before you put it in the truck.

I'm curious how balanced the manufacturer gets it before shipping.
The cheap Chinese examples on Amazon are shipped with little/no effort to balance the 4 cells. It took 3 nights of charging at 0.025 amps to get the LFP resistors to bleed/balance the battery.

I could have installed it unbalanced, of course, but I wanted it to be capable of being charged all the way to 14.6V

Checked it this morning as I walked through the garage on the way to work. Showed 14.58 volts after one night on my 3 amp LFP charger. Seems solid since the charger is only rated at 14.4 volts.

I have a 5 year old version of the battery I linked below. I used it for powering a Humminbird 360 (fancy fish finder) in my kayak and it showed 14.48 volts after sitting for a month or more. This battery is a survivor. I was in Florida for a kayak bass tournament and got in a hurry while loading up, after a long day on the water. I left the battery sitting on my bumper and it fell off, only to be run over by my buddy who was following me out. Case was cracked, but the cells themselves were still intact, it held a charge and worked fine. That was when I KNEW LFP was the right/safe decision to run on my kayak. I did make sure to charge it outside for the first week or two..........you know just in case. I didn't want to burn down the AirB&B where my buddies and I were staying.

I probably don't have the patience to "balance cells" or watch a fancy charger trickle at a miniscule pace.......but I definitely applaud you and @HammaMan for your efforts.

12v 30AH Lithium Battery Tall – Amped Outdoors

 

[Snakebitten]

Thank you!

I've always leaned to "you get what you pay for", but Covid/Post-Covid has me less a believer, if you know what I mean.

I suspect that's not only a better quality example of a small 12V LFP, but as you stated, it's a great warranty with a company that already has a good reputation.

Keep us posted how it works out in your truck.

 

[Jmitchelltfo]

Thank you!

I've always leaned to "you get what you pay for", but Covid/Post-Covid has me less a believer, if you know what I mean.

I suspect that's not only a better quality example of a small 12V LFP, but as you stated, it's a great warranty with a company that already has a good reputation.

Keep us posted how it works out in your truck.

I definitely know what you mean. I've read so many horror stories about transmissions, turbos, wastegates, batteries........the list goes on and on. Hopefully we see some improvements in that area......it would be great to see some American brands that were known for manufacturing great cars. Maybe these tariffs will encourage.........wrong thread.

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