OVERTHUNK — AUX LiFePO4 100Ah battery

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At some point I'm going to rework the 200's house electrical. When I built it in 2017 there wern't as many Li options so I went with AGM. Wouldn't go that way again.

Most likely I will go with a RELiON LT next time. A prime reason of that over the Battleborn is the heating strategy. The Battleborn uses battery energy to heat while the RELiON uses charger energy. This is a big flaw in the Battleborn because it results in inaccurate state of charge display on the Manager 30. This is because the heating is internal and bypasses the shunt. I've had the Battleborn run down to low charge cutoff while sitting in the driveway while the display said high 90 SOC.

The Battleborn is a great product. It's served me well. I just feel the RELiON has a bit of an edge when it comes to charging/heating tech. Also having a remote on/off switch to turn off the battery is huge. No more ought-gauge wire to a external high-current shut-off switch.

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82SC said:


Geez this info is so varied all over the internet
His engine isn’t even running
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I'd take this video with a big grain of salt. They did a poor job of describing the setup and batteries, barely mentioning this was a Lithium-ion battery. Which really should never be put under the hood as there is real fire risks.

I think the battery you've installed is a LiFePO4?

Some of the trades is that Lithium-ion is more energy dense and has more high discharge rate (c-rate) capability. LiFePO4 still has great discharge performance but one wouldn't want to do much beyond C1 or C2 rates. For a 100Ah battery, that's about 100-200 amps, most being closer to the former. Which is also dependent on the BMS. For any battery, it's probably better to run the winch circuit off the main starter battery as this can be more readily supported by the engine/alternator.

I'll echo the earlier points by others on BMSs. That's going to be critical to any successful Lithium chemistry installation.

Another major point - BMS cutoffs won't protect the battery completely from heat. The reality is that any Lithium at high states of charge and exposed to high heat, regardless of active charge/discharge, will see significant premature wear.

For a battery in your proposed location, I would strongly recommend fabricating a heat shield.
 
Write up soon

100Ah marine grade LifePO4
With low and high temp cutoff
With Bluetooth app to monitor battery

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I will after I load it up with fuses!! Lol

Ordered tie downs
Shock mount protection
Antenna mount
Traction board mount and tie downs
And with shipping and exchange rate it was still a good deal!
 
I share the same opinion as @TeCKis300 regarding having one of these under the hood. No Go!

Also, before you take the plunge and go all in wiring this up, i would STRONGLY suggest running some tests on their claims with their BMS

There are now dozens upon dozens of these rebranded Lipo4s popping up on amazon with crazy claims, but many have been tested and their claims are 100% false, which is dangerous as hell!

Check out "Will Prowse" on youtube, or the "DIY Solar Power Forum" for more in depth info.

Also, not sure how that battery would take a load when winching on a constant pull.

I may have missed it, but how you planning on charging this?
 
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linuxgod said:
A good LiFePO4 will have temp protection. I built my own LFP battery for my trailer about 18 months ago and I used an Overkill (JBD) BMS. There are cheaper BMS options which are typically incorporated into the battery, but if it doesn't have its own protection then the battery is IMO garbage.

The BMS sits inline on the negative side of the battery. Most good BMS will have a ~120A discharge limit, give or take, and won't be suitable for winching. I've seen some higher discharge limits but they are via the crappier BMS options.
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Good Man!

Overkill BMS is what i am running on my server rack lithiums in the camper. But thats a whole different story! :P
 
Boston Mangler said:
I share the same opinion as @TeCKis300 regarding having one of these under the hood. No Go!

Also, before you take the plunge and go all in wiring this up, i would STRONGLY suggest running some tests on their claims with their BMS

There are now dozens upon dozens of these rebranded Lipo4s popping up on amazon with crazy claims, but many have been tested and their claims are 100% false, which is dangerous as hell!

Check out "Will Prowse" on youtube, or the "DIY Solar Power Forum" for more in depth info.

Also, not sure how that battery would take a load when winching on a constant pull.

I may have missed it, but how you planning on charging this?
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Even the venerable SLEE is jumping on the lithium under the hood band wagon.



I understand the concern but I have not heard of any real world examples of disasters. In theory sure….But the Aussies have been beating the LiFePO4 batteries under the hood and winching with them too. US has been slow to try it. But SLEE consulted with Battleborn and came up with their setup.

Will Prose really likes the SOK batteries. And that’s what I’m running.
 
If I was doing my set-up over I would get one of these to mount to the drawer unit and behind the seats:

bigbattery.com

12V RAZORBACK- LiFePO4 - 138Ah - 1.76kWh - BigBattery.com

12V RZBK LiFePO4 138Ah 1.76kWh. Worlds Thinnest RV & Van Battery! Zero Maintenance. More Power, less weight. Easy Plug & Play Install. Order yours from BigBattery.com today!
bigbattery.com bigbattery.com

Other than the minimal space savings, I am not sure of the advantage of mounting any aux battery under the hood unless it is a dual battery to compliment the starter unit - not a house battery.
 
My Renegy LiPo is in the back along with the loads it powers and the DC/DC charger. its cooled by the rear AC when needed (or heated as the case may be)

In my defender it is in the battery box which is under the drivers seat. That compartment gets hot (exhaust routing and no insulation, etc), you can see the amount of charge go down when it's hot, on a victron monitor. Same thing in the cold, the BMS stops charging until it heats up protecting it. I do use them for heated blankets as well so overnight I can pull 40-50% out of the battery.

Overall I have been happy with the batteries.. for a mid range Lithium they preform well. the one in the 200 is powering the fridge 100% of the time, and the truck only gets driven a few miles a day during the week right now.

If you battery is rated for engine bay temps I guess go for it... DCS comes to mind.
 
82SC said:
Even the venerable SLEE is jumping on the lithium under the hood band wagon.



I understand the concern but I have not heard of any real world examples of disasters. In theory sure….But the Aussies have been beating the LiFePO4 batteries under the hood and winching with them too. US has been slow to try it. But SLEE consulted with Battleborn and came up with their setup.

Will Prose really likes the SOK batteries. And that’s what I’m running.
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I think some of the divide is that there are people here that traversed this path well ahead and burned their own hand on the pot handle so to speak. Bringing some real combined experience. The title here says OVERTHUNK. To that point, we're trying to help you build a system that works reliably. Under all conditions. Not just the nominal ones.

No disrespect and telling it like it is, but Ed Martin - in sales to sell the sizzle, and only has some experience with the steak. You can lookup the humble beginnings on this board taking early critique...

Many ways to skin a cat. Some better than others. You're obviously putting some thought and budget behind this and just want to see you succeed.

If you're really into off-roading and crawling, the underhood temps are at another level that is going to compromise reliability. Winches in real life pull amps well beyond what any LiFePO4 BMS will allow. @Boston Mangler is looking out as he's had real experience with inrush currents.

If you're just building a day to day mall crawler, sure it'll get by for awhile.
 
TeCKis300 said:
I think some of the divide is that there are people here that traversed this path well ahead and burned their own hand on the pot handle so to speak. Bringing some real combined experience. The title here says OVERTHUNK. To that point, we're trying to help you build a system that works reliably. Under all conditions. Not just the nominal ones.

No disrespect and telling it like it is, but Ed Martin - in sales to sell the sizzle, and only has some experience with the steak. You can lookup the humble beginnings on this board taking early critique...

Many ways to skin a cat. Some better than others. You're obviously putting some thought and budget behind this and just want to see you succeed.

If you're really into off-roading and crawling, the underhood temps are at another level that is going to compromise reliability. Winches in real life pull amps well beyond what any LiFePO4 BMS will allow. @Boston Mangler is looking out as he's had real experience with inrush currents.

If you're just building a day to day mall crawler, sure it'll get by for awhile.
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Thanks, Well Said Sir

Also, for others, take a look at what lipo4 Slee is using…

Is it a $200-300 cheapy off Amazon with unrealistic specs?

I don’t even need to watch the video to know it’s not. :)
 
Boston Mangler said:
Thanks, Well Said Sir

Also, for others, take a look at what lipo4 Slee is using…

Is it a $200-300 cheapy off Amazon with unrealistic specs?

I don’t even need to watch the video to know it’s not. :)
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As I stated it’s Battleborn Lithium that SLEE used so I guess no one has to watch the video….

Price doesn’t necessarily mean quality but SOK comes in a little bit cheaper then Battleborn. But internet sensation Will Prose likes them alot. You don’t have to watch that video either…

It’s going to be charged with a Redarc bcdc.
Linked with a Redarc SBI212D
Also with a Redarc High Amp Relay
 
82SC said:
As I stated it’s Battleborn Lithium that SLEE used so I guess no one has to watch the video….

Price doesn’t necessarily mean quality but SOK comes in a little bit cheaper then Battleborn. But internet sensation Will Prose likes them alot. You don’t have to watch that video either…

It’s going to be charged with a Redarc bcdc.
Linked with a Redarc SBI212D
Also with a Redarc High Amp Relay
Click to expand...

Excellent.

I missed that you’re using an SOK. 👍🏼
 
Switched. I wanted a little more safety features like high and low temp cut off and BT monitoring.

I wanted heated blankets too as I take truck in snow but was constrained by size a little. SOK has one with all the features and heat blanket but was a little too big for the space.

But I figure with this if I start the engine up in the cold. The batt may not want to charge or discharge due to low temps. But engine heat should quickly remedy that. And if it’s a real problem I might add heat blanket that has auto thermostat.

High temps is the question and I’ll report days once I start running it in warm conditions and see how the charge profile and discharge profile change.
 
I applaud you trying LFP under the hood, while I have not yet finished mine .. still looking for best heated 100Ah that that fits without major surgery. I have committed to charging through a BCDC1240, using a BlueSea ML-RBS to link to stater battery for a) emergency starting, b) winch boost. My concerns are cold temps as I know charging below freezing will kill. I'm not concerned about high temps, or occasional very high loads. I've had LFP's under hood or at least as starter battery in Mazda, Porsche and Lotus street and track cars for too many years to worry about such.

Good to see Kaon using an aluminum battery clamp/shelf. I really don't know why slee uses a thick SS bracket. I copied the shape of the slee using aluminum for both starter and auxiliary batteries.







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