Need a battery recommendation.

[TruckCamper]

Come on guys! If you are going to make statements in here, please base them on facts. Here is a quick comparison of an AGM in OEM Bronco sizing to both a diesel truck starting lithium and a lithium marketed for auto use. Which one do you think will run a winch faster/longer? Which will be the worst?

Answer is Lithium are not designed for winch loads. They can't take the sustained amp draw that an AGM battery can.

None of these lithium batteries have a listed continuous amp draw rating. Meaning they can take short power burst for seconds not minutes. I'll venture to guess the BMS will cut power after ~30 seconds to protect the battery. Who wants to test it?

Also... The battery you mentioned:
https://lithiumhub.com/product/ioni...o4-car-post-starter-heater-battery-bluetooth/
Is NOT the same as AGM. It's only 40AH. Meaning the if it could take a winch at full 600amp load the battery would be dead (to zero) in under 4 minutes.

Interstate AGM H7 @ Costco is listed at 80AH. Yes, for longevity it's ideal to not discharge past 50%... However, you can discharge further and it will take the continuous winch amp draw till dead (no BMS to cut off) for nearly twice as long.

I'd love to go lithium. We have a 150AH RedArc lithum in our Raptor for the 2,000w inverter that charges off the alternator and roof mounted 200w solar. Our travel trailer has 600AH lithium with 1,200w solar and generator backup.

Go ahead and prove me wrong. I'd love to see a full continuous 600amp draw on any of these lithium batteries for even 60 seconds...

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[Brian_B]

Answer is Lithium are not designed for winch loads. They can't take the sustained amp draw that an AGM battery can.

I don't believe you.

 

[Brian_B]

I don't believe you.

And here is why

I'll give you that "specific" Lithium batteries may be unsuitable. But you are making the generic blanket assumption that it applies to all. Details matter, and you are glossing over a lot.

Lithium has a ~much~ lower internal resistance than AGM or Lead Acid. A lithium cell will run rings around a lead-based battery all day long -- ASSUMING the internals are built to handle it. That's where details matter.

If you take a bunch of lithium 18650s and solder them together with #20 wire - well then, of course it's gonna fail on a continuous high amp draw. But if you build an automotive battery right, a lithium battery will smoke a lead acid all day long - more cycles, more consistent voltage while discharging, faster charges, and higher/faster amp discharges. There is a huge difference between an "Automotive" battery and something like a Milwaukee M18.

AH has a little bit to do with it - given that a lithium cell is 3.6V, you string a bunch in series to get (close to) 12V, then you stack those in parallel to get your AH capacity (depending on internal construction of the lithium cell). More stacks in parallel, more amps you can support going out (again ASSUMING it's constructed to do so, Anitgravity was pretty clear that higher AH rated batteries had higher surge amp limits because of this).

Lead Acid though, you get about 2.0V per cell, and to get capacity, they just physically make the cells bigger... so you get whatever internal resistance all the lead terminals and plates will give you, really no matter how many AH you purchase.

If you made a lead acid battery with poor terminals and weak lead plates (and those exist, go look at something like a SLA 12400 - 40AH, but meant to power something like a scooter, not a winch or starter) -- then it would be the same thing you are assuming ALL lithium batteries are.

I'll give you that Lithium has drawbacks - but amp draw DEFINITELY is not one of them. I've got a set of lithium batteries at work that will do 2800A for an hour straight. They are pretty large and industrial, not automotive batteries - but again, it all has to do with construction, not the chemistry.

And I know for a fact that I've winched with my Antigravity. No, not for 10 minutes straight, because that's absolutely retarded (100' of line, you can't use all of it anyway, and at 30'/min spool speed... what the hell are you trying to winch anyway?) , but I never hit the BMS cutout on the winch - probably because the alternator can recharge it almost as fast as you can discharge it with the winch, if you actually stop to consider duty cycling and heat on the winch.

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