100AH Lithium cant handle start up draw

[RichieFromBoston]

For my AUX battery I recently went to a reLIon 100AH lithium battery run through a redarc 1225d and after installing this, my ARB twin compressor died after a tad more than a year. seeing as I run 37s and use my rig as intended a lot airing up happens a lot, Also the addition of the Red Winch exploroer 2 it requires air for its air brake system. So I went looking for a solid serious copressor and came across the extreme aire magnum( a bit overboard) I know, but I dont want to mess with or wrry about my OBA at all. Pulling out the failed ARB twin was a project and for what it cost It should have lasted, but it didnt. The guys at extreme aire warned me that wiring to the STARTER battery was the way to go. But cmon man, LITIHUM, well they werent wrong simply trying to start the magnum while truck was running, redarc is charging up already charged lithium did nothing BMS on lithium shut it right down. So now Im thinking did I wire the fairly extensive controls etc for the extreme aire wrong? So I grabbed the odyessey 100AH from my house hooked it to compressor static, and compressor sparked right up. SO long story short ran 4guage wire from rear of truck all the way up to starter battery and all is well. Not complaining by any means, but never thought a 100AH would shut itslef down, but at .82amp draw on startup clearly litihum isnt up to that much,not now at least.
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[luthj]

What is the operating current of the compressor? We can use that to estimate the startup surge.

What battery are you using? What is its surge current rating?

After any install its up to the installer to perform voltage drop checks. While I think you may have some other issue, its possible for very low voltage due to drops, to cause motor damage.

 

[Superduty]

I'm not sure i fully understand.

Are you saying that wiring the ARB off the lithium is what killed the ARB? The lithium couldn't produce enough power?

Sent from my SM-G973U using Tapatalk

 

[john61ct]

First off LI is a generic umbrella term, I hope you are using LFP.

Next a proper setup from quality bare cells + suitable BMS would have no problem with a high-current discharge rate,

like 10x that of any lead for the same Ah capacity.

You probably have a "drop-in" where the cheap underpowered BMS limits the C-rate to a tiny fraction of what the cells can do.

I advise skipping those in general.

 

[dreadlocks]

Air Compressor = 82A (****************************************) for 100PSI, but compressor is rated for 150PSI, so thats not a max amp I dont think.
Your Lithium Max Discharge Rate = 100A
CCA On your Starter Battery, likely 800A

The way you have it wired now up to your lithium your getting nothing from your alternator because that piddly 25A charger.. with an 82A Air Compressor, you should wire that ************ right up to the alternator like the manufacturer suggested.. they were right, you were wrong.

for reference my LFP battery outputs ~85A running my microwave off a 1200VA inverter.. but I only need it to operate for like 2mins tops, and it still takes a good 10% SoC for those few mins.. but my LFP battery handles it fine with its 200A max output.

 

[luthj]

Obviously tying to your starter is the best approach.

Another options is an NTC thermistor. Also known as inrush current limiters. Once you know your surge current limit, you can choose one or more current limiters (series/parallel as needed). These will reduce startup surge for the couple seconds required to get them warm, after which they conduct normally.

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A third option would be a large capacitor in parallel with the battery, which would help reduce the ~200ms current spike.

 

[5spd97]

Battleborn states 200 amp surge for 30 seconds on its 100 amp/hr battery. My 7.3 E350 has a main plus auxilliary with 850 cold cranking amps each. I dont think lifepo4 batteries are intended as starter batteries.

 

[john61ct]

Battleborn states 200 amp surge for 30 seconds on its 100 amp/hr battery

To put it brutally, that's because that is a crappyexample of a LFP battery.

In more detail, BB has designed a "packaged" or "drop-in" system. Their low-current restrictions are due to the designed limitations of their BMS, i.e. keeping costs low, and

have **nothing** to do with the LFP chemistry itself.

In other words, **that** LFP drop-in was not designed for cranking.

They make LFP cells in tiny cylindrical form factor, would you expect one of those to crank your engine?

If high C-rates are important to you there are thousands of cell/BMS combos that will meet your needs. In a new-to-you technology, you need to educate yourself and/or ask for advice before handing over your credit card.

Although TBH I can't see much point in spending all that money just for cranking.

 

[dreadlocks]

the BB and other drop ins are competing with Deep Cycles, which dont put out high amps either and make terrible starting/winch/air tool compressor energy sources until you have a large enough bank of em that you can output high amps without high losses..

Starter Batteries and Deep Cycles have very little overlap.. my single BB runs my 1200VA inverter like a champ, with practically no losses, I'm pretty sure it'd run this guys air compressor too.. Victron suggests 200AH of FLA batteries as minimum for this size inverter, if I went with a dual battery LFP setup I could output 200amp constantly w/no high C rate losses and it'd be more than 2x what the inverter ever needed.

Whats the point of having a 100AH battery you can draw empty in 10mins? I've no idea who would want to do that.. If you wanna run big accessories, you shouldn't be doing that off a single battery regardless.. Ive seen a few Lithium cells start a diesel engine in the negative digits, yeah they can output some serious frigging amps.. but that also drains em so quickly they have very limited use.

 

[john61ct]

Even when supported by a strong Alternator input some load types benefit from less voltage sag.

Not to mention very high initial surge currents, usually don't last more than a second.

LFP can even be used for vehicle propulsion, where transitory 5C rates are normal.

The big takeaway here: if you use a BMS, **that** is what will limit your discharge rate.

Also, buy the tool suited for the job

"damn this titanium material sucks, this screwdriver I bought won't even drive roofing nails into pine!"

 

[5spd97]

Not to mention that the typical auto alternator is not designed to charge
Lifepo batteries and does a poor job with FLA.

 

[67cj5]

I think you will find that the ARB Twin Draws 56.5 Amps @ 40psi and the ARB Single High Output Draws 26.2 Amps @ 40psi

Hope that helps,

I thought the whole idea of running lithium batteries was because they could handle a High Draw, But when you do the maths The 56.5 Amps that the Twin uses is about an 1/8th of the Currant Draw that a winch uses being around 360 to about 550 Amps .

If you compare the Twins Currant Draw compared to a Fridge then yes you could say it was fairly high but when compared to a winch 56.5 Amps is quite minimal.

 

[67cj5]

the BB and other drop ins are competing with Deep Cycles, which dont put out high amps either and make terrible starting/winch/air tool compressor energy sources until you have a large enough bank of em that you can output high amps without high losses..

Starter Batteries and Deep Cycles have very little overlap.. my single BB runs my 1200VA inverter like a champ, with practically no losses, I'm pretty sure it'd run this guys air compressor too.. Victron suggests 200AH of FLA batteries as minimum for this size inverter, if I went with a dual battery LFP setup I could output 200amp constantly w/no high C rate losses and it'd be more than 2x what the inverter ever needed.

Whats the point of having a 100AH battery you can draw empty in 10mins? I've no idea who would want to do that.. If you wanna run big accessories, you shouldn't be doing that off a single battery regardless.. Ive seen a few Lithium cells start a diesel engine in the negative digits, yeah they can output some serious frigging amps.. but that also drains em so quickly they have very limited use.

Yep, Funny you should say that because during a bored moment back last winter I hooked up a 1000w/240 Inverter to a 60Amp FLA standard car battery and I plugged a 700w ( Output ) Microwave in to it and it worked although the alarm on the inverter bleeped for a second or two Once it had got over the serge of the microwave it worked flawlessly, But doing the maths by rights that 1000w/2500Surge Inverter should of needed 83.33 Amps and after I let it do it's thing for about 3 or 4 minutes and everything was fine and the battery was good, In that 4 minutes the micro wave used about 216 Watts / 12v = 18 Amps.

But at a 1000w that is an hourly rate at 83.33 Amps, So I can't see how his compressor would flatten his battery in such a short time and I would hazard a guess that either his battery was nearly flat to start with or the battery has a fault,

 

[dreadlocks]

Oh you can get a BMS that handles high current, but last I looked one that could handle ~600A was about 75% the price of a BattleBorn LFP... handling high current through electronics that are made to last, is not cheap.. even high amp motor/pwm controllers for like Golf Carts quickly start to approach 4 digit price tags when you get to the top of the line ones, and those are simpler than a BMS.

FLA's are dumb in comparison w/no electronics involved, so high amps is cheap.. but inefficient.

 

[dreadlocks]

Yep, Funny you should say that because during a bored moment back last winter I hooked up a 1000w/240 Inverter to a 60Amp FLA standard car battery and I plugged a 700w ( Output ) Microwave in to it and it worked although the alarm on the inverter bleeped for a second or two Once it had got over the serge of the microwave it worked flawlessly, But doing the maths by rights that 1000w/2500Surge Inverter should of needed 83.33 Amps and after I let it do it's thing for about 3 or 4 minutes and everything was fine and the battery was good, In that 4 minutes the micro wave used about 216 Watts / 12v = 18 Amps.

But at a 1000w that is an hourly rate at 83.33 Amps, So I can't see how his compressor would flatten his battery in such a short time and I would hazard a guess that either his battery was nearly flat to start with or the battery has a fault,

You're not accounting for the high C losses, a single 12V FLA say with 100AH is rated that at a 20h discharge rate.. If you discharge it in 1h, its more like a 50AH battery.. that you dont want to draw down more than 50%, so you got 25AH of usable capacity at those loads out of a 100AH battery.