Any limit to how fast lithium ion batteries charge?

[DaveInDenver]

The Lincoln chart does not show a 100% duty cycle for 200A. They list a 100% duty for 400A and suggest 3/0. This agrees closely with the equations, which say 3/0 AWG for one hour at 290A will reach 150°C. A 25% derating for unforced cooling is probably appropriate.

This actually occurred to me last night in class. I'm doing SMAW in the current welding school cycle (continuing education requirements). They use 2 AWG cables on the welders (Lincoln Invertec 275 funny enough). Noticed the leads were getting warm doing 7018 at 125A after a couple of hours. Of course showering them with slag probably doesn't help at all. I'm not pushing 100% duty with swapping rods and periodically cooling the bead plate.

 

[DaveInDenver]

Wonder if the 5500 the O.P. owns has the defective 220A alternators. It appears it's OEM 4801313AC, which is Denso part number 421000-7001, part of their commercial part catalog.

https://www-odi.nhtsa.dot.gov/acms/cs/jaxrs/download/doc/UCM541508/RCLRPT-16V739-1542.PDF

This goes to dwh's comment about intermittent vs continuous duty on an alternator. I couldn't find the duty cycle rating, though at high engine idle the alternator can source it's full rating.

http://www.dieseltruckresource.com/...s-6-7l-only-170/high-output-altenator-271756/

Rated output - 12V, 220A
2 Point Characteristics - 95A min @ 1600rpm, 193A min @ 2500rpm

Output volts -15.0V
Field current - 8.0A

So with a ratio of ~3.3 (crank pulley (7.872") to alternator pulley(2.360"))

@700rpm engine idle - Alternator rpm = 2310
@1100rpm high idle start - Alternator rpm = 3630
@1500rpm high idle top speed - Alternator rpm = 4950

 

[dwh]

When considering lithium, Id be much more concerned about safety measures that battery temp sensors provide than what alternator temp sensors provide.

Well, it's going to have a BMS to handle that and protect the battery from overload.

So that makes alternator overload a more important question.

 

[dwh]

Wonder if the 5500 the O.P. owns has the defective 220A alternators. It appears it's Denso part number 210-0677.

https://www-odi.nhtsa.dot.gov/acms/cs/jaxrs/download/doc/UCM541508/RCLRPT-16V739-1542.PDF

Does he actually have that? I thought he was just speculating.

 

[DaveInDenver]

Does he actually have that? I thought he was just speculating.

He'd have to confirm, but it appears these are the ones used the past few years in the dual alternator option. It's the only 220A Denso lists for the Ram HD trucks. They also use this alternator in the police package for the Chargers.

 

[jonyjoe101]

The only thing I have to add, if you have 1000 ah of lithium batteries and you drain it to 200 ah and then you charge it at 400 amps. Its going to take much longer than 2 hours.

You can charge it quickly to 90 percent at 400 amps, but then as it gets full the battery will act like a lead acid battery. The remainder 10 percent might take another 4 or 5 hours or longer. As it gets full, the voltage remains the same but the amps will go down.

This I notice from charging the smaller 18650 lithium cells, The large 100 ah/ 200 ah batteries are made up of hundred of these cells (or lipo04 cells which are similar cylindrical). When I charge these 2000 mah cells, I charge them at 1 amp, it should take 2 hours, but in reality it always takes between 3 to 5 hours to charge each cell. They charge at 1 amp up until they reach a voltage of 4.10, then the remainder of the time the amperage will drop slowly, when the voltage reaches 4.20, the charge is at the 100 milliamp range and almost fully charge.

The 94 ah lithium battery I built using 184 cells behaves in a similar manner. Even though I only charge it at 10 amps from my solar panel, when its almost full it wont even take the full 10 amps, it starts only taking 5 amps or less. It can take several days to fully charge. I was thinking it would be quicker to charge than my agm, but the lithium is always on absorb mode for days at a time. In 4 months its only been fully charge twice where it tripped the battery BMS to stop charging. After a full day of charging it will read about 12.3 volts, which is good enough for my needs.

Originally I was also under impression from what I read that the lithiums could be fully charge quicker but I havent really notice that in my use. But with lithiums you dont have to quess if you really have a full battery. If the voltage reads 12.6, you got a full battery, with lead acid if it reads 12.6 who knows what it really has? when it was brand new it might be full. With lithium 90 percent might be good enough, it also wont damage the battery to undercharge it, it will make it last longer.

Also how you connect them together in parallel, and where you connect the charger to will come into play. If one battery charges to full before all the others the charger will stop, the batteries will eventually equalize but you wont really be at full charge.

 

[LeishaShannon]

You can charge to ~ 97% before the current tapers off, <.5C is best for long life so you'd be looking at just under 2 hours for 20-100%

 

[DiploStrat]

Some comments from research and NOT from personal experience:

-- One claimed advantage of a Lithium battery is that it does not need to be fully recharged. In fact, several manufacturers that I have talked to stress that it is better to stop at about 90% and not float the battery. This is, of course, exactly the opposite of a lead acid which will sulfate if not fully recharged and will always do better if floated. It has been suggested that one should set the "float" voltage of a normal solar controller as low as possible that that it will effectively stop charging when the battery reaches 90% or wherever the charge rate drops.

-- Amp hours are amp hours. If you need 400Ah of lead acid, you still need 400Ah of Lithium. The claimed advantage is in battery life. 400Ah in lead acid would probably demand an 800Ah battery bank to limit discharge to 50% and get the most cost effective life out of your batteries. Lithium batteries claim many more cycle and thus you might be able to get by with a 500Ah bank. In this case you would be going down to 10 or 20%, but you might still have more cycles. Look closely at the published specs of the Lithium batteries - you will note that they still benefit from NOT being fully discharged. And, of course, you can do what dwh advocates - use a smaller lead acid bank, discharge deeply, and simply replace earlier. Probably cost a lot less and save you a lot of weight. Look at the life cycle charts for the batteries you are considering.

Again, these are comments from research, not actual use. Caveat emptor!

Reading through this, you begin to realize that the much vaunted "smart" multi stage chargers are not really that smart. Any lead acid battery is going to effectively charge in stages - the charger need only be smart enough to monitor voltage and current flow and maintain, drop, and limit as needed.

The key thing is that lead acid batteries REALLY need that last bit of charging while it appears that Lithium batteries do not.

 

[romz26]

For my vape batteries I've charged them at 1.5c for a quick charge, using my powerlab charger. But with my lipo rc car batteries I've pushed them to 3c. With no ill effect.

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