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Old 10-22-2020, 08:05 AM   #1
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Lithium Batteries - Generator Cranking Amps

I am reading more and more that starting my Onan generator (450 Cold Cranking Amps) damages Lithium Batteries over time.

First I learned that Lithium batteries are not good at providing the required 450 Cold Crank Amps. A 100ah battery can provide 200amps for 30seconds. If I need 450amps to start the generator, then the minimum is two 100ah batteries, but it would be "better" to have three.

Now I am reading that pulling that high a load from the batteries damages them over time, simply due to the physics of Lithium batteries.

So, does starting an Onan generator actually decrease the lifecycle of Lithium batteries? I had one salesman say that since I am wired through an inverter, the inverter resolves the negative impact on the Lithium batteries....

Example of the discussion on damage:
https://www.lithiumpros.com/blog/cra...ium-batteries/
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Old 10-22-2020, 08:26 AM   #2
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Quote:
Originally Posted by BadWolfe View Post
I am reading more and more that starting my Onan generator (450 Cold Cranking Amps) damages Lithium Batteries over time.

First I learned that Lithium batteries are not good at providing the required 450 Cold Crank Amps. A 100ah battery can provide 200amps for 30seconds. If I need 450amps to start the generator, then the minimum is two 100ah batteries, but it would be "better" to have three.

Now I am reading that pulling that high a load from the batteries damages them over time, simply due to the physics of Lithium batteries.

So, does starting an Onan generator actually decrease the lifecycle of Lithium batteries? I had one salesman say that since I am wired through an inverter, the inverter resolves the negative impact on the Lithium batteries....

Example of the discussion on damage:
https://www.lithiumpros.com/blog/cra...ium-batteries/
Interesting.......are you reading this specifically about LiFePO4 batteries?? LiFePO4 handles high loads better actually than LA batteries in terms of the Puekert effect........can you share where you are reading this, I'd like to research.

Of course if you take any battery past it's planned capacity that's not good but if you had 3 100A BBs you would have more than enough for the 3-5 seconds of cranking for your generator.

If you are in a motorized vehicle then just use the chassis batteries to start the generator
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Old 10-22-2020, 08:45 AM   #3
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3 to 5 seconds of cranking to start a generator ?
Maybe yours, but a cold, gas, generator isn't going to start in 4 seconds. It takes 15 or more for mine to start.

In defense of lithium batteries, the generator CCAs are at 0 degrees F.
It will draw much less at 70 degrees, as much as 1/2 the CCAs.

Wire it to the chassis battery, making sure you have some kind of charger to support its running OR wire in so that the boost switch closes, connecting the chassis batteries temporary, while cranking.
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Old 10-22-2020, 10:33 AM   #4
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450 amps,? My 10 kw diesel genset only takes about 220 amps to start. My 3.2 diesel, only 125 at 60 F.. If yours is gas or propane, would imagine less. With lithium, unlike lead acid, little drop in voltage and subsequent rise in amp draw, should start your generator faster. But if in doubt, do as twinboat says and use you boost switch to combine start and house batteries when starting gen. The BMS in a good lithium battery should prevent any long term damage to the battery.
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Old 10-22-2020, 11:26 AM   #5
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3 to 5 seconds of cranking to start a generator ?
Maybe yours, but a cold, gas, generator isn't going to start in 4 seconds. It takes 15 or more for mine to start.

In defense of lithium batteries, the generator CCAs are at 0 degrees F.
It will draw much less at 70 degrees, as much as 1/2 the CCAs.

Wire it to the chassis battery, making sure you have some kind of charger to support its running OR wire in so that the boost switch closes, connecting the chassis batteries temporary, while cranking.
Yeah our QD7500 (Diesel) will typically start in 3-5 secs as long as it is primed properly

Agreed on other issues
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Old 10-22-2020, 12:04 PM   #6
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Originally Posted by paul65k View Post
Interesting.......are you reading this specifically about LiFePO4 batteries?? LiFePO4 handles high loads better actually than LA batteries in terms of the Puekert effect........can you share where you are reading this, I'd like to research.

Of course if you take any battery past it's planned capacity that's not good but if you had 3 100A BBs you would have more than enough for the 3-5 seconds of cranking for your generator.

If you are in a motorized vehicle then just use the chassis batteries to start the generator
Thank you for your response. The link in my post takes you to one discussion about Lithium vs Lead batteries and the damage caused to Lithium. I have found Battle Born also briefly mentions that Lithium batteries are not good for that Cold Cranking Amps with a generator.
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Old 10-22-2020, 12:15 PM   #7
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That entire article was a redirect to get you to buy their batteries; because they're better;

It is for these reasons that XS Power Lithium Powerpacks have a computer built into every pack. This computer constantly monitors voltage and temperature and can avert disaster in milliseconds. Don’t take the step to Lithium-ion in your high performance car with an inferior and dangerous battery. Choose XS Power for years of safe, trouble-free service!

Most Lithium batteries have a 'computer' built in. Mine do, and will shut off the batteries if drawn on too hard.
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Old 10-22-2020, 12:21 PM   #8
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600ah lithium.
1500w solar.
10k generator (known to be hard starting, high power draw)

When starting, the higher voltage and reduced sag spin the generator much better than previous lead acid batteries and it starts much quicker than before. Even when the batteries are at low SoC.

Ymmv.
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Old 10-22-2020, 05:16 PM   #9
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When my start batteries failed during a trip, used the boost switch to merge my lithium house batteries with the failed start batteries, this is a Cummins ISM 500 hp, probably 800+ starting amps required. Did this for a month till I got new start batteries. Noticed no reduction in capacity in the lithium batteries and engine started faster due to the higher voltage.
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Old 10-22-2020, 05:58 PM   #10
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Originally Posted by HarryStone View Post
That entire article was a redirect to get you to buy their batteries; because they're better;

It is for these reasons that XS Power Lithium Powerpacks have a computer built into every pack. This computer constantly monitors voltage and temperature and can avert disaster in milliseconds. Donít take the step to Lithium-ion in your high performance car with an inferior and dangerous battery. Choose XS Power for years of safe, trouble-free service!

Most Lithium batteries have a 'computer' built in. Mine do, and will shut off the batteries if drawn on too hard.
So they have a BMS.....OMG I wonder why Battle Born, or every other drop-in manufacturer didn't think of that

What a crock!!
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Old 10-22-2020, 05:58 PM   #11
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Yeah, 600 amp-hours of LiFePO4 batteries should have a problem starting a large engine. I upgraded from 4 to 7 100 amp-hour BattleBornBatteries. It gives me longer air conditioner run time after sunset. I no longer carry a generator with us for camping.
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Old 10-22-2020, 06:03 PM   #12
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i also had the concern about lithium batteries and the 450 cca that onan specs. i do not have lithium batteries. i do have a victron battery monitor and have used it to monitor battery draw when starting out 5500 lp generator. i only see a load of around 125 amps when starting the generator.
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Old 10-22-2020, 06:26 PM   #13
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600ah lithium.
1500w solar.
10k generator (known to be hard starting, high power draw)

When starting, the higher voltage and reduced sag spin the generator much better than previous lead acid batteries and it starts much quicker than before. Even when the batteries are at low SoC.

Ymmv.
How low a state of charge ?

Many claim they can draw them down almost twice as much as flooded batteries.

Have you tried your generator at 10% SOC ?
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Old 10-22-2020, 07:09 PM   #14
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How low a state of charge ?

Many claim they can draw them down almost twice as much as flooded batteries.

Have you tried your generator at 10% SOC ?
Have found my lithium batteries at 20% SOC will start a 150 amp draw air conditioner with no problem. When I had lead acids, at 50% SOC, battery voltage would drop enough to trip the inverter at 10.5 volts. Never seen my lithiums drop below 12 volts even with that 150 amp starting load.
That's the reason my main engine appears to start faster on lithium because there is no voltage sag and subsequent rise in amps. Starter will turn faster at 12 or 13 volts compared the the 10 or 11 when used with lead acid. My anecdotal experiences with lithium batteries, your experiences may vary.
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