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Old 07-12-2017, 05:32 AM   #1
Toa Kraka
 
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Default [VE] Minimum battery capacity for internal combustion engine?

It appears that Vehicles doesn't require an internal combustion engine to be accompanied by an Energy Bank for ignition purposes. Is this an oversight, or should it be assumed that a small rechargeable battery sufficient for ignition is included in the weight of an ICE? If it's an oversight, are there any recommendations for the minimum capacity of a battery used exclusively for ICE ignition?
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Old 07-12-2017, 05:42 AM   #2
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Default Re: [VE] Minimum battery capacity for internal combustion engine?

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Originally Posted by Toa Kraka View Post
It appears that Vehicles doesn't require an internal combustion engine to be accompanied by an Energy Bank for ignition purposes. Is this an oversight, or should it be assumed that a small rechargeable battery sufficient for ignition is included in the weight of an ICE?
It's not required, many IC engines are *not* electrically started. Don't be fooled by the fact that automobile sized ones have been for a while, the originally were crank started after all, and big engines are often started by a separate small pony engine.

But no, it's not separately stated any more than electric motors are. Internal energy conversion is pretty much ignored - what Vehicles isn't ridiculously complex enough for you already?
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Old 07-12-2017, 05:51 AM   #3
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Default Re: [VE] Minimum battery capacity for internal combustion engine?

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It's not required, many IC engines are *not* electrically started. Don't be fooled by the fact that automobile sized ones have been for a while, the originally were crank started after all, and big engines are often started by a separate small pony engine.
Yes, the book mentions that early-TL6 ICEs are hand-cranked. I'll clarify my question: For an electrically-started ICE, what's the minimum recommended energy bank capacity?
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What, Vehicles isn't ridiculously complex enough for you already?
Of course not! ; - )
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Old 07-12-2017, 09:31 AM   #4
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Default Re: [VE] Minimum battery capacity for internal combustion engine?

Doesn't using an energy bank like this assume that it will be used for propulsion as in a hybrid car as opposed to being a component of the main engine's starter system? Much as you don't buy a computer module to model the engine control system...
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Old 07-12-2017, 10:27 AM   #5
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Default Re: [VE] Minimum battery capacity for internal combustion engine?

Not knowing anything about cars other than some vague theory, I guess the answer really depends on how much energy a starting takes and how many such starts you want it to have before recharging with the ICE.
Then again, in the real world, rechargeable batteries have loads of other complexities like number of deep cycles, how long they hold charge in different temperatures, etc.
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Old 07-12-2017, 10:32 AM   #6
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Default Re: [VE] Minimum battery capacity for internal combustion engine?

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Originally Posted by Toa Kraka View Post
It appears that Vehicles doesn't require an internal combustion engine to be accompanied by an Energy Bank for ignition purposes. Is this an oversight, or should it be assumed that a small rechargeable battery sufficient for ignition is included in the weight of an ICE? If it's an oversight, are there any recommendations for the minimum capacity of a battery used exclusively for ICE ignition?
It's not really an issue of capacity (starter motors run for seconds), it's an issue of peak power output. A typical car battery is around 10 kW for at least 30s.
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Old 07-12-2017, 11:28 AM   #7
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Default Re: [VE] Minimum battery capacity for internal combustion engine?

Power Plants include ignition sources appropriate for their TL and type. Most would be impossible to design from components in the system anyway (glow plugs?).

Last edited by sir_pudding; 07-12-2017 at 11:45 AM.
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Old 07-12-2017, 11:34 AM   #8
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Default Re: [VE] Minimum battery capacity for internal combustion engine?

So make a failed Ht roll or "minor" damage count as needing to change the battery? Makes sense.
Some of us need to dial back on the unwieldy excessive detail. It's an alluring pit of minutia.
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Old 07-12-2017, 06:31 PM   #9
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Default Re: [VE] Minimum battery capacity for internal combustion engine?

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It's not really an issue of capacity (starter motors run for seconds), it's an issue of peak power output. A typical car battery is around 10 kW for at least 30s.
The CCA rating on my not very impressive jumpstarter works out to 86.4 kWs for the 1.2 V per cell for 30 seconds definition. In general you only need to push the engine through its cycle several times (which usually is no more than a few seconds), and not as hard as it can push itself, so you're looking at no more than a few seconds of the engine output. Most actual installed batteries are bigger than that, presumably so you can start the vehicle several times without needing to recharge the battery.
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Old 07-12-2017, 08:11 PM   #10
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Default Re: [VE] Minimum battery capacity for internal combustion engine?

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The CCA rating on my not very impressive jumpstarter works out to 86.4 kWs for the 1.2 V per cell for 30 seconds definition. In general you only need to push the engine through its cycle several times (which usually is no more than a few seconds), and not as hard as it can push itself, so you're looking at no more than a few seconds of the engine output. Most actual installed batteries are bigger than that, presumably so you can start the vehicle several times without needing to recharge the battery.
That, and also to let you run lights, radio, whatever, for a while without the engine.
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