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250C support LiHV???


Ak89
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Building a new mod and like the idea of using one of Turnigy's "Bolt - High Voltage" LiPo packs: A little more Wh at my maximum dimensions.

However, I can't for the life of me determine, for sure, if the board can support the higher voltage to make use of the additional capacity. Would I be able to set the per-cell maximum charge voltage to 4.35? (Rather than 4.2v on standard LiPos) Can't seem to find a specific entry in Escribe....

And would the fully charged voltage (17.4v) harm the board? The datasheet lists max as 16.8, but that seems a little too perfect to me. Why would the MAX be a voltage the board is expected to see, without any safety margin? I assume this is merely a statement of a 4-cell maximum, but what if those 4 cells were of a slightly higher voltage?

I have contemplated a help ticket, but I currently have one open on a different topic and not really getting any helpful answers, so I thought this question would be better posed to the masses.

Any thoughts?

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Thoughts....

I would think 16.8 is the max the board is expected to see....  There may be a safety margin built in (you would have to ask Evolv about that) ... so if it has safety margin then you want to use it and disregard safety??? Another thing is the onboard charge circuit.... can it charge to 17.4 volts????  the CSV curve for li-po shows 100% @ 4.2 v...... Does the battery manufacturer have a CSV curve file or do you have a CSV curve file for 100% at 4.35V ?

How much extra vape time do you expect out of an additional .6 volts?

 

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By safety margin I was meaning damage to the board.... Electonics are often built with a bit of overhead to allow for transients that may push voltage over what the ideal would be. I'm just wondering what that overhead would be on the 250c. And whether it can brushed without damage.

The charging circuit is the biggest mystery. Would make the whole endeavor a little pointless without the ability to take advantage of the additional voltage.

I don't know how much additional time I would gain, but that extra voltage would provide approx. 4% to 5% increase in capacity. Not huge, but beneficial if I could actually make use of it....

As far as discharge curves, I plan to run a battery analysis on whatever battery I decide on using. So finding a pre made csv wouldn't be needed.

Still thinking out loud here. I appreciate your thoughts retird.

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Update:

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Hi,

It can use them no problem, but the board will not be able to overcharge them unfortunately. Our reference mods use these kind of batteries without issue.

Thanks,
Nick Coutris
Evolv, Inc

So my understanding is that the board can take the additional voltage, but the charge circuit is capped at 4.2v per cell. So external charging would be required to reach full capacity of the battery. Bummer.

But it brings up a new thought: The possibility of additional pigtails to attach an external charger without disconnecting the battery from the board.... Seems "easier" and less likely to break something with repeated plugging/unplugging. However, would everything play nice? Would the 250C "fight" with an external charger if both are connected at the same time, but only the external actually charging? 

Anyone tried this?

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