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LiFpO4 when you don't live-aboard


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19 minutes ago, Guest said:

What put me off 5x cell was 50%=2.2V. (11V)  Discharge curve YinLong

discharge characteristic curve

Yes! But that will still will crank your diesel... Unlike a 11v LA. 

All these things your encountering are the reason I shelved my LTO start battery project 🤣

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50 minutes ago, Guest said:
1 hour ago, aardvarkash10 said:

Nope.  It will start quicker, and given the duty cycle of a starter, 15% higher supply voltage is a "meh".

 

I used to do 6v to 12v conversions on VW beetles. StArter was one of the things we left stock standard.  Man, they cranked and fired inside one revolution!!!

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Still be a "meh" at 25% aye?

Yup.

Starters are series-wound motors are pull huge current at 0 rpm but the current rapidly drops as starter revs increase.  As long as you are not being stupid (30 seconds engagements repeated without a break), a starter motor will take a LOT of punishment.

 

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Thanks for that 

"What cells are you using that are rated for 0.01C at 3.65v that's out there." ( O.001C 😬)

IIRCly Both Will & Andy have charged to O amps terminal current to batteries "full capacity"?

My CALB 230Ahr came with product specs in Chinese. So resorted to Prowse and Andy OGG coming to the conclusion that absorb was for lead in the main, and perhaps to balance but was not really necessary.  For day to day. I've only ever top balanced once (8mnths after installing) was in a hurry so left it on bulk until HVD, then balanced   manually until it started charging again, rinse repeat to 0.5A at 3.65V. Then synced  Victron BMV. To 100%. Rested they returned to 3.35V/cell.

Six months later, cells are well balanced  but SOC is way out~ So I about to do it again, this time a bit better informed. Now have 2x Heltec 5A balancers  and a new "absorb" V regime.

Cheers CD!

 

 

 

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32 minutes ago, Guest said:

IIRCly Both Will & Andy have charged to O amps terminal current to batteries "full capacity"?

I doubt any lfp could support that even a handful of times. The li-ions would be getting depleted very fast!

32 minutes ago, Guest said:

Six months later, cells are well balanced  but SOC is way out

SoC numbers literally become a random number generator after a few half cycles. 

Not even laboratory grade couloumb counters can get accurate SoC over many cycles without fully charging. 

I have to laugh when manufacturers claim they can maintain a SoC between 40%-80%...

I encountered a so called system just recently which was under performing.

We disconnected all the loads and fully charged the cells, surprise surprise, each cell some how magically absorbed 70%...

I use a method of counting couloumbs each charge. If I put 1000watts in then that's how many I have to take out. Anything left over is an unknown. 

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1 hour ago, waikiore said:

This thread confirms that I am happy to stay a Luddite in my Kauri log with small solar and Yanmar 😇 

Lead acid chemistry rules!!!!

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1 hour ago, aardvarkash10 said:

Lead acid chemistry rules!!!!

2013-05-02_9172_BatteryExploded_tif.jpg.34e08e6c4472006728a9148ab7a1325b.jpg

The battery in this photo is from the 65-ft sloop Blue Peter. As the engine was turned on to leave, there was a loud bang and the battery exploded. Fortunately, nobody was hurt.

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9 minutes ago, CarpeDiem said:

2013-05-02_9172_BatteryExploded_tif.jpg.34e08e6c4472006728a9148ab7a1325b.jpg

The battery in this photo is from the 65-ft sloop Blue Peter. As the engine was turned on to leave, there was a loud bang and the battery exploded. Fortunately, nobody was hurt.

See, excitement AND simplicity.

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11 hours ago, CarpeDiem said:

2013-05-02_9172_BatteryExploded_tif.jpg.34e08e6c4472006728a9148ab7a1325b.jpg

The battery in this photo is from the 65-ft sloop Blue Peter. As the engine was turned on to leave, there was a loud bang and the battery exploded. Fortunately, nobody was hurt.

lack of maintaince I would say. How many check the water in older batteries or rely on seeing the little green light in the glass?

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