Just another Several EV battery thoughts


Electri-Cal
 

As an idea, IF a coot is motoring  ( or someone else ) uses say 10 to 15 amps to putt around, maybe higher in wind, tide, or extra coots aboard is there a battery problem ?  The battery sizes are defined # 24- 27 as popular ones for marine uses.  The area needed is wherever fits that size case securely.  I figure a sailboat needs an hour of run time minimum, not to exceed half comfortably, or 60% of battery capacity without excess harm. AS batteries age they don't hold a charge as well, so deduct for that.  From my uses I see a drop off in power gradually through long drain /run times. 

With an average 100 amp hour battery, that,s around 50 hrs available, tapers off and the Hummingbird depth finder automatically stops working at about 11.2 volts as a safety feature.  By guesstimate, thats 40 good amps to have at minimum draw, so with weather wave action losses, that 100 amps will be around 2 hours, except for one factor !!  When I Need to get back, time to go, getting cold, stiff, hungry, pottie break, park closes or daylight ends, nobody just putts in after the win dies.  I want back NOW, so I crank it up just when it's getting tired, that is when the trouble starts.  Just one more half mph, pleasssee !!

In my opinion, it's NOT the run time in the am, quiet sea, or marina that counts.  I want enough to get back with (double power use) some ( &@@! ") headwinds, full bladder, empty belly, and tired.  Those are  my thoughts on battery power, for what it's worth.  I am ONLY comfortable with a good marine series 27 deep cycle setup, that is also with a back up, in a power boat.   THe deepest power 27 size battery adds maybe 8 lbs. as a single battery in a sailboat, just put it down low and balanced as  needed. -------  Yes, surprise runs 4 batt. main 24 v. pack, plus back up 2 pack, but no sail gear to fuss with loading, stepping, etc., for my trailering it's worth it, as long as it's quiet as well.  I may add a sail, cause I own the gear, but my best power is electric, with the full setup needed for safety.

I will be at Fern Ridge, maybe I'll day trip it, thanks to the excessive costs, and management problems.  Glad I don't have to have a slip.  Just grab me if you'd like a putt around, sometimes I'm just not as aware of who is interested, ok ??    A lake like this is like a beautiful lady, who's Always sick !!  Too bad triangle is so shallow, I still think Dexter works easiest, and always full, that's except for the highway on one side.

A Nice Day - Go Get You Some !! ----  cal



   


 

10-15 amps (24 volts) isn't taxing your batteries much. Each bank is two 100 A/H batteries in series? 10-15 amps is only 10-15% of the maximum safe discharge rate, 5-7.5% if you're running four batteries in one bank.

Although it doesn't pencil out for best total range, having a reserve battery bank just for speeding back to the dock, ramp, or restroom at the end of the day is the way to go for you. But electric boaters should cultivate patience, and strong bladders. ;o)

If the batteries get down to 11.2 volts each, it's time to stop, like the depth sounder. It's hard to get an exact idea how much charge there is in a battery when it's in use -- to do that the battery need to rest several hours -- but I'd guess that 11.2 volts with a light load works out to well beyond 50% discharge. I used 12 volts per battery (24 volts) under light load for when I charged Tuffy's flooded cell batteries.

https://groups.io/g/oregoncoots/files/Motors/BatteryBasix.gif

Take care of your batteries! Due to making an assumption, I killed Tuffy's group 24 deep cycle Interstate batteries. An expensive assumption. <sigh> This year she's gonna have two new group 27 AGM$. Nice as they'll be, I woulda preferred to get a few more seasons outa the flooded cells...

On 4/12/2021 9:01 AM, Electri-Cal wrote:
As an idea, IF a coot is motoring  ( or someone else ) uses say 10 to 15 amps to putt around, maybe higher in wind, tide, or extra coots aboard is there a battery problem ?
...
With an average 100 amp hour battery, that,s around 50 hrs available, tapers off and the Hummingbird depth finder automatically stops working at about 11.2 volts as a safety feature.  By guesstimate, thats 40 good amps to have at minimum draw, so with weather wave action losses, that 100 amps will be around 2 hours, except for one factor !!  When I Need to get back, time to go, getting cold, stiff, hungry, pottie break, park closes or daylight ends, nobody just putts in after the win dies.  I want back NOW, so I crank it up just when it's getting tired, that is when the trouble starts.  Just one more half mph, pleasssee !!
...
--
John <jkohnen@boat-links.com>
George Washington as a boy was ignorant of the commonest accomplishments of youth. He could not even lie. (Mark Twain)
--
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Electri-Cal
 

Just read this note.  Yep, be aware of different batt. details and the devil therein !!  I will still stick to the flooded cells for now, couple reasons.  The draw down at high power needs could do more damage to sealed cells, they get only one venting, which does not show from a sealed looksee of the case.  You have no way to check each cell for uneven acid or voltage capacities.  So with 24 volt, the batteries can become unevenly partially discharged, not good for balancing those cells.  That new one I accidentally cross hooked should have died, acid sprayed out, -- but it is now back on line rebalanced, damn lucky there, if a sealed  blows, it's a -- way more expensive mistake, or possible explosion, 

I have vented batteries, through misuse, or accident, but I can and have removed the caps and added acid or water to rebalance that cell. Not often, the center cells can vent unevenly, like on my cabin cruiser, so checking water twice a year or so is not a big deal.  Sealed batts, -- with the information I have on them, it is not recommend to do fast or deep draw.  If they do a partial vent they are permanently weakened, that has happened also.  I prefer to have the ability to test each  2.2 volt cell and keep a record.  However, it's still a matter of choice so I still like the new marine forklift type high capacity wet cells I have now.   Of course I don't have a sail, so my bottom line needs are greater out on the water, for safety.  Everybody has a different take on batteries, no big deal as long as they work when needed.

Power on, Fun in place and heading out ---  Cal