Battery cranking voltage 10.4V

[Bonmotwang]

Since I got meters on my boat and ski. Out of curiosities, I checked the battery voltage when it is cranking to start.

Both of them have been fully charged by external chargers.

On my boat (947 Carb), voltage dropped from 12.7V to 11.8V. (Compression is 125/125)
On my ski (787 Carb, 97 SPX). voltage dropped from 12.5V to 10.4V. (Compression is 150/150).

They both start right up after a few seconds of cranking. But isn't ski voltage kind of too low? From my electronics knowledge base, 10.4V is at very end of the discharge curve. 11.8V is very standard.

What is your rule of thumb on your battery voltage readings.

Thanks

Paul

 

[Coastiejoe]

10.4 is borderline for the MPEM to work. You are right on the bubble. Below that it may not generate spark. Probably time for a new battery.


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[Bonmotwang]

Good to know. Thanks.


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[Bonmotwang]

Any recommendations on a battery?

 

[Coastiejoe]

Any QUALITY battery will work. I would NOT buy the cheap generic batteries, they simply don't hold up. Most have moved over to the Gel Cell battery. I bought a moderately priced Gel Cell battery and it started the ski two times. And then it was junk. I then bought an Acid battery that cost me $129 and it has been perfect,,,


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[Bonmotwang]

http://www.batterybuyer.com/bombard...7-motorcycleatv-battery-p-11908.html?CDpath=1
Is this one good enough for a few seasons?


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[Mekanix]

At least 310 amps sealed lead acid like the yuasa YTX20HL-BS.
Make sure its the HL and not just he L (H=heavy duty and more CCA 270 vs 310)
Just google that on amazon and I think it was $87 which is well worth it !
This is all I run now. Its not as tall as the stock one but it fits the tray.

Also where is your meter picking up the voltage?
Is it calibrated well enough ?
Is there any line drop from where your measuring?

The one your looking at is 275CCA which is ok but its stressing the battery.

 

[Bonmotwang]

At least 310 amps sealed lead acid like the yuasa YTX20HL-BS.
Make sure its the HL and not just he L (H=heavy duty and more CCA 270 vs 310)
Just google that on amazon and I think it was $87 which is well worth it !
This is all I run now. Its not as tall as the stock one but it fits the tray.

Also where is your meter picking up the voltage?
Is it calibrated well enough ?
Is there any line drop from where your measuring?

The one your looking at is 275CCA which is ok but its stressing the battery.

Just curious, how much of difference will 275CCA do vs 310CCA? (I wouldn't use my ski at 0F anyway, LoL).
At 70F, their CA rating will be pretty much the same. Should be over 800Amps

The meter is at the battery terminals. Calibrated to my lab instrumental multimeters.

I guess what I will do is keep it on the charger till the last minute before heading out.

 

[Mekanix]

I've killed two of the 275's over time from regular use and had to charge it if it sat for a few weeks. But so far not with the 310's. It always cranked strong and started with that.

I think stressing them near their max is doing some damage inside. The first one I killed was just possibly a faulty one but the second one failed the exact same way.

Also I hate the idea of having an inferior battery and being stranded. I think 90-150 $ is well worth it for piece of mind as well as longevity.

 

[Bonmotwang]

I've killed two of the 275's over time from regular use and had to charge it if it sat for a few weeks. But so far not with the 310's. It always cranked strong and started with that.

I think stressing them near their max is doing some damage inside. The first one I killed was just possibly a faulty one but the second one failed the exact same way.

Also I hate the idea of having an inferior battery and being stranded. I think 90-150 $ is well worth it for piece of mind as well as longevity.

Thanks, that's enough to go with 325Amps

 

[Bonmotwang]

Thanks, that's enough to go with 325Amps

Called the manufacturer and got the datasheet.
DEKA ETX16L has been upgraded to 325CCA.
I also phoned the vendor, they are updating the website right now. Soon that link will say 325CCA. LoL.

I will probably get this ETX16L then.