Earthx 680 or Earthx 900 ??

[Larry DeCamp]

My o-320 cranked like crazy with an Etx680 that replaced the Odessy. But that was a 150 HP / 7:1 compression. My new IO-360 with 8.5 : 1 might like more juice. My question is:
* Voltage produces starter torque independent of the resistance from the engine ?
* However, more displacement will require more WORK (energy) from the battery to produce the same number of revolutions.
* The assumptions above would conclude the only benefit from the larger battery is realized from extended cranking ( hot start )
Your insight / experience would be appreciated.

 

[DavidHarris]

I have a Superior XPI-IO-360-A1HC2 with 180 hp in my RV7A. It starts from an ETX680 and has been working well for the past four years.
According to the EarthX site, it has 320 cold cranking amps, while an Odyssey PC680 has only 170. EarthX is a great battery.

 

[airguy]

I have a Superior XPI-IO-360-A1HC2 with 180 hp in my RV7A. It starts from an ETX680 and has been working well for the past four years.
According to the EarthX site, it has 320 cold cranking amps, while an Odyssey PC680 has only 170. EarthX is a great battery.

I use the 900 in my 9A with an IO360, lightweight prop and 8.5:1 compression. It spins the engine quite well.

 

[Freemasm]

.....* Voltage produces starter torque independent of the resistance from the engine ?....

Weight would probably be unnoticeable. Is there a downside other than cost.

To your question, Yes the increases daisy chain:
Counter torque -> required wattage -> amp draw

 

[scrollF4]

Wait. A primary driver for which battery you use revolves around your alternator's charging amperage. If you have a 60 amp alternator, either the ETX680 or ETX900 will work. However, if you have a 70 amp alternator or greater, you do NOT want the ETX680: Use the ETX900, or you can damage the smaller battery.

Here's the reference from EarthX's manual, page 36:

Lithium batteries have a low resistance to charge current, which is why charge up so quickly. This is very different than a lead acid battery, which is naturally slow to charge. As such, users are often surprised by the very noticeable increase in charge current from their vehicle alternator. This is normal and expected and generally not a concern. The only concern is if the charge current exceeds the maximum charge rating of the battery. For example, a customer with a 60-amp alternator switches to our ETX680 (rated for a maximum of 60 charge amps) from a similar sized lead acid battery...

 

[dmattmul]

Wait. A primary driver for which battery you use revolves around your alternator's charging amperage. If you have a 60 amp alternator, either the ETX680 or ETX900 will work. However, if you have a 70 amp alternator or greater, you do NOT want the ETX680: Use the ETX900, or you can damage the smaller battery.

Here's the reference from EarthX's manual, page 36:

Lithium batteries have a low resistance to charge current, which is why charge up so quickly. This is very different than a lead acid battery, which is naturally slow to charge. As such, users are often surprised by the very noticeable increase in charge current from their vehicle alternator. This is normal and expected and generally not a concern. The only concern is if the charge current exceeds the maximum charge rating of the battery. For example, a customer with a 60-amp alternator switches to our ETX680 (rated for a maximum of 60 charge amps) from a similar sized lead acid battery...

Second that, these batteries have the ability to suck up amps at an incredible rate. Also, just because an alternator is rated at 60 amps does not mean it won't output more than that. My B&C 60-amp alternator will output 70 amps for a few minutes on take-off. (I do use the Earth-X recommended trickle charger 90% of the time but there are times when I cannot) The other factor to use a 900 or even a 1200 is the additional storage capability to supply energy in case of an alternator failure or in my case a b-lead connector breaking. (Now only use Burndy)