VAF Forums

VAF Forums (https://vansairforce.net/community/index.php)
-   Reviews (https://vansairforce.net/community/forumdisplay.php?f=93)
-   -   Picked up an earthX LiFePo4 battery at Oshkosh (https://vansairforce.net/community/showthread.php?t=127942)

jclark 12-26-2015 10:24 AM

Quote:

Originally Posted by burgundyja (Post 1040156)
I have a io-360 200hp with thick and short cables. What is the smallest size earthx that will start the engine?

I would try the ETX680. I *think* that is the number of the one they have as a potential "replacement" for the PC680.

When we did Widget's that model number did not exist.

I am sure they will correct me if I am wrong. That is what I will be installing to turn a an O-360 (180 HP) as soon as I can get a few other projects cleared up. :-)

James

scrollF4 12-26-2015 10:43 AM

Quote:

Originally Posted by jclark (Post 1040166)
I would try the ETX680. I *think* that is the number of the one they have as a potential "replacement" for the PC680.

When we did Widget's that model number did not exist.

I am sure they will correct me if I am wrong. That is what I will be installing to turn a an O-360 (180 HP) as soon as I can get a few other projects cleared up. :-)

James

No, wait, you must use the battery matched to your alternator output. If you have the standard 60 amp alternator, then the ETX680 is the right battery because it's designed to accept up to 60 amps of charge. I installed PlanePower's 70 amp alternator: Thus, I bought the ETX900 which accepts up to 80 amps of charge.

This is vital, because LiFePO4 batteries take the alternator's MAXIMUM charge output after engine start and alternator activation. After about 10 or 20 seconds, the charge drops down to current load. Imagine trying to force 70 amps charge into the 60 amp ETX680...not good.

While you're at it, recheck the gauge cable you have running from the alternator to the battery. It'll get that max amperage workout every single time you start the engine and charge.

I love my EarthX ETX900. Like Scott Farnsworth said, it turns the prop sp powerfully I swear I could taxi the aircraft on starter power alone. :cool:

jclark 12-26-2015 06:04 PM

Quote:

Originally Posted by scrollF4 (Post 1040169)
No, wait, you must use the battery matched to your alternator output. If you have the standard 60 amp alternator, then the ETX680 is the right battery because it's designed to accept up to 60 amps of charge. I installed PlanePower's 70 amp alternator: Thus, I bought the ETX900 which accepts up to 80 amps of charge.

This is vital, because LiFePO4 batteries take the alternator's MAXIMUM charge output after engine start and alternator activation. After about 10 or 20 seconds, the charge drops down to current load. Imagine trying to force 70 amps charge into the 60 amp ETX680...not good.

While you're at it, recheck the gauge cable you have running from the alternator to the battery. It'll get that max amperage workout every single time you start the engine and charge.

I love my EarthX ETX900. Like Scott Farnsworth said, it turns the prop sp powerfully I swear I could taxi the aircraft on starter power alone. :cool:

SO TRUE!!! What he said!! :-)

I (probably incorrectly) assumed that you were running a 55-60A alternator.

James

burgundyja 12-26-2015 06:24 PM

Alternator
 
I have a plane power alternator 30 amp. I think that my small avionics bus is about 5 amps. So that is 25 amp of charge. I am looking at the etx18 or etx24. This is a very light airplane.

vic syracuse 12-27-2015 07:13 AM

PC 925 replacement?
 
Which would be the right one to replace the PC925 with a 60 amp B&C alternator. It looks like it would take the ETX 1200 to not lose any cranking amps or standby AH's, but it looks a little pricey. I would be really nice to lose the weight of the PC925 from the aft end of the RV10.
Vic

EarthX Lithium 12-28-2015 03:21 PM

Which EarthX battery?
 
Quote:

Originally Posted by vic syracuse (Post 1040313)
Which would be the right one to replace the PC925 with a 60 amp B&C alternator. It looks like it would take the ETX 1200 to not lose any cranking amps or standby AH's, but it looks a little pricey. I would be really nice to lose the weight of the PC925 from the aft end of the RV10.
Vic

Hi Vic,

Thank you for the question. In matching up a lead acid to a lithium battery, the amount of amperage the alternator puts out is very important to match up and if this was the only requirement, any of the aircraft batteries would work in your plane that has the 60 amp alternator but that is only one piece of the equation.

Next you need to match up the amount of amperage your battery has in the event your alternator fails, which is the most critical, and you are on battery power only. Based on this, the 1H 1C rate for the PC925 is 21.9ah, the ETX680 has 12.4ah, the ETX900 has 16ah and the ETX1200 has 24.8ah. Based on this, the ETX1200 is most suitable.

The last part of the equation is the cranking power. The PC925 has 330CCA, the ETX680 has 320CCA, the ETX900 has 400 CCA and the ETX1200 has 600CCA.

The weight savings is amazing on all of them. The PC925 weighs 26 pounds. If you choose the ETX680, you save 22 pounds; the ETX900 you save 21 pounds and if you choose the ETX1200, you save 18 pounds. The cost of the EarthX battery is definitely more than the PC925 which price is around $135. The difference is cost from the ETX680 is $244 more or $11/pound to reduce that amount of weight. The ETX900 is almost $15/pound to reduce that amount of weight and the ETX1200 is $33/pound to reduce that amount of weight. There is no cheaper way to reduce the weight on your plane and the weight loss does add up in fuel savings and increased horse power as well as a side benefit.

Hope that answers your question!

Fly Lightly,
Kathy

vic syracuse 12-28-2015 03:37 PM

Thanks.
 
I agree with all of your points. Let me ask it this way... given an aircraft with 2 alternators and a TCW backup battery for the EFIS, wouldn't the 900 be a viable alternative without losing anything other than the AH capacity? Cranking capacity should be better, correct?

Vic

EarthX Lithium 12-28-2015 03:45 PM

Quote:

Originally Posted by vic syracuse (Post 1040677)
I agree with all of your points. Let me ask it this way... given an aircraft with 2 alternators and a TCW backup battery for the EFIS, wouldn't the 900 be a viable alternative without losing anything other than the AH capacity? Cranking capacity should be better, correct?

Vic

Yes, as long as you know you are getting a battery with less usable amp hours than the PC925, all the other parts of the equation line up. You are very welcome to call us at (970) 674-8884 if you have any questions as we are here to help support you in making a decision you are comfortable with!

Fly Lightly,
Kathy

burgundyja 12-28-2015 04:50 PM

smallest earthx
 
what is the smallest just for starting? I don't care if my alternator quits and I lose power. I have a 30 amp alternator. I was looking at the 18 and 24 model.

EarthX Lithium 12-28-2015 04:57 PM

Quote:

Originally Posted by burgundyja (Post 1040691)
what is the smallest just for starting? I don't care if my alternator quits and I lose power. I have a 30 amp alternator. I was looking at the 18 and 24 model.

Tell me more about your airplane, what engine do you have?

Fly lightly,
Kathy


All times are GMT -6. The time now is 04:27 AM.