Elect. Guru help

[danjor]

LifePo4 battery's are not the same as LiPo which are what most people think of when they say battery's catching fire or exploding. LifePo4 batteries are very safe and if they are sealed in a plastic waterproof housing there as safe as sealed lead acid batteries. They are more expensive than lead but the big difference is out of a 10ah lead battery you get roughly 4-5ah of use able power before the voltage drops too low but with a LifePo4 10ah battery you get roughly 8ah of use without voltage drop! So you get almost double the use able life and depending on the battery you can jump start your car with it. I have a 100ah LifePo4 that I plan on using on a trolling motor setup whenever I get around to setting it up.

[GregAndrew]

Depending on the size required, the larger capacity batteries would be for travel use. Mothership and trips to Mexico for me in particular. Thanks for all the timely info guys.

[PescadorPete]

Greg,
I measured the Hobie bank tank pump (Tsuanmi 500) with no load (no water in the tank).

12V --> 0.32 amps 3.84 watts
6V --> 0.23 amps 1.38 watts

so roughly 40% of the power @6V vs. 12V.

I can measure it with a full tank of water this weekend if it helps, let me know.

BTW, Ohms law is not the way to look at this, its an inductive motor load, not a resistor.

Pete

[GregAndrew]

Hey Pete, how did you measure it, and did you happen to measure it with water? Looks like the batteries are going to be very affordable for LifePo4.

Originally Posted by PescadorPete

Greg,
I measured the Hobie bank tank pump (Tsuanmi 500) with no load (no water in the tank).

12V --> 0.32 amps 3.84 watts
6V --> 0.23 amps 1.38 watts

so roughly 40% of the power @6V vs. 12V.

I can measure it with a full tank of water this weekend if it helps, let me know.

BTW, Ohms law is not the way to look at this, its an inductive motor load, not a resistor.

Pete

[jruiz]

Originally Posted by GregAndrew

Hey Pete, how did you measure it, and did you happen to measure it with water? Looks like the batteries are going to be very affordable for LifePo4.

Here are the specs on the same pump under load for 12V and 13.6V. 1.4A current draw at 12V. So it should be less than that for 6V

[PescadorPete]

Here it is with a Hobie bait tank, full of water, pump under load:

12V --> 1.37A
11V --> 1.20A
10V --> 1.06A
9V --> 0.91A
8V --> 0.77A
7V --> 0.64A
6V --> 0.52A
5V --> 0.39A

Good thing I did this. When I had the tank full, I noticed the front seam is split and leaking . Not from abuse, maybe a manufacturing defect? Time to get out the 5200.

[momo fish]

interesting... Where is best place to buy batteries? Looking to get 2.. Are you all saying a 6 can last as long as a 12? Sorry not an ee so keep it simple for us non-mcgiver types

Originally Posted by danjor

LifePo4 battery's are not the same as LiPo which are what most people think of when they say battery's catching fire or exploding. LifePo4 batteries are very safe and if they are sealed in a plastic waterproof housing there as safe as sealed lead acid batteries. They are more expensive than lead but the big difference is out of a 10ah lead battery you get roughly 4-5ah of use able power before the voltage drops too low but with a LifePo4 10ah battery you get roughly 8ah of use without voltage drop! So you get almost double the use able life and depending on the battery you can jump start your car with it. I have a 100ah LifePo4 that I plan on using on a trolling motor setup whenever I get around to setting it up.