SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old Jan 13, 2013, 09:37 AM
Registered User
USA
Joined Jan 2002
4,860 Posts
Quote:
Originally Posted by MikeCr View Post
That's a great little generator. I used one in my previous job for field work. Just wish I could afford one.

Mike
I wanted one and saved for a while time before I got one. I've heard of people finding the occasional good deal on Craigslist.
Ohmic is online now Find More Posts by Ohmic
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 13, 2013, 09:41 AM
Registered User
USA
Joined Jan 2002
4,860 Posts
When it was time to replace the stock battery in my car I replaced it with a Sears Die-Hard Platinum battery. It's an AGM battery with a 10 year warranty.
Ohmic is online now Find More Posts by Ohmic
Reply With Quote
Old Jan 13, 2013, 11:07 AM
Registered User
So. Cal.
Joined Oct 2004
8,454 Posts
Quote:
Originally Posted by everydayflyer View Post
I do know that many who use deep cycles in parallel; for trooling motors tend to just charge them and use them until they start to perform poorly. I have seen and read about many such setups which fail in two years or less . Many smart boaters replace their deep cycles every year or two. I feel that most electric flyers would feel that this is to short of a service period.
We both know that poor longevity has nothing to do with the fact that they've been used in parallel and everything to do with the way they have been treated. Likely abused with habitual overdischarge, etc.

Have you stopped your oft-mentioned previous practice of using and charging your deep cycles in parallel?
mrforsyth is online now Find More Posts by mrforsyth
RCG Plus Member
Reply With Quote
Old Jan 13, 2013, 11:59 AM
Southern Pride
everydayflyer's Avatar
Haralson County GA. USA
Joined Oct 2004
34,839 Posts
Sorry Mark but I disagree. If both are new and of same quality then using in parallel is fine as long as one bothers to check them including load testing individually from time to time. Using mixed ones of different capacity and past useage history can work but they need more careful monitoring. There is no way I would have replaced my failing 6 year old one with a new one and placed them in parallel.

I am presently using a single 50Ah AGM and may or may not purchase another pair of 125Ah flooded ones. I do have enough chargers,power supplies and LiPolys that I can spend less than one hour charging at home and be good to go for a normal flying session. Being 6 miles and 10 minutes from my filed has its advantages. If I happen to go to a site with no AC power for an extended flying session I do have a Honda 2000 now.


Charles
everydayflyer is offline Find More Posts by everydayflyer
Reply With Quote
Old Jan 13, 2013, 12:35 PM
Registered User
So. Cal.
Joined Oct 2004
8,454 Posts
Absolutely agree that one should do periodic checks of all batteries and remove any from service that may be failing. My two deep cycles are of different brands and one is three years older than the other. I rotate which one I take to the field so I know that they're both still fine and perfectly acceptable for parallel operation.

I would recommend spot checks on all batteries that are used in parallel, even if they're identical and purchased on the same day.
mrforsyth is online now Find More Posts by mrforsyth
RCG Plus Member
Reply With Quote
Old Jan 13, 2013, 01:59 PM
wjs
William
United States, MI, Brighton
Joined Oct 2012
1,966 Posts
Quote:
Originally Posted by mrforsyth View Post
Absolutely agree that one should do periodic checks of all batteries and remove any from service that may be failing. My two deep cycles are of different brands and one is three years older than the other. I rotate which one I take to the field so I know that they're both still fine and perfectly acceptable for parallel operation.

I would recommend spot checks on all batteries that are used in parallel, even if they're identical and purchased on the same day.
How can parallel charging work right on pb? One may be at 12.x and other at 13v at cutoff (for example). So one may never get full charge? Same with LVC. One may be higher V, and hide the fact that other is V is too low.
wjs is offline Find More Posts by wjs
Reply With Quote
Old Jan 13, 2013, 03:01 PM
Registered User
So. Cal.
Joined Oct 2004
8,454 Posts
What you've described is not physically possible. While not intuitive and overtly obvious at first glance, two (or more) batteries of same nominal voltage that are connected in parallel via a low impedance connection will soon be at the same electrical potential (voltage) and undercharging or overdischarging one of the batteries is not possible.

When connecting in series, the issues that you've described are a very valid concern.

Here is the one of the best places to start to learn more about parallel operation of Pb / LiXX batteries: http://www.rcgroups.com/forums/showthread.php?t=932319
mrforsyth is online now Find More Posts by mrforsyth
RCG Plus Member
Last edited by mrforsyth; Jan 13, 2013 at 04:03 PM. Reason: added detail
Reply With Quote
Old Jan 14, 2013, 11:49 AM
I meant to do that
eMoon's Avatar
United States, NY, Albany
Joined Sep 2011
664 Posts
A quick question.

I'm trying to make my case nice and tidy (and safe) so I'm attempting to conceal any loose wires or contacts. To that end my case will contain an ac power supply, charger and the field battery. I have the PRC 220 power supply http://www.progressiverc.com/prc220-power-supply.html and a 4s10AH LifePo4 battery. My largest lipo I will be charging is a 3S 2200 at 2c max.

Rather than the typical binding posts and unplugging from ac to dc power sources I want to install a selector switch that would act as a selector and on/off switch. That way I won't have constant live binding posts in the case from the LiFePo4 either. My thoughts are to use a double pole 3 position toggle or rotary switch. I'm not sure of the rating I would need though, or if one is available at the ratings I'm suspecting.

Would one of you be kind enough to help?
eMoon is online now Find More Posts by eMoon
RCG Plus Member
Last edited by eMoon; Jan 14, 2013 at 12:45 PM.
Reply With Quote
Old Jan 14, 2013, 12:14 PM
3D? I only got two thumbs!
United States, MA
Joined Jul 2012
1,557 Posts
An interesting read on the death of a lead acid battery in a series/parallel setup:
http://physics.ucsd.edu/do-the-math/...-of-a-battery/
AeroKen is offline Find More Posts by AeroKen
Reply With Quote
Old Jan 14, 2013, 02:07 PM
Registered User
United States, MN
Joined Feb 2011
4,377 Posts
Quote:
Originally Posted by newTOpro View Post
A quick question.

I'm trying to make my case nice and tidy (and safe) so I'm attempting to conceal any loose wires or contacts. To that end my case will contain an ac power supply, charger and the field battery. I have the PRC 220 power supply http://www.progressiverc.com/prc220-power-supply.html and a 4s10AH LifePo4 battery. My largest lipo I will be charging is a 3S 2200 at 2c max.

Rather than the typical binding posts and unplugging from ac to dc power sources I want to install a selector switch that would act as a selector and on/off switch. That way I won't have constant live binding posts in the case from the LiFePo4 either. My thoughts are to use a double pole 3 position toggle or rotary switch. I'm not sure of the rating I would need though, or if one is available at the ratings I'm suspecting.

Would one of you be kind enough to help?
Well your power supply tops out at 18A. So really the question is how much can your charger pull from the LiFepo4 battery?

How about something like this?
http://www.digikey.com/product-detai...189-ND/3190606

You are right though putting a switch between supply and charger is difficult since the amps are much higher then say the AC side of the power supply.
grimbeaver is offline Find More Posts by grimbeaver
Reply With Quote
Old Jan 14, 2013, 02:24 PM
I meant to do that
eMoon's Avatar
United States, NY, Albany
Joined Sep 2011
664 Posts
Ha! Forgot to post the charger. It's a 106b which can only go up to 10amp output.
eMoon is online now Find More Posts by eMoon
RCG Plus Member
Latest blog entry: Christmas Time
Reply With Quote
Old Jan 14, 2013, 04:04 PM
wjs
William
United States, MI, Brighton
Joined Oct 2012
1,966 Posts
Quote:
Originally Posted by newTOpro View Post
A quick question.

I'm trying to make my case nice and tidy (and safe) so I'm attempting to conceal any loose wires or contacts. To that end my case will contain an ac power supply, charger and the field battery. I have the PRC 220 power supply http://www.progressiverc.com/prc220-power-supply.html and a 4s10AH LifePo4 battery. My largest lipo I will be charging is a 3S 2200 at 2c max.

Rather than the typical binding posts and unplugging from ac to dc power sources I want to install a selector switch that would act as a selector and on/off switch. That way I won't have constant live binding posts in the case from the LiFePo4 either. My thoughts are to use a double pole 3 position toggle or rotary switch. I'm not sure of the rating I would need though, or if one is available at the ratings I'm suspecting.

Would one of you be kind enough to help?
These look like perfect little 50amp switches. They have other switches too that have LED and lower amps, etc.
http://www.wiringproducts.com/conten..._switches.html

I am using this power gate in my box (when it arrives). It charges the bat from AC and switch automatically between the two glitch free. Complete hands off. Just plug in to AC, or not. Charger will use AC if available, or 12v bat as backup when not. When AC plugged in, 12v bat will charge using the built in four stage charger.
http://www.powerwerx.com/batteries-c...switching.html
wjs is offline Find More Posts by wjs
Reply With Quote
Old Jan 16, 2013, 10:14 AM
I meant to do that
eMoon's Avatar
United States, NY, Albany
Joined Sep 2011
664 Posts
Thanks, you helped me realize 20amp switches are what I require.
eMoon is online now Find More Posts by eMoon
RCG Plus Member
Latest blog entry: Christmas Time
Reply With Quote
Old Jan 31, 2013, 03:02 PM
I meant to do that
eMoon's Avatar
United States, NY, Albany
Joined Sep 2011
664 Posts
Thought I would circle back as to where this discussion has led me...

http://www.rcgroups.com/forums/showp...&postcount=145

Finally made a home for the 4S LiFePo field battery.
eMoon is online now Find More Posts by eMoon
RCG Plus Member
Latest blog entry: Christmas Time
Reply With Quote
Old Jan 31, 2013, 07:22 PM
wjs
William
United States, MI, Brighton
Joined Oct 2012
1,966 Posts
Quote:
Originally Posted by newTOpro View Post
Thought I would circle back as to where this discussion has led me...

http://www.rcgroups.com/forums/showp...&postcount=145

Finally made a home for the 4S LiFePo field battery.
Thanks. You inspired me to get going and finish mine. Not sure the bottom switch is needed. If you turn off the charger, is not that the same effect. Would there ever be a need for that switch? How many charges are you getting on a 2200mah lipo. Looks like only about 3-4 depending on how much you want to drain down.
wjs is offline Find More Posts by wjs
Last edited by wjs; Jan 31, 2013 at 07:28 PM.
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Question How do you take your Lipo batteries to the field? Left Coast DJ Batteries and Chargers 26 May 26, 2012 06:02 PM
For Sale 1-4 cell LiPo Field Charger w/ 12v Gel Cell Battery Package jmead Aircraft - Electric - Batteries & Chargers (FS/W) 1 Mar 18, 2006 09:22 PM