Please need advice, do I need a new charger for a 1500 battery?  
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All Forums >> Radios, Batteries, Clubhouse and more >> Batteries & Chargers >> Please need advice, do I need a new charger for a 1500 battery?
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Please need advice, do I need a new charger for a 1500 ... - 5/28/2002 6:05:16 AM   
motoadve


 

Posts: 268
Joined: 4/19/2002
From: San Jose, AL, USA
Status: offline 		Im buying a Futaba NR4F Reveiver NiCd 4.8V 1500mAh Flat batery and in the past all my batteries has been the ones that comes with the Futaba radios the 600mAh batteries and the charger I have is the same that comes with the radio.

Do I need a new charger for this new bigger battery?
Can I charge it with my old charger?

thanks
       Post #: 1

Please need advice, do I need a new charger for a 1500 ... - 5/28/2002 5:48:36 PM   
Red Scholefield



Posts: 4980
Joined: 12/8/2001
From: Newberry, FL, USA
Status: offline 		Yes, you will need a new charger. Something capable of charging between 75 and 150 mA. Charging with the exisiting charger that came with your system will be marginal at best and take a very long time to fully charge a pack that has been fully discharged.

_____________________________

Red S.
AMA 951 Leader Member

(in reply to motoadve)
       Post #: 2

Please need advice, do I need a new charger for a 1500 ... - 5/28/2002 6:20:41 PM   
lv2fly


 

Posts: 4
Joined: 5/28/2002
From: Pensacola, FL, USA
Status: offline 		A better answer would be...
You Should get a new charger.

You can charge any size battery pack (of the same voltage) with the charger you have, you just may have to adjust the charge time.

You can roughly determine the charge time for any battery pack with a simple formula.

The stock Futaba chargers charge at 50 mAh.
This means that every hour on charge it is putting about 50 mAh of power into the battery.
Therefore (if we lived in a perfect world) it would take 12 hours to charge a 600 mAh pack. (50 x 12 = 600).

Unfortunately, we don't live in a perfect world and there is some current loss in the lines, in the pack and some other variables. This is why it takes about 17 1/2 hours to charge a 600 mAh battery at 50 mAh.

So, if you want to use your new pack before you can get a new charge, you can. Just be aware that it will take aprox. 40 hours to charge the battery.

(in reply to motoadve)
       Post #: 3

Please need advice, do I need a new charger for a 1500 ... - 5/28/2002 7:06:28 PM   
howardm4


 

Posts: 119
Joined: 12/31/2001
Status: offline 		Disagreed. Batteries need a certain charge rate to really
get them going. Lower than that and you're essentially just
trickling them.

While C/10 is the standard slow charge, if your wallwart
charger cannot provide at least C/15-C/20 rate, then you should
get a new charger.

(in reply to motoadve)
       Post #: 4

Please need advice, do I need a new charger for a 1500 ... - 5/28/2002 7:13:41 PM   
Red Scholefield



Posts: 4980
Joined: 12/8/2001
From: Newberry, FL, USA
Status: offline 		howardm4 A+

: lv2fly C-

University of Battery Technolgy
Batteries 101

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Red S.
AMA 951 Leader Member

(in reply to motoadve)
       Post #: 5

Please need advice, do I need a new charger for a 1500 ... - 5/28/2002 7:54:55 PM   
Jazzy



Posts: 1106
Joined: 1/8/2002
From: Erie, PA, USA
Status: offline 		Red,
What about using the TX side of the wall wart to charge the 4 cell pack? At least until Motoadve gets a better charger.

_____________________________

Aww $#!^.... I left the )@#& transmitter at home!

(in reply to motoadve)
       Post #: 6

Please need advice, do I need a new charger for a 1500 ... - 5/29/2002 8:59:20 PM   
hebertjj


 

Posts: 323
Joined: 1/18/2002
From: Knoxville, TN, USA
Status: offline 		Guys, I just had to weigh in on this one to see what grade I'd get from Red.

Jazzy, how about using the quick charger for your electric toothbrush? (Just kidding.) Good grief guys! We're talking about the batteries that keep our planes from crashing! Don't be going around with these half fasting cluges, especially if you're not sure of what you're doing.

Here's my read on the situation. If you're going to be using ANY battery configuration other than the standard packs that came with the system, GET A PROGRAMMABLE CHARGER!!! If you don't want to do that, stay with the standard packs and chargers.

The fact that moto had to ask this question tells me that we don't need to be telling him all these rates and capacity numbers, but tell him to get something like a Dymond ST or a Super Nova and look at it as a long term investment in the hobby. (Maybe Red has a better bang/buck suggestion). Also get a $5 dollar timer and do Red's "pulse" charge trick as listed in his page. (That last was a suck-up to get a higher grade from Red.)

Joel

(in reply to motoadve)
       Post #: 7

Please need advice, do I need a new charger for a 1500 ... - 5/30/2002 2:51:31 AM   
Red Scholefield



Posts: 4980
Joined: 12/8/2001
From: Newberry, FL, USA
Status: offline 		You got an A w/o the suck up, that will get you the +.

As for the comment on the tooth brush charger, don't laugh. There are a lot of appliance chargers lying around the house that work great for our application. You just have to know the minimum on how to measure the charge current on the particular battery you intend to marry up with it. It's covered by the Wall Wart article on the Battery Clinic web page (blatant commercial again enticing you to visit). I am amazed at the number of people that do, over 120-200/day and I ain't selling nothing.

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Red S.
AMA 951 Leader Member

(in reply to motoadve)
       Post #: 8

Please need advice, do I need a new charger for a 1500 ... - 5/30/2002 9:43:11 PM   
Jazzy



Posts: 1106
Joined: 1/8/2002
From: Erie, PA, USA
Status: offline 		Well Joel,
The purpose of this thread is to answer the starter's questions and provide a means, if necessary and possible, to deal with the situation at hand. We merely offer suggestions, answers, and ask questions.
My question was to Red openly since the response may, or may not, have answered some reader's questions or thoughts. It may also lead to a possibility that would improve conditions until a better means of obtaining the same or similar goals arrived. (Besides, I didn't feel like going down to the basement to retrieve the information on that particular morning )
As this thread has similarities to at least one other I did not mention a "fast charger." Yes, the Dymond Super Turbo and FMA SuperNova are very good options and will serve the user in a wide variety of applications.
But, that was not part of the original question or subsequent postings of the originator.
After reviewing the information located in my basement, I read from an article submitted by Red on RCOnline that the 50mA TX side of the charger will charge a 4 cell pack at 90mA. This IS better than the 50mA output of the stock charger's RX side and will not harm either the charger or the battery pack. At least until he is ready to and does get a more efficient charger the TX side will work in the meantime.
Remember: Some of us have spent years, not to mention $$, obtaining the level of knowledge we have. We obtained it from many sources including posts such as these. Investigation of how the suggestions and answers were arrived at promotes further understanding and subsequent knowledge from which we form our own opinions. Responding to questions with answers we have already researched and obtained suitable knowledge on is simply part of the sharing of information greatly valued in this hobby/sport.
Factual information, hearsay, and opinions,are often mingled within posts such that one may be indistinguishable form the other. Readers determine the validity of the responses based on a variety of things. These things include: the # of a person's posts (unfortunately), the consensus of opinion, the offering of facts and research data, and many others.
Criticizing others without researching their responses does not promote a friendly and educational atmosphere. Taking a moment to explore another's point of view may reveal possibilities previously unknown.

Judge not lest ye be judged.

< Message edited by Jazzy -- May 31 2002 12:18AM >

_____________________________

Aww $#!^.... I left the )@#& transmitter at home!

(in reply to motoadve)
       Post #: 9

Please need advice, do I need a new charger for a 1500 ... - 5/31/2002 8:48:27 AM   
hebertjj


 

Posts: 323
Joined: 1/18/2002
From: Knoxville, TN, USA
Status: offline 		Boy! I ought to just shut up, but I can't leave it alone!

Jazzy, I think you're just upset because I got an A+ from Red, and you didn't (neener, neener, neeee ner! )

"Judging not" may cut it for determining who gets to Heaven, but Motoadve better start judging lest thy airplane falleth from Heaven and striketh the firmament. The situation at hand is Moto has a battery pack and doesn't have an overnite charger for it. 90 ma from the Tx side will still take about 20 hrs to fully charge a discharged 1500 mah pack. If he flies enough to drain them down to 20% charge every day and only charges them 8 or 9 hrs between flying days; after a few days he's going to be down to about 550 mah when he takes them off the charger in the morning. 90 ma is not any better than 50 ma if you still end up crashing because you thought you had 1500mah in your battery pack and you only had 600mah.

I get back to the fact that Motoadve had to ask this question in the first place means he needs to get another charger NOW (and read Red's battery pages)!

In conclusion, the answer to Motoadve question is ... NO! Get a programable, peak detecting, charger or at least a bigger wall wart that will charge your 1500 mah packs with at least 150 ma that will fully charge his discharged pack in 12 to 14 hrs.

Joel

(in reply to motoadve)
       Post #: 10

Please need advice, do I need a new charger for a 1500 ... - 5/31/2002 12:06:02 PM   
Jazzy



Posts: 1106
Joined: 1/8/2002
From: Erie, PA, USA
Status: offline 		Hey Joel!
I whole heartedly agree that a better charging method is in order. "...until he is ready to and does get a more efficient charger ..."
BTW, a minimum of 25 hours, according to my calculations, would be needed to come close to reaching a full capacity state of the pack when charging at 90 mA (C/16.7). Once you drop below the C/10 rate the charging efficiency decreases significantly. Without further analysis I would much rather charge at 90 mA than 50 mA (C/30). But then again, that's my opinion.

(You know, we haven't heard from motoadve at all... . He's probably just sitting back and watching the show! )

Yes, he DOES need a better charger... to answer his question more directly. I can be very particular at times.
I just had an airplane "falleth to the firmament." It is not something I want to have happen frequently. Design instability and inexperience with biplanes lead to it's demise not battery failure.
A 1500 mAH battery pack will probably never reach full useable capacity if charged at 50 mA. Those cells need a minimum 'soaking' to be content. 50 mA is only C/30 which is barely an acceptable trickle rate only replacing about 67% of the ~5% lost daily.
I should have done what he is doing right now- asking for help. Instead, I chose to experiment and spend lots of time and money on... stuff. My knowledge, foresight, and the electronic's technologies were advancing at slightly different rates.
Yep, peak detecting is the way to go. I do still use a c/10 long, slow, charging method now and then-when it is called for. Generally, my two SuperNovas do all the work without the need for questioning the process.

I hope someone is learning from our seemingly pointless banter!

Brownie points? Nah. I never did care for them. Respect and kindness are biggies with me.

Jeff

_____________________________

Aww $#!^.... I left the )@#& transmitter at home!

(in reply to motoadve)
       Post #: 11

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