Model Boat Mayhem

Please login or register.

Login with username, password and session length.
Pages: [1]   Go Down

Author Topic: NiMH Batteries - Maintenance for best performance?  (Read 4060 times)

craig dickson

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 335
  • Location: Brigg North Lincolnshire United Kingdom
NiMH Batteries - Maintenance for best performance?
« on: February 10, 2014, 07:17:05 pm »

Hi Folks

I currently use a five cell (6 volt) Sanyo eneloop battery pack or powering my receiver and two servos in boat installations. I use a Ripmax (4.8-8.4 volt) charger to top up the charge between runs which takes about 40 minutes. Once the light on the charger changes from red to green I disconnect it considering the pack fully charged.

Would you know however, whether it is necessary at all to completely discharge these batteries to ensure long life and a full charge?

Or is it okay to do what I do and constantly top them up before a run?

If it is beneficial to discharge them completely, is it necessary for every re-charge? Or is it something needed to be done only occasionally?

Your comments will be appreciated.

Cheers
Craig :-)

Logged
Forget all insults, always remember compliments.

black magic racing

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 338
  • when winning is all . it stops being a hobby
  • Location: stockport,manchester
Re: NiMH Batteries - Maintenance for best performance?
« Reply #1 on: February 10, 2014, 08:55:42 pm »

it is advisable to discharge them fully every now and then and also to slow charge them as well as they can hold a memory and not charge to there full potential,just my theory %%
Logged
FAST is never FAST enough
Black Magic Racing with BMPRS    Telford Model Boat Club
Birkenhead Model Power Boat club Vice Commodore

Stavros

  • Guest
Re: NiMH Batteries - Maintenance for best performance?
« Reply #2 on: February 10, 2014, 09:00:37 pm »

I htought it was the nicad packs that retained a memory..........never dishcharged my MINH batts just use and charge before use
 
 
Dave
Logged

RMH

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 298
  • Location: Oxfordshire
Re: NiMH Batteries - Maintenance for best performance?
« Reply #3 on: February 10, 2014, 09:07:08 pm »

I believe Nicads should be stored discharged and NiMh should be stored fully charged.
Logged

Tug-Kenny RIP

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 7,625
  • Location: Newport. S Wales
Re: NiMH Batteries - Maintenance for best performance?
« Reply #4 on: February 10, 2014, 09:18:50 pm »


If you discharge a NimH battery then it's very difficult to re-start the charge process.

I have found the charger ignores it, so I have to connect a fixed voltage temporarily to give it a kick start before commencing with the proper charger.     O0


Ken

 
Logged
Despite the high cost of living   .......... It remains popular

vnkiwi

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,593
  • Location: SE Asia
Re: NiMH Batteries - Maintenance for best performance?
« Reply #5 on: February 10, 2014, 09:46:43 pm »

Stavro's right, Nicads have memory problems.
Batteries should be fully charged after use, then if necessary recharged as a topup before use, depending on the time in storage.
They should never be left in the boat or equipment between use, and stored in a dry container, with silica gel packs if need be. Moisture is their worst enemy.
I run NiMH batteries in all my boats, just don't bother with Nicads any more.
Logged
If it ain't broke. Don't fix it !

craig dickson

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 335
  • Location: Brigg North Lincolnshire United Kingdom
Re: NiMH Batteries - Maintenance for best performance?
« Reply #6 on: February 10, 2014, 09:50:45 pm »

Thank you very much for all of your input so far. I stand to learn a lot :-))

Craig
Logged
Forget all insults, always remember compliments.

Martin [Admin]

  • Administrator
  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 23,340
  • Location: Peterborough, UK
    • Model Boat Mayhem
Re: NiMH Batteries - Maintenance for best performance?
« Reply #7 on: February 11, 2014, 10:13:53 am »


Found this on the Team Novak website:



Ni-MH BATTERY CARE SHEET
www.teamnovak.com


Basic Ni-MH Battery Care
Ni-MH packs should be charged at a maximum rate of 4.5-5.0 amps until
warm (not hot), and used as soon as they are done charging for optimum
performance. If the pack sits for more than 10 minutes you will not get full
performance. You can “re-peak” a pack that has sat longer than 10 minutes
to improve performance (re-peak only once).

Some may tell you that it is good to get the packs a little hotter for racing
applications. This technique may offer slightly better initial performance,
but the long term effects are detrimental to the cells and is not recommended.
Delta Peak chargers (chargers that look for a voltage threshold to determine   
when the charge cycle is complete) are not good for regular use with Ni-MH
cells, as this method causes excessive battery heating and results in internal
damage to the structure of the cell. Pulse chargers should never be used.
We recommend using the Novak Millennium Pro (#4490) or the Novak Ionic
(#4475) chargers in the Novak Ni-MH2 charge mode.
New Ni-MH cells often false-peak the first couple of times they are charged.
This is the nature of the Ni-MH cell. If the battery pack is not warm to the
touch, a false-peak has occurred, and the charge cycle should be re-started.

Batteries Used Weekly
Batteries that are used every week should be fairly easy to maintain. You can
either run the batteries down until the vehicle runs slowly, or discharge the
pack to 0.9 volts per cell (for a 6 cell pack that would be 5.4 volts) using a
quality discharger that has a cut-off voltage setting like the Novak Smart
Tray (#4500--available 3/2004). The Smart Tray is a digital microprocessorcontrolled
equalizing discharger that discharges each individual cell of the
battery pack with no risk of damaging the batteries, as each cell’s discharge
is shut off after reaching the preset cut-off voltage.
When the battery pack has cooled back down to room temperature, it can
safely be charged again for reuse. For the best performance, we recommend
no more than two (2) cycles per day.

Batteries Stored More Than 2 Weeks
If you do not use your batteries weekly, you will get better performance if
some care is taken before storing your packs. After using the packs for the
final time, put about 2-5 minutes of charge back into the batteries and then
store them. When you use the packs again, discharge them to 0.9 volts per
cell and let them cool completely before charging. The discharge before
charging will give the best performance and should help prevent false-peaking.


Using Battery Equalizing Trays Before Charging
There are a numerous battery “equalizing” trays available from manufacturers
who all have different views on the usage & maintenance of Ni-MH
batteries. Through extensive testing, we have found that Ni-MH batteries
should not be discharged below 0.9 volts per cell, and that battery trays
can be very helpful in maintaining pack performance and consistency.
We highly recommend using an equalizing discharge tray that has a userselectable
cut-off voltage like the Novak Smart Tray (#4500). The Smart
Tray also features individual status LEDs to let you know when each cell has
completely discharged. Using the Novak Smart Tray before each charge
will give you the best possible performance from your batteries.

Packs That Continue To False-Peak
Some customers may experience false-peaks with sport packs, receiver packs,
or packs that have been previously abused or are very old. This can be due to
lower quality cells or the construction of the packs. The Ni-MH cells in these
packs are often never discharged properly so the cells can be very problematic.
The first thing that should be done for these packs is to discharge them and
let them cool completely. Next, charge them at a lower amp rate than
normal. When a false-peak occurs, try restarting the charger. If it the pack
continues to false-peak you may need to set the charger up differently.
The Ni-Cd Linear charge mode found in the Novak Millennium Pro and the
Novak Ionic chargers uses voltage threshold to determine the battery’s peak.
For a problematic Ni-MH pack, this may be the only way to get it to take a
full charge. Set the charger at your desired current with the voltage threshold
set to 4 mV/cell. If false-peaking continues, increase the voltage threshold
by 2 mV/cell. Do not exceed 10 mV/cell. If you reach this setting and
repeated false-peaking continues, you can activate the Trickle charge in the
Millennium Pro by turning this feature on in the Edit Charge mode. If a
false-peak occurs now, the trickle mode will continue to charge the pack at
a very slow rate. Let the trickle charge continue for about 10 minutes, then
restart the normal charge cycle. When the pack finishes the normal charge,
the trickle will start again, so make sure that you remove the battery from
the charger at the end of the main charge cycle (after it peaks) if it has
successfully charged and did not false-peak. Remember to turn off the trickle
charge function for future use.
Logged
"This is my firm opinion, but what do I know?!" -  Visit the Mayhem FaceBook Groups!  &  Giant Models

Netleyned

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 9,051
  • Location: Meridian Line, Mouth of the Humber
    • cleethorpes mba
Re: NiMH Batteries - Maintenance for best performance?
« Reply #8 on: February 11, 2014, 10:28:54 am »

We all have to bin our delta peak chargers then????


Ned
Logged
Smooth seas never made skilful sailors
Up Spirits  Stand fast the Holy Ghost.
http://www.cleethorpesmba.co.uk/

vnkiwi

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,593
  • Location: SE Asia
Re: NiMH Batteries - Maintenance for best performance?
« Reply #9 on: February 11, 2014, 11:12:26 am »

manufacturers
who all have different views on the usage & maintenance of Ni-MH
batteries.

Hardly Ned, they even state the above quote.
Do what your battery manufacturer recommends.
Logged
If it ain't broke. Don't fix it !

Netleyned

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 9,051
  • Location: Meridian Line, Mouth of the Humber
    • cleethorpes mba
Re: NiMH Batteries - Maintenance for best performance?
« Reply #10 on: February 11, 2014, 11:30:00 am »

We all have to bin our delta peak chargers then????


Ned


That was a tongue in cheek statement from me vnkiwi,
I had just read that one of Martin's and then had a trawl around
the net and found a half dozen different ideas on the subject.


I use 6v packs for my yachts and these are in use twice a week weather permitting.


These are used for about 2 hours at a time driving a sail winch, rudder servo and receiver.
When I get home I take them out and put them on a Fusion NX83 delta peak charger until the green light
comes on.
They are then disconnected and left until the morning of use when they are put back on to top up until green light.


This is the fifth year these batteries are starting and they are as good as new.


These are 2600 mAH packs from Component Shop.


Ned

Logged
Smooth seas never made skilful sailors
Up Spirits  Stand fast the Holy Ghost.
http://www.cleethorpesmba.co.uk/

vnkiwi

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,593
  • Location: SE Asia
Re: NiMH Batteries - Maintenance for best performance?
« Reply #11 on: February 11, 2014, 11:37:02 am »

yep, realized that Ned.
Every battery manufacturer will tell you something different in the details, and the charger manufacturers will tell you a wee bit different to suit their products.
Let common sense, (cant spell for nuts), prevail, as your doing, and have done.
I found Nicads a pain, now use NiMH, and have for years. Never came across that explanation that Martin found, before.
Lipo are another story all together.
Enjoy your boating Ned
cheers

Logged
If it ain't broke. Don't fix it !

craig dickson

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 335
  • Location: Brigg North Lincolnshire United Kingdom
Re: NiMH Batteries - Maintenance for best performance?
« Reply #12 on: February 11, 2014, 06:58:59 pm »

Hi Folks

Wow! Thank you all very much for your interesting and helpful responses. There appears to be some differing opinions in certain aspects but interesting just the same.

The detailed article put up by Martin is especially informative - thank you. The section where it said that modern NiMH packs often "False-Peak" the first couple of times they are charged is something I can relate to. The second time I charged a new 5 cell pack (after my boat had had a good run), my Ripmax intelligent charger showed a full charge (green LED) after only 10 minutes. I assumed the charger was faulty thinking that no way could it have delivered a full top up in that time. I plugged in a second identical spare charger and it went for a good 30minutes before switching from red to green.

That only happened the one time so I think that this was perhaps a "False-Peak" example and not down to a faulty charger. I have changed my radio control units to Hitec with the telemetry which gives a low receiver battery pack warning to the transmitter. At least that way if my boat battery pack runs low on voltage I will get an audio warning and know to stop the boat as soon as possible.

Excellent information guys!

Thank you.

Craig :-))
Logged
Forget all insults, always remember compliments.
Pages: [1]   Go Up
 

Page created in 0.096 seconds with 22 queries.