Popriv

Just got home with my new hydramax 2000 NiMH and was going to put it on my wall wart. First I checked it with my loaded multi tester and I get no movement of the needle... No voltage!!! Is this normal? I thought there would be some charge in it.. Is This battery DOA?

Thanks

Steve

guver

My Feedback: (325)

Lots of them have 0 volts. I'm not saying it is a good thing.

bluebird26

These Hydramax batts lose alot of charge in storage in my experience. I would say your batts stuffed if it is zero volts .
I have replaced my 2000 mh NiMh batts with LiFe 1800mh from HK.These hold charge between flying . I can now charge when convenient. Not just before flying as with NiMh you become a slave to the charger.
Cheers
Duncan

Popriv

Two new batteries, both read 0 volts right out of the package..... H'mmmmm, should I return them?

Steve

Goldenduff

Hi BLUEBIRD,

I've used heaps of lipos from HK (all have been great! even if the next 5 I order are dudd I'm not bothered as saved heaps)

Thinking of getting in to LiFe- are HK's okay?  Are they way heavier per mah compared to Lipos? Bearing in mind you can only use 80%mah of lipo (can you use all mah of LiFe)?


Thanks

landeck

My Feedback: (1)

Put them on a wall wart charger for 15 hours at a C/10 charge rate and then test them. To form NiMh batteries you should cycle them three times.

Bruce

JPMacG

My Feedback: (2)

I think it just means that the packs were sitting on the shelf for a while before they were sold to you. NiMH cells self discharge at a relatively high rate. As said above, charge them at C/10 then cycle them to determine capacity. Do this 2 or 3 times. If they don't come close to the advertised capacity then return them. You may have been given old packs.

Rodney

If they truly read zero (not even a flicker on the meter) chances are they are really dead. If you put an ohm meter on them, do you get a reading. If so, they are toast, if not you have a defective voltmeter or leads on the voltmeter. If you get a bit of deflection on the voltmeter, do the forming charges as stated above and check for capacity.

Red Scholefield

My Feedback: (9)

Absolutely, return them. No battery should read zero volts. If you actually short one down and let it set for 24 hours there should be some voltage evident. This is actually a factory quality test we used. It was known as the short down, spring back test - done on single cells in lot sampling. Do not do this on a multi-cell pack as one or more cells could be driven into reverse if the whole pack is taken to zero volts under some finite load.

landeck

My Feedback: (1)

Red, he is using a "loaded multi tester" to test the battery. If this meter is designed for use with RC battery packs, it may not start desplaying a reading until some voltage greater than zero. Therefore he should put it through one full charge cycle to see if it is a good battery.

Bruce

Popriv

Its a hobbico ESV, I didnt think to try a no load tester..

If I understand this correctly, last night I charged

1. Hydrimax 2000 - 15 hours at 50ma - I added 750 ma
2. Hydrimax 2000 - 15 hours at 110 ma - I added 1520ma

Both batteries indicate good to fly on my ESV..

Regarding your last sentance " see if its a good battery " how can I tell?

I dont have a cycler but I do have a 4.8v 700mah light bulb... can I use that to discharge to say 4.8v then recharge?

I also just realized my FMA direct cellpro multi4 charger will allow me to charge Nimh at any rate I choose so would I be better off setting it for 200mah?

Battery says " standard charge is 200ma for 11 hours "

What would tell me the battery is bad?

Thanks for your help..

Steve

Popriv

All responses appreciated but its funny they range from:

"Batteries are no good, return them"

to

Just charge them up and they will be fine....



Soooo confusing.... lol


steve

landeck

My Feedback: (1)

Charge it at the 110 ma rate for 25 hours. That will give a full charge. Then let it sit for a day to see if it holds its charge. If it does then use your FMA direct cellpro multi4 charger to cycle the battery twice checking its capacity. If it is within 95% of the rated capacity, then the battery is fine.

Note that your cellpro multi 4 is a peak charger which can give a false reading if used on a new battery which has not had a oleast one full charge.

Bruce

Popriv

I think I got it, 1st charge with wallwart because it wont shut off SO I have to time it. 25 hours at 100mah should load 2500ma in battery. this will assure a full charge. THEN, after setting the 1st charge, its ok to use the cellpro
On 1st charge Cellpro will/may shut off too early so I wont get a full charge...

Cellpro does not cycle tho so I'm back to that 4.8v lightbulb for discharging

If its a 4.8v 700mah bulb and I ran it for 1 hour, that would use 700 mah from the battery?

2000mah battery - 700mah leaves 1300ma in the battery ??? am i in the ballpark?

how low should i take it before recharge

thanks steve

landeck

My Feedback: (1)

You are getting there. Discharge with the bulb for two hours (1400 mah) or until the bulb begins to dim. Then wait until the battery is cool or 10 minutes, which ever is longer. Then recharge with the cellpro and see how many mah you put back in. It should be up to 20% more than what you took out. If so the battery is fine.

I suggest you get a good battery cycler. Good luck.

Bruce

Airplanes400

My Feedback: (349)

Here's the best way to test them ...
For anyone who said, "Just charge them up and they will be fine." Ask them to install the battery in their plane and fly it for a day so you can test the battery. By their response, you can then return the battery.

No battery should ever go to 0.0 volts. If it does, it is dead. You may be able to force a charge into it, but that charge will be gone within 24~48 hours. The battery is not reliable. Cycling it is a waste of time. It's dead/shorted out. If you have a battery pack made up of several cells, then one or more of the cells are dead. When one cell is dead, no current can go through it, even if the other cells are good. You will get a reading of 0.0 volts

Return the battery. Chances are, its been sitting on the shelf of the hobby store for more than a year. It's dead. It can't be revived.

guver

My Feedback: (325)

All voltages will add. Only with an open will the reading be zero regardless of the other cells voltages.

Popriv

what about the fact that I was using a loaded tester to read the batteries? would that be a factor in my 0 reading?
I didnt think of testing with a non loaded tester before I put a charge into them...

Jazzy

Popriv,

You will get (and are getting) a variety of answers here. Many are founded by tried and proven knowledge/techniques.

Because you checked them with a loaded meter it is hard to tell what the actual floating voltage of the packs were. Given that, you have basically only one recourse: Charge and see.

Given you have 2000mAh packs, the C/10 charge rate is 200mA.
If you use your 50ma wall-wart you can leave it on charge pretty much indefinitely without harming the pack. The trouble is, it may never reach full charge because the charge rate is 1/4 the C/10 rate. NiCDs and NiMHs self discharge so think of them as leaky bottles. If you don't put water (charge) into the bottle (cells) fast enough to overcome the discharge rate AND properly 'form charge' the cells they may never attain their full productive capacity.

The 110mA wall-wart should provide enough current to give the cells in the pack sufficient charge. At rates below the C/10 rating you need to add 30-75% more charge. I did many experiments a few years ago regarding charge rates and their ability to fully charge packs. The lower the charge rate the more time (and subsequently more charge) is required.
That being said, 24-30 hours at 110mA should be fine (similar to what was mentioned above). Again, this rate should not harm the packs if left on for long periods of time. As always, periodically check the temp of the pack to see if it is getting warm. Warm is normal as a pack begins to reach full charge. Hot is not good and cease and desist charging immediately. The packs should start getting warm after 16-18 hours but leave them on for a few hours more provided they don't start getting excessively warm/hot.

I use to have a myriad of appliance timers to help charge times and for short pulse charges for maintaining full charge. These might be a good option for you to use.

Using a 700mA bulb to discharge: I used to use something similar but found I didn't have the time to sit and watch the voltage of the packs as they discharged.
If you use this method, keep track of the time it takes to discharge the cells to 0.9V/cell. This is the level used at the factory to rate the cells. This is also what we call "cycling" a pack. For a 4 cell pack the cut-off voltage is 3.6V. For 5 cell packs it is 4.5V. Discharging below these levels is dangerous because a cell may reverse its polarity in the pack and then the pack is worthless. You should get a little over 2 hours of discharge time (if the draw is REALLY 700mA). Keep in mind that a fully charged 4.8V pack will have an initial floating voltage close to 5.25V. The current draw from a 4.8V bulb will be higher than 700mA at voltages above 4.8V and less at voltages below 4.8V. kind of a trade-off.
As mentioned above, you should get 90% or better of the rating of the pack. Since you don't have a charger/discharger unit you will have to rely on your measurements and time keeping ability.

Several diagrams were posted here before about making your own loaded/unloaded voltmeter. Try doing a search for "Loaded Voltmeter" or similar. It may provide you with simple instructions. I made one myself and trust it above something someone else made. I can check the voltage loaded and unloaded with the flick of a switch.

A great deal of information and knowledge can be had from Red's Battery Clinic. I highly recommend you take a look.

Best of luck and Happy New Year!!

Jeff

HoundDog

My Feedback: (49)

Lost 2 planes to Hydromax batteries and others have too. Never use them again, Not even for set up. A123's for big gassers. 2000 MAH sanyo Enerloops ... they come charger ... Had a new pack chargerd it ounce let it sit, and no loss of voltage in 3 months. Nothing better "yet". But that's just my Opinion take it for what it's worth.

Airplanes400

My Feedback: (349)

Loaded tester or not, if you got a 0.0v reading, your batteries are dead. Throw them away.

When rechargable batteries are operating correctly, they will drain themselves gradually. Once they are allowed to drop below 0.8 v per cell, they begin to burn themselves up quickly. If ignored, the battery will go to 0.0 volt and become unusable/dead. While you can force a charge into them through several cycles, that charge will be short lived. The battery will operate correctly for a brief period, then suddenly drop to 0.0v.

Like I previously wrote, if any of these guys tell you to force/cycle the battery to get a charge into it, let's see if they are willing to put that battery into their plane and fly it around for a day. Chances are, most of them show some degree of fear/panic and uncertainty in their facial expression, and have an inflection in their voice. Then, they will decline the offer. If anyone does take you up on the offer, here's what will happen. The battery will suddenly short/drain under load and go to 0.0 volts ... then the plane will crash.

guver

My Feedback: (325)

Just test them with an unloaded voltmeter to see if they spring back up to a (close to) nominal voltage. This would at least allow you to eliminate that particular variable.

mighty9

My Feedback: (10)

I had a brand new hydramax that had zero volts i charged it and cycled it 5 times and it was with in 50 mah every time. It was over the 2000 mah rating every time. i have now flown it a total of of 14 hours on the ignition of my gas plane .I cycled it again last nite and got 2047 mah hours on my accucycle. Glad i didnt throw mine away

Popriv

I have a question about the planes you lost... If the battery is checked, and looks good, before each flight would you be safe to fly or are you saying that the battery just died mid flight? I always check with a loaded tester before every flight. I was thinking any issue would be how long the batteries lasted not that they would died completely in mid flight....

steve

Jazzy

I would happily cycle his packs on my SuperNova. If they cycled well and did not rapidly self-discharge, I would absolutely put them in one of my aircraft. No cringe, no inflection, no lie.

Popriv,

Here is a link to a simple load/no load meter I made.
[link=http://www.rcuniverse.com/forum/m_6061222/mpage_1/key_loaded%2Cvolt%2Cmeter/tm.htm]Loaded Voltmeter[/link]

Hopefully you know someone that can properly cycle and test the batteries for you.