I've had an issue the last couple of years with some PowerEx 9v batteries used in my Digitrax 402DT throttle With a Super Chief System. I'll use one for some weeks (I tend to operate just for a half hour at a time, maybe 45-60 minutes) and then eventually the throttle will become erratic, and the display will show a below 6v level. That seems like a normal situation. I then put it in a PowerEx (Maha) charger and it blinks rapidly, indicating it's a bad battery. I know it's not bad, so the next day I place it in the throttle again and it shows a 7+v level and it functions normally. Eventually it falls below a usable level (sometimes this cycle happens 2-4 times) and so far, I've been able to recharge it. So, here's my question. What unit (battery, charger, throttle) is not acting correctly? As in, why do I get an indication the battery is faulty and it really isn't? Thanks all.
Which PowerEx batteries? The white ones are 9.6v. Our club bought 10 of the original white ones and a 10 position charger. Within a year the batteries would not hold a full charge. At home, I had the same batteries and the 4 position charger - And had no problems. Eventually there was a lot of complaints on the msg boards and it appears that the 10 position charger was over-charging the batteries. I complained to the company I ordered them from and they sent me replacement black batteries(Imedion), but would not replace the charger, We then bought three 4 position chargers, but we do not leave them in the chargers overnight. The first person in the door the next day places them in the chargers, and they seem to charge up within about 45 minutes. We did lose a couple over the past 2 years, but in both instances the member left the battery in the throttle and it was totally discharged and will not take a full charge.
I am a little concerned about you 7v reading. With my meter, I get 9.6v for a fully charged battery, and at around 8v a radio throttle will start losing contact with the UR91/UR92 base station. If you are not using radio throttles, they will last longer as they are getting power while plugged in(but they will NOT charge the battery from the UP5). You mention you have a DT402, but not if it is a simplex or duplex throttle.
BTW, Digitrax is removing support for the older simplex throttles and UR91 base stations as they cannot get 900 mHz parts any more. They will fix the simplex thottles/base station as long as they can get parts. They will still upgrade older simplex throttles to duplex, but the UR91 simplex base station cannot be upgraded tp a UR92 base station.
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
Hi Jim, thnx for replying. The batteries are the white metal hydride. The charger is the 4 position charger. I am using the 402DT duplex radio throttle. My voltage readings are what the throttle indicates. I'm not knowledgeable on how exactly batteries discharge and then charge. Could the batteries get "fatigued" around 7v. or less. And then when allowed to "sit" they gain some charge? I ask because if I try to charge a battery when it has a good level (7v-9v) the charger will flash rapidly indicating it has too high a level to charge (per the Maha manual). So maybe it's the charger?
As long as you have the matched charger and batteries it should be fine. Battery charge rates are determined by the batteyr chemistry and by the capacity of the battery. The 9.6V ones actually have a lower amp hour rating than the 8.4 volt ones (they have an extra cell to get up to the 9.6 volts, which means they have to be smaller cells to still fit in a 9V size battery). So the 9.6V ones need to be charged at a slightly slower rate than the 8.4V ones. If the charger is flashing an overcharge warning, it's not (or shouldn't be) putting anything into the battery.
Yes, a discharged battery can recover a small amount of its charge if left to sit, so that may account for the difference after it sits for a few hours. But that's not repeatable over and over, eventually it will be dead. Or ruined.
Which is the next point - test the voltage with a meter, not just the throttle display. If the battery really is being discharged down to 6 volts, it's probbaly ruined. That's under 1V per cell. When overly discharged, one cell can reverse polarity. This would also cause the charger to indicate an error when trying to recharge it.
Before getting another battery - verify that you do have the correct charger for the 9.6V versions of the battery. If you've only been charging them to 8.4V (the 'regular' ones), this may be the reason why this has happened.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
So Randy, I've considered not waiting for the battery to run down to below 7v and put it in the charger sooner. But the same thing happens, flashing indicator. In the charger manual it mentions the charger can indicate a "bad" battery if it is charged too soon (i.e. A higher level of charge still in the battery). It's like I have to fine that sweet spot where it's run down enough to take a charge but not too run down and ruined. So my follow up question to everyone is what batteries and chargers do you all use in conjunction with your Digitrax 402DT throttles At home and/or at your clubs? And how do you use them and recharge them? Thanks all.
I see a new PowerEx battery that has a black casing (not the Imedion brand). Is this just a repackaging of the original white battery or is this a new unit? Anyone have experience with these? Also, anyone have experience with Tenergy or other brands?
jrbernier...If you are not using radio throttles, they will last longer as they are getting power while plugged in...
If not using radio (or infrared), then batteries are not needed.
Alas my throttles are 402DT duplex radio
I haven't been to the club for a while so they probably have newer batteries now but they went out and bought the 8.4V Maha batteries despite me saying they should get the 9.6V ones. Half the people would say they lost control and swap batteries after an hour or so, I usually ran all day on the same one. We did have some that after a number of shows just stopped holding a charge - didn't help they sometimes spent weeks in the trailer with no heat or AC.
The Imedion black ones are the best batteries - 9.6V and low self discharge which menas after you charge them if they just sit there for a few weeks they will still be nearly fully charged - the white ones will drain down even when just sitting there. These are the ones:
https://www.amazon.com/Powerex-Self-Discharge-Precharged-Rechargeable-MHR9VP/dp/B01FV0U5WG/ref=sr_1_2_s_it?s=hpc&ie=UTF8&qid=1479944139&sr=1-2&keywords=batteries+powerex
ANd this is the proper charger for them, but it should also work witht he white batteries:
https://www.amazon.com/PowerEx-MH-C490F-DCW-Worldwide-Battery-Charger/dp/B0002WKD80/ref=pd_sim_23_1?_encoding=UTF8&psc=1&refRID=4EH3CGJA7DZZTZTEKHER
I might have tripped over something. I used the throttle at the end of a session to measure the level As I always do. After super chief is powered down I take out the battery from the throttle, pause, and put it back in to see the level. That has been how I measure the level All along. Today I was running and the throttle went into "idle" so I plugged it into the up5 loconet panel To weaken it. It showed a level of 8.4v, yet when I took it out of the throttle and put it back (as I normally do) it showed 6.7v. So, could the throttle be giving a false reading? And if it was really 8.4v would the Maha/PowerEx charger (the mh-c490f) not charge it because it sensed it as full, or high level?
You are getting fooled by the fact that the DT40x throttles report TWO voltages - one, usually the lower one, is the BATTERY voltage, the other, usually higher (and 8.4 is a little low) is the voltage on the railsync lines in the loconet cable (which is where a throttle without a battery gets its power - plug your throttle in without a battery in it and you will still see a voltage reading). With my Zephyr which has a fixed track voltage at about 12.5, when I plug throttle in I usually get 10.2-10.8, which is about right give the UP panels have a pair of diodes in them which reduces the voltage slightly. Over a very long Loconet run this can be lower, which is why there is the plug in the sdide of even a UP5 to plug in a PS14 wall wart for extra power. The radio unit MUST have a power supply, it cannot work purley on the power supplied by the Loconet cable - but you'd have constant loss of control problems if you didn't have that.
The throttle display isn;t meant to be an accurate voltmeter (hmm, idea, use my variable power supply to see how close it is). It will always indicate about .7V too low because there is a diode in the circuit to prevent the battery from being connected backwards (which is why you can safely roll them over to store them in the throttle - battery + to throttle - won't hurt the throttle because of the protection diode and the battery won't drain - at least not in the short term, never leave a battery in the throttle for weeks at a time), so you really need to test with an actual meter. Testing just the battery will show the no-load current as a standard multimeter will put very little load on the device being tested. To test under load, put the battery in the throttle but leave the cover off and with the meter set on volts, touch the probes to the battery terminals.
The throttle showing 7 (which may be as much as 7.7) is to me way too low for a battery that is supposed to be 9.6V when fully charged. I dount the issue is the throttle though. You can test by putting in a regualr 9V alkaline battery and seeing what it shows. It should be over 8 volts on the throttle display.
Thnx Mel, good info. Thnx Randy, I'll measure it with a meter tomorrow, never even thought to do that. But after all this discussion it leaves the original question - why won't the battery charge? I used it still again last night for about 20 minutes so it still has a charge left in it. But why won't it recharge? Maybe the charger? Let's see what the meter says tomorrow. Thnx all.
Well I think I have connected the dots and have solved my "problem", which really isn't a problem at all. I measured the battery with a multimeter and found it read 9.5v. Then I put t on a dt402 duplex throttle and it read 6.6v. So there's my confusion. When under a load it shows a much lower voltage. When I think the battery needs charging it doesn't . And in fact the Maha/PowerEx charger won't charge it (I.e. Flashing LEDs) because it considers it fully (nearly) charged! So really no problem at all, I (as always) just needed a little education. Being a lone wolf has its disadvantages. Thnx to you all for your input. As always, I appreciate your help and knowledge.
6.6V under the load of the throttle is a discharged battery. Or a defective throttle drawing too much power. I'm surprised the throttle works at all if that is the reading you get. If the voltage across the battery terminals is 6.6V, the throttle is getting 6V or less (after the reverse polarity protection diode) and while I haven't had any of mine apart lately to look I'm pretty sure the battery feeds a voltage regulator since the main processor chip inside would run on 5V most likely. 6V feeding a 5V regulator is too low for it to work properly. That the charger blinks when the battery is inserted leads me to beleive the battery is the problem rather than the throttle. You can check by doing the same measurements with a regualr 9V alkaline battery. It should be right around 9V no load, and I would expect no less than 8V under load with a fresh new battery. Should be higher, at least for a while.
Thnx Randy, kinda. I thought I figured out I had no problem and then you add more knowledge to the discussion . Only kidding! . Anywho, I'll try a new alkaline battery tomorrow to see what's up. But a question. Doesn't the multimeter reading outside the throttle of 9.5 indicate a good battery? Couldn't the charger be saying its a fairly fully charged battery (as per the manual)? Couldn't the throttle display circuitry be faulty without the actual performance of the throttle be faulty? Just asking?
Fully charged it should be 9.6V, although that could just be the meter. With no load even a dead battery can indicate full voltage. The voltage produced by a battery is determined by the cell chemistry, so with no load you almost always get the actual voltage. If it can sustain that with a load is what determines how charged it actually is.
OK thnx. I'll keep monitoring it and see what develops. Who knew simple batteries could be so baffling.