Has anyoen tried something liek this?
https://www.amazon.com/Luniquz-Creative-Lithium-Batteries-Rechargealbe/dp/B00WIB8HLI
DOuble the capacity of the Imedion low-self discharge 9.6V rechargeables. Plus the way these operate (since LiIon cells are 3.7V each) is that they have a boost converter built in which produces a constant 9V at the terminals until the batteries are too far discharged, at which point it shuts off completely. These sort of things are not suitable to short high current bursts but the DT40x throttles are a relatively low current steady draw rather than bursty, exactly what these things are made for. My only question is, do they fit? There are some brands of rechargeables that simpyl will not fit in the batter compartment.
They look pricy, but the low self discharge Imedion 9.6V oens are almost $13 each, for for $4 more you don't need a special charger AND they should last a lot longer - both per charge and in the number of charge cycles they can handle.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Mel,
Are these 'thicker' than normal 9v batteries? Could you take a micrometer to them and post the results? I just Googled them and like you mentioned - four 600 ma cells and a charger for under $20!
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
Can you recharge a lion battery (like those being discussed) in a charger designed for ni-mh batteries, I.e. PowerEx batteries and their mh-c40f charger?
Tophias Can you recharge a lion battery (like those being discussed) in a charger designed for ni-mh batteries, I.e. PowerEx batteries and their mh-c40f charger?
No, the charging protocols are not the same.
CG
jrbernier Mel, Are these 'thicker' than normal 9v batteries? Could you take a micrometer to them and post the results? I just Googled them and like you mentioned - four 600 ma cells and a charger for under $20! Jim
Absolutely not. And if those inexpensive Li-ion batteries (and $20 for 4 including the charger is definitely inexpensive) don't have full protection built into the battery, it is very possible for the wrong type of charger to cause the battery to catch on fire. Li-ion batteries are great when it comes to power density and low self discharge, but they do need protection circuitry to cut off output or charging input if the temperature gets too high, and in a multi-cell pack they need circuitry to keep the cells balanced when recharging.
Thnx, that's good to know about li-on battery types in general. Makes you have to consider if you would ever want to put a li-on battery (any brand) on a charger and walk away overnight. Or am I just being too over cautious? This doesn't happen with ni-mh, does it?
Ni-mh batteries aren't designed to be left on the charger all the time either. If you do, you will destroy the battery's capacity. Once charging stops, they should be taken off, not left on perpetual trickle charge, which is what most chargers do.
Li-ion chargers that are properly designed will cut off once the battery is charged. Leaving them on the charger probably has long term effects even if the charger does not cut off, but that's not what makes them catch fire. What catastrophically damages a Li-ion battery is charging at the wrong rate. There are two points in the charge curve, initially they run at a constant current - you feed back X amps into the battery without regard for the voltage - the voltage will be low and gradually rise. Once it rises to a particular level, the charging needs to switch to constant voltage mode, where the voltage remains the same but the current gradually drops as the battery is fully charged. That's why you can charge them with a lab power supply - any decent one will have a constant current and constant voltage setting
https://www.youtube.com/watch?v=jNmlxBXEqW0
Thanks for the measurements. They are identical to my ULTRALiFE & IMEDION batteries. I have ordered a set of 4 with charger
Let us know how they work out. They should run a LOT longer than any Ni-mh battery, for the simple reason that Li-ion cells are nominally 3.7V each so you can;lt get either the 8.4 or 9.6V you get from nicad or ni-mh (1.2v each) cells. Thus those 9V Li-ion batteries incorporate a boost converter circuit to generate 9V. The benefit here is that the converter can get 9V out of the cells well down on the discharge curve. With your typical 9.6V Ni-mh battery, as it gets used up, the voltage drops. As we know, the Digitrax throttles are somewhat sensative to voltage, and will cut out or at least start acting erractic long before the battery is totally discharged. The boost converter on these Li-ion batteries will keep the voltage above the Digitrax cutoff through much more of the battery capacity. The cutoff will probably be swift and sudden though - once the cell voltage drops too low to properly power the boost converter, they tend to just shut off and produce no output. This could be an advantage - there would be no wondering if it's the battery or something else, as at our club when people are swapping out batteries after only an hour or so thinking the battery is at fault when it's not. If the throttle shuts off, there will be no question it's time to swap the battery.
rrinker Let us know how they work out. They should run a LOT longer than any Ni-mh battery, for the simple reason that Li-ion cells are nominally 3.7V each so you can;lt get either the 8.4 or 9.6V you get from nicad or ni-mh (1.2v each) cells. Thus those 9V Li-ion batteries incorporate a boost converter circuit to generate 9V...
Actually, according to the reviews, they use two cells in series, do not incorporate a boost converter, and hence will only to charge to about 8.5 volts.
No load voltage will be higher than with a load. I don't think there is any danger using these - very few circuits actually run on 9V, most are 5V anyway, so the first thing after the battery connector (if they haven't forgotten) is a protection diode and then a voltage regulator.
That's kind of disappointing they don;t use a boost converter, that 8.4V won;t hold up long under load, and just two cells will net only 7.4V, not enough for many 9V powered electronics. There must be two different ones though, if Mel's charge up to 11.1V - that's 3x 3.7V cells, but fully charged no load they should be 4.2V per cell so an initial 12.6V which would quickly drop.
One of the Youtube electronics bloggers surely has opened one of these up to see what's inside, I'll find that.
OK - The EBL-855 charger and four 600 mHa batteries have arrived and are in the charger. Per the user manual, the blue LED will become darker and will charge the battery at a 20 ma until the MCU protection board kicks in.
It appears there is no boost converter in these batteries. I am going to take them to the club Wednesday and put them in some DT400R and DT402D throttles.
Well, it's about 2 PM on Sunday afternoon. I checked the battery charger before I left for church and the blue LED's were all dark. I just checked each of the batteries and the are charged to between 8.44 and 8.51 volts. I pulled two of them and inserted them in a DT400R and a DT402D throttle. I checked the voltage 'under load' and they did not seem to drop(I put a 8.44v battery in the DT400R and a 8.51v battery in a DT402R). I have not left them plugged into the LocoNet as I want only the throttles to 'drain' them. I did plug them momentarily into the system just to assign them each a loco. I will spin the encoder knobs every once in a while to simulate commands be sent over the 'wire'...
Drove down to the club this morning - I put a charged battery in a DT400R & a DT402D. I let two trains run, changing the throttle speed every 10-15 minutes.
After 3 hours, I measured the batteries while they were still under load(in the throttle). The battery in the DT400R was 8.4v and the battery in the DT402D was at 8.2v. This is not really any better than the PowerEx or Imedion batteries. I think I am going to look around for some with the 'Boost' technology ....
Wait though, after 3 hours they were effectively where they started, at least the one in the DT400R. The DT402D though, that was pretty signigificant drop if it started at 8.51. These batteries are supposedly nearly 3x the capacity of the Imedion at 600mAH vs what, 230mAH. I've been told by people who know battery design far better than I do that 600maH is a reasonable number for a Li-ion in a 9V size. I've seen som others advertising 800maH and higher - thoise a certainly scams as the chemistry vs size would not allow that capacity in that size container. But it really sounds like these 600maH ones are also falsely rated if they don't hold up
Kind of disappointed, I thought maybe there was finally a way around my idea of just fitting my own boost converter circuit to my throttles (voiding the warranty). Actually I wanted to try a boost converter and power it from a pair of AA batteries instead of a 9V - 2 AA will fit in the same space in the battery compartment, and AA's can be had with some insane capacities. Even AAA's will have a greater capacity than a 230-250 mAH 9V. The real trick is to examine the circuit - if all power in the throttle is derived from a 5V regulator, it would be possible to bypass the regulator and design a boost converter to put out 5V. A 5.3V Zener could provide overvoltage protection.
Maybe there are some better Li-ion "9V" options.
NEVER use LIPOs in equipment not designed for LIPO batterys. There is a reason for the fire hazard warnings if they aren't properly taken are of. LIPOs are great because they provide a constant output as they discharge, however you NEED to have a low voltage dectector to prevent the battery from over discharging, which will damage the cells. Damaged cells most likely won't cause trouble until they are recharged and may catch on fire. Chargers should be able to balance the cells (this is why there is the small wires for charging), or the cells can become damaged if not correctly balanced.
Also, NEVER use a damaged LIPO battery. If the battery is damaged, it can take hours to a few days before it catches on fire. Always check the battery and make sure it is not swollen, puntured, etc.
Following the safety instructions and using comon sense will guarantee problem-free use of LIPO batteries
Thnx Kyle. I think I'll leave the li-on's to the ones that came with my power tools and continue with the PowerEx's in the Digitrax throttle.
It's not all bad, you just need to be sure you buy a proper charger to go with Li-ion batteries. The Digitrax throttles have no recharge circuitry in them for Li-ion or ANY battery chemistry so there's no danger there. Putting Li-ion batteries in your PowerEx charge - no good. Another place they won't work - I think it's the MRC throttles have a rechargeable battery built in. It's almost certainly a NiCad or Ni-mh battery. You absolutely can not swap in a Li-ion battery there, the charging circuitry is not made for Li-ion and Bad Things will happen.
However, until some alternative is found, these 9V Li-ion batteries seem pretty useless in Digitrax throttles anyway. With 3x the capacity of Powerex but no more life - there's no point. If they really did last almost 3x as long on a charge as you might expect - it would be worthwhile switching.