My battery preferences in order of value for money.
Gel Cell, but only if you can't afford:
NiCd. Best value for money overall.
NiMh. Not bad but have only half the useful re-charge cycles compared to NiCd.
Li-Ion & Li-Pol. Not my cup of tea just yet. Too many issues with charging and self combusting.
Best wishes,Tony Walsham (Remote Control Systems) http://www.rcs-rc.comModern technology. Old fashioned reliability.
I run all of my locos on 14.4 volts (12 batteries). On the older installations, I've got two 6-cell packs built into the tenders of the locos. These cannot be removed. On newer installations, I've got three 4-cell clips that can be removed by taking off the coal load of the tender. On this installation, the batteries can be removed from the clip and dropped into the charger for easy recharging and replacement. (See notes above about isolating bad cells.)
I like the removable packs because I can quickly swap out old for new batteries and keep running, as opposed to having to remove the loco from the tracks to recharge the internal battery packs. As the older installations fail, I'll probably replace them with the 4-cell clips. Certainly my future projects are going to be done that way.
Later,
K
NiMh Are great as they don't really have the memory effect problem like NiCad and these days are just about as cheap....depending where you buy them. I wasn't aware of the combustion problem with LiIon. Most of my photo equipment is LiIon and haven't had any troubles at all for over 5 years.
underworld
I've put this into a couple of other forums. If you want to get the latest on battery technologies try going to this link and choose the Batteries & Chargers forum. http://www.rcgroups.com/forums/index.php
Electric RC flying is growing by leaps and bounds and there's a lot of practical experience and info in this forum.
My recommendations for battery types in model RR would be NiMh 1st then Nicad. Nicads are heavier and have less energy density. Both types are proven and are safe if used properly and not abused. They both can withstand heavy amp loading and physical abuse. Over discharging will not cause safety hazards and charging at high rates is also safe with most. Obvious cheapo batteries found at bargain basement prices probably will not provide good results.
Nicads are probably going to be harder to find in the future because of environmental issues. Modern Nimh's made for high discharge applications are affordable and readily available. I've used them for 7 years of flying in my high amp applications (35+ A). They obviously do wear out but the amp draws in model RR'ing are nowhere near what we do in flying so their life span should be very acceptable.
Lithium technology has been a real boon to RC flying because of the energy density issue. A lot of voltage in a light weight package which is very important in RC flying. In model RR'ing weight is probably not an issue but size form factor might be. The problems with Lithium Polymer (LiPo) batteries is that they are 1- fragile (thin foil packaging), 2-can only be charged at their mah rating, 3-should not be over discharged, 4- shouldn't be discharged at higher than they are rated (this is pack specific and noted on the packs), 5- more costly than Nicads and Nimh's. Now if you take into account all these issues they perform exceptionally well. They do need a specific LiPo aware charger, don't ever ever try charging them with a Nimh/Nicad charger , a fire could and probably will happen if you do.
The major problem I see in RC model RR'ing with Lipo's is that none of the speed controls (ESC's) are lithium aware. This means that they will continue to draw power from the pack when the pack reaches 3V per cell. Lipo's shouldn't be discharged to less than 3V per cell, the RR ESC's do not have the curcuitry to cut off power when the pack reaches this limit. This is where you'll find problems like packs puffing and not delivering afterwards and the possiblity of the pack actually igniting. In RC flying we use lithium aware ESC's that shut down motor power (flight control power to the servos is maintained) when the pack reaches 3V per cell thus avoiding the over discharge problem.
A new technology is being tested and used in flying now also. These are high amp output lithium ion (LiOn) cells found in Dewalt 36V power tool packs. These cells, known as A123's, are lithium ions in an aluminium can with vents in the button head. A number of pilots are using them in high amp applications with success. They do need a special charger and they are more expensive than NiMh's but they seem to be a burgeoning technology that is very viable. Over discharge is still an issue but not an "explosive" one as with LiPo's. I haven't used these yet but am planning on trying them this flying season in my higher amp applications.
Other LiOn haven't been too success because they are not made for high amp draws. Their packaging is tougher than LiPo's and they are lighter than NiMh's and Nicads for their voltage rating.
Again if you go to the link above and look through the threads or search for specifics on a battery technology you'll find tons of info. The forum is extrememly active so if you ask a question you'll probably get an answer very quickly (sometimes in minutes!). It does help if you know you voltage and amp needs that way you can see what types of batteries apply to your application.
Hope this helps,
Dave
I have no arguments with any of the above, except.
AA NiMh/NiCd batteries have an inbuilt max current capability. Anything over ½amp (500 ma) draw will be supplied by the cells but at the cost of a significant reduction in the life of the AA cells. They are designed to give a low current for a long time.
Plus, NiMh only have half of the lifespan of NiCd cells.
So, my opinion is NiCd still provides the "best value for money".
TonyWalsham wrote:AA NiMh/NiCd batteries have an inbuilt max current capability. Anything over ½amp (500 ma) draw will be supplied by the cells but at the cost of a significant reduction in the life of the AA cells. They are designed to give a low current for a long time.Plus, NiMh only have half of the lifespan of NiCd cells.So, my opinion is NiCd still provides the "best value for money".
Hi Kevin. Once again I cannot find fault with the argument.
Except: I can only really discuss the various chemistries available here in Australia.
I acknowledge the logic of having twice the capacity equalising the useable life spans.
However here in Australia we cannot get the really high capacity NiMh cells in other than SubC for a reasonable price. I have never seen such things as 4/5ths A's available over the counter. Or even high capacity D cells. They don't exist at an affordable price anyway.
3,300 NiMh sub C cells, the biggest I can get readily, cost me more than twice the price of 2,400 mah NiCd Sub C cells. So, I guess, at least for Australia anyway, we are back with NiCd being twice the value of NiMh.
Oh and by the way, the life span of both NiCd and NiMh chemistry for AA size cells will be shortened by overcharging and overdraining.
There are no big online discounters of batteries in Australia and importing them is impractical as the freight costs would be a killer.
Here are a couple of vendors selling various Nimh and Nicad cells. I've dealt with the first three and have had good service from them. The cells listed are high output cells and will hold up to our hobby needs. I really am not familiar with the inexpensive bargain cells available at discount stores, so I can't venture an opinion on them
http://www.cheapbatterypacks.com/main.asp?sid=696862&pgid=loosecells
http://www.battlepack.com/loosecells.asp
http://www.maxamps.com/index.html?lmd=38519.529109
http://www.batteriesamerica.com/newpage8.htm
Again I highly recommend going to the rcgroups link I posted and checking out the battery forum for additional info. I would suspect that there are RC car forums out on the world wild web that have info also, though from my understanding the RC car guys usually are using those larger sub C size cells that might not be applicable to model RR'ing because of their size.
BTW, Tony's RC system looks to be the one that offers the best bang for the buck and I know he's been in this arena for a long time.
TonyWalsham wrote: Hi Kevin. Once again I cannot find fault with the argument.Except: I can only really discuss the various chemistries available here in Australia.I acknowledge the logic of having twice the capacity equalising the useable life spans.However here in Australia we cannot get the really high capacity NiMh cells in other than SubC for a reasonable price. I have never seen such things as 4/5ths A's available over the counter. Or even high capacity D cells. They don't exist at an affordable price anyway.3,300 NiMh sub C cells, the biggest I can get readily, cost me more than twice the price of 2,400 mah NiCd Sub C cells. So, I guess, at least for Australia anyway, we are back with NiCd being twice the value of NiMh.Oh and by the way, the life span of both NiCd and NiMh chemistry for AA size cells will be shortened by overcharging and overdraining.There are no big online discounters of batteries in Australia and importing them is impractical as the freight costs would be a killer.
You might try eBay or online sources such as the ones dottney has listed. I find great deals on large and small batteries at Hamfests but I have also bought some in off season from people on eBay.
underworld wrote: TonyWalsham wrote: There are no big online discounters of batteries in Australia and importing them is impractical as the freight costs would be a killer.You might try eBay or online sources such as the ones dottney has listed. I find great deals on large and small batteries at Hamfests but I have also bought some in off season from people on eBay. underworld
TonyWalsham wrote: There are no big online discounters of batteries in Australia and importing them is impractical as the freight costs would be a killer.
Underworld.
With respect, you might try reading the last line of my posting again.
S&G,
I hope we didn't muddy the waters for you. Essentially if you want to do battery power I think most of us agree that using Nicad or Nimh cells is the best way to go. Unless you're an electronics tinkerer you'll be best off using something like Tony's RCS system. He offers a complete package or a speed controller that you can use with an inexpensive RC transmitter & receiver (Hitec's Ranger is only $40-see http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXARP0**&P=).
There are other RC systems out there but as I said before Tony's system seems to be the most bang for the buck- his EVO Basic is $60. So for the radio system & speed control you've got $100. Then you'll spend some money on batteries. Obviously if you want bells & whistles (literally) you spend more.
Connecting everything is really pretty simple- 2 wires from motor to speed control, plug in the speed control to the radio receiver, plug in the battery pack to the speed control.
Again hope this helps,
The Home of Articulated Ugliness
TonyWalsham wrote: There are no big online discounters of batteries in Australia and importing them is impractical as the freight costs would be a killer.Underworld.With respect, you might try reading the last line of my posting again.
I did see the last line. I thought there might be some Ebay dealers in Australia or New Zealand. Are there hamfests (amateur/short-wave radio shows or swap meets) near you? If there are it might be worth a look.
Thanks Guys, I think I'll use whatever Goodson puts in for the mauler, but I'm using AA's for my other loco (an 0-4-0 sled) The post is in scratch building under Drive Chain.
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