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I have an electric train powered by 2 D cells. But they are quite cumbersome and I have only AA charger and a bunch of good quality AA rechargeable batteries. So I want to tweak my electric train and make it run on some amount (to be calculated) of AA cells. Is it possible?

(will current given by AA cells be enough, maybe there are some other factors why producers put D cells and not AA cells)

Marian Paździoch
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    Look at the datasheets of the cells (provided current) and at the power/current demand of the train, then compare. – PlasmaHH Jul 12 '16 at 08:55
  • Most likely you can, there are converters to use an AA cell in place of a D. **Don't** connect AAs in parallel as differences in charge level can cause large currents to flow. So you can only use 2 AA cells at a time. Rechargeable AA cells can deliver a reasonable amount of current, probably even more than a cheap zink-carbon D-cell can. – Bimpelrekkie Jul 12 '16 at 08:59
  • ["Why D cells are used"](http://electronics.stackexchange.com/a/116047/11606) – Ignacio Vazquez-Abrams Jul 12 '16 at 09:01

1 Answers1

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Are the cells IN the train. If there are two in series then 2 x AA will probably work and you are very unlikely to do damage by trying them.

You can buy sleeves that an AA battery is inserted to making it the same physical size as a D cell as seen here.
Operating lifetime and peak current will be less and they MAY not have enough current capability to start the motor in some cases.

Use either Alkaline non-rechargeable or high capacity NimH.

@FakeMoustache suggests that you should not put multiple AA cells in parallel. Doing so is usually considered unwise but MAY be viable with reservations. If you do so they MUST be all at the same state of charge. ie putting 2 or 3 fully charged batteries in parallel will probably not cause major problems. Doing so will possibly shorten the cycle life of the batteries.

If connecting batteries in parallel, it would be wise to insert 2 or 3 batteries in to a holder in parallel, leave them for a few minutes and then check whether there is any noticeable heating. Also check voltage of the 3 with a meter. If this works OK the first few times it will PROBABLY continue to do so.

While the chance of fire is small if all batteries are equally charged, if safety or the life of the locomotive is of concern then you may be wiser not to use this method. (I would, with due care). YMMV.

Russell McMahon
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