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I recently asked Can I trickle-charge (constant current) NiMH cells in parallel?. Looking at the answers and on further reflection, some points now stand out to me.

First, This question has a major fundamental flaw in that it shorts the two batteries together (doh!), as pointed out by one answer. I've for the moment accepted that answer because that's obviously a problem that needs to be addressed before my real question (what are the implications of using a shared constant-current power source for two NiMH batteries in parallel?) can be addressed.

It seems to me that fixing this is fairly simple: just put a diode in front of each battery. This could of course raise its own issues, which I'd love to hear about. I've asked in a comment on the currently accepted answer, but received no reply.

At any rate, this question needs either an edit changing that key point (and invalidating that answer) or needs to be asked again without that fundamental error. (I don't find the question "can I short two batteries together" interesting, and so feel no urge to leave it on the site.)

Second, the answer has been downvoted at least twice and has more downvotes than upvotes. I'm at a bit of a loss to understand what's wrong with it (none of the downvoters explained how the question should be improved), though I have a couple of ideas. One is the fix above; perhaps people were downvoting because shorting batteries together is stupid. (I don't see that as a good reason to downvote, rather than just explain that it's a bad idea, but each to his own.) Another is that I did not explain in the question (though I did in a couple of comments) that I have indeed read up on NiMH battery charging in a textbook, and perhaps people are downvoting because they believe I've done no research on this. (One comment suggested reading a data sheet; the explanations their of NiMH behaviour seem to me clearly far inferior to the textbook chapter I was reading.) Summarising what I've read would also be a change I'd make to the question.

Possibly related to above, the other answer on the question ignores any issues of charging in parallel and seems to be trying to address whether I can trickle-charge NiMH at all (he seems to say no, which directly contradicts my textbook) and a claimed requirement for external voltage limitation that I don't understand (and is not mentioned in the textbook, which textbook seems to imply there's no need for such a thing). I've asked about this in comments on that answer (perhaps I'm missing something big here), but received no reply.

At any rate, to get towards what I'm aiming for (assuming it's not completely stupid for reasons I as yet have no clue about), I need to do a rewrite of this question that appears to totally invalidate one answer and maybe invalidates another answer (if it was ever valid in the first place) and a comment on the question. This seems like it would introduce a fair amount of confusion, and so I am thinking it may be better just to create a new question with the errors fixed and details about the textbook source added.

If I did do this, I'd want to delete the old one since, as-asked ("can I short batteries together" due to an error in the schematic, though that's neither the title nor the intent), it's not a question of interest to me. Worse, without editing, it looks like and might be confused with the new question. (Not to mention that the majority of voters seem to think it's not a good question to have on the site.)

So what's the best way to put the idea of shorting batteries together behind us and ask the question I want to ask?

Edit:

The downvote issue seems to be resolved: either someone removed a downvote or the question got several more upvotes. I'm going to assume that any that remain are just the usual random rather than indications of serious problems with the question.

It appears that there's disagreement on whether connecting the batteries together without backfeed protection really is a problem or not. Given this, it seems better to keep the discussion about it all in one place instead of distributing it over separate questions.

So I'm going to rewrite the question to use a new schematic with the backfeed protection diodes and include "are these necessary?" as part of the question, which will leave the current answer relevant (albeit answering only part of the question).

Thanks for the help with and discussion about this.

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If there are already answers that address the flaw or the original question, accept them and make a new question.

Otherwise, the question may have been closed or remained unanswered..In that case, edit it, which will move it to the top of recently active questions..So it will anyway appear sort of like a new question.

Another alternative, which is only acceptable if there haven't been major contributions from other users (e.g. answers, edits) is deleting a question and asking a new one.

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  • \$\begingroup\$ Ok, so I am getting the strong sense I should not delete the original question, nor change it since it has an answer that addresses the major flaw in the design. So unless you have advice otherwise, I'm going to change the title to ask the stupid question obvious from the schematic ("Should I short two batteries together?") and tweak the text slightly to explain what's up with that, and write a new question with a similar, but corrected schematic about charging two batteries in parallel that fixes the shorting issue. Am I understanding you that that is the correct way to go? \$\endgroup\$
    – cjs
    Jan 12, 2023 at 15:37
  • \$\begingroup\$ Dont edit the question IMO.. \$\endgroup\$
    – tobalt
    Jan 12, 2023 at 15:47
  • \$\begingroup\$ So, to be clear, if someone else is looking to trickle-charge NiMH cells in parallel, is that a question and set of answers that's going to be useful to them, perhaps even coming up before my question that doesn't have that "short the batteries together" flaw? \$\endgroup\$
    – cjs
    Jan 12, 2023 at 16:21
  • \$\begingroup\$ Put yourself in the position of the other contributers to your question. If you edit it now suggesting it is a dumb Q in the first place, it ridicules everyone who tried to give a sensible answer. We have all been in your position and made stupid mistakes and put them on display.. Swallow it and be proud that you have saved many people with the same idea time in their life (if they find it)..And yes, others will totally also have the same stupid ideas. Noone is unique in that regard \$\endgroup\$
    – tobalt
    Jan 12, 2023 at 17:21
  • \$\begingroup\$ I am happy to admit that I made a mistake that caused the question entirely to miss what I was trying to get at; I am not clear on why I shouldn't edit the question to say so right at the start, rather than leave it (especially) with a title that's rather misleading about what it turns out I was really asking with that schematic, and will be exactly the same as the title of a different question. \$\endgroup\$
    – cjs
    Jan 12, 2023 at 17:40
  • \$\begingroup\$ (Perhaps another way of putting this is, I want to ask "can I charge these with constant current in parallel?" and yet the question body shows me not charging with constant current in parallel, but discharging one cell while charging the other, with hugely variable current. Is it sensible to leave a title on the question that is so different from what's going on in the body?) \$\endgroup\$
    – cjs
    Jan 12, 2023 at 17:43
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    \$\begingroup\$ BTW, I also worry that when I post another, different question that has the exact same title, people will vote to close as duplicate when they see that there's an older question with the same title. Are they really going to look closely at both and see that they're actually two different questions? \$\endgroup\$
    – cjs
    Jan 12, 2023 at 17:56
  • \$\begingroup\$ Yeah the latter is a valid concern Im afraid..You could make it clear in the first sentence that the former had a fundamental flaw. But wait what others have to suggest on this matter. \$\endgroup\$
    – tobalt
    Jan 12, 2023 at 17:59
  • \$\begingroup\$ Personally, I find questions with fundamental flaws to be highly informative. As long as the flaw is explained clearly; usually (hopefully) in the accepted answer. I agree with tobalt here: create a new question that builds on the previous one by linking it. \$\endgroup\$
    – JYelton
    Jan 12, 2023 at 18:10
  • \$\begingroup\$ @JYelton Oh, I am very much swayed by the argument that the question and the one good answer are reasonable to leave up; I'm just not so swayed about leaving in what I think is a misleading title, when another question with the same title (and a body that matches the title) is going to go up soon. \$\endgroup\$
    – cjs
    Jan 12, 2023 at 18:49
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    \$\begingroup\$ @cjs I hear you. Perhaps title the new question "Can I trickle-charge (constant current) NiMH cells in parallel, with this fix?" Literally just adding a hint to anyone viewing it that it's been tweaked. Just a few words added to the title would suggest to me that it's not a copy-paste or something. \$\endgroup\$
    – JYelton
    Jan 12, 2023 at 19:04

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