DGT PI

Perhaps a dumb question but the DGT PI according to the producer DGT in Holland should not be used with " rechargeable batteries ". Printed in the User Manual page

In this times such a company does not care a bit about being ¿ a bit ecofriendly ?
I can only imagine that the slightly lower running voltage of rechargeable batteries is not liked by the Raspberry PI inside ¿?

And BTW the Raspberry PI is a powerful computer. Why did they not add a simple battery NiMH charger for two rechargeable batteries ?
Maybe this post is ridiculous but I think we are aware of what we are doing to the Planet Earth ...


Maybe here is the answer ...

https://cleantechnica.com/2017/07/12/netherlands-one-least-sustainable-eu-countries-dutch-get-green-image/

https://auclimate.wordpress.com/2020/04/15/the-netherlands-sustainable-image-how-much-is-true/

It is an interesting question. The key difference between normal alkaline batteries and Nicad batters besides voltage is that Alkaline batteries create their power through a chemical conversion so the throughput is essentially throttled. However, a Nicad works similar to a capacitor in that it uses a chemical process to store power and can release that power quickly with very high throughput.

In devices that could potentially pull a high drain and whose circuits are so designed to rely on Alkalines to restrict the draw may be damaged by rechargeables or cause those rechargeable batteries to overheat and catch fire.

However, some my low drain chess computers say to not use rechargeables and I suspect the manufacturer could not be bothered putting in the extra bit of circuitry to convert the current into the correct voltage while also guarding against a too higher power draw.

As a point of interest, back in my CB says I had a handheld unit that came with a rechargeable battery cradle for the standard battery port. When using rechargeables, it required fewer cells and attained a longer range - demonstrating the ability of rechargeables to throughput more power on demand.

I think it comes down to the manufacture covering their backsides should there be a manufacturing fault with the product that causes a partial or complete short circuit. With Alkaline batteries, they will warm up, might pop their seal and leak but a rechargeable could catch fire or get hot enough to melt plastics.

@Rubicon0367

Thanks and interesting. I made a search and now comes another " unknown " which would be ...

What if I buy Non rechargeable AA Lithium batteries ?  which do exist ... and seem to last loinger then AA NiMH batteries ...

 

I do not know enough about modern rechargeables or Lithiums to comment. It would be worth your while looking up spec sheets for modern rechargeables as they may have built in current output limiting in their USB charging circuits.

All depends if Lithiums are capable of outputting high current and therefore high heat or are throttled like Alkaline batteries.

It’s over to an up-to-date electrical engineer who we hope is active on these forums to enlighten us - or else seek out your answer on a electronics hobby forum somewhere.

 

Thanks and yes you are right. This was just out of curiosity and now it turned to be an interesting topic bit OT here in the chess.com playground 

Hopefully we have a chess player who knows the miraculous ways of how the batteries have influence in killing electronic boards  

Will do some searches in the internet as I am doing already ...

I personally doubt that using rechargeables in my chess computers or your DGT Pi would have any adverse effect on the circuit if it behaves normally on normal batteries and there is no evidence of a fault causing high drain.

You would need to be aware that rechargeables drop off rapidly at
the end of their cycle (possibly mid way through a lengthy game). Also if there was a fault that caused a malfunction or hazard using rechargeables, you’d have no come back with DGT given their clause.

So it is up to you what you decide.

The reason why I do not use my rechargeable Nicad batteries I have knocking around in my home in my chess computers is because while conceptually they are a great idea for the environment, in such low load tasks such as chess computers they are, by and large, impractical. The batteries will either taper off too quickly when they need charging (which is why they are ill-advised in cycle lights and torches) or they will bleed power when not in use for a period of time so one has to wait hours to use the chess computer until the batteries have been recharged.

Newer rechargeables that claim to be more like standard Alkaline in their charge retention may well be different.

So perhaps the best bet would be Lithium though I suspect even Alkaline batteries would give long service in even the DGT pi. I can expect a year from alkaline batteries in one of my chess computers.

Thanks and that was going to be my next question. 

Perhaps some long time DGT PI users acn add something ??

Anyhow one has to maintain the rechargeable NiMH batteries at 100% and format them from time to time. As a photographer I have loads of rechargeable batteries.

BTW I asked this question to DGT support and so far after more then a week they have not responded and I just hope that is not usual business if I run into troble with my board 

 

Thanks for letting me know

I cannot see anything in this Energizer information document about reasons why rechargeables cannot be used in place of disposable batteries. I am sure if there were then a company like Energiszer would have seen litigation claims and would either had to design the issue out or make a statement about a specific risk.

It it is a useful read though in terms of comparisons between Lithium, Alkaline and NiHM batteries.

I still think "Do not use rechargeable batteries" is a get-out clause in case of a manufacturing issue or if the components in the device go bad due to age or misuse.

If the product is working properly then I personally do not think there is a risk.

https://data.energizer.com/pdfs/nickelmetalhydride_appman.pdf

From my experience, the issue with using rechargeable batteries is that the they do not work well with the methods that certain manufacturers employ to measure a battery’s charge to turn on the low battery indicator. Some devices have the low battery indicator on even for fully charged rechargeable batteries. 

Rechargeable batteries output 1.2 V instead of usual 1.5 V. Usually this is not a problem, but can become one when they are used in series. The voltage drop with three cells is thusly from 4.5 V to 3.6 V, with four from 6 V to 4.8 V etc.

(I am in no way an expert in electronics, but I imagine some gadgets don't like this.)

-Izmet Fekali

 

Interesting and thanks

 

Well have been doing my home work and the voltage can not be the reason. Look at the attached image. After 1/3 of the life of the Alkaline battery it is in the range of the NiMH battery and then it gets worse while the rechargeable battery keeps its voltage of 1.2 volts constantly and much better as well as has a longer time keeping that voltage even after Alkaline has reached 1V rechargeable battery still maintains 1.2V.

Searching about batteries I found this page
https://batteryuniversity.com/learn/

 

 

Wow, thank you for the link.  I will enjoy reading through the page.

You are right that Rechargeables have better stamina but they also give up pretty quickly which presents you with the issue of the batteries giving out mid way through a tournament timed game.

Chessroboto also makes a valid point that some devices will prematurely switch off to prevent malfunction whey they detect a voltage threshold decided by the manufacturer.  On occasion this may be because the device in question is required to do some management tasks on shutdown such as file management.  That got me thinking about your DGT pi verses my old chess computers.

My chess computers use volatile memory to save the current game and possibly tablebases.  The RAM chip is kept live via a nominal current from the inserted batteries.  Once they are removed, anything stored there disappears.

Modern tech tends to use Solid State storage and indeed the Pi stores its chess engines on an SD card.  The question here is how the current game and possibly tablebases are stored.  If they are stored on solid state memory on the Pi or to the SD card then we're in file management territory - where sudden power loss leads to corrupted files.

I have a Game Boy Advanced cartridge called Kasparov Chess.  Decent enough software.  It saves the current game on shutdown (when one one turns the console off) and is somewhat unreliable.

The problem for me is that manufacturers never explain why they state "Do not use rechargeable batteries" in their manuals and I think they should have to.  This would mean that where there is no justifiable reason, they would not be able to state as such.

 

I have seen there is a battery status indicator on the DGT PI and so one can judge ti exchange or not to exchange the batteries.

Most rechargeable AA batteries come in sets of 4 and DGT PI uses two of them.

 

My observation coincides with what ifekali explained. The device will see that the charge is low when using rechargeable batteries because of the lower voltage output. How this will affect a device will depend entirely on how the device is designed to handle low battery charges/outputs.

The image is also a link to the Battery Stuff  website.  The bottom paragraph on the image shows that the whole 1.2v being an issue is unfounded and that co-insides with my experience of using 8 rechargeable AAs in a digital RC transmitter for cars and helicopters and not experiencing an issue while gaining extra range.

At the end of the day, there may be no specific reason why the manual for the DGT pi advises against rechargeable batteries other than some legal eagle said so.

Edit:  I have to include the link separately because the image as link thing did not work properly:  https://www.batterystuff.com/kb/articles/battery-articles/proper-care-and-feeding-of-a-nimh-battery.html

I have a little experience with raspberry pi and electronics, I’m a retired electrical engineer, though my expertise is bulk power transmission. Depending on the type of battery cell, the capacity to rapidly discharge will present a hazard. This is especially true with lithium polymer based cells, as current can easily rise to levels which will cause severe overheating, sometimes with explosive results. For this reason, circuitry to detect and limit excessive current is an important part of any responsible design. The raspberry pi board, readily available these days for your own projects in several variants, does not itself include regulation circuitry. Power supply add-on boards are typically used to provide this function. The designers of the DGT pi device chose not to include this component, for whatever reason. They should rethink that.