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Replacement Battery - Non Van Related


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Well its sort of non van related. :D

 

I recently got a couple of portable dvd players cheap for when travelling.

 

They run from mains or car so its not so much of a problem but the batteries seem to be dead.

 

I dont have a manual but assume steady red means charging and flashing red means fully charged but they only appear to charge for a few minutes then say full but nothing is there.

 

I opened the battery pack up and it appears to be a bank of 12aa batteries @ 7. 2 v 4ah.

 

So, my question is, should i simply replace with more aa rechargable and wrap in some way or, with the advancements in battery technology, would i be able to put something like a lipo battery in? Or would it then need a dedicated charger?

 

Just beginning our adventure. 95% of my time on CT I use my phone. As a result correct spelling and grammer will be used sparingly. This is due to fat fingers. Please don't let it bother you.

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I had a battery pack similar to that fail in a radio a couple of years back and replaced it complete ( correct no of bateries encased) from a firm of the net but can't for the life of me remember where. Maplin sell various individual aa tagged ( so you can solder together to make a pack) If you have a local model shop that does radio controlled models it might be worth a visit as they will have various sorts of rechargeable battery packs and they should be able to help with charging info as well.

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I had a battery pack similar to that fail in a radio a couple of years back and replaced it complete ( correct no of bateries encased) from a firm of the net but can't for the life of me remember where. Maplin sell various individual aa tagged ( so you can solder together to make a pack) If you have a local model shop that does radio controlled models it might be worth a visit as they will have various sorts of rechargeable battery packs and they should be able to help with charging info as well.

Ill have a look see what i can find out. Not many hobby shops around me so don't think that will be happening any time soon but a great suggestion none the less.

Just beginning our adventure. 95% of my time on CT I use my phone. As a result correct spelling and grammer will be used sparingly. This is due to fat fingers. Please don't let it bother you.

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7. 2 volt 4 Ah and 12 cells means two banks in series so cells rated at 2000mAh and with NiMh the charger may be trickle, temperature sensing or Delta V and since there are two lumps stuck to cells I would guess on temperature sensing.

 

Idea is when battery is flat electrical energy is converted to chemical energy so battery remains cool but once fully charged electrical energy is turned into heat instead so when battery gets hot charger turns off.

 

As long as replaced with two 7. 2 volt 2000mAh batteries and the heat sensors are stuck on the battery is should not really matter what shape they are. My camera uses 7. 4v 1620mAh battery although slightly smaller I am sure these would do.

 

The NiMh battery comes in two types. Those designed to hold a lot of power and those designed to maintain the power. So a 1200mAh AA battery likely designed to have long shelve life often come ready for use i. e. charged but a 2500mAh battery will normally come flat and although hold more energy have a high self discharge.

 

I would not worry about if label says 7. 2 volt or 7. 4 volt still means 6 cells per battery.

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You're assuming the batteries are unserviceable but could it be the charging circuit at fault? Maybe you could strip the pack down and attempt to charge using a standard AA charger, if they charge fine you know the charging circuit is at fault.

 

I don't know much about LiPos to comment authoritatively but I know they need dedicated charging algorithms and one designed for NiMH batteries is unlikely to be suitable.

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