Replacing a Freeplay Plus battery pack

[AyeMayanor]

I have a Freeplay Plus radio that hasn't held a charge for a few years. I've been using it on AC power but it would be nice to get the portability back.

Took it apart tonight: The radio uses a 3.6v 650mAh AA size battery pack.

Question: Do I have to replace with a battery pack of the same capacity? I already know the answer is "No" when other devices are concerned but I thought I should ask since the Freeplay charges by solar panel, windup generator and AC.

Radio Shack has the 650mAh replacement, but with Battery Station's custom pack service I can get a 2400mAh pack.

Thanks in advance.

 

[Turbo DV8]

...but with Battery Station's custom pack service I can get a 2400mAh pack.

Man, that's a lot of cranking!:sweat:You'd have to crank all day and night just to charge the 650 mAh pack! I would say as long as you are replacing the pack with the same type of rechargeable cell (NiCd with NiCd) then you will be OK regardless of capacity. But now that I have said that and have done a double-take on those capacities, I'm going to recant. The 650 mAh pack is likely NiCd, but to get 2400 mAh you are looking at NiMH most likely. The NiCd's are going to hold a charge a lot longer than the NiMH, which tend to have very high rates of self-discharge in storage compared to NiCd. NiMH also is even less forgiving of neglect (non-use) than the NiCd's which have failed you. I would stick with the 650 mAh NiCd pack.

 

[AyeMayanor]

Thanks. I guess it would be best to replace it with the same pack since I really can't complain about it's performance. If it ain't broke, eh?

I forgot to mention that I've had this radio for almost 10 years and it has seen a lot of use. The NiCds didn't fail, they just reached the end of their life cycle. It was 7 or 8 years before they stopped holding a charge. Not bad at all.

The Freeplay Plus Radio
http://www.ccrane.com/radios/wind-up-emergency-radios/freeplay-plus-radio.aspx

 

[Lynx_Arc]

hmm interesting dilemna... If the radio works all the way down to low amounts of voltage (partial charge) and you didn't want to have to recrank it as often and didn't use it all the time I would be tempted to consider some LSD nimh cells. when they were charged they would hold the charge for a long time and you could charge them up farther (more capacity). You could even get by with 2AAAs and have more capacity than the nicads if you needed higher voltage to operate with less cranking than, say having 2100mah nimh AAs.

 

[AyeMayanor]

I considered LSD cells but the NiCds held a good charge. I'd listen to the radio 8-10 hours a day and read with the built-in LED light for another few hours at night, all on a single weekly charge.

BTW, I use the AC adapter for full charging. Cranking to a full charge would be impractical: If the batteries were "dead", one minute of cranking would generate 30 minutes worth of radio power. Solar charging is slow but at least there's zero labor involved It's great for taking on picnics and by the pool.

On second thought, maybe I should use the LSD cells, just to bring it up to date.

 

[BVH]

I'd definitely use the LSD Nimh cells. The LSD's will hold their charge every bit as long and probably longer than Nicads and you'll get about 3 times the capacity. It's a no-lose mod. As long as you've opened up the radio to replace them, why would you not go LSD?

 

[OrBy]

I may have a different view on what action you should take here.
Last time I checked the charging requirements for NiCd and NiMH differ.
If the radio's charging circuit is made for NiCd cells (witch at 650mAh in the AA form factor they most likely are) and you put NiMH (LSD or other wise) in there - your gonna fry the cells. It may take a while but you are not going to get your 7-8 years out of them.

I would suggest sourcing the highest capacity NiCd cells from a good OEM (Sanyo?) and seal it back up - you should get your self another 10 years or better of service. As an added suggestion: test how much current the radio charges the cells at then do the math and figure out how long it takes to charge the cells at that current. Then when you do charge it - try to not leave it plugged in much longer then that so that you are not overcharging the cells. I have a feeling that the charger is simply a low current trickle charger that just never turns off. This would make it really bad for NiMH but since NiCd are more robust they tend to do fine al long as they are cycled every once and a while like it sounds like you are doing with your usage pattern already.


Another thing to think about - depending on the space inside - is there room to fit a larger sized cells inside like a C or a D NiCd? That could get you weeks of play out of one charge without having to worry about voltage or charging issues!

 

[Turbo DV8]

Last time I checked the charging requirements for NiCd and NiMH differ - your gonna fry the cells. It may take a while but you are not going to get your 7-8 years out of them.

+1

I did not know you could charge the cells directly from the wall wart. But even then, I would not use NiMH. They are very sensitive to overcharging, and your simple wall wart adapter has no method of terminating the charge. NiCd is very forgiving of overcharging if it is a low current, as the wall wart probably is. I would not even think of putting NiMH in there and charging it with the wall wart. You will be underwhelmed by the service life.

 

[Lynx_Arc]

if it were easy to replace the batteries I would use the radio till it got low... estimate the charge rate of the charger and time how long to charge it. If you run it off AC (always trickle charging) you might as well forget nimh batteries. The ultimate thing to do if you can get to the batteries is to be able to take them out and charge them and put them back in and just wire a switch to disconnect the AC charging system so you can not drain or charge when plugged in.

 

[Turbo DV8]

The ultimate thing to do if you can get to the batteries is to be able to take them out and charge them and put them back in and just wire a switch to disconnect the AC charging system so you can not drain or charge when plugged in.

I was thinking the same thing today. If you don't mind mounting an external cell holder, you could use LSD NiMH cells and run the thing continuously for a couple weeks, then simply pull them out for a recharge on a proper battery charger. I have a large Sony radio that I run eight hours a day on LSD Hybrids, and the charge lasts for two or three weeks until the first cell takes a dump.

Regarding the idea to estimate how long it takes the wall wart to charge a NiMH battery pack... this is feasible, until the first cell fails and makes the pack unbalanced. The pack will stop powering the radio earlier and earlier because the first cell failed, but you will be charging it the same amount, so all the other cells that were not fully depleted will receive an overcharge, leading to a speedy demise of the other cells. On the other hand, if you were to start with some well-balanced LSD cells, such as Eneloop, by the time one cell croaks, it's pretty near time to replace the others anyway, so it's not a big loss to overcharge and kill the remaining cells anyway.

 

[Lynx_Arc]

I have a stereo by my bed I listen to at night that stays running all the time on AC at low enough volume I only hear it in bed. when power goes out I hook a 6v SLA to it and run the radio for days through the DC input jack. If your radio has a DC in seperate of AC corded power you could think about rewiring it to a smart external charger... not sure that would work but I have wired 4/5A sized NIMH to wired on a nimh charger and charged them and detected delta V changes.

 

[AyeMayanor]

Thanks for the variety of suggestions. I've decided to go with a direct replacement after having considered the risks involved with using the wrong cells.

 

[AyeMayanor]

Just wanted to give a little update:

I emailed the C. Crane company (that's where I got the radio) and asked about the charging circuit. The reply was, yes, the charging circuit is limited to 650mAh and a pack with higher capacity would not charge properly. I was told that they do sell the replacement packs, though they aren't listed on the website, so I ordered one the next day.

 

[BVH]

Is yours the Freeplay plus that has the small solar panel, hand crank and a multitude of chrome buttons on the front? If so, how did you get your radio open. I see no visible attachments on mine?

 

[BVH]

just determined i have the freeplay Summit. Disregard above post.

 

[Handlobraesing]

What about single cell Li-Ion? The charge efficiency is almost 100%, so you will catch more of what you generate

 

[AyeMayanor]

What about single cell Li-Ion? The charge efficiency is almost 100%, so you will catch more of what you generate

I considered that, as well as all the other suggestions, but in the end decided to go with the original NiCad configuration because there's no question that it works.

BVH: Like your Summit, the Freeplay Plus has a solar panel and crank, it's just a lot bigger. It's held together by a few screws and came apart without a fuss.