I have a Tivoli Audio Model One tabletop radio that has 2 power options (220V and 12V DC 800 mA), but no battery.
The 12V adapters you can buy from Tivoli seem to be rated at 20W and 1000 mA
I'd like to order a battery pack made of 18650 cells to take this excellent radio to my garden, but I'm wondering if these packs can deliver enough watts and how many mAh I should go for for a couple of hours of listening, let's say 5 hours.
I'm no expert at any of this stuff.
Any hint?
Thanks

 

I would use a 12V sla battery, you can get them in 3Ah, 7Ah, and they are easier to charge.

 

I would use a 12V sla battery, you can get them in 3Ah, 7Ah, and they are easier to charge.

And also weigh 5 times as much.

Divide the battery’s capacity by the current draw (800mA) to get the hours on a charge.

Eg. An 1600 mAh battery will get you about two hours of play on a charge.

For comparison, 8 AA alkalines will get you about 2.5 hours.

 

Use a 12v/5000mAH powerbank (with 5.5mm or car ciggie outlet) and a suitable lead; a no messing, off-the-shelf solution that'll give over 5h of runtime.

eg this one from Amazon


+ this cable

 

3S 18650 lithium-ion pack should work (12.6V nominal); easiest way to charge is to buy a 12.6 V lithium charger wall wart. How much capacity really depends on how loud you play it and how thirsty the radio is. Conventional transistor radios could run a very long time on a set of cells, but they had efficient speakers and very low power amplifiers (100 mW).

 

Probably the 3 amp-hour SLA battery will cost less than the fancy battery pack and be good for many more cycles. And the 7AH battery will play for over nine hours, And the SLA battery is less likely to start a fire from any charging malfunction. And it can be partially recharged across te car's 12 volt electrical system.