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Old 7th May 2011, 10:11 PM   #1
Lacey is offline Lacey  United Kingdom
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Exclamation Boombox Battery

Hi,

I'm currently using a 12v 8ah motorbike battery in my boombox but i think the batterys on it's last legs and I'm not getting the same performance out of it these days. Does anyone have any recommendations for a new battery. I'm using the AM6-Basic amp which can take up to 15volts i think so if anyone has tried higher voltage batteries please let me know with your recommendations.

Also want to try and stay clear of bike/ car batteries as they are designed to be constantly charge etc.

Cheers,

Jayson UK
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Old 7th May 2011, 11:42 PM   #2
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It really depends what your budget is and what's readily available.

Lead-acid batteries like the one you have already got are fine for portable amps, but have the disadvantage that they can spill acid. You can get them in 'leisure' (jelly) types such as the Yuasa brand, but they are expensive. Both tend to be heavy.

NiCd (nicad) batteries are 1.2V each and come in standard battery sizes, they have better shelf-life than NiMh (nickel-metal-hydride) which also come as standard cells with a bigger capacity/size than NiCds but they self-discharge pretty quick, so you need to use them frequently or top them off a lot. You could run 10~12 NiCds or NiMh.

Then there are a variety of lithium cells, they run 3~3.6V, so depending on flavour you could run 4 in series, they have the best weight/charge but are the fussiest to maintain, some older flavours spontaneously caught fire when charging but this is less common now, they tend to be expensive but are popular for electric flight.

All types require care when charging, you can destroy them by overcharging at high rates, but most will tolerate continuous trickle charging.

NiCds are being phased out (I was told) but still seem to be readily available, the 'D' cell types intended for emergency lighting are probably an economic way to buy them or NiMh would get my recommendation for convenience versus utility versus cost if you can tolerate the comparatively high self-discharge.

You need a charger of some kind, the ones designed for modelling use are probably the cheapest way to go with a fast charge option and auto shut-off, although many of these are designed to run off a car battery so you need an additional 14.4V supply (CB mains adapter).

w
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Old 8th May 2011, 10:29 PM   #3
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You can use a 12V Li-Ion screwdriver battery. They work well and usually have a nice auto charger with them. Their capacity are also very good but depends on how much you are willing to spend.

Regards,

Simon H.A.
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Old 9th May 2011, 04:06 PM   #4
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As far as leas acid goes, Yuasa NP7-12 can be had for 15 or less, they are unspillable & can even be used in any orientation except upside down - I've been using one on its side for years.

You might also consider 12v li-ion battery packs from China like this one (no affiliation)

12V/9800mAH Portable Li-ion Rechargeable Battery Pack ! | eBay UK

More expensive, I'm dubious of whether they really hold 9800mAH, but much lighter. Can't draw as much current from them as a SLA though, so for a powerful boombox it may not be enough.
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Old 9th May 2011, 04:35 PM   #5
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I don't recommend those blue plastic wrapped li-ions, the connections are flimsy and break easily. Also the 4.8ah one I had was nowhere near the stated capacity.

I've just ordered a 6.8ah li-ion 12v cctv in a black plastic case for 15 sterling. I'll report back on how it performs.

Right now I'm using Yuasa NP7-12 like lost-eden or 10xAA batteries.
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Old 10th May 2011, 01:17 AM   #6
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Quote:
Originally Posted by fraction View Post
I don't recommend those blue plastic wrapped li-ions, the connections are flimsy and break easily. Also the 4.8ah one I had was nowhere near the stated capacity.

I've just ordered a 6.8ah li-ion 12v cctv in a black plastic case for 15 sterling. I'll report back on how it performs.

Right now I'm using Yuasa NP7-12 like lost-eden or 10xAA batteries.
which ones are you referring to? I have a bunch of cheap blue Li-ion and the majority are working fine. cobaltox and ironphos' 14500's, 18650's, and 38120S's

Your ideal solution would be 4S LifePO4. get a good cheap charger like a Turnigy Accucel 6 and wire in a balance plug (JST-XH) and a voltage monitor.

3S Li-ion is 11.1V nominal. 4S LiFe is 12.8V nominal with a much longer operational lifespan, decades.

something like these... http://www.ebike-bmsbattery.com/inde...Fdid%3D1&did=1

Last edited by carlsbad64; 10th May 2011 at 01:21 AM.
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Old 10th May 2011, 09:33 AM   #7
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Not sure of the serial, it was blue, 4.8ah and had a USB charger lead as well as the 12v one.
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Old 18th September 2011, 12:02 AM   #8
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Quote:
Originally Posted by fraction View Post
I don't recommend those blue plastic wrapped li-ions, the connections are flimsy and break easily. Also the 4.8ah one I had was nowhere near the stated capacity.

I've just ordered a 6.8ah li-ion 12v cctv in a black plastic case for 15 sterling. I'll report back on how it performs.

Right now I'm using Yuasa NP7-12 like lost-eden or 10xAA batteries.
Hi im deciding on what battery to use on my project, I want something light so was wondering if you had any more info on the "6.8ah li-ion 12v cctv in a black plastic case"

I am going to use a lepai LP-2020A+ amp and would like to get over 10 overs of use - maybe i'll go for a 9800mah version // the battery packs are soo light compared to a SLA battery

whats your opinions on a solar power charger?
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Old 18th September 2011, 12:08 AM   #9
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The ebay cctv battery packs are li-po batteries, not li-ion, even though they state that.

Capacity is roughly 2/3rds of the stated, and voltage is 11.1V average, not 12V.
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Old 18th September 2011, 12:29 AM   #10
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Quote:
Originally Posted by Saturnus View Post
The ebay cctv battery packs are li-po batteries, not li-ion, even though they state that.

Capacity is roughly 2/3rds of the stated, and voltage is 11.1V average, not 12V.
so i guess you wouldnt recommend them then?

Whats your opinion on a battery - I would like something to run the lepai LP-2020A+ for like over 10 hours - Am I expecting too much from a cheap solution?
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