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I'm after some for the Bike Lights and just wondered if there are any recommendations at the moment ?
Ideally from somewhere I can use Pay Pal as I'm skint but have money in my Pay Pal
Cheers
Maplin often have a good discount and have good capacity.
Bear in mind that they will only be 1.2v and therefore will not give the same power output/burntime.
Aldii's batteries are worth avoiding. Very poor output!
Maplin are ok
Vapextech are good, pretty cheap and quick delivery, you can use Paypal. http://vapextech.co.uk/
Ready To Go from 7 Day Shop
I've always used good to go from 7 day shop as well. Not the highest capacity but they hold charge when not in use which is good for bike lights.
Ever ready Energisers from just about anywhere.
Just measured a 4 year old one that was sitting in my drawer, last charged a few weeks ago; still holding 1.35 volts.
Sanyo Eneloop XXX, the highest rated, best storage leakage and great capacity. Expensive but better than the other 20 or so batteries I've used and measured over the past few years.
That said any 18650 light will slay them.
7 Day Shop own brand AA 2900ma are the best I've found. I also use their AAA 1100ma in our hire dive torches. They match the burn time of alkaline batteries although, as pointed out, they are actually a lower voltage.
Bear in mind that they will only be 1.2v and therefore will not give the same power output/burntime.
Burn time is dependant on capacity, not voltage.
As someone said above, for bike lights get some of the ones that stay charged.
Sanyo Eneloop XXX, the highest rated, best storage leakage and great capacity. Expensive but better
THIS
Burn time is dependant on capacity, not voltage.
Power is watts
Watts are volts x amps
Reduce one and you reduce the total watts.
1.2 x 2 = 2.4
1.5 x 2 = 3
Lower volts do give lower burn times/less power than the same in 1.5
Power is watts
Watts are volts x amps
Reduce one and you reduce the total watts.
1.2 x 2 = 2.4
1.5 x 2 = 3
Lower volts do give lower burn times/less power than the same in 1.5
No. That equation says nothing about burn time, which as I said is related to capacity. I'm not disputing a 1.2v NiMH won't be as bright as a 1.5v Alkaline/ZnCl battery. But saying it won't last as long because it has a lower nominal voltage is wrong.
EDIT: It's like saying a more fuel efficient car has a longer range than a less efficient car without even considering the size of the fuel tank.
ross980 - Member
I'm not disputing a 1.2v NiMH won't be as bright as a 1.5v Alkaline/ZnCl battery.
Assuming it's LED, does a lower voltage necessarily give lower power, given there's some electronics in there controlling it all?
That equation says nothing about burn time,
It does. You seem to think the light will just be a bit dimmer but it wont [ it might actually dependent on the driver but lets not complicate things here].
The amount of power the light uses is watts it is set by the light not the batteries or their power but the light. If it uses X amount on full.
So lets assume a light uses 200 watts to work.
a 1.2 v with 2000 amp hour only has 2400 watts stored in it
a 1.5 v with 2000 amp has 3000 watts
Which do you think runs the 200 watt the longest?
you need to factor in both volts and amps to know
It's like saying a more fuel efficient car has a longer range than a less efficient car without even considering the size of the fuel tank.
The car [ the light] is the same we are not comparing different cars or lights.
The fuel tanks [ the batteries] have different amounts of energy stored in them when they are the same size
Think same size fuel tank one with high octane fuel and one with low octane fuel.
obviously if you reduce the size of the tank or the battery capacity it will run for less. i have not claimed otherwise.
Someone recommend a charger?
Is that lidl one any good?
@JY No. You obviously don't understand the difference between Watts (Power, i.e. rate of change of energy) and Joules (Energy).
Anyway, I can't be arsed to get into an argument about it.
Cheers.
Someone recommend a charger?
http://www.batterylogic.co.uk/technoline/technoline-BL700.asp
Possibly cheaper elsewhere.
Junkyard - lazarus
So lets assume a light uses 200 watts to work
The power it consumes will depend on the voltage driving it - but not in the way you suggest above, you need to remember V = IR also.
Your example not hard to complete but ICBA
Eneloops. It's not just about capacity. The eneloops have a flatter discharge curve so hold the voltage longer. They can also be recharged a lot more time than any other's that I've found
Eneloops are the best recarbs out there. Couple that with the Technoline charger above and that's hard to beat.
Another vote for Eneloops here.
Another vote for Eneloops and a BL700 charger
You obviously don't understand the difference between Watts (Power, i.e. rate of change of energy) and Joules (Energy).
I dont so feel free to educate me as its not an argument its a debate/education
Given your car/fuel tank example I dont think you understand either.
the lower voltage battery has less power, if they have the same capacity.
Just comparing the nominal voltages and amp hours is a bit simple. You have to look at the full discharge curve.
Alkaline AAs start off at 1.5V, but soon drop below this. Probably down to about 0.8V before they are discharged.
Whereas NiMH batteries start at about 1.3V, and stay fairly constant, dropping to about 1.1V when empty.
This also depends on the current you are using. Most rated capacities are based on a low current, ie 100mA. Alkaline batteries don't work very well with high currents, so the voltage will drop even quicker, and you will get less energy from it.
So you usually get more energy (ie more Watt hours), and longer run times, from the NiMH batteries (assuming decent quality batteries, charged properly).
OK but needs more maths 😉
happy to retract them/ accept I have been educated/learnt something
Ta