Are larger amps in DC to DC converters worth it?

[ebike11]

Hi
I currently have 2 voltage converters in the 72v - 36V range.
Caps aren100V but amps are 10A

Seen some bigger ones that are 25A and in the 96V - 36V range but the caps arent any higher...they are still rated 100V

What would the advantage of having an extra 15A?
Im mainly using converters for lights and horn.

 

[amberwolf]

Is what you are using requiring higher currents than you have available?

If yes, then you need a bigger converter.

If no, then you don't, unless you're going to add mroe stuff that needs more current.


Caps only need to be rated as high as the possible input voltage. If you use a higher voltage than that, you risk blowing them up.

 

[Chalo]

It's my impression that voltage converters are most efficient when run at most, but not the maximum, of their capacity. So the question for you is, how much current do you need (taking into account that LED lights usually have a bad power factor)?

Whatever that number is, times about 1.5, should be the approximate rating of your converter. Use a higher capacity converter than that if you expect to add 12V accessories later.

 

[ebike11]

It's my impression that voltage converters are most efficient when run at most, but not the maximum, of their capacity. So the question for you is, how much current do you need (taking into account that LED lights usually have a bad power factor)?

Whatever that number is, times about 1.5, should be the approximate rating of your converter. Use a higher capacity converter than that if you expect to add 12V accessories later.

Hi
I have 3 lights
1 has 7 CREE XM-L T6 LED bulbs
2 have 4 CREE XM-L T6 LED bulbs

They sell an optional 8.4V battery pack to use with each light so Id have to triple that since I have 3.
But I dont know how many Amps it would be

 

[Chalo]

Hi
I have 3 lights
1 has 7 CREE XM-L T6 LED bulbs
2 have 4 CREE XM-L T6 LED bulbs

They sell an optional 8.4V battery pack to use with each light so Id have to triple that since I have 3.
But I dont know how many Amps it would be

It's the driver electronics, not the LED emitters, that dictate the current demand of your lights. Are you lights intended to run on 12V, 8.4V, or a range of voltage?

You could answer some of your own questions with a multimeter, but none of us are going to be able to guess accurately how much wattage or volt-amps you use.

If your lights don't misbehave when you use the horn, and the horn works correctly, your voltage converter is probably more than adequate. I can't imagine that the three lights you've described, plus a horn, would come close to using 12V 10A even if their power factor is bad and the LEDs are driven very hard. You could wire them all to the same converter if its rating is accurate. Your 12V devices won't behave any differently if you put them on a bigger DC-DC converter.

 

[fechter]

What would the advantage of having an extra 15A?
Im mainly using converters for lights and horn.

Less heat. If you run a typical chinese converter at the maximum rating, it will probably burn up after a few minutes. If you load is like half the rating, then the smaller one will probably be OK.

 

[ebike11]

Hi
I have 3 lights
1 has 7 CREE XM-L T6 LED bulbs
2 have 4 CREE XM-L T6 LED bulbs

They sell an optional 8.4V battery pack to use with each light so Id have to triple that since I have 3.
But I dont know how many Amps it would be

It's the driver electronics, not the LED emitters, that dictate the current demand of your lights. Are you lights intended to run on 12V, 8.4V, or a range of voltage?

You could answer some of your own questions with a multimeter, but none of us are going to be able to guess accurately how much wattage or volt-amps you use.

If your lights don't misbehave when you use the horn, and the horn works correctly, your voltage converter is probably more than adequate. I can't imagine that the three lights you've described, plus a horn, would come close to using 12V 10A even if their power factor is bad and the LEDs are driven very hard. You could wire them all to the same converter if its rating is accurate. Your 12V devices won't behave any differently if you put them on a bigger DC-DC converter.

Ok thx
I got the 25A converters to replace the 10A ones.
They advertised input voltage from 48 to 96V
My pack is 24S which is around 100V give or take a volt but usually 100.5 hot off the charger.
I was hoping the caps themselves inside the converter would be higher than 100V since they advertised that up to 96V pack can used but they are 100V, the same size that are in my 10A converter

Im worried that the caps might blow if I use my slightly over 100V pack with the converter.
Does anyone know if caps that are rated at 100V can take a bit extra before they blow? For example the stamped rating is 100v on the caps but is there anyway voltage leeway?

 

[fechter]

Im worried that the caps might blow if I use my slightly over 100V pack with the converter.
Does anyone know if caps that are rated at 100V can take a bit extra before they blow? For example the stamped rating is 100v on the caps but is there anyway voltage leeway?

Yes, there is a fair amount of overhead in the ratings. The caps may deteriorate faster at higher voltages, so may eventually fail earlier than if kept at a lower voltage. Heat is more of a factor in lifespan though. As soon as you start riding, the pack voltage will drop quickly and be in a good range so they won't spend much time above 100v.