12V 35 Watt HID searchlight Circuit Help

[easy.rahil]

Hello all experts and designers. i m in need of a small and easy to make circuit for HID searchlight.
HID is 35Watt H3 single beam and battery is 12V 7Ah Lead Acid rechargeable.
I want this circuit as a battery charger with LED indicator for low battery/full battery & over charge protection. And to run around of 80 minute or more with this full charged battery.
If anybody can help me regarding this issue.
Thanks in advance.

 

[Boncuk]

Use an LM317T to limit the charging voltage to 13.8V. That makes an overcharge indicator unnecessary.

For an "end of charge" indication use a comparator and set the trip point to 13.8V.

Boncuk

 

[easy.rahil]

Thanks Boncuk, but where is schematic? i have nothing to charge a nd want to make a charger with above said features, any help?

 

[Boncuk]

The schematic is contained in the LM317 datasheet.

If you don't have anything to charge you might as well forget about a charger circuit.

Boncuk

 

[4pyros]

i have nothing to charge a nd

What is a "nd"?

 

[ericgibbs]

What is a "nd"?

charge and want

 

[4pyros]

Thanks Eric, I see it now. Andy

 

[easy.rahil]

when i run HID directly with battery front glass and steel reflector getting too hot even rubber parts gives bad smell of burning in just 15 minutes. why it happens? do i need to reduce the current? does HID ballast handle current? a tutorial needed

 

[4pyros]

Yes HID will get hot and yes the ballast should regulat the current.

 

[tcmtech]

My info says the H3 type bulbs are typically a filament type halogen bulb which does not need any type of ballast.

If it was an arc tube type HID (metal halide) bulb it simply would not light up when directly connected to a 12 volt battery.

The reason things get hot is simply because halogen bulbs produce a high level of heat due to the amount of power being dissipated from the small mass of the bulb.

 

[easy.rahil]

while using Halogen filament H3 bulb it dissipate normal heat but while using HID Xenon H3 it is getting hot. i tested with fully charged battery and it runs total of 55 minutes. and i think it should run atleast 90 minutes with full charged battery.
My question is that do i need any regulator circuit to regulate current at 3 Amp max to HID?

 

[carbonzit]

Doesn't the HID lamp include a high-voltage converter and ignitor? If so, it should already be regulated. I can't see how you'd need to regulate the input; it's normally connected to an automobile battery, isn't it?

It sounds like the lamps just get hot.

 

[easy.rahil]

yes it has ballast and relay attached. if it is nt using too much current thn why it doesnt last for atleast 90 minutes with 12V 7Ah battery? any clue?

 

[carbonzit]

So, let's do the arithmetic:

You say the lamp is 12V, 35 watts, so let's say it draws 3A nominal.

Battery is 7Ah, so theoretically, it should run the lamp for 7/3= 2.3 hours.

However: the lamp (the actual HID device) may be rated at 35 watts, but the converter isn't 100% efficient, so the actual current draw is probably more than 3A. Which might explain the shorter run time.

Do you have any way of measuring the converter's actual current draw? That would probably tell you something useful.

(Also, what condition is the battery in? Is it new?)

 

[easy.rahil]

battery is new almost. battery runs in a readymade hid searchlight and runs 80 minute whn fully charged. i think i should use Ampere by using Multimeter. is it good and perfect idea to measure?