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7Ah SLA Battery for 100W HID

Helios

Helios

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Hey this isn't lasers but its batteries and still really cool!

I am building two 100w HID spotlights using the THOR Colossus as a base.
411Pe3Tt%2BqL._SY300_.jpg


I am building these for some friends. They are not up to date on li ion charging procedures so the last thing I want is to make them a battery pack.

My question is will the stock 7Ah SLA battery be up to the task? The stock bulb is 130W so it would seem it should be no problem...however I know that the HIDs generally require a spike of current to start. Once started I have read that in reality it will draw less than 7 amps as they are exaggerated and more 80-85W kits.

I think I'm good but want to make sure before I drop $220 on the parts.

Thanks!
 





djQUAN

djQUAN

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I don't have 100W kits but on 35W ballasts, Peak current draw at warm up is about 6.5A and drops down to about 3.5A at full brightness and at operating temp.
 
Helios

Helios

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Yeah I'm guessing a 10-12amp start up... I think I read it somewhere but can't find it
 
T

Things

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They will be fine with the startup. If they draw 7A while running, it means you should *in theory* get an hour out of 7Ah SLA. However SLA's capacity drops pretty rapidly so I'd expect maybe 45 mins or so at best from a fresh battery.
 
Helios

Helios

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Thanks! I thought so I just wanted to air my thoughts here before I have two torn up spotlights and two hacked up HID kits that won't turn on.
 
BShanahan14rulz

BShanahan14rulz

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You can always buy new cells when the old ones die, they aren't terribly expensive.

Halogen has a high startup current too.
 
Helios

Helios

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The lights are here!

But I thought up a new potential problem...this battery will be 12ish volts after a fresh charge. After its on for awhile the battery will drop voltage. In a halogen it would just lead to a dimmer light but a ballast driven HID will abruptly shut off if the input voltage gets too low. So couldn't this make my run times like less than 10 minutes?! I could get a boosting voltage regulator but I didnt budget for that. :cryyy:
 
Cyparagon

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They'll usually work down to 8V or so. Your SLA is long dead anyway by the time it gets that low.

You'll still only get 10-20 minutes, but that's because your battery capacity is so low. The 7AH rating is typically at a 1A draw, and you're pulling a bit more than 1A.
 
Helios

Helios

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Gotchya. Well I will try it and if it sucks I do have 20 LiFePO4 18650 cells laying around I could play with. Need to charge the pack somehow though without breaking the bank.

Thanks
 
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djQUAN

djQUAN

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HID ballasts are a constant power load so they will draw more current when the battery voltage drops which will be very hard for SLA batteries.
 
Helios

Helios

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I just tested it and it does indeed fire up! I only ran it for maybe 45 seconds so I don't know run times but I'm pleased it starts up just fine.

Thanks all
 
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