200W LED Light Bar

[aham2003]

Putting a 22" 200W LED bar on one of my karts. What would be a good battery (V/MaH) that would run the light for several hours before requiring a battery charge.

Thanks

 

[anickode]

For several hours? You need like a full size marine deep cycle (trolling motor battery).

200w = 17 amp drain at 12v. So several hours (let's call it 5?) 85ah, and you never want to run deep cycles fully empty, so 100-110ah capacity. Which would be a group 31 deep cycle. And that will weigh ~60 lbs and cost you $100-150 for a cheaper one.

 

[bob58o]

Something like 72 Watts might be more reasonable.
Do you really need 200 Watts?

https://www.amazon.com/Nilight-Lights-Driving-Lighting-Warranty/dp/B00WE46ZWC

This claims to have a 12V 6 amp output (72 watts). Might be able to get about an hour of lights before it needs recharging. Weighs just over a pound.
https://www.amazon.com/TalentCell-Rechargeable-11000mAh-20000mAh-Portable/dp/B01337QXMA

With a 72 watt light bar and 3-5 hrs of use without recharging... You could probably use something like a 32 - 35 amp hour battery which will still weigh around 25lbs.
https://www.apexbattery.com/interst...ivj6xFhifRIJ6YS6LJViRGDsn8AY--ixoCRR4QAvD_BwE

 

[Nosandwich]

For several hours? You need like a full size marine deep cycle (trolling motor battery).

200w = , and you never want to run deep cycles fully empty,

What's the point of a deep cycle battery then? Trust me, I've run em dead plenty of times and then recharged them
No problem. Now...a cold cranking car battery.....

 

[anickode]

What's the point of a deep cycle battery then? Trust me, I've run em dead plenty of times and then recharged them
No problem. Now...a cold cranking car battery.....

It's pretty standard procedure for prolonging the life of deep cycle batteries over the course of years. Solar systems, golf carts, EVs, etc.

Yes, they will hold up longer at Deep drains than starting batteries will, but it's still not good for them to routinely be drained below 50%

Starting batteries shouldn't be drained anywhere near 50%.

 

[bob58o]

I was under the impression that in order to get max life out of deep cycle batteries you shouldn't drain them too hard. Like a solar battery bank for off-grid living... I'd want a bank big enough where I could go a few days with no sunlight and still not drain below 50%. But I guess you need to work out the cost effectiveness considering the price of the batteries and how often you will need to replace them.

$3000 battery bank replaced every 3 years (smaller bank with constant deep discharge means batteries need replacing sooner) is the same as a $6000 battery bank that needs to be replaced every 6 years (larger bank not discharged as deeply). But if the $3000 battery bank only lasts two years and the battery bank twice the size lasts 6 years, the larger bank becomes much cheaper in the longer run.

I suppose that could be worked out if you had the specs showing number of cycles the battery is good for vs discharge %. A battery bank twice the size might last 3 times as long (meaning it is probably more cost effective to get the bigger battery if going to use on a regular basis, instead of replacing the smaller battery / battery bank more often).

 

[Nosandwich]

It's pretty standard procedure for prolonging the life of deep cycle batteries over the course of years. Solar systems, golf carts, EVs, etc.

Yes, they will hold up longer at Deep drains than starting batteries will, but it's still not good for them to routinely be drained below 50%

Starting batteries shouldn't be drained anywhere near 50%.

.....And...exactly the opposite of fisherman who have bass boats.

Now.....we're talking about ONE battery here...not a bank, and how often the battery would be drained. Finally, OK, great, discharging less than 50% increases battery life, but HOW MUCH does discharging beyond that decrease battery life.

Sorry, all I know is from fishing in the real world with one battery, not interweb info on solar systems.

 

[bob58o]

.....And...exactly the opposite of fisherman who have bass boats.

Now.....we're talking about ONE battery here...not a bank, and how often the battery would be drained. Finally, OK, great, discharging less than 50% increases battery life, but HOW MUCH does discharging beyond that decrease battery life.

Sorry, all I know is from fishing in the real world with one battery, not interweb info on solar systems.

If you look at the graph I posted. There doesn't seem to be much of a difference in cost effectiveness between 50% discharge and 100% discharge. This seems odd to me, but that is what the random interweb graph shows. If you drain it 50% might as well drain it all the way.

If using a 200W light bar (16.7 amps) for 3 hours, you would discharge a 50 amp hour battery 100% (not really but more to come on that). The graph shows you might get 225-250 cycles when discharging 100%. 750 total hours. If you got a 100 amp hour battery, the 200W light bar would drain 50% of the battery in 3 hours. The graph shows around 450 - 500 cycles. 1500 total hours. 100 amp hour battery with 6 hours of 17 amp use would drain it 100% and you might get 250 cycles. 1500 total hours. $100 for a 50ah battery. $175 for a 100ah battery.
50 ah battery lasts 750 hours ($0.13 per hour).
100 amp hour battery lasts 1500 hours ($0.12 per hour)

You should also consider that a 50 amp hour battery is probably rated 50 amp hour when discharged over the course of 10 or 20 hours. When discharged over the course of 3 or 6 hours, the ah rating may be significantly less.
Maybe 50ah with a 5 amp load? Maybe 34ah with a 17amp load?

So with 17 amp load, a 50 amp hour (10 hour discharge) battery might only be a 34ah battery, last two hours per charge and give you 250 cycles..
$100 / 500hrs = $0.20 per hour.

A 100 amp hour (10 hour discharge) battery with a 17 amp load might only be a 85 ah battery. If used for the same 2hr between charges it might last 750 cycles.
$175 / 1500 hrs = $0.12 per hour.

If you loaded the 100ah the battery with 17amps for 5 hrs between charges... It might give you 250 cycles.
$175 / 1250 hours = $0.14 per hour.

I didn't account for the exponentially diminishing capacity of the batteries throughout their life. You'd get less hours then I used for calculations and the bigger battery would be even more cost effective. Now just calculate the price difference of the gas used to haul the extra weight around and you'll be set. LOL

 

[aham2003]

For several hours? You need like a full size marine deep cycle (trolling motor battery).

200w = 17 amp drain at 12v. So several hours (let's call it 5?) 85ah, and you never want to run deep cycles fully empty, so 100-110ah capacity. Which would be a group 31 deep cycle. And that will weigh ~60 lbs and cost you $100-150 for a cheaper one.

Not consecutive hours. It would be intermittent use. Say 10 rides at 30 minutes each. Would like it to be able to do that on 1 charge.

 

[Bwdeaton]

Something to consider is the actual wattage the LED's are being driven at. The 200w rating is probably nowhere close to real life. I have a 32" led light bar I purchased off amazon rated at 180w, which would be 15a draw at 12v, however, when I measure it with a current meter, it is really only drawing around 3.5-3.6A.

I also have a 22" light bar, but I haven't measured the current on that, but I could check. Likely the light bar will draw much less than the declared wattage on the listing.