sealed beam headlight amperage draw

[GAmes]

Does anyone know about how many amps/hr a 12 volt sealed beam headlight will draw? I have the task of discharging a 1000 amp hr lithium battery and want an estimate of how long it might take.

 

[BigPapa]

I don’t know about “amps/hr”, but a standard H6054 like we use in our older buses draws @ 5amps high beam and @ 2.75amps on low.

 

[GAmes]

Thanks Scott. It has been on for 4 hours. Starting voltage was 12.33. Four hours later still 12.33 I don't have any way to measure how many amps are still available. I'm going to give it 4 more hours and see how it is doing.

 

[BigPapa]

Hook that sucker up direct to a grid heater or some other heating element and let it eat.

 

[GAmes]

I just realized that I typed in too many zeros. It's a 100 AH battery. I thought about a grid heater but I don't think they are designed for long time activation. After 7 hours the voltage dropped to 12.28 so I'm giving it another 5 hours this morning.

 

[AH64ID]

Any idea what the wattage of the bulb is?

A 55w bulb will draw 4.47A at 12.3V. That would take over 22 hours to drain a 100Ah Lithium battery to 0% SOC, but since you started at 12.33V it shouldn’t take as long.

Lithium batteries hold their voltage much longer as they are depleted, which is why they can be routinely run down to 20% SOC with minimal voltage loss and not effect the electronics using the battery power.

 

[GAmes]

I have a 10 amp charger and it took 6 hours to recharge after about 12 hours with the headlight hooked up, so about 5 amp/hour. According to the rep at Dakota my voltage should be about 13.4 after charging but it was only 12.79. I may have a bad one out of the box or my multimeter might not be 100% accurate. I bought three batteries so I'm testing the other two for comparison. Kudos to Dakota for their customer service. To insure I was charging them correctly they sent me a 10 amp charger for free. I'll be using it to compare the charging I get from the four bank 10 amp Noco Genius charger I bought for the boat.

Anyone have a use for the 36 volt lithium battery charger that came with the three batteries? I can't use it in my application.

 

[AH64ID]

It should take a lot longer than 6 hours to recharge a depleted 100AH Lithium battery with a 10AH charger, more on the order of 18-24 hours, or more.

For example my 300AH bank takes ~30 hours to get from 50% SOC to 100% SOC with a 55AH charger, but only 4-6 hours to from 50% to 90%. Lithium will not have as much thermal loss, but it still takes time to get batteries topped off.

 

[GAmes]

It wasn't fully depleted. My problem is that I have no way to measure what the charge perceentage is.

 

[AH64ID]

It wasn't fully depleted. My problem is that I have no way to measure what the charge perceentage is.

You can do it with a voltmeter. Ask Dakota for a SOC chart.

 

[Ozymandias]

Charging end voltage should be 14.4 Volts, most generic chargers are not capable to do this unless they are Lithium ready.

13.4 Volts and a little above that is what I see and have seen the last 5 years.

I guess you run these battery's with a BMS system?

Depending on the usage I highly recommend a Battery Monitor to keep track of SOC.
For example this one from Victron Energy.
https://battlebornbatteries.com/pro...MI4YuQ--mf9AIVzB6tBh0Q0w33EAQYASABEgLoh_D_BwE

 

[GAmes]

I have two lithium chargers. The four bank and a single that dakots sent me. All Dakota batteries have an internl BMS. The second battery I tested charged to 13.52. Third battery is being depleted for testing right now.

My boat came with a form of SOC moniter, it is an led light bar.
https://www.cabelas.com/shop/en/pro-charging-systems-battery-fuel-gauge

 

[Ozymandias]

I see, it works solely with the Voltage, no shunt involved to really measure what's going in or out.
This won't work with a Lithium battery.

So you have the Lithium for your boat?

 

[Ozymandias]

Just as a reference, my BMS cuts out on 12.2 Volt.
And you can discharge 100AH from a 100AH Lithium battery, sometimes even more.
Best I had was around 110% discharge before the BMS switched.

 

[Ozymandias]

And for longevity, the Lithiums like it the most go keep them within a range from 20-80% SOC.
They dont like it to be fully charged every time you use them.

I accomplished that by limiting my charge voltage to 14.4 instead of 14.6-14.8 that would be possible.
I only go to 14.5 every other week for balancing the cells.

 

[GAmes]

Yes, they are in my boat. Two to power the 24 volt elctric trolling motor and one for the electronics. Dakota has some very good instructions on their website which I'll adhere to.

 

[The patriot]

volts x amps= watts

 

[GAmes]

volts x amps= watts

My question was how many amps does an old fashioned sealed beam headlight draw Doesn't matter, the test is over. One of the three lithium batteries I bought won't charge beyond 12.4 volts.

 

[AH64ID]

Without knowing the watts of the bulbs all you can do is guess, but there are many different wattage bulbs.

 

[GAmes]

Without knowing the watts of the bulbs all you can do is guess, but there are many different wattage bulbs.

I was hoping there was a standard for headlight bulbs.