Question on Burn Test

[ams511]

I recently purchased a used Halcyon Proteus 3 10w HID light. I did a burn test using the instructions in the manual. It said to stop the test once the voltage from the battery reaches 10 volts. Well I got tied up, so I stopped the test at 9.8 volts. The strange thing is when I shut off the light the battery voltage increased to 10.8. Is this normal? Is this an additional safety factor that Halcyon does not want factored in?
It only took 1 hour and 20 minutes to reach 9.8 volts, while Halcyon claims a burn time of 2 hours.

 

[rjack321]

It is normal for battery voltage to increase when the load is removed. It doesn't really have anything to do with "safety"

Was this gel cell cycled a couple times before you did the burn test? Takes awhile for them to "open up" and take a full charge.

 

[ams511]

I am not sure what the prior owner did with the battery. He says the light was only about a year old and has a few dives on it. Judging from the condition, I believe him. When I received the light I tried to start it and it would not light. I recharged the battery and the charger light did not go on. I left it plugged in over night and in the morning the red light was lit. So I figured it was good to go.

 

[cool_hardware52]

I am not sure what the prior owner did with the battery. He says the light was only about a year old and has a few dives on it. Judging from the condition, I believe him. When I received the light I tried to start it and it would not light. I recharged the battery and the charger light did not go on. I left it plugged in over night and in the morning the red light was lit. So I figured it was good to go.

Any used lead acid battey is suspect in my opinion. Lead acid batteries are very easily damaged by over discharge, and by self discharge in storage. The good news is replacements are inexpensive.

A lead acid powered device that has a intermittant use pattern should include a "float" charger that can be left connected to the battery all the time to prevent damage due to self discharge. I don't know what the specs are on the charger you have. If it states that it can be left connected long term it should be an automatic "float" charger. If it recommends not using it long term it's not automatic and will likely boil the battery.

If the battery was allowed to discharge down to the point where the light would not ignite then it has very likely been damaged, i.e. suffered a permanent loss of capacity.

As stated before the voltage under load and the open circuit voltage are sure to be different unless the load is tiny.

Tobin

 

[ams511]

Thanks for the reply Tobin. The charger is from Halcyon and can be left connected to the battery. Halcyon's instructions say if using the light frequently leave the battery on the charger. If not, then charge the battery before storage. The odd thing is they recommend charging every 6 months if not in use. On the other hand, Dive Rite recommends charging once per month when not in use. I assume both manufacturers use similar technology.

I think you are correct that the battery was left discharged for too long and it damaged the cells. I will give it another burn test as suggested by rjack to see if the burn time improves any. If not, I will just buy a new one for $20.00 or so and use this as a backup.

 

[rjack321]

Sounds like it was really low, which is bad.

I would cycle it a bit higher on the charge curve. Ie don't draw it all the way down to10 volts. Go from ~11V up to full charge a couple times. Don't worry about "memory" that's not going to happen from just a couple of cycles.

Deep discharges on lead acid batteries definately shorten their life (or more accurately - use their life up faster). Since you're trying to revive this one, burn testing all they way down is not so great.

I wouldn't compare with diverite unless your sure your talking about the exact same battery chemistry.

But as Tobin mentioned, lead acids have the benefit of being inexpensive. So if nothing else, you have a spare with a known capacity.

 

[cool_hardware52]

Thanks for the reply Tobin. The charger is from Halcyon and can be left connected to the battery. Halcyon's instructions say if using the light frequently leave the battery on the charger. If not, then charge the battery before storage. The odd thing is they recommend charging every 6 months if not in use. On the other hand, Dive Rite recommends charging once per month when not in use. I assume both manufacturers use similar technology.

I think you are correct that the battery was left discharged for too long and it damaged the cells. I will give it another burn test as suggested by rjack to see if the burn time improves any. If not, I will just buy a new one for $20.00 or so and use this as a backup.

A true automatic float charger can and should be used full time. A float charger will offset the self discharge of the battery without overcharging to the point of boiling the electrolyte.


Tobin