Battery Load tester
- Thread starter dstock
- Start date
Haf-E
Expedition Leader
A load tester for short duration testing? or something that is able to be left on to drain a battery to estimate the capacity?
I have a Harbor Freight load tester that has worked well - but is their typical quality... What is the process you are using to "recover" the battery?
I have a Harbor Freight load tester that has worked well - but is their typical quality... What is the process you are using to "recover" the battery?
dstock
Explorer
Something that could be left on to drain the battery. Currently, I am improvising using ARB fridge and low voltage cutoff to bring the battery down to the 10 volts, which will take a lot longer than 5 hours but they said that is ok. Unfortunately, this will not help with the testing process below as it's not a constant drain.
Following the Odyssey guidelines:
"11.2V OCV is 0% state of charge. We recommend the 5 hour rate of discharge to 10.0V from a full state of charge. So, at 137W or 11.5A it should take 5 hours to reach 10.0V (read voltage while load applied) from a full state of charge. When the load is removed, it will recover to 10.5-11.5V or so. The higher the rate of discharge, the less efficient the discharge and the shallower the depth of discharge. The idea is to deeply discharge the battery the recharge at 25A not to exceed 15.0V. If the battery vents or overheats at less than 15.0V then the battery may be severely sulfated and have a high internal resistance causing overheating. If the battery vents, hisses or gets so hot you cannot hold your hand on it then discontinue charging. Warm is ok but hot is not. J
If after several cycles the battery performs at less than 80% of its rated capacity (from a full state of charge of 12.84V OCV minimum) then replacement would be recommended. So if you use the 5 hour rate of discharge and it runs less than 4 hours after several cycles, then it would be performing at less than 80% of its rated capacity. "
Following the Odyssey guidelines:
"11.2V OCV is 0% state of charge. We recommend the 5 hour rate of discharge to 10.0V from a full state of charge. So, at 137W or 11.5A it should take 5 hours to reach 10.0V (read voltage while load applied) from a full state of charge. When the load is removed, it will recover to 10.5-11.5V or so. The higher the rate of discharge, the less efficient the discharge and the shallower the depth of discharge. The idea is to deeply discharge the battery the recharge at 25A not to exceed 15.0V. If the battery vents or overheats at less than 15.0V then the battery may be severely sulfated and have a high internal resistance causing overheating. If the battery vents, hisses or gets so hot you cannot hold your hand on it then discontinue charging. Warm is ok but hot is not. J
If after several cycles the battery performs at less than 80% of its rated capacity (from a full state of charge of 12.84V OCV minimum) then replacement would be recommended. So if you use the 5 hour rate of discharge and it runs less than 4 hours after several cycles, then it would be performing at less than 80% of its rated capacity. "
dwh
Tail-End Charlie
Haf-E
Expedition Leader
Regular car lights won't give a constant load - the wattage they draw will drop off as the voltage drops. Many of the LED lights will work better as they use a current limiting circuit to keep the LED's at a more constant brightness. Kinda expensive though...
A non-constant load would be OK since what is really needed is just a repeatable test condition.
Not sure of what I think of repeatedly draining the battery to 10.0 vdc though - its a pretty severe thing to do to a lead acid battery...
A non-constant load would be OK since what is really needed is just a repeatable test condition.
Not sure of what I think of repeatedly draining the battery to 10.0 vdc though - its a pretty severe thing to do to a lead acid battery...
dstock
Explorer
I have a pair of 55 watt Hella driving lights that will at least get me discharged faster (but not faster then their 5 hours) than using the low voltage cutoff off on my ARB fridge. I'm going to give it at least one cycle to their spec and see where it ends up.
mep1811
Gentleman Adventurer
Haf-E
Expedition Leader
Those types of battery load testers are only for use for a short time period as they get really hot quickly. They do make a nicer variable version which I have that I like better as it can be used on 12 or 6 volt batteries of different capacity by adjusting the load level...
http://www.harborfreight.com/500-amp-carbon-pile-load-tester-91129.html
http://www.harborfreight.com/500-amp-carbon-pile-load-tester-91129.html