Battery capacity testing. Review of DTL150, a $35 battery capacity tester.

[A64Pilot]

The Concorde Component manual may be some interesting reading, especially for capacity testing and trying to recover lost capacity if a battery fails the capacity test. (conditioning charge procedure)

You can get some capacity back sometimes by cycling, but you will get more back following the manual procedure.

There is even a deep discharge recovery procedure for that battery that’s sat on the shelf for years.

Both the conditioning charge and the deep discharge are intentional monitored overcharges with the purpose of converting sulphation back I believe into lead.

https://batterymanagement.concordebattery.com/BatteryDocs/5-0171.pdf

The Lifeline manual is much more comprehensive and explains things better in my opinion.

Lifeline is Concorde’s ground batteries and if you talk to the Concorde folks the Lifeline and Concorde aircraft batteries are essentially identical, excepting of course the FAA PMA approval and their use profile, Concorde starting of course, Lifeline primarily deep cycle

https://lifelinebatteries.com/wp-content/uploads/2015/12/6-0101F-Lifeline-Technical-Manual-Final-5-06-19.pdf

Then just if you’re curious the Company history is interesting, 100% US made, owned entirely by the Godber family. If you look at the Company phone tree you will see several Godber names so they are still apparently running things.

(my data is a few years old) but I wouldn’t expect things have changed.

Call their tech support line, you will speak to someone who knows their stuff, not someone who’s read the manual.

[Scottknoll]

Just some feedback from following the Concorde CMM procedure. Batteries both failed capacity check. 85% is the minimum and we had 66% and 3%. Conditioning charge per the CMM resulted in a 102% and 88% capacity check. Reached out to Concorde, they said no impact to battery life if the capacity check and conditioning charge are followed as defined in the CMM. Used a DC load and DC power supply from Amazon ($280). Would have gladly replaced if unairworthy, but happy to put off buying two $850 batteries.

[Bartman]

Just yesterday, I replaced the AGM battery in my 328i

It was the original battery....... from 2014.  I was impressed.

I am certain it would not pass a test for quite some time, but you could not tell it until this past month.  It was obvious it was not going to last thru winter.  The car requires battery registration and that was my first experience with that.  A bit of a PITA.

[philiplane]

If you don't discharge the battery at the rate specified, you won't get a true reading of the capacity. Meaning you can't discharge at half the rate for double the time. It doesn't work that way. 

[Scottknoll]

Exactly. The CMM defines what the load needs to be and for how many minutes. 51 min (85%) is a good cap check. In our case with a 13.6Ah battery, we applied a 13.6A load until the battery reaches the rated end point voltage (20v for the RG24-15). If your dc load can’t do tenths, you can follow the guidance in Concorde Tech Bulletin 13. It gives time adjustments (49 minutes = 85%) if you run the test at 14A in our example. But don’t just double the load for half the time. The documentation is very good and easy to follow. Equipment to test is not very expensive unless you want the automated testing equipment from Concorde.

[PT20J]

45 minutes ago, Scottknoll said:

Just some feedback from following the Concorde CMM procedure. Batteries both failed capacity check. 85% is the minimum and we had 66% and 3%. Conditioning charge per the CMM resulted in a 102% and 88% capacity check. Reached out to Concorde, they said no impact to battery life if the capacity check and conditioning charge are followed as defined in the CMM. Used a DC load and DC power supply from Amazon ($280). Would have gladly replaced if unairworthy, but happy to put off buying two $850 batteries.

What load and power supply did you use?

[Scottknoll]

The CMM specifies the minimum power and load requirements based on your Ah rating. What I used may not work for everyone.

Most dc power supplies that I found were 30v. For a 28v battery, Concorde says the conditioning charge could go as high as 34v. So I found this 50v power supply. Load tester is 500v 15A and met what I needed but may not work well for 12v batteries with higher Ah ratings. They have a 150v 40A version too.

ET5411A+ Electronic Load Tester... https://www.amazon.com/dp/B0C9LY63FZ?ref=ppx_pop_mob_ap_share

HYELEC DC Power Supply,50V 6A... https://www.amazon.com/dp/B09XTWKVLD?ref=ppx_pop_mob_ap_share

 

[EricJ]

40 minutes ago, philiplane said:

If you don't discharge the battery at the rate specified, you won't get a true reading of the capacity. Meaning you can't discharge at half the rate for double the time. It doesn't work that way. 

There's a correction that can be used to adjust for the discrepancy if a lighter load is used.   It's not a large difference, especially for an AGM battery.

[EricJ]

1 hour ago, Scottknoll said:

Just some feedback from following the Concorde CMM procedure. Batteries both failed capacity check. 85% is the minimum and we had 66% and 3%. Conditioning charge per the CMM resulted in a 102% and 88% capacity check. Reached out to Concorde, they said no impact to battery life if the capacity check and conditioning charge are followed as defined in the CMM. Used a DC load and DC power supply from Amazon ($280). Would have gladly replaced if unairworthy, but happy to put off buying two $850 batteries.

That's a good result for rehab success!   Reading the manual FTW! 

[Pinecone]

11 hours ago, Bartman said:

Just yesterday, I replaced the AGM battery in my 328i

My experience with BMW batteries is not so great.  The original battery in my 2002 M3 lasted 2.5 MONTHS.

[Will.iam]

Soooo can you not just turn on all your electronics in the airplane and start a timer to see if they are still functioning in one hour?  Would this not be the best test and confidence you need to know your radio / ADI loads will be avail for at least that amount of time?

 

[jetdriven]

as long as you have a sophisticated amp gauge that is showing around 30A, yes that would work too.

[larryb]

Circling back to the tester current capacity vs. the Concord spec. I finally found some math to calculate the effect.

From the Concord Lifeline manual, their Peukert constant is 1.12

From Wikipedia the Peukert formula can be reduced to

t=(C/I)^k

t = actual time of discharge

C = Capacity, 13.6 for our Concord

I = Discharge rate, 5A for my tester

So t=(13.6/5)^1.12 = 3.07

 

A straight calculation of discharge time would be 13.6/5 = 2.72 hours

 

3.07/2.72 = 1.13. So the lower discharge rate will result in 13% more capacity.

 

So if we take the Concord airworthy spec of 85%, multiply by 1.13 due to the lower discharge rate, then we need to see 96% capacity with the 5A test to meet airworthy standards. Note that a new battery should read 113% with the 5A discharge. 

 

Reference material. H = 1 in our case.

 

 

 

 

 

[EricJ]

34 minutes ago, larryb said:

Circling back to the tester current capacity vs. the Concord spec. I finally found some math to calculate the effect.

From the Concord Lifeline manual, their Peukert constant is 1.12

From Wikipedia the Peukert formula can be reduced to

t=(C/I)^k

t = actual time of discharge

C = Capacity, 13.6 for our Concord

I = Discharge rate, 5A for my tester

So t=(13.6/5)^1.12 = 3.07

 

A straight calculation of discharge time would be 13.6/5 = 2.72 hours

 

3.07/2.72 = 1.13. So the lower discharge rate will result in 13% more capacity.

 

So if we take the Concord airworthy spec of 85%, multiply by 1.13 due to the lower discharge rate, then we need to see 96% capacity with the 5A test to meet airworthy standards. Note that a new battery should read 113% with the 5A discharge. 

 

Reference material. H = 1 in our case.

 

 

 

 

 

Yes, this is how I do it in MathCAD:

[DonMuncy]

Geez, you guys make my head spin. I know only slightly more than red to positive, black to negative.