(ET) HL-Controller vs The E-meter

[Jim Coate <jbc coate org>]

I think that the E-meter and the Harry Landis Controller may be mutually
exclusive (I say never having tried it).

The e-meter has a lot of great features but all the programmable
parameters can make it tricky to use. So bear with me for a longish
explanation...

When the tractor is in use, the e-meter counts actual Amp-hours used
(although the % remaining 'fuel' gauge is corrected based on Puekert
number, but that is another story). So far, so good.

When the tractor is charging, the e-meter shows *corrected* amp-hours 
put back into the pack. This correction is based on the "Charging 
Efficiency" (CEF) that the e-meter calculates based on past charge 
cycles. For instance, if the CEF is 90% then when 10 actual amp-hours 
are returned, the e-meter will show that 9 amp-hours have gone in. I 
won't tell you how many years of using an e-meter it took for this 
detail to penetrate my skull.

The CEF is recalculated with each complete charge cycle. A complete 
cycle (or "reset to zero") requires 5 conditions to be met:
1) At least 10% of the batteries capacity must be used (so very shallow 
discharges don't count)
2) 100% of the KWhrs removed must be returned by the charger
3) The pack voltage must rise above the 'charge voltage' parameter (say 
40 volts)
4) The current must fall below the 'charge current' parameter (say 4.4 
amps)
5) Conditions 3 & 4 must be met for ***at least 5 minutes***.

With a standard battery charger, the charge cycle starts off with a high 
current (say 20 amps) and the pack voltage starts slowly rising as the 
battery charges. As the bulk of the charge gets done, the voltage rises 
more quickly as the current falls quickly. If the charge parameters on 
the e-meter are correctly set, the meter sees a complete cycle and is 
happy. Out of the box, the e-meter starts with a CEF of 90% and then 
updates this value each cycle as it learns about the particular battery 
pack.

If the charger keeps going after the e-meter sees it as full, positive 
amp-hours are accumulated, but as soon as you start driving/mowing it 
jumps back to zero and starts counting negative as it should.

Now add a Landis controller to the charger. As I understand it, the 
charger no longer runs continuously until done, but rather cycles on and 
off. On an empty battery the off time is short, and becomes longer as 
the battery reaches full charge. So now even when all the KWhrs have 
been returned to the battery pack, the 5 conditions for a reset may not 
be met - particularly #5 that requires the conditions to hold for at 
least 5 minutes.

The result may be that the e-meter never sees a "complete" charge
cycle, so it doesn't reset to zero properly and it doesn't recalculate 
the CEF. Or worse yet it occasionally does see a reset after sitting on 
the charger for days and ends up calculating a horrible charge efficiency.

Some options to get the e-meter to reset to zero on complete cycles 
might be:

- Make sure the 'charged voltage' is below the final voltage of the 
charger & HLC combo; make sure the battery capacity is set correctly

- Increase the 'charged current' parameter from say 2% to 4% of the pack 
capacity, so the charge current doesn't have to fall off as far

- Change the time to meet the charged parameters from 5 minutes to 1 
minute (F05)

- Manually set the CEF (F06) - "not recommended" per the instruction manual

Could also set the e-meter to count KWHrs in/out, which are not 
corrected in any way (F04) and use the human brain instead of the 
e-meter brain to track things.

I'll be curious to hear the results of any experiments.


oleoranch aaahawk com wrote:
>    I have several "Landis controllers" and I had one on a tractor
> with an E Meter.  The E Meter keeps track of all battery functions
> including ah out and back in.   With the Landis controller the
> charger was never able to replace all the ah I has used.  Even
> if I let the tractor sit plug in for 2 weeks. The Landis controller
> is fine for maintaining full batteries for long periods of sitting
> but will never fully recharge the batteries if you use the tractor
> on a regular basis.
> R.

_________
Jim Coate
1992 Chevy S10
1970's Elec-Trak
http://www.eeevee.com