(ET) Fwd: E-15 not getting out of first speed

[john j casey <jjcrmc verizon net>]

> 
> Would a specific gravity test be in order?
> Cheers, jack
> 
> On May 17, 2017, at 1:03 AM, David Roden wrote:
> 
>> On 17 May 2017 at 0:35, Briggs, Michael wrote:
>> 
>>> I'm wondering if I'm just not charging long enough. I'm using a Landis
>>> charge controller. 
>> 
>> I would definitely try bypassing it.  That said, if it's been 
>> undercharging 
>> the battery for some months or years, the damage to the battery (hard 
>> or 
>> permanent sulfation) is probably long since done.  
>> 
>> A sulfated battery will have a lower on-charge maximum voltage, lower 
>> operating voltage, and reduced capacity.  These phenomena aren't 
>> reversible 
>> in any meaningful way; the damage is permanent.
>> 
>> I already suggested measuring your batteries' voltage under load (while 
>> driving the tractor and perhaps mowing).  I don't see any other way you 
>> can 
>> determine whether they can maintain enough voltage to run the tractor 
>> properly without connecting a voltmeter to them and reading it under 
>> load.  
>> Sorry, but "they can hold a charge well enough to mow for a while" 
>> doesn't 
>> really tell us anything of value here.
>> 
>> As for measuring their capacity, the easiest and cheapest (if 
>> approximate) 
>> way I've found requires a 12v inverter, preferably with a capacity of 
>> at 
>> least 1000 Watts; an AC powered analog clock with hands (check garage 
>> sales 
>> and thrift stores); and a 120v load of some kind. 
>> 
>> The ideal load will put a 75 amp load on the battery, because then you 
>> can 
>> compare the battery's actual measured capacity to its factory reserve 
>> capacity specification.  For a golf car battery, reserve capacity is 
>> normally stated in minutes of operation at a constant 75 amps until the 
>> battery falls to 5.25v under load.
>> 
>> Most cheap inverters are around 70-85% efficient when running at around 
>> 2/3 
>> load.  Let's take 80% as a reasonable approximation.  If you have a 
>> really 
>> good inverter with higher efficiency, just plug that value into the 
>> math 
>> that follows.
>> 
>> This is not lab equipment and the actual current and voltage will vary 
>> over 
>> the test, but remember, I said this is an approximation!  At an average 
>> of 
>> 12v, an average 75 amp avg load will be an average 900 watts from the 
>> battery.  Allow for 80% efficiency and you get 0.8 * 900 == 720 watts 
>> of AC 
>> load to put on the inverter output.  This can be approximated pretty 
>> well 
>> with three 250 Watt incandescent light bulbs.  
>> 
>> If all you have at hand is a small (< 1000W) inverter, you can still do 
>> this 
>> measurement, but then you have to convert to amp-hours and adjust for 
>> Peukert capacity.  It's just a little more time and a little more math.
>> 
>> Connect the inverter to a pair of charged 6v batteries in series.  Set 
>> the 
>> clock to 12:00:00 and plug it into the inverter, along with the lights. 
>> Let 
>> 'er rip. 
>> 
>> When the batteries are effectively flat (around 10.5 volts under load), 
>> your 
>> inverter should automatically shut down.  You may have to keep an eye 
>> on it, 
>> though, because some inverters will start up again when the battery 
>> voltage 
>> rises after a rest, throwing off the test.
>> 
>> When the lights go off and the clock stops, read the hours and minutes 
>> of 
>> reserve capacity from the clock.  Assuming you used 750W of lights, 
>> convert 
>> to minutes and compare to the batteries' factory specification.  
>> Typical 
>> golf car batteries' RCs are 105 to 125 minutes.  A battery is 
>> considered 
>> spent when its capacity is below 80% of specification.
>> 
>> 
>> David Roden - Akron, Ohio, USA
>> 
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>> 
>> 
>> 
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>