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

From: Robert Laird <rsl360 gmail com>
Sent: Monday, May 22, 2017 12:29 AM
To: et
Cc: Briggs, Michael
Subject: Re: (ET) E-15 not getting out of first speed

I've seen something similar to this on my E20. The thing pretty much seemed to have a mind of it's own, with relays doing stuff late, or at the wrong time. It turned out that the electronic card had leaky diodes. This is not something that shows up in a normal diode check. If I remember correctly, all the diodes but one tested correctly with the diode setting on a digital meter. But one of them was pretty strange, with some voltage in both directions. Not the same voltage, so it we still acting like a diode, but not a very good diode. This led me to check all the diode, and many of them had a lot of leakage in reverse. Not enough to show up in the standard diode test, but enough to really mess things up. I replaced all the bad diodes and all my troubles were cured.

Robbie

On Sun, May 21, 2017 at 10:08 PM, tb <tbamc gbta net> wrote:

I've no idea--mine's an E12--but I'm sure someone will know!

Thon

On May 21, 2017, at 8:37 PM, Briggs, Michael wrote:

Thon,

    This is the first I've heard of the centrifugal switch. After some quick googling it does seem like it could be involved. I only found mentions of a centrifugal switch on the E12; does the E15 have one?

    It's on the back of the drive motor?

Thanks!
Mike

Michael S. Briggs, PhD

UNH Physics Department

(603) 862-2828

From: tb <tbamc gbta net>
Sent: Sunday, May 21, 2017 8:16 AM
To: Briggs, Michael
Cc: et
Subject: Re: (ET) E-15 not getting out of first speed

When I've had similar problems it's been the centrifugal switch connector  behind the drive motor. Plugging/unplugging several times restores function. May not be your problem but really easy to check.

Thon

On May 20, 2017, at 9:25 PM, Briggs, Michael wrote:

Update on this. I charged the batteries for a nice long time, last doing some charging yesterday. This afternoon I took it out to mow - and right away couldn't get out of first speed. I thought to myself "WTF self? The batteries are fully charged - I thought this was a low voltage issue". I measured the pack voltage while the mower deck was on (temporarily bypassed the seat safety switch) and it was around 35.6 Volts, if I remember correctly. That seemed fine considering the three motors do draw a lot of current. I also measured the voltage at the control fuse to see if there might be any substantial voltage drop across any unexpected resistance before that point, and got the same voltage reading.
   So I decided to keep mowing, chugging along super slow, for about 20-30 minutes. Then, all of a sudden, it went up into higher speeds. Woohoo! But WTF? I kept mowing for probably 70-90 more minutes, zipping around with the tractor working perfectly.
   This behavior seems like more of a loose connection kind of thing to me. If it was a problem due to low voltage (from bad batteries or unexpected voltage drop somewhere in the circuit), I wouldn't expect that to just all of a sudden disappear. Of course, it could be a loose connection causing an unexpected voltage drop....
   Any thoughts on where a loose connection might be that would cause this behavior? For the first 20-30 minutes, when it wouldn't get out of first speed while in gear, it would still get out of first speed while in neutral, spinning the motor up nice and fast. I've checked the connections at the solenoids and the main power disconnect switch. The connections are solid, although at the disconnect there are some burn marks at the fusible link - but yesterday I had the vague recollection of accidentally shorting a wire there a few years ago, causing an arc that may have caused those burn marks. At least I think I remember that.... two little kids and lack of sleep is making my memory fuzzy).
   The good news is the batteries seem to be fine - I had no trouble mowing the entire yard (and the portion I was mowing initially was very long since I didn't mow it last week, since the slow-motion effect kicked in after mowing for an hour or so).
   Thoughts?

Thanks,
Mike

________________________________
Michael S. Briggs, PhD
UNH Physics Department
(603) 862-2828
________________________________

________________________________________
From: john j casey <jjcrmc verizon net>
Sent: Wednesday, May 17, 2017 11:52 AM
To: noaddress drmm net
Cc: elec-trak cosmos phy.tufts.edu
Subject: Re: (ET) E-15 not getting out of first speed

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

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

Note: mail sent to the "etpost" address will not reach me. To send

me a private message, please use the address shown at the bottom

of this page : https://urldefense.proofpoint.com/v2/url?u=http-3A__www.evdl.org_help_&d=DwICAg&c=c6MrceVCY5m5A_KAUkrdoA&r=_8_87ljwK8CqxgbaTpLUeg&m=W4Sbmb_wvlh4onymDb5EC1ura0y-w5nX2-4ZMBnObhQ&s=VcGAjsmUaKu2b8skh1bU0R9Qz98I9JIIGOcaRblgFo8&e=

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

_______________________________________________

Elec-trak mailing list

Elec-trak cosmos phy tufts edu

https://urldefense.proofpoint.com/v2/url?u=https-3A__cosmos.phy.tufts.edu_mailman_listinfo_elec-2Dtrak&d=DwICAg&c=c6MrceVCY5m5A_KAUkrdoA&r=_8_87ljwK8CqxgbaTpLUeg&m=W4Sbmb_wvlh4onymDb5EC1ura0y-w5nX2-4ZMBnObhQ&s=07CQNyC__yPO4YU9J0ejsAmz4pqpgh6HrcnsTOuc9PE&e=

_______________________________________________
Elec-trak mailing list
Elec-trak cosmos phy tufts edu
https://urldefense.proofpoint.com/v2/url?u=https-3A__cosmos.phy.tufts.edu_mailman_listinfo_elec-2Dtrak&d=DwICAg&c=c6MrceVCY5m5A_KAUkrdoA&r=_8_87ljwK8CqxgbaTpLUeg&m=W4Sbmb_wvlh4onymDb5EC1ura0y-w5nX2-4ZMBnObhQ&s=07CQNyC__yPO4YU9J0ejsAmz4pqpgh6HrcnsTOuc9PE&e=

_______________________________________________
Elec-trak mailing list
Elec-trak cosmos phy tufts edu
https://cosmos.phy.tufts.edu/mailman/listinfo/elec-trak

_______________________________________________
Elec-trak mailing list
Elec-trak cosmos phy tufts edu
https://cosmos.phy.tufts.edu/mailman/listinfo/elec-trak