Warning, this message is pretty long.
On 17 May 2017 at 22:20, Hank Ralston wrote:
I have always disliked the random "age of the battery" charging
settings.
There's nothing elegant about the GE charger, but there's actually some
rationale to the timer settings. Older batteries have less capacity, so
with a dumb charger like this one, charging them the same length of time as
new ones overcharges them.
What should we look for in either specifications &/or brands of external
golf
cart battery chargers should we consider?
A few things to think about:
1. Bulk current capability. You want a charger with a bulk phase current
capacity of around 10% of the batteries' C20 capacity. To get good life,
batteries seem to need a good sock in the gut at the start of the charge.
Thus low current chargers aren't just slow, they're not a great investment
in the long run.
Most golf car batteries are 220 to 250AH, so a 25 amp charger would be
about
right for a large frame ET. You could probably get by with a 15+ amp
charger, but 20+ is better. A small frame machine would be fine with a 10
or 12 amp charger.
2. Brains: Flooded golf car batteries are pretty forgiving (compared to gel
or AGM batteries and - goodness knows - lithium). But a little
intelligence
in the charger will extend their cycle life.
I'd want to see an IU or IUI algorithm. That would be constant current to
a
voltage limit of 43.2 to 44.4 volts, then constant voltage at that voltage
until the current falls to 0.02 * C20 (2% of the battery's C20 amp hours
expressed in amperes).
What should happen next would depend on what kind of ET you have.
The large frame tractors are a particular charging challenge because they
have battery taps for the lift and lights. Unless you never use the lift
or
lights, they unbalance the battery pack with each cycle. This means that
some batteries in the pack are discharged more than others.
The "right" way to deal with this would be to quit tapping the pack.
Either
convert the lift and lights to 36v, or add one or two DC:DC converter(s) to
provide the 12v and 18v (or 24v) from the 36v battery.
I've been sorely tempted by some of the obscenely cheap Chinese-made DC:DC
converters I see on Ebay, but I'm leery of reliability issues. I'd hate to
have one fail and put the full 36v onto its load.
Barring that, the large frame ET battery needs aggressive equalization on
every charging cycle. In bringing up the more-discharged batteries,
equalization overcharges the batteries that are less discharged. This
inevitably shortens battery life. So it goes. :-(
Small frame ETs discharge their batteries evenly, so they need equalization
only once in a while. I'd say maybe every 10 or 15 cycles, so for many of
use just a couple of times a year. You want to monitor the specific
gravity
of the cells, though, and equalize if they're getting too far apart.
Equalization is the last I in the IUI algorithm. To equalize, instead of
shutting off at the end of the constant voltage phase, you charge constant
current at the (0.02 * C20) rate until either the voltage stops rising, or
the on-charge voltage reaches 46.8 volts (flooded batteries). (Either
condition should terminate charge.)
As for specific charger brands, I don't know every brand out there by any
means. Here are a few that I've looked at and, in one case, used for my
ETs. I would love to hear from other people with experience.
DELTA-Q: I rather like Delta-Q chargers. They're smart. The problem is
that
Delta-Q won't sell to individuals. Maybe one of the ET parts dealers could
work with Delta-Q to develop appropriate charging profiles for large-frame
and small-frame tractors. (Jim Coate, Harold Zimmerman, are you listening?
Any thoughts?)
Delta-Qs have some other issues I'm not 100% comfortable with. They're a
Canadian company, but the chargers are manufactured in China. And I'm not
entirely sure about the availability of service should one develop a fault.
Those would be matters for our friendly parts dealer to check into.
https://www.amazon.com/gp/product/B00C5NV2DY/ref=s9_acsd_hps_bw_c_x_4_w
QUICK CHARGE: I've looked briefly at these chargers too. They're somewhat
old-tech and heavy, but seem sturdy. They're US-made. They have some
smarts, but not as much as the Delta-Q chargers.
Looking at the QC literature, I can't tell how much their algorithm relies
on time and how much on voltage and current. It APPEARS that they're a IU
/
IUI charger, but the 12-hour scale on their charge profiles worries me.
They have a way to extend the absorption phase. That might handle the
equalization. All in all though I'm not sure QC's chargers are as smart as
their price would suggest. They are probably an improvement on the GE.
https://www.quickcharge.com/select-a-charge-on-board-chargers.html
http://www.chargingchargers.com/quick-charge/obsc36-25.html
SONEIL: Darryl McMahon is on this list and is a dealer (distributor?) for
Soneil chargers. The inexpensive Soneils are too small (low-current) for
ET
use, but I remember him mentioning the 3624SR16 10-amp charger (adequate
for
a small-frame ET) at a pretty attractive price a few years back.
http://soneil.com/product/model-3624sr16/
This model would be more suitable for a large frame tractor, but I don't
know whether it could handle the equialization needed:
http://soneil.com/product/model-3640sr40/
Maybe Darryl is reading this, and can weigh in on whether the Soneil
chargers can be configured to equalize aggressively enough to deal with
large frame pack imbalance.
Some if not all Soneils are made overseas (mostly in China, I think). I
know nothing about their repair-ability. Darryl would probably know more
about those issues.
12V CHARGERS: This might be the cheapest route. It's what I use ATM.
I charge both my E15 and New Idea rider with 3 individual 12v "Exide" brand
automatic automotive chargers (cycle-dropping algorithm) made by Cliplight
in Canada. They still make something similar to my chargers, which are over
20 years old, but they claim the current version is smarter.
http://www.cliplight.com/battery-chargers/12v/10-amp-linear-charger/
https://www.amazon.com/Cliplight-Volt-Amp-Battery-Charger/dp/B003F1G8PM
I use East Penn G24 gel batteries in both tractors, 3 in series in the New
Idea and 6 in series-parallel in the E15. These are C20 rated 74ah with a
reserve capacity of 140 minutes at 25 amps.
The Cliplight chargers are rated 10a and peak at 12a into flat batteries.
This is fine for the New Idea, and a little on the light side for the E15.
On the E15, I use a 12v tap for the lights and a 24v tap for the lift. I
haven't had any problems with the lift at 24v, touch wood. YMMV.
These batteries are over 20 years old now. Just in the last year or two,
they've finally started to lose capacity significantly. They now test at
only 30-40ah at 22 amps, or around 50-70% of original capacity. But I
figure the charging routine I've used all this time hasn't done too badly.
Warning: one hazard of using multiple chargers is that you need to monitor
them, or have some kind of voltage monitor on each battery. If one charger
fails and doesn't properly charge its battery, you can ruin that battery
the
next time you use the ET.
OTHER CHARGERS: If anyone has had positive experiences with other charger
brands, please post your comments.
David Roden - Akron, Ohio, USA
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