On 07/17/2015 11:47 AM, Lee Hart via EV wrote:
From: EVDL Administrator via EV <[email protected]>
I have one of those "Watts Up" meters. It works nicely, within its
limitations. It's US made (!), and appears to be really well built. I use it
a fair bit.
However, the specs claim a current capacity of 50 amps continuous and 100
amps peak. I think that's wildly optimistic. The shunt is built in, and
you're right, the lead wires are only #14. I wouldn't use it at over 10-15
amps continuous. Even at 15a, I keep a fan blowing on it.
I have one as well. I agree with David; it's well made and works as advertised.
But indeed, it failed while continuously charging a battery at about 20-25
amps. An autopsy revealed that it burned open the tiny shunt, which then
applied full voltage across the current sensing circuit, and blew out the
electronics as well.
I'm apparently not seeing all list postings. This from Lee is all I've
seen of the thread.
I looked at the Wattsup and mate and decided the wire did look too small
to pass entire battery current. That could be up around 100 amps. I
thought of putting one meter per 20ah battery but didn't much like that
solution. I have on order a couple of these:
http://www.evwest.com/catalog/product_info.php?cPath=37&products_id=162
I already have shunts installed.
The first battery install went very well. Two 20ah ebike batteries move
the golf cart very nicely up the steepest hills I have. Range is a
guesstimated 5 miles. I bought a total of four 20ah batteries so I will
devote the other two to another golf cart. I look forward to getting
the above meters installed so I can monitor voltage sag, current, and
amphour accumulations.
Here are some photos of the first golf cart:
https://plus.google.com/photos/102434734002949174273/albums/6172547067287965665
I ordered two 72v 30ah batteries for my Zap. I plan to do the same with
the Zap: make provision for about 5 batteries in parallel but install
only two to begin with.
The battery supplier assures me that the overcharge protection is on the
discharge wires as well as the charge wires. That should allow me to
charge with any old charger. I plan not to use the charge wires at
all. Right now, I'm charging only with a little 2amp charger going into
both batteries. I did charge briefly with a big golf cart charger @
about 18 amps but didn't want to leave it unattended.
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