Next Meeting of Inverters Anonymous?

 

I have a problem.  I keep blowing up inverters.  Then I find myself on eBay
looking for more to buy.  I am running a 63 Amp alternator with a 4 HP
engine.  It still has the built-in voltage regulator.  It is connected to an
85 Ah deep cycle battery.  I have had, so far, 4 different inverters ranging
from 300-800 watts connected to it which I was using to power battery
chargers mainly.  One of the battery chargers is a Vector 40 amp Smart
Charger.  The other is a Schumacher 15 amp automatic charger that is no
longer automatic.  I thought it would be safe to power the 15 amp charger
with a 300 watt MSW inverter as it usually draws less than 200 watts.
Before it died the ammeter needle was bouncing up and down.  I thought the
problem was a loose connection inside the charger.  I checked all
connections and then tried another 300 watt MSW inverter.  The first one now
thinks that either the battery is too low or it is overloaded.  It almost
works.  The second one shorted out and blew the fuse.  It may be possible to
repair but it'll have to wait.  Most recently my 800 watt Vector SST
inverter quit working while powering the two chargers.  It is under
warranty.  It now says "OL" all the time.  I can't really include the Wagan
700 watt inverter in this scenerio because it was destroyed by overvoltage
when I connected it to the alternator without a battery in parallel.  I
replaced 5 or 6 capacitors and it seemed ok until I used it briefly to power
the battery chargers and then accidently ran a coffee maker with it which no
doubt was a little bit too much for it.

So, my question is can anyone tell me why a battery charger would cause the
failure of so many inverters?  I suspect the Schumacher charger to be the
problem and will not use it on my next inverter but is it possible the
Vector Smart Charger is causing the problem?

I need to charge two sets of batteries that are about 100 feet apart.
Charging directly from the alternator will work fine for my main battery
bank but I still need to charge the other one somehow.  So far the built-in
voltage regulator in the alternator keeps up with the inverters demand and
keeps the deep cycle battery charged and apparently is not overcharging it.
I have been looking at the different charge controller circuits so I can
have the option of charging directly but I'm afraid the battery life will
diminish without the regulated 3-stage charging  I also like the option of
using the setup as an AC generator but I'm tired of destroying inverters.

Please help.

BTW I found a 1250 watt Inverter for only $50.  Anyone ever heard of Homier
aka HDC?  They have few specs for it.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&itemX42999174&ssPageNam
e=STRK:MEWA:IT#ebayphotohosting
.

 



Typically, chargers are designed to use the top portion of the input
sine wave.  The charger expects 164 volts +- at peak.  A MSW inverter
doesn't reach anywhere near this voltage, topping out at 120 volts or
less.  Even some smaller generators under load will "flat-top" and not
deliver the wave the charger wants.

Are your small inverters seeing the chargers as a huge load and
plotzing?  Dunno, but it seems like a possibility.  A true sine wave
inverter would be a costly solution, but less costly than burning up
multiple MSW inverters.


One option is to make a version of the old rotary converter used by
theatres and trolley lines.  At the far end of your line, you power a
small electric motor, which in turn powers a second small alternator,
which charges your battery.

FWIW, For a single deep-cycle battery, your alternator setup has the
potential to cause problems.  If you go down to an 80% DoD on the
battery, and then recharge, using the alternator without any other
load, or current limitation, the charge rate will be far faster than
the optimal C/20 or slower rate that deep-cycles like.  An 85aH
battery C/20 rate is less than 5 amps.  Even a C/10 rate is only
roughly 8.5 amps.

However, if you only use the top 20% of the battery capacity, the
voltage regulator and battery resistance will limit the charge current
and your battery may be fine.  I'd absolutely drop out the load on the
battery if it reached down to 12 volts.  Otherwise, you'll be like me,
hoping for some magic method to restore capacity in batteries that
were charged too fast to many times.

 



ranging

overvoltage

I suspected there might be something to that.  I'd asked somewhere before
about this but I guess I didn't know precisely what question to ask.


built-in

Interesting idea.  Sound kinda redundant but I'll think about it.


The larger battery bank I'm charging is 440 Ah so even if it was charging at
the full 63 amps it would not be an extreme overcharge but I prefer keeping
it around 40 amps max.  My smaller battery bank is 220 Ah.


That's why I like the Vector charger because it seems to know how fast to
charge batteries.  Even if someone without knowing any better set it for 40
amps on a 100 Ah battery it would probably not exceed 15 Amps.  Plus it's a
3 stage charger and can get them almost to 100% in a reasonable amount of
time.

 

wrote:



Charging a battery from a battery charger powered by an inverter powered by
a battery charger (alternator) is about as redundant as you can get.  :)

If I were you, I think I would concentrate on making the alternator charge
the batteries directly, as they are designed to do. I would try my best to
remove the AC charger from the loop.
--
Bob

 



Yea, I agree.  I need to figure out some way to power an inverter from the
alternator without having to have a battery in the system for voltage
stabilization BUT having that battery makes the device much for versatile
such as I could use a drill or jigsaw etc without having to start the
engine.

I just got an ammeter and connected it and the built-in voltage regulator in
the alternator seems to being doing a very good job of charging my bank of
four 220 Ah 6 volt batteries (series parallel for 12 volts).  Matter-of-fact
the charge rate is almost identical to what I'm getting with my Vector 40
amp Smart Charger.  It will not do an equalizing charge with the existing
voltage regulator but since I'm working with only generators and do not have
them running all the time I have not been doing adequate equalizing anyway.
Gotta figure that one out before it's too late (these particular batteries
are fairly new).  I have been monitoring the voltage via a Vector inverter
(the ONE that I have not blown up yet) and with some loads the battery
voltage has been getting up to about 13.9 but since this is not a very valid
indicator I have been determining full charge with a hydrometer and current
draw: when the ammeter reads just below 10 amps I figure they are pretty
much fully charged.