| Author |
Message |
Doyle Gaither (Texasborderdude)
Registered Member
Username: Texasborderdude
Post Number: 99
Registered: 3-2007
Posted From: 70.222.226.206
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 18, 2007 - 8:26 pm: | |
Just before I start my daily trip, I fire up a desktop computer and monitor to load up my gps software. It usually takes 20 minutes or so to load the gps etc. so I like to stay on shore power til the last minute. I've connected a UPS to take over as soon as I disconnect the shore power or go off the genset. Here's the problem, once my bus house circuit is fed by my inverter, the voltage spikes up to 140 volts or so and the UPS won't accept this voltage level and starts the battery backup. It's only good for 30 to 40 minutes of backup, so I can't operate the destop computer while I drive. If I start on the desktop on inverter generated current, it works...but I have no battery backup if I use all my storage battery capacity. Do I need some sort of voltage regulator for my inverter; or is there a voltage adjustment on my Trace 2500?
Thanks,
dg |
Tom Caffrey (Pvcces)
Registered Member
Username: Pvcces
Post Number: 1147
Registered: 5-2001
Posted From: 65.74.67.83
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 18, 2007 - 9:26 pm: | |
Doyle, I believe that your inverter needs servicing. You didn't say which series you have, but you probably should use a DMM that reads true RMS to find out what your inverter output is.
They are fairly common but the $10 ones probably won't give you an accurate reading. If the RMS voltage is much over 120 VAC, then the inverter is probably out of spec.
The manual should tell you what the output is and state the tolerance, such as + or - 5%. This would mean that you inverter ought to produce no more than 126 VAC.
Many of the Trace models will produce full voltage until the battery bank is discharged 25 or 30%; after that, the voltage drops at about the same rate as the battery bank.
The effect is real noticeable when using a microwave.
For what it's worth.
Tom Caffrey PD4106-2576
Suncatcher
Ketchikan, Alaska |
Tony LEE (T_lee)
Registered Member
Username: T_lee
Post Number: 8
Registered: 11-2007
Posted From: 124.180.32.13
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 19, 2007 - 1:32 am: | |
If your inverter is one of the fake-sinewave type, it puts out a higher peak voltage in the middle to make up for the bits of the sine wave on the side that are missing.(sorry for the highly technical description but hope you get the idea) Your UPS is probably monitoring the peak voltage on the supply and reacting to that instead of measuring the RMS voltage which the inverter puts out which is close to 110V.
If your inverter is a true sine wave type, forget I mentioned it.
afterthought -
Yes the Trace 2500 is a fake sinewave type.
Only hope for you - if my theory is correct - is to adjust the high voltage switch point ON YOUR UPS. Generally they are adjustable and depending on the actual waveform of the inverter, you may have to raise it by 20%
(Message edited by t_lee on November 19, 2007) |
Don Evans (Doninwa)
Registered Member
Username: Doninwa
Post Number: 93
Registered: 1-2007
Posted From: 66.45.165.58
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 19, 2007 - 12:13 pm: | |
Doyle
A few thoughts. Well thoughts might be giving them to much credit but here goes.
It might be the short time it takes the inverter to come on after shore power is DCed that is triggering the UPS.
You might try turning on some other AC loads like lights or a heater before pulling the shore plug to see if that would hold the voltage spike down. Not sure if the inverter would like that.
You could also try a small dedicated inverter for the computer only.
Or just pull the plug before you start the computer. The house bank should charge as soon as you fire up and hit the road. Assuming you have provisions for charging the house bank from the engine.
Good luck
Don 4107 |
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