| [GMCnet] Interesting electrical/battery issue [message #259627] |
Thu, 21 August 2014 16:29  |
glwgmc
Messages: 1014
Registered: June 2004
Karma: 10
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Senior Member |
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I have four large golf cart batteries as a house bank for the Royale. The bank is rated at 460 amp hours and is five or six years old. I decided to run the microwave off an inverter so changed out the modified sine wave inverter and installed a Xantrax SW 2000. It is a full sine wave inverter and says it will put out 2000 watts for five minutes and 1800 watts continuous. The microwave is a modern Panasonic inverter based unit so it modulates output directly rather than time slicing to get lower outlet like older microwaves. It is rated to draw 12.7 amps at full power and runs easily from a 15 amp wall plug.
The problem is, it will not run at full power off the inverter. It stays on for only a few seconds before the inverter shuts down with an overload message. It will run at up to 80% power level, but not beyond. At 80% the voltage sagged to 11.3 volts while running and was drawing 153 amps for 1729 watts according to my Xantrax battery meter. According to the plate on the microwave it should only be drawing 1524 watts at full power. As soon as the microwave shut off the battery voltage moved up to 12.4. At 50% power the battery voltage sagged to 11.5 and the unit was drawing 93.5 amps. At 70% power voltage sag was to 11.6 and amp draw was 122. In both cases the battery voltage returned to 12.3 to 12.4 volts as soon as the microwave stopped.
Thinking the interconnect cables might be adding too much resistance I changed out all the cables from 1ga to 00. The battery interconnect cables are wired to properly balance the load across all four batteries and none are longer than 18". The battery to inverter cables are also 00 and 30" long. All the connectors are soldered in place, the mounting studs are clean and the batteries fully charged. I even swapped the Iota 75 amp converter/charger that was in the Royale for the 60 amp PD that was in the Clasco just to make sure there was no issue there. With those cables in place the 80% power voltage sag was still to 11.7 volts while drawing 150 amps.
I added a second automatic transfer switch to switch between shore/generator power and the inverter power for a series of new power strips installed around the inside of the coach. I did not want to tie into the current house panel to avoid any grounding issues plus the existing wall plugs are not where we need them for the way we live in the coach. The microwave is plugged into a dedicated 120volt line running from that second transfer switch. That line is a 12-3 appliance extension cord 25' long. The microwave runs just fine when I plug the coach into a 15 amp shore power plug.
So, whats up? We had a similar set up (four 6vdc golf cart batteries and a 2000 watt Heart converter/battery charger/Inverter) in our old Beaver Patriot and it ran a similar size microwave off the inverter just fine. The only thing I can think of is that the battery bank may be nearing the end of its useful life. Any of you electrically minded folks have a suggestion or an idea as to how I might go about testing the battery bank itself? Can you think of anything else I might have overlooked that would cause this issue? Thanks.
Jerry
Jerry Work
The Dovetail Joint
Fine furniture designed and hand crafted in the 1907 former Masonic Temple building in historic Kerby, OR
Visitors always welcome!
glwork@mac.com
http://jerrywork.com
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Jerry & Sharon Work
78 Royale
Kerby, OR
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| Re: [GMCnet] Interesting electrical/battery issue [message #259633 is a reply to message #259627] |
Thu, 21 August 2014 17:02  |
Mike Kilroy
Messages: 80
Registered: July 2006
Location: Farmersville, OH (near D...
Karma: 0
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Member |
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How freaking BIG r it Batts?
475ah?? Not likely..
Golf cart size r like 125ah.
So 2 in series and then 2 more in par is 250ah.....
Sent from my Verizon Wireless 4G LTE Smartphone
-------- Original message --------From: Work Jerry Date:08/21/2014 5:29 PM (GMT-05:00) To: Gmc Forum Subject: [GMCnet] Interesting electrical/battery issue
I have four large golf cart batteries as a house bank for the Royale. The bank is rated at 460 amp hours and is five or six years old. I decided to run the microwave off an inverter so changed out the modified sine wave inverter and installed a Xantrax SW 2000. It is a full sine wave inverter and says it will put out 2000 watts for five minutes and 1800 watts continuous. The microwave is a modern Panasonic inverter based unit so it modulates output directly rather than time slicing to get lower outlet like older microwaves. It is rated to draw 12.7 amps at full power and runs easily from a 15 amp wall plug.
The problem is, it will not run at full power off the inverter. It stays on for only a few seconds before the inverter shuts down with an overload message. It will run at up to 80% power level, but not beyond. At 80% the voltage sagged to 11.3 volts while running and was drawing 153 amps for 1729 watts according to my Xantrax battery meter. According to the plate on the microwave it should only be drawing 1524 watts at full power. As soon as the microwave shut off the battery voltage moved up to 12.4. At 50% power the battery voltage sagged to 11.5 and the unit was drawing 93.5 amps. At 70% power voltage sag was to 11.6 and amp draw was 122. In both cases the battery voltage returned to 12.3 to 12.4 volts as soon as the microwave stopped.
Thinking the interconnect cables might be adding too much resistance I changed out all the cables from 1ga to 00. The battery interconnect cables are wired to properly balance the load across all four batteries and none are longer than 18". The battery to inverter cables are also 00 and 30" long. All the connectors are soldered in place, the mounting studs are clean and the batteries fully charged. I even swapped the Iota 75 amp converter/charger that was in the Royale for the 60 amp PD that was in the Clasco just to make sure there was no issue there. With those cables in place the 80% power voltage sag was still to 11.7 volts while drawing 150 amps.
I added a second automatic transfer switch to switch between shore/generator power and the inverter power for a series of new power strips installed around the inside of the coach. I did not want to tie into the current house panel to avoid any grounding issues plus the existing wall plugs are not where we need them for the way we live in the coach. The microwave is plugged into a dedicated 120volt line running from that second transfer switch. That line is a 12-3 appliance extension cord 25' long. The microwave runs just fine when I plug the coach into a 15 amp shore power plug.
So, whats up? We had a similar set up (four 6vdc golf cart batteries and a 2000 watt Heart converter/battery charger/Inverter) in our old Beaver Patriot and it ran a similar size microwave off the inverter just fine. The only thing I can think of is that the battery bank may be nearing the end of its useful life. Any of you electrically minded folks have a suggestion or an idea as to how I might go about testing the battery bank itself? Can you think of anything else I might have overlooked that would cause this issue? Thanks.
Jerry
Jerry Work
The Dovetail Joint
Fine furniture designed and hand crafted in the 1907 former Masonic Temple building in historic Kerby, OR
Visitors always welcome!
glwork@mac.com
http://jerrywork.com
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Mike (AC8V) & Vickie Kilroy
'73 Canyon Land 26' sidebath
455/ceramic filled crossovers
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| Re: [GMCnet] Interesting electrical/battery issue [message #259636 is a reply to message #259627] |
Thu, 21 August 2014 17:32 |
bwevers
Messages: 597
Registered: October 2010
Location: San Jose
Karma: 5
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Senior Member |
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Jerry,
Somebody here once mentioned the "Peukert Effect" where the battery capacity is much reduced from fast discharging.
Maybe it's a combination of the this and age....
Regards,
Bill
Bill Wevers GMC49ers, GMC Western States
1975 Glenbrook - Manny Powerdrive, OneTon
455 F Block, G heads
San Jose
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| Re: [GMCnet] Interesting electrical/battery issue [message #259643 is a reply to message #259633] |
Thu, 21 August 2014 18:04 |
k2gkk
Messages: 4452
Registered: November 2009
Karma: -8
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Senior Member |
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And 12.7 Amps from a 120 V line is 1524 Watts!
Five to six year old batteries will be lucky to put out more than 50-60% of their original rated Amp-Hour ratings.
A competent battery shop can do a check on each of the batteries, but they'll probably have to disconnect to check each one to do that check.
Time to head for Sam's or Costco and get four new batteries!
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~~ ~ D C "Mac" Macdonald ~ ~~
~ ~ Amateur Radio - K2GKK ~ ~
~ ~ USAF and FAA, Retired ~ ~
~ ~ ~ Oklahoma City, OK ~ ~ ~
~~ ~ ~ "The Money Pit" ~ ~ ~~
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> Date: Thu, 21 Aug 2014 18:02:12 -0400
> From: mike@kilroywashere.com
> To: glwork@mac.com; gmclist@temp.gmcnet.org
> Subject: Re: [GMCnet] Interesting electrical/battery issue
>
> How freaking BIG r it Batts?
>
> 475ah?? Not likely..
>
> Golf cart size r like 125ah.
>
> So 2 in series and then 2 more in par is 250ah.....
>
>
> Sent from my Verizon Wireless 4G LTE Smartphone
>
> -------- Original message --------From: Work Jerry Date:08/21/2014 5:29 PM (GMT-05:00) To: Gmc Forum Subject: [GMCnet] Interesting electrical/battery issue
> I have four large golf cart batteries as a house bank for the Royale. The bank is rated at 460 amp hours and is five or six years old. I decided to run the microwave off an inverter so changed out the modified sine wave inverter and installed a Xantrax SW 2000. It is a full sine wave inverter and says it will put out 2000 watts for five minutes and 1800 watts continuous. The microwave is a modern Panasonic inverter based unit so it modulates output directly rather than time slicing to get lower outlet like older microwaves. It is rated to draw 12.7 amps at full power and runs easily from a 15 amp wall plug.
>
> The problem is, it will not run at full power off the inverter. It stays on for only a few seconds before the inverter shuts down with an overload message. It will run at up to 80% power level, but not beyond. At 80% the voltage sagged to 11.3 volts while running and was drawing 153 amps for 1729 watts according to my Xantrax battery meter. According to the plate on the microwave it should only be drawing 1524 watts at full power. As soon as the microwave shut off the battery voltage moved up to 12.4. At 50% power the battery voltage sagged to 11.5 and the unit was drawing 93.5 amps. At 70% power voltage sag was to 11.6 and amp draw was 122. In both cases the battery voltage returned to 12.3 to 12.4 volts as soon as the microwave stopped.
>
> Thinking the interconnect cables might be adding too much resistance I changed out all the cables from 1ga to 00. The battery interconnect cables are wired to properly balance the load across all four batteries and none are longer than 18". The battery to inverter cables are also 00 and 30" long. All the connectors are soldered in place, the mounting studs are clean and the batteries fully charged. I even swapped the Iota 75 amp converter/charger that was in the Royale for the 60 amp PD that was in the Clasco just to make sure there was no issue there. With those cables in place the 80% power voltage sag was still to 11.7 volts while drawing 150 amps.
>
> I added a second automatic transfer switch to switch between shore/generator power and the inverter power for a series of new power strips installed around the inside of the coach. I did not want to tie into the current house panel to avoid any grounding issues plus the existing wall plugs are not where we need them for the way we live in the coach. The microwave is plugged into a dedicated 120volt line running from that second transfer switch. That line is a 12-3 appliance extension cord 25' long. The microwave runs just fine when I plug the coach into a 15 amp shore power plug.
>
> So, whats up? We had a similar set up (four 6vdc golf cart batteries and a 2000 watt Heart converter/battery charger/Inverter) in our old Beaver Patriot and it ran a similar size microwave off the inverter just fine. The only thing I can think of is that the battery bank may be nearing the end of its useful life. Any of you electrically minded folks have a suggestion or an idea as to how I might go about testing the battery bank itself? Can you think of anything else I might have overlooked that would cause this issue? Thanks.
>
> Jerry
> Jerry Work
> The Dovetail Joint
> Fine furniture designed and hand crafted in the 1907 former Masonic Temple building in historic Kerby, OR
> Visitors always welcome!
> glwork@mac.com
> http://jerrywork.com
>
>
>
>
>
>
>
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| Re: [GMCnet] Interesting electrical/battery issue [message #259670 is a reply to message #259627] |
Thu, 21 August 2014 20:20 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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The newer digital hand held testers are pretty good at doing a pass fail. You have to have a fully charged battery and dial to the rated Ah. The push button gives you an instant green or red. Must draw for like a couple uS and then extrapolate the result as there is no big heet generating resistor like the old days. Mine is even made in USA, sorry it's not close by for the brand name. So far it has been accurate at testing batts for me. Also, you say the problem started with the new inverter?? Can you scope the AC to see if the wave goes to crap when under microwave load. The 2 items may not play well together. For laughs add some resistive load like a 100watt incandescent lamp in parallel to see if that tricks it happy.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] Interesting electrical/battery issue [message #259689 is a reply to message #259627] |
Thu, 21 August 2014 22:07 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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glwgmc wrote on Thu, 21 August 2014 17:29<snip>
The problem is, it will not run at full power off the inverter. It stays on for only a few seconds before the inverter shuts down with an overload message. It will run at up to 80% power level, but not beyond. At 80% the voltage sagged to 11.3 volts while running and was drawing 153 amps for 1729 watts according to my Xantrax battery meter. According to the plate on the microwave it should only be drawing 1524 watts at full power. As soon as the microwave shut off the battery voltage moved up to 12.4. At 50% power the battery voltage sagged to 11.5 and the unit was drawing 93.5 amps. At 70% power voltage sag was to 11.6 and amp draw was 122. In both cases the battery voltage returned to 12.3 to 12.4 volts as soon as the microwave stopped.
<snip> The cable moves were all the right idea.
<snip>
So, whats up? We had a similar set up (four 6vdc golf cart batteries and a 2000 watt Heart converter/battery charger/Inverter) in our old Beaver Patriot and it ran a similar size microwave off the inverter just fine. The only thing I can think of is that the battery bank may be nearing the end of its useful life. Any of you electrically minded folks have a suggestion or an idea as to how I might go about testing the battery bank itself? Can you think of anything else I might have overlooked that would cause this issue? Thanks.
Jerry
Jerry,
The dance is over and I hope you are ready....
First: The draw-down could be either an in sufficient connection or the Peukert problem.
Have you done the experiment where you actually put the meter right on the lead of the battery posts??
- If no, Try that and tell me what you find. Because if the terminal (at the posts) does not sag as much, then you have to restart chasing this problem there.
- If yes, then it is the Peukert exponent coming to get you. Newer batteries might do better, but that "snap back" is a result of internal resistance that is a combination of sulfation and circulation in the cells. The internal resistance will also increase with temperature that is a normal result of working the cells. Flooded cells (with caps and visible electrolyte) count on the circulation to get the most out of the chemistry. Sulfation just happens to old Lead Acid batteries and there isn't a lot that can be done about it if the bank is ever discharged, and even banks that are never discharged seem to have this problem.
Next: Do you remember how much that old Heart inverter/charger weighed???
It had a transformer and a circuit tuned to 60Hz. It did a pretty clean sine. The new "Pure Sine" devices are not. If you know about audio equipment, one of the thing that used to be talked about was harmonic distortion. What you may be fighting is the digital war that is going one between the microwave and the inverter.
Unfortunately, without being there with a small heap of analysis gear, I can't be any more help than that. I can tell you that I had a similar go-around with a vary similar system on an owners cruising sloop a few years back. What won was an isolation transformer between the two. Like you need another 40#.
Good Luck
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Interesting electrical/battery issue [message #259739 is a reply to message #259627] |
Fri, 22 August 2014 08:13 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Jerry,
I have the SAME problem with Double Trouble! I have a second ATS that when the Xantrex SW-2000 is on it ONLY powers the microwave
and NOTHING else!
The Xantrex is fed by two Trojan 225 AH six vdc batteries in series. I thought that the problem was caused by a lack of battery
power and was going to parallel two more Trojan 225 AH six vdc batteries but with what you've noted below it seems that's not going
to work.
Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
USA '75 Avion - Double Trouble TZE365V100426
AUS '75 Avion - The Blue Streak TZE365V100428
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org [mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Work Jerry
Sent: Thursday, August 21, 2014 4:29 PM
To: Gmc Forum
Subject: [GMCnet] Interesting electrical/battery issue
I have four large golf cart batteries as a house bank for the Royale. The bank is rated at 460 amp hours and is five or six years
old. I decided to run the microwave off an inverter so changed out the modified sine wave inverter and installed a Xantrax SW 2000.
It is a full sine wave inverter and says it will put out 2000 watts for five minutes and 1800 watts continuous. The microwave is a
modern Panasonic inverter based unit so it modulates output directly rather than time slicing to get lower outlet like older
microwaves. It is rated to draw 12.7 amps at full power and runs easily from a 15 amp wall plug.
The problem is, it will not run at full power off the inverter. It stays on for only a few seconds before the inverter shuts down
with an overload message. It will run at up to 80% power level, but not beyond. At 80% the voltage sagged to 11.3 volts while
running and was drawing 153 amps for 1729 watts according to my Xantrax battery meter. According to the plate on the microwave it
should only be drawing 1524 watts at full power. As soon as the microwave shut off the battery voltage moved up to 12.4. At 50%
power the battery voltage sagged to 11.5 and the unit was drawing 93.5 amps. At 70% power voltage sag was to 11.6 and amp draw was
122. In both cases the battery voltage returned to 12.3 to 12.4 volts as soon as the microwave stopped.
Thinking the interconnect cables might be adding too much resistance I changed out all the cables from 1ga to 00. The battery
interconnect cables are wired to properly balance the load across all four batteries and none are longer than 18". The battery to
inverter cables are also 00 and 30" long. All the connectors are soldered in place, the mounting studs are clean and the batteries
fully charged. I even swapped the Iota 75 amp converter/charger that was in the Royale for the 60 amp PD that was in the Clasco
just to make sure there was no issue there. With those cables in place the 80% power voltage sag was still to 11.7 volts while
drawing 150 amps.
I added a second automatic transfer switch to switch between shore/generator power and the inverter power for a series of new power
strips installed around the inside of the coach. I did not want to tie into the current house panel to avoid any grounding issues
plus the existing wall plugs are not where we need them for the way we live in the coach. The microwave is plugged into a dedicated
120volt line running from that second transfer switch. That line is a 12-3 appliance extension cord 25' long. The microwave runs
just fine when I plug the coach into a 15 amp shore power plug.
So, whats up? We had a similar set up (four 6vdc golf cart batteries and a 2000 watt Heart converter/battery charger/Inverter) in
our old Beaver Patriot and it ran a similar size microwave off the inverter just fine. The only thing I can think of is that the
battery bank may be nearing the end of its useful life. Any of you electrically minded folks have a suggestion or an idea as to how
I might go about testing the battery bank itself? Can you think of anything else I might have overlooked that would cause this
issue? Thanks.
Jerry
Jerry Work
The Dovetail Joint
Fine furniture designed and hand crafted in the 1907 former Masonic Temple building in historic Kerby, OR
Visitors always welcome!
glwork@mac.com
http://jerrywork.com
_______________________________________________
GMCnet mailing list
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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