Inverter Voltage Drop (Overload)

[jcarlilesiu]

Hi everybody. Out here boondocking in Wall SD. This is our first true dry camping experience. From here we move to Shell Creek Campground in Bighorn National Forest (boondocking) and then on to Yellowstone (boondocking).

Before the trip, I installed a GoPower 1500watt high surge inverter, (2) 6v golf cart batteries from Costco, and purchased parallel Honda EU2000i generators.

The inverter worked great last night, TV, lights, charging devices, etc. This morning, I attempted to make a cup of coffee with a small electric drip brewer.

Voltage on the GoPower inverter was showing about 13V before turning it on. When I turned it on, the inverter showed a output power of 40%-50%. However; the voltage dropped to like 10V on the gauge, and the inverter started beeping/flashing the red light.

If I am understanding this correctly, the inverter has the available wattage, but the batteries are under too much stress and can't maintain voltage. Is that correct?

The coffee maker states that it uses 650 watts, well within the available power the inverter can handle.

BLACK+DECKER 5-Cup Coffee Maker DCM600B | BLACK + DECKER

When I hooked up the inverter, I used GoPower's quick install kit:

Inverter Fuse and Cable Install Kits | Go Power!

The fuse was installed in the battery compartment, and the total run to the inverter is probably 24". From there, the supply that ties into the power center is probably about 10 feet in the 233s (from the front bunk end table where the inverter is installed to the power distribution center).

Just trying to figure out why voltage drop is killing me. The batteries should have more than enough power available to run this 650 watt load for 5 minutes and the inverter certainly is up to the task.

Any ideas?

[Paulie1138]

Some fast ideas. Did you leave the inverter on the whole time? (Turn it on only when needed)

Did you just plug in the trailer plug for power and use the inside outlets? (If so, then you must turn off your trailer's 12 volt CONverter and other non essentials at the breaker box)

Did you charge the batteries fully? (Most off the shelf batteries are not fully charged, and may have sat a while, further lowering the charge).

Consider adding a 75-100 watt minimum solar panel to help with the float charge to top off the batteries, and the genset to do the bulk charge earlier in the day. (After 7-8 or so to avoid making noise for neighbors, but before 10-11 so the solar can top you off during peak sunshine)

[jcarlilesiu]

Originally Posted by Paulie1138

Some fast ideas. Did you leave the inverter on the whole time? (Turn it on only when needed)

Did you just plug in the trailer plug for power and use the inside outlets? (If so, then you must turn off your trailer's 12 volt CONverter and other non essentials at the breaker box)

Did you charge the batteries fully? (Most off the shelf batteries are not fully charged, and may have sat a while, further lowering the charge).

Consider adding a 75-100 watt minimum solar panel to help with the float charge to top off the batteries, and the genset to do the bulk charge earlier in the day. (After 7-8 or so to avoid making noise for neighbors, but before 10-11 so the solar can top you off during peak sunshine)

Here are some answers to your questions:

Yes, the inverter was left on the whole time, but has a sleep mode, and went into sleep mode when there was no load.

The converter, AC, and microwave were turned off at the breaker. The water heater and fridge were set on Propane. No other loads but the outlets were turned on the inverter.

Yes, batteries were charged up for several days (plugged in) prior to leaving for the trip. The first two nights were in campgrounds with power. The voltage showed at about 13/14V even after having the inverter on in sleep mode all night with exception of some items being charged.

We do have a small solar charger but is mainly used for keeping the batteries topped off when in storage. The bunk end blocks it when camping. In any case, I don't think the batteries were running low.

Using 2/0 wire provided by GoPower, I should have enough capacity to send the correct amps (about 5) to the inverter to run the coffee maker.

I just can't figure out why my batteries can't supply enough power to the inverter to run the watts its designed for.

[rsdata]

well it could be a poor connection at some place along the line...

your inverter is telling you the batteries do NOT have enough voltage to do the job... SO

Get yourself a voltmeter at any Walmart or hardware store for less then $10...

use the voltage tester to test the voltage output of the batteries hooked up...

they should measure over 6 volts... from the + and - terminals ( 12 V+ from one battery + to the other battery - ) then turn on the inverter ( which will probably beep) while measuring and you will probably find they are less than 5 volts... ( 10 volts total) this means the batteries are NOT fully charged...

get them charged back up or risk losing them...

also depending on your solar cell hookup, I have seen some of them actually discharge batteries when not in sunlight... which might be the cause for the battery condition

[rsdata]

Using 2/0 wire provided by GoPower, I should have enough capacity to send the correct amps (about 5) to the inverter to run the coffee maker.

Volts X amps = watts

12 X unknown amps = 650 watts

650/12 = unknown amps

unknown amps = 54 amps plus inverter energy conversion losses about 15% = ~60 amps needed from the battery to power your coffee maker at 650 watts

[carlsbad]

Originally Posted by jcarlilesiu

Here are some answers to your questions:



Yes, the inverter was left on the whole time, but has a sleep mode, and went into sleep mode when there was no load.



The converter, AC, and microwave were turned off at the breaker. The water heater and fridge were set on Propane. No other loads but the outlets were turned on the inverter.



Yes, batteries were charged up for several days (plugged in) prior to leaving for the trip. The first two nights were in campgrounds with power. The voltage showed at about 13/14V even after having the inverter on in sleep mode all night with exception of some items being charged.



We do have a small solar charger but is mainly used for keeping the batteries topped off when in storage. The bunk end blocks it when camping. In any case, I don't think the batteries were running low.



Using 2/0 wire provided by GoPower, I should have enough capacity to send the correct amps (about 5) to the inverter to run the coffee maker.



I just can't figure out why my batteries can't supply enough power to the inverter to run the watts its designed for.

The 650watts AC is 65amps DC from the battery to the inverter. You are within the limits of 2/0 wire. If you have a long run from the inverter to the batteries and it's actually 2g wire you have a problem.

If you have the option, turn off the low voltage shutoff.

[babock]

Originally Posted by jcarlilesiu

Yes, batteries were charged up for several days (plugged in) prior to leaving for the trip. The first two nights were in campgrounds with power. The voltage showed at about 13/14V even after having the inverter on in sleep mode all night with exception of some items being charged.

You need to turn off everything that is charging your batteries and let them sit 30 minutes and check the voltage. A fully charged battery is 12.7V ± 0.1V so the 13/14 that you are seeing shows the battery is getting charged....likely your small solar panel.

If you suspect a voltage drop, use a meter and measure from the positive of the battery to the positive of the inverter while under load. Do the same for the negative points. In an ideal world this measurement will be 0V but reality is a few tenths of volts on each leg because of connections and wire resistance. This test will show you which leg has the greater voltage drop and allows you to correct it if it seems out of whack.

[carlsbad]

If I owned Forest River I would make this standard equipment on every single camper.

Find somebody with a clamp meter and see what your batteries pull at no load, 10watts AC, 100watts AC, and on your coffee maker.

Every RV owner is eventually an electrician and plumber.

[babock]

Originally Posted by carlsbad

Find somebody with a clamp meter and see what your batteries pull at no load, 10watts AC, 100watts AC, and on your coffee maker.

The one you pictured can not measure DC current if that is what you intended.

There are other models that do measure DC. Typically, a DC clamp meter is a lot more money than one that just measures DC.

I am going to be installing a battery monitor that measure current across a shunt. More accurate and cheaper than a clamp meter.

[carlsbad]

Originally Posted by babock

The one you pictured can not measure DC current if that is what you intended.

Good catch. I see that now. It's the next model up. Same concept. A good AC/DC multimeter and clamp meter.

I thought maybe prices had dropped since I bought mine. I paid about $250 for mine.

[babock]

Yeah...I love Fluke meters. I don't buy inexpensive meters. Seen too many that are just way off. My friend at work(fellow EE) had an inexpensive meter and he was ready to get his alternator replaced because of the voltage he was measuring. I put my Fluke on there and confirmed his meter was bad.

[jcarlilesiu]

Thanks for all the comments. Trying to figure out why Go power would send a 2/0 cable for the 1500 watt inverter if that isn't large enough to meet the load demand. Doesn't make much sense.

[rsdata]

Trying to figure out why Go power would send a 2/0 cable for the 1500 watt inverter if that isn't large enough to meet the load demand.

where did you get that thought from...2 AWG wire will carry 181 amps in chart I looked at...
https://www.powerstream.com/Wire_Size.htm

12 V X 181 A = 2,172 watts theoretical power x .85 efficiency = 1846 delivered watts... well within the 1500 advertised watts of the inverter

you said

and the total run to the inverter is probably 24"

did you mean 24 feet or 24 inches?

no matter the number you are only talking 0.16 ohms per 1,000 ft of wire... not much voltage drop in the wire...
100 Amps @ 0.16/1,000 and a 10 foot run = 0.16 volts drop per 10 foot of 2 ga wire... that amounts to about a 1% loss in power for every 10 feet...

A fully charged lead acid battery is 12.6-12.7 volts so delivered voltage to the inverter is about 12.4+ volts using a 10 foot run... not bad... but you said 24 inches, so the loss is negligible...

Your connections to the batteries and the inverter need to be stout and clean... I have seen more power lost at bad electrical connections than in long wire runs.

Are you sure that you did just not run down the batteries and not get them charged fully back up again which caused the inverter to alarm due to low voltage when you ran the coffee in the morning?

[jcarlilesiu]

Originally Posted by rsdata

where did you get that thought from...2 AWG wire will carry 181 amps in chart I looked at...
https://www.powerstream.com/Wire_Size.htm

12 V X 181 A = 2,172 watts theoretical power x .85 efficiency = 1846 delivered watts... well within the 1500 advertised watts of the inverter

Somebody else said that the 2/0 may not be enough.

you said

Originally Posted by rsdata

did you mean 24 feet or 24 inches?

24" to 36" from the battery to the inverter. From the inverter to the power distribution panel about 10'

Originally Posted by rsdata

Your connections to the batteries and the inverter need to be stout and clean... I have seen more power lost at bad electrical connections than in long wire runs.

I spent some time pulling all the terminal connections and cleaning all corrosion before the trip. Maybe didn't get them clean enough.

Originally Posted by rsdata

Are you sure that you did just not run down the batteries and not get them charged fully back up again which caused the inverter to alarm due to low voltage when you ran the coffee in the morning?

Positive. As soon as I remove the load, the batteries bouncing back up, and then after some time show 12-13v on the gauge. I know its not trust worthy, but the 4 lite LED indicated built in also indicates the batteries are fully charged.

[babock]

You need to measure with a meter. 12-13V means nothing in determining battery voltage. For example, 12.0 means a 50% discharged battery and 12.7 would be a fully charged battery.

Originally Posted by jcarlilesiu

Somebody else said that the 2/0 may not be enough.

Are you using 2/0 or 2? Huge difference.

Do you have anything charging the batteries during this test? I am talking converter or solar. If so, remove all of it and repeat your test and measure batteries with a good meter right at the battery.

[Bluepill]

In a situation like this, the FIRST Thing is to make sure that the batteries are actually fully charged, otherwise all other tests are meaningless.

Best way is with a dedicated Automotive Charger, rather than using the converter. If you have a WFCO converter, be aware that they are famous for not fully charging batteries.

[dmdomokos]

Originally Posted by jcarlilesiu

Hi everybody. Out here boondocking in Wall SD. This is our first true dry camping experience. From here we move to Shell Creek Campground in Bighorn National Forest (boondocking) and then on to Yellowstone (boondocking).

Before the trip, I installed a GoPower 1500watt high surge inverter, (2) 6v golf cart batteries from Costco, and purchased parallel Honda EU2000i generators.

The inverter worked great last night, TV, lights, charging devices, etc. This morning, I attempted to make a cup of coffee with a small electric drip brewer.

Voltage on the GoPower inverter was showing about 13V before turning it on. When I turned it on, the inverter showed a output power of 40%-50%. However; the voltage dropped to like 10V on the gauge, and the inverter started beeping/flashing the red light.

If I am understanding this correctly, the inverter has the available wattage, but the batteries are under too much stress and can't maintain voltage. Is that correct?

The coffee maker states that it uses 650 watts, well within the available power the inverter can handle.

BLACK+DECKER 5-Cup Coffee Maker DCM600B | BLACK + DECKER

When I hooked up the inverter, I used GoPower's quick install kit:

Inverter Fuse and Cable Install Kits | Go Power!

The fuse was installed in the battery compartment, and the total run to the inverter is probably 24". From there, the supply that ties into the power center is probably about 10 feet in the 233s (from the front bunk end table where the inverter is installed to the power distribution center).

Just trying to figure out why voltage drop is killing me. The batteries should have more than enough power available to run this 650 watt load for 5 minutes and the inverter certainly is up to the task.

Any ideas?

Just came back from boondocking in Sequoia and was doing exactly the same thing. 2 new GC2 6v batteries, 1500w inverter vs Coffee maker. Coffee maker won. We just couldn't keep the batteries charged enough. We have a Zamp 160w solar setup, but no good in clouds. We ran the generator for 2 hours every night. As others have pointed out, WFCO converter and 2 hours of generator time don't equal anywhere near charged batteries. Same voltage drop, 12.6 or 12.7 to start and then the inverter cuts out. Lots of threads on how voltage reading doesn't really tell you how charged your batteries are. I ended up using a battery jumper to the inverter to help it make coffee on the mornings we just didn't have enough power.

[camaraderie]

Umm...just a thought....wet cell batteries can't DELIVER any more current than they can ACCEPT during charging which is at most 25% so you are asking your batteries to deliver MORE INSTANTANEOUS current than they are capable of. You need to fire up the generator, or add more batt's or give up on electric drip coffeemakers while booning.

We need a new invention...just like your fridge we should have coffee pots that switch to propane when no AC is present! Coffee pot would need to be level of course!

[babock]

Originally Posted by camaraderie

Umm...just a thought....wet cell batteries can't DELIVER any more current than they can ACCEPT during charging which is at most 25% so you are asking your batteries to deliver MORE INSTANTANEOUS current than they are capable of. You need to fire up the generator, or add more batt's or give up on electric drip coffeemakers while booning.

We need a new invention...just like your fridge we should have coffee pots that switch to propane when no AC is present! Coffee pot would need to be level of course!

If you look at the Trojan T-105 spec, they show a chart where the battery is being discharged at 250A. Not sure where you got this 25% number.

http://www.trojanbattery.com/pdf/dat...ata_Sheets.pdf

[dmdomokos]

My experience has been that you can run a coffee pot off an inverter if your batteries are charged. My learning curve on this whole thing is learning how to fully charge a battery and what a fully charged battery looks like. Add in converter inefficiencies, length of time to charge (way longer than I thought) you get to the real problem us newbies have trying to run a coffee pot off 2 6v batteries. They are really never fully charged and you need them to be close to full to brew up a few pots. I also learned through all this we are big energy hogs.