Electric Blanket

[Raz]

Originally Posted by Gilda

You don't need a heated floor. Two simple solutions are a shag area rug and bunny slippers!\

An image that will make me smile all day! Raz

[blodn1]

Lol!

[Dudley]

To cut through all the math about dc current draw, a cheap and fairly accurate way is a dc watt meter before the inverter. Hobby shops sell them for checking power draw on electric powered planes . Hobby King has a wide selection for pretty cheap, all the way up to 130 amp.Watt meters Handy if you don't have a meter on you inverter or no inverter. They can also be used on a solar setup to see how much your putting in. Most have volt/watt/amps.

[SherryNPaul]

Jim, your cork floor looks beautiful. Lora, I'm glad to hear your report on 9 years with cork in the kitchen. We just put cork in our kitchen, as well as most of the house, and I love the look, feel, and quietness, but was a bit concerned about using it in the kitchen. Thanks for the info. I felt it was a good, eco-friendly alternative to carpet elsewhere, as I'm not fond of carpeting.

[Carol H]

Originally Posted by P. Raz

An image that will make me smile all day! Raz

Only problem is the dogs might think they are great chew toys!

[Jim Bennett]

Originally Posted by SherryNPaul

Jim, your cork floor looks beautiful. Lora, I'm glad to hear your report on 9 years with cork in the kitchen. We just put cork in our kitchen, as well as most of the house, and I love the look, feel, and quietness, but was a bit concerned about using it in the kitchen. Thanks for the info. I felt it was a good, eco-friendly alternative to carpet elsewhere, as I'm not fond of carpeting.

We use very little carpet on our projects these days, with hardwood being the most popular, followed by tile/stone, and then engineered flooring like cork. Carpet is generally only used in basements, and some for second floors if there is one.

That is another good consideration you mention, that I really hadn't considered, and that is how quiet it is to walk on.

[Lora]

Here are two pics of my floor. This is the area between the sink and cooktop so it gets lots of traffic.

From above and then looking across.

[Night Sailor]

Originally Posted by Dudley

To cut through all the math about dc current draw, a cheap and fairly accurate way is a dc watt meter before the inverter. Hobby shops sell them for checking power draw on electric powered planes . Hobby King has a wide selection for pretty cheap, all the way up to 130 amp.Watt meters Handy if you don't have a meter on you inverter or no inverter. They can also be used on a solar setup to see how much your putting in. Most have volt/watt/amps.

I have a LinkPRO which shows me what is going in and coming out of the batteries.

At present I am running on shore power. My new batteries are pretty much topped up, but I pulled my water heater to replace it with a new one with gas and electric and was shipped the wrong model. I have another one on order but not due in until next week. So I have the gas off and no heat at present except the electric blanket which I have been running on high with shore power.

The batteries were only showing 0.1 Amps going in on float, so they seem to be pretty much topped up.

Now might be a good time to try running the electric blanket, one side l, on high and other settings, and study the current draw. That should be 11 Amps above any other inverter loads.

[Bob Miller]

FWIW: charge rate of .1 amps may not indicate that the battery(s) is/are fully charged, it only indicates that the battery is at or near the voltage of the charger. If the charger voltage is lower than optimal, the charge rate is lower.

Actual battery voltage, taken about 2 hours after the charger is disconnected, of 12.6+ volts, or a hydrometer reading can tell if it is "Fully Charged".

[Carol H]

Originally Posted by Night Sailor

The batteries were only showing 0.1 Amps going in on float, so they seem to be pretty much topped up.

Only way I know of to be sure its toped up & holding the charge is to discount everything connected to the battery and let it sit for a number of hours then take a reading in its resting state as Bob suggests.

[Mike Magee]

7 pages of comments that have run all over the place, but I don't think anyone has mentioned the ElectroWarmth mattress pads! Our family had these pads atop the mattresses on all our beds. I have one on my bed at home, and I bought a 12V one for the trailer. Power draw is lower than an electric blanket. It's more efficient because heat rises (to the sleeper, in this case). My recollection is that the ElectroWarmth pad only uses about 2 amps on average. It has a thermostat and it cycles on and off, with 10 heat settings.

[Raz]

Originally Posted by Night Sailor

I have a LinkPRO which shows me what is going in and coming out of the batteries.



The batteries were only showing 0.1 Amps going in on float, so they seem to be pretty much topped up..

Try a multimeter on the 2 amp scale. With a 500 amp shunt you are trying to measure at 0.02% of full scale. Raz

[Bob Miller]

Looking at current flow to see if the battery is fully charged is like looking at the odometer to see how much gas is in the tank. It can be done, but it's only correct in a perfect world.

Mrs Ohm's husband told us long ago that, in order to have current flow, that you must have a "Difference in Potential". If the battery is at 12.3 volts and the output of the charger is only 12.4 volts, current flow will be limited by the .1 volts difference in potential and the internal resistance of the battery.....

Many a power converter/charger has been junked because the output of the battery charger section was to low to ever get the battery fully charged. Conversely, many a battery has been ruined by the charging voltage being to high and pushing the battery above 12.8 or so volts, resulting in boiling and plate damage. .

[MCDenny]

The LinkPRO will also show voltage, amp hours consumed and State of Charge. If it's set up right and it shows 100% SOC you are done.

[Bob Miller]

Good info, then what is the battery voltage when it's "Fully Charged" and the charger has been off for at least an hour.

[Carol H]

Originally Posted by Bob Miller

Good info, then what is the battery voltage when it's "Fully Charged" and the charger has been off for at least an hour.

I was actually taught that it should be off the charge & load for a least 10 hours in order to obtain the true state of charge. Have read some of the so called net battery experts suggest 12 hours.

[Raz]

Originally Posted by Bob Miller

Looking at current flow to see if the battery is fully charged is like looking at the odometer to see how much gas is in the tank. It can be done, but it's only correct in a perfect world.

These battery monitors appear to be originally designed for much larger systems than RV's and as such a value of 0.1 amps is probably not accurate. Thus my suggestion to use a multimeter if Conrad wants an accurate reading. But if the charger is operating correctly, with a charging current of 100 mA (more or less) I think it's a safe bet the battery is pretty much charged.

Mrs Ohm's husband told us long ago that, in order to have current flow, that you must have a "Difference in Potential". If the battery is at 12.3 volts and the output of the charger is only 12.4 volts, current flow will be limited by the .1 volts difference in potential and the internal resistance of the battery.....

I think you mean the wire resistance here.

[David Tilston]

Actually, I thought that the battery has a fair bit of resistance as well.

[Raz]

Originally Posted by David Tilston

Actually, I thought that the battery has a fair bit of resistance as well.

Since you are measuring at the terminals the effect of the internal resistance is incorporated in the measurement.

[David Tilston]

But the point was that 0.1 VDC has to push through resistance, both internal, and external. What is being measured at the terminals is the battery voltage. The resistance of the battery is incorporated in the sense of voltage drop, (rise?) under current flow, but the remaining 0.1 VDC wont cause much current flow, and the internal resistance of the battery is still in the circuit.

As an exaggerated example, if the wire has a resistance of 5 ohms, and the battery also has a resistance of 5 ohms. With a voltage differential of 0.1 VDC, the current flow should be 0.01 ADC. VS 0.02 ADC if the battery has 0 ohms.

Am I incorrect in this?