Insulated battery box: incandescent bulb for heat good idea?

[hammick]

My 16s 280ah EVE batteries have been on the slow boat for a month. I am going to insulate the battery box that housed my 48v L16 Trojans. Plan is to use rigid foam board insulation on the top, bottom and side of the box. I have read a few post about heating wraps for the battery but figured a simple incandescent light bulb would be the easiest. I could set it on a timer or have it come on at a set temperature.

The light bulb will not be needed most of the winter. My insulated garage where the batteries are located rarely drops below 37 degrees Fahrenheit and usually closer to 50 degrees. Why are people using heater wraps or pads over a simple light bulb?

Thanks.

 

[Bob B]

My 16s 280ah EVE batteries have been on the slow boat for a month. I am going to insulate the battery box that housed my 48v L16 Trojans. Plan is to use rigid foam board insulation on the top, bottom and side of the box. I have read a few post about heating wraps for the battery but figured a simple incandescent light bulb would be the easiest. I could set it on a timer or have it come on at a set temperature.

The light bulb will not be needed most of the winter. My insulated garage where the batteries are located rarely drops below 37 degrees Fahrenheit and usually closer to 50 degrees. Why are people using heater wraps or pads over a simple light bulb?

Thanks.

I think a light bulb would be more prone to failing.

I used to have an automatic propane generator that would fail to start if it was very cold. I was running a light bulb inside it to keep the temperature up and that worked ok til the light bulb failed. Then I had to go out in really cold weather and a power outage to try to get it started.

Edit .... Oh, after that, I put a stick on silicone pad heater in it controlled by a thermostat .... never had any more problems while I lived there.

 

[hammick]

I think a light bulb would be more prone to failing.

I used to have an automatic propane generator that would fail to start if it was very cold. I was running a light bulb inside it to keep the temperature up and that worked ok til the light bulb failed. Then I had to go out in really cold weather and a power outage to try to get it started.

Thanks for the response.

I though about the bulb burning out. I could easily install two bulbs in the enclosure. One as a backup. I would know if a bulb burned out either through my battery temperature sensor or my shunt based battery monitor. I have the ability to remotely monitor each. I'm using a combination of Insteon and wifi plugs from Amazon to control my lights and outlets remotely. My cost to install two lamps in the enclosure would be less than $20 including the dual wifi plug.

 

[Bob B]

Thanks for the response.

I though about the bulb burning out. I could easily install two bulbs in the enclosure. One as a backup. I would know if a bulb burned out either through my battery temperature sensor or my shunt based battery monitor. I have the ability to remotely monitor each. I'm using a combination of Insteon and wifi plugs from Amazon to control my lights and outlets remotely. My cost to install two lamps in the enclosure would be less than $20 including the dual wifi plug.

Go for it .... let us know how it works out.

 

[hammick]

Go for it .... let us know how it works out.

Well I'm not convinced yet. I do know that incandescent bulbs waste 90% of their energy as heat. Not sure how long a 40w bulb would need to be on to heat up the batteries. Once the solar starts charging powering the bulb isn't an issue.

 

[averagejoe]

9.372 bazillion rural folks in the U.S. use/used 100 watt incandescent light bulbs in their well houses/covers (the high-tech rednecks put them on a thermostatic switch) to keep their wells from freezing. When it was announced these supposed energy wasters would no longer be made, there were people buying them by the case!

You could use a lower wattage bulb, just maybe more of them. Then you would have a backup or three. Whichever wattage you choose, you need to do some testing to see what temp you can maintain inside your battery box with which wattage bulbs. A 100 watt incandescent bulb produces about 300 BTU/hour. This is the least efficient solution, since you're heating air to in-turn heat the battery, but it is pretty simple.

A battery thermal wrap (most I've looked at are thermostatically controlled) runs at 50-100 watts, and may need to come off in warmer times of the year to prevent the battery from overheating. A little googling suggest these are the priciest solution.

A battery heating pad (cheaper ones require a thermostatic switch) sit under the battery and draw about the same 50-100 watts though there is no need to remove them from underneath during warmer times. Again, a little googling reveals there are less expensive, and there may be a manufacturer or two who can make a custom sized pad for you. Or you may look for RV tank heating pads, and maybe find one in a size to fit your battery system's footprint. Seems like the RV pads usually have a thermostat built in and can run on 12 volts (which doesn't help too much with your 48 volt system).

As to your question of why a pad or a wrap versus a simple lightbulb, I will guess people don't want a "redneck" solution, or worry the lightbulb as a heater may not have UL approval (our safety Nassis here in the U.S.A. for all you nice furren members), or don't want a bunch of room taken up by lightbulbs.

You might look at this person's post for more info on heating pads/wraps. https://diysolarforum.com/threads/i...ent-bulb-for-heat-good-idea.14845/post-166025

If you're looking for approval, then you have my permission to do whatever you like (within the limits of the law).?

 

[chrisski]

I remember touching a LED 100 watt equivalent bulb because I thought they put out much less heat than an incandescent 100 watt bulb. My wife got a kick out of that as the LED burnt to the touch. Three of those LED bulbs would pull 100 watts and my guess is they would put out a similar amount of heat, at least based on my non-scientific touch test.

 

[averagejoe]

I remember touching a LED 100 watt equivalent bulb because I thought they put out much less heat than an incandescent 100 watt bulb. My wife got a kick out of that as the LED burnt to the touch. Three of those LED bulbs would pull 100 watts and my guess is they would put out a similar amount of heat, at least based on my non-scientific touch test.

LEDs of nearly any "incandescent wattage equivalent" are a non player as heaters. The reason 100 watt incandescents were used as heaters was that they are 10% efficient as a light source (meaning 90 watts of their consumption is waste heat - about 300 BTU/hr). I've got 300 watt equivalent LEDs in my garage, and I can take them out of the socket by hand when they are running. There are in fact parts of the LED light assembly which could burn me, but you'll notice the LED bulbs are very well ventilated and without removing the diffuser, you're not going to get near the hot part.

100 watt equivalent LEDs draw about 15-20 watts, so you'd need 5 or 6 of them to get close to a single incandescent.

 

[chrisski]

100 watt equivalent LEDs draw about 15-20 watts, so you'd need 5 or 6 of them to get close to a single incandescent.

Well maybe my touch test was not as scientific as I thought.

 

[ghostwriter66]

We actually use regular ol' fashioned 200W incandescent bulbs in many of our systems that do not like to operate below freezing in order to keep them warm - bulbs cost us less than 2.00 at the local grocery store ... PLUS if we have to go into those shacks to do any type of work its like brighter than the sun in there... win-win ...

 

[HRTKD]

Batteries are very dense. I question the effectiveness of an incandescent bulb at getting a 280 Ah battery thoroughly warm.

I'm using pad heaters that are controlled by a thermostat designed to turn on at 35° F and off at 45° F. There are a couple of threads that discuss methods for keeping LiFePO4 batteries from falling below 32° F.

 

[AREA351]

My 16s 280ah EVE batteries have been on the slow boat for a month. I am going to insulate the battery box that housed my 48v L16 Trojans. Plan is to use rigid foam board insulation on the top, bottom and side of the box. I have read a few post about heating wraps for the battery but figured a simple incandescent light bulb would be the easiest. I could set it on a timer or have it come on at a set temperature.

The light bulb will not be needed most of the winter. My insulated garage where the batteries are located rarely drops below 37 degrees Fahrenheit and usually closer to 50 degrees. Why are people using heater wraps or pads over a simple light bulb?

Thanks.

Why are you worried about temps when it's no were near having any issues with your cells?

 

[beaker]

Look into ceramic heat emitters, that fit in a standard light socket. Also look at line voltage thermostats. That's how I kept my chickens above freezing in Minnesota.

 

[hammick]

Why are you worried about temps when it's no were near having any issues with your cells?

I'm not sure I follow. My batteries will be delivered soon. I will be installing them in our garage located in Montana. At some point this winter there could be a prolonged cold snap that will take my batteries below 32 degrees. If not great. But I need to be prepared in case it happens. At some point in the future it will happen. And it's likely to happen when I am 1,200 miles away.

 

[AREA351]

I'm not sure I follow. My batteries will be delivered soon. I will be installing them in our garage located in Montana. At some point this winter there could be a prolonged cold snap that will take my batteries below 32 degrees. If not great. But I need to be prepared in case it happens. At some point in the future it will happen. And it's likely to happen when I am 1,200 miles away.

"My insulated garage where the batteries are located rarely drops below 37 degrees Fahrenheit and usually closer to 50 degrees."

 

[hammick]

"My insulated garage where the batteries are located rarely drops below 37 degrees Fahrenheit and usually closer to 50 degrees."

True but anything is possible in Montana. That's why I am not going to bother with expensive and complicated heater wraps. I'm going to put an incandescent light bulb in there plugged into a $5 wifi plug that I can control with the "Smartlife" app. I can turn it on, off and set timers from our main home which is 1,200 miles away.

When checking the batteries or BMS I can also use it for light. Win Win like Ghostwriter says.

When we are gone our inverter is powering the refrigerator which is loaded with frozen goods. Not to mention my security cameras, remote generator start, etc. If my inverter shuts down I'm screwed.

Also if you go by the Trojan Lithium charge rates you are supposed to drop the charge current as your batteries lose temperature. So if Trojan is correct this bulb could be useful year round for charging at full rate.

 

[HRTKD]

@hammick, area351 was simply quoting what YOU posted in the first post of this thread. You were the one saying it wasn't going to drop below 37° F in your garage. Now it's going to go below 32° F? Well, which is it?

 

[hammick]

@hammick, area351 was simply quoting what YOU posted in the first post of this thread. You were the one saying it wasn't going to drop below 37° F in your garage. Now it's going to go below 32° F? Well, which is it?

I said "rarely drops below 37 degrees". Off grid at 5,100' in Montana anything can and eventually does happen which is why I am devising a plan to keep my batteries warm when needed. And chances are if something bad is going to happen I will be 1,200 miles away. Like last February when my panels got covered with snow and ice for two weeks. Finally found a guy to get up there on snowmobile and clear them off. My L16 batteries were at 10% by then. Not good.

 

[hammick]

Batteries are very dense. I question the effectiveness of an incandescent bulb at getting a 280 Ah battery thoroughly warm.

I'm using pad heaters that are controlled by a thermostat designed to turn on at 35° F and off at 45° F. There are a couple of threads that discuss methods for keeping LiFePO4 batteries from falling below 32° F.

That is a good point. But I have the ability to monitor my battery temperature 24/7. And with the ability to turn the bulb on/off at any time I could probably keep the batteries within a 5 - 10 degree range pretty easily by running the bulb for a number of hours a day when the sun it shining. In other words never let it drop below say 73 degrees.

 

[AREA351]

I personally would use a grey/black tank heating pad set with a thermostat if that is the case.