Renogy Smart Lithium Battery with Self-heating

SolarShed

New Member
Hi,

Looking for experience and knowledge about using self-heating LiFeP batteries in the winter (for my shed).

Could somebody explain to me how well these self-heating batteries work in Canadian winters where temps can go as low as -35oC at night and stay below 0oC for months. My solar system is in my shed where its susceptible to the temperature changes.

I'm considering getting the new Renogy Smart Lithium 12V 100 amp battery with Self-heating.


MY concern is, if the temperatures being below 5oC for months at a time, would that mean the heater will be on for months?

How does this affect the longevity of the battery, and even safety?

Can I leave the charge controller connected throughout the winter months (like I did with my lead acid batter) and let the battery and charge controller figure stuff out?

It says it requires 4 amp of power to run the heaters. Being a 100 amp hr battery, and could be dark for upto 9 hrs a day in the winter months, would this even work?

thanks
 

Short_Shot

Solar Enthusiast
The heater will not run 100% duty cycle if it's well insulated but yes, as long as it's cold it will try to warm itself up. I'm not sure about their units but the battery heaters I've seen switch on at a given temp and off at a given higher temp so they don't just run forever.

You will likely have success with an abundance of insulation around the batteries. However much you think you need and then add more. It's likely that they won't run the heater very often at all.

I'd contact them and see if they know anything about expected watt hour consumption over time but I'd suspect with insulation they won't run constantly.

You could consider Battleborn as well. They have heated models and supposedly great customer service.
 

SolarShed

New Member
The heater will not run 100% duty cycle if it's well insulated but yes, as long as it's cold it will try to warm itself up. I'm not sure about their units but the battery heaters I've seen switch on at a given temp and off at a given higher temp so they don't just run forever.

You will likely have success with an abundance of insulation around the batteries. However much you think you need and then add more. It's likely that they won't run the heater very often at all.

I'd contact them and see if they know anything about expected watt hour consumption over time but I'd suspect with insulation they won't run constantly.

You could consider Battleborn as well. They have heated models and supposedly great customer service.
thanks for your reply! I found some information. Turns out, that it doesn't use the power from the battery to heat itself (or it shouldn't), it uses the power coming in from the terminals. This helps me in understanding that part.

I'm just curious if the self-heating batteries are more risker for fires. BB are great, but unfortunately I have all other Renogy smart products so I want to take advantage of this smart battery with my existing system.
 

Short_Shot

Solar Enthusiast
thanks for your reply! I found some information. Turns out, that it doesn't use the power from the battery to heat itself (or it shouldn't), it uses the power coming in from the terminals. This helps me in understanding that part.

I'm just curious if the self-heating batteries are more risker for fires. BB are great, but unfortunately I have all other Renogy smart products so I want to take advantage of this smart battery with my existing system.
Huh.

Seems like it would be necessary at night to consume power from itself though. It's obvious that it would be "powered" while charging though.

The terminals ought to be connected to the battery too so I don't see how it could somehow not pull from the cells unless the bms they use has a special setup.
 

SolarShed

New Member
I know, its kind of strange but it makes sense only because if you are constantly using battery power to run the heaters, you might get into a loop that it kills your battery sooner than later (short term and long term).

So its kind of like your in a cold night and the battery can't charge but can discharge (below -20, via the BMS) then morning light comes, the charge controller pumps voltage to the terminals but the BMS diverts it to the heaters and then when the internal temperature increases, heaters turn off and then directs power to cell.....
 

Short_Shot

Solar Enthusiast
Well it wouldn't be constant. It should be on a thermostat, and could be disabled when not discharging but that would leave you with a cold battery if you suddenly need it.

That kind of makes sense but it sounds like you'll need it for discharging too sometimes.
 

SolarShed

New Member
Well it wouldn't be constant. It should be on a thermostat, and could be disabled when not discharging but that would leave you with a cold battery if you suddenly need it.

That kind of makes sense but it sounds like you'll need it for discharging too sometimes.
you're right. Your only hope is that the battery doesn't reach -20 oC (or more) before the sun comes up because otherwise, it will shut off the discharging (including to the charge controller) and that is what is going to supply the power to run the heaters (via the solar panels). So, even with BMS and self-heating in cold, harsh environments, it could be a bit tricky.
 

Short_Shot

Solar Enthusiast
I think you'll be OK with sufficient insulation though. Remember they self heat slightly too when charging and discharging so insulation helps even more.
 

Short_Shot

Solar Enthusiast
There is a trade off. The LTO will handle low temps without a heater. Depending on where you live and average winter temps that might be an advantage.
Well it would definitely have to be priced out.

I don't think lto needs a bms as a 6 cell pack is good for higher voltage than lfp, but it would also most likely be a diy project or it'll cost twice as much per battery.

And I believe op wants to avoid diy.

So for the extra cost you'd be able to build a whole shed, insulate it, and put up extra panels to offset the heater power needs.
 

Northernchateau

Solar Enthusiast
Well it would definitely have to be priced out.

I don't think lto needs a bms as a 6 cell pack is good for higher voltage than lfp, but it would also most likely be a diy project or it'll cost twice as much per battery.

And I believe op wants to avoid diy.

So for the extra cost you'd be able to build a whole shed, insulate it, and put up extra panels to offset the heater power needs.
Let me ask, how much power do you think you need?
I will say that Renogy is a nice piece but a DIY set-up at that price would yield more amp-hours.
 

Northernchateau

Solar Enthusiast
I guess my only thing is, your in a camper and if the battery temp drops below 0c, LIFEPo4 batteres should not be charged.
Yes I see it has heaters but the power from the heater needs to come from somewhere. If tyhere is limited sunlight, what then?
I am thinking if I was not a DIY kind of person and lived in the great white north like you I would be looking at LTO batteries like below.
Yes they cost more but IMO they are better suited for the cold environment your talking about.
 
Top