herrakonna
New Member
So I am planning on replacing my current SLA battery bank with LifePO4 batteries which have built in heating (2x Renogy 100Ah) as I live in a cold climate and use my compact motorhome year-round, both for frequent overnight trips and it is also my daily driver.
C.f. https://eu.renogy.com/12v-100ah-smart-lithium-iron-phosphate-battery-w-self-heating-function/
The scenario I am dealing with is the following: I have used the motorhome for a weekend during the winter (when no solar is available) and the battery bank is depleted to ~10-20% capacity and I want to recharge the battery bank via the alternator when driving, but the outside temperature is -10C and the vehicle cools down to the ambient outside temperature overnight.
The batteries I will be using have built-in heating such that when a charging source is available, they will use that charging input to heat themselves until they reach a safe charging temperature internally, and will then begin to recharge. However, the length of time that it takes for the batteries to warm themselves up in the winter is likely going to be 20-30+ minutes which means that shorter trips will not recharge the battery bank any appreciable amount (unlike the current SLA bank). So I am considering options for pre-heating the batteries so that they reach a safe charging temperature faster and benefit as much as possible from recharging from the alternator every time I drive the vehicle.
I have a diesel Webasto system installed which heats the engine block and interior, which I run for ~20-30 minutes before I drive the vehicle when the temperatures are below freezing, but the interior heating it provides is not sufficient to affect the temperature of the batteries.
So I am considering surrounding each battery with a 12V heating pad, wired up via a relay such that they turn on only when the Webasto is running, drawing power from the house bank (which I understand should be fine even if the batteries are below +5C). Another option is to configure a thermostat and have them operate either when the Webasto is running or the engine is running, until the thermostat cutoff temperature is reached.
The ideal solution would function such that when the Webasto turns on, the heating pads also turn on and begin pre-heating the batteries. When I then start the vehicle ~30 minutes later, the batteries are either already over +5C, or nearly so, and the battery's internal heating can heat them the rest of the way, and charging occurs much sooner after starting the vehicle (perhaps even immediately) than if the batteries begin heating themselves only when the vehicle is started.
Having both the self-heating batteries and heating pads provides a "belt and suspenders" approach to warming the batteries as effectively as possible to benefit as much as possible from alternator charging each time the vehicle is driven.
Powering the heating pads from the house bank rather than the starter battery prevents draining the starter battery more than the Webasto already does.
Thoughts?
C.f. https://eu.renogy.com/12v-100ah-smart-lithium-iron-phosphate-battery-w-self-heating-function/
The scenario I am dealing with is the following: I have used the motorhome for a weekend during the winter (when no solar is available) and the battery bank is depleted to ~10-20% capacity and I want to recharge the battery bank via the alternator when driving, but the outside temperature is -10C and the vehicle cools down to the ambient outside temperature overnight.
The batteries I will be using have built-in heating such that when a charging source is available, they will use that charging input to heat themselves until they reach a safe charging temperature internally, and will then begin to recharge. However, the length of time that it takes for the batteries to warm themselves up in the winter is likely going to be 20-30+ minutes which means that shorter trips will not recharge the battery bank any appreciable amount (unlike the current SLA bank). So I am considering options for pre-heating the batteries so that they reach a safe charging temperature faster and benefit as much as possible from recharging from the alternator every time I drive the vehicle.
I have a diesel Webasto system installed which heats the engine block and interior, which I run for ~20-30 minutes before I drive the vehicle when the temperatures are below freezing, but the interior heating it provides is not sufficient to affect the temperature of the batteries.
So I am considering surrounding each battery with a 12V heating pad, wired up via a relay such that they turn on only when the Webasto is running, drawing power from the house bank (which I understand should be fine even if the batteries are below +5C). Another option is to configure a thermostat and have them operate either when the Webasto is running or the engine is running, until the thermostat cutoff temperature is reached.
The ideal solution would function such that when the Webasto turns on, the heating pads also turn on and begin pre-heating the batteries. When I then start the vehicle ~30 minutes later, the batteries are either already over +5C, or nearly so, and the battery's internal heating can heat them the rest of the way, and charging occurs much sooner after starting the vehicle (perhaps even immediately) than if the batteries begin heating themselves only when the vehicle is started.
Having both the self-heating batteries and heating pads provides a "belt and suspenders" approach to warming the batteries as effectively as possible to benefit as much as possible from alternator charging each time the vehicle is driven.
Powering the heating pads from the house bank rather than the starter battery prevents draining the starter battery more than the Webasto already does.
Thoughts?
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