Espar D5 switches off for low voltage.

[Vndlfsn]

• New 12 V 200 amp hour AGM Renogy battery installed in September.
• Solar charge controller indicates battery is full before I turn the system on.
• Main breaker is off..
• Ambient temperature is 28°
• Inverter is off.
• Espar controller set to 93° and the thermostat to 55.
• System and furnace switches are on, fan is set too low.
  Battery is outside.
  2 100w solar panels - van is outside but it has been cloudy.

Results: after 30 minutes espar system has shut itself off due to low voltage and the solar charge controller indicates 12.3 V.

Any advice or experience out there? Many thanks in advance!

[1der]

Ambient temp is 28F, what is temp of battery itself and mounted outside? Without any battery heating, the battery is likely in low temp protect and not receiving ANY charge regardless of sun or shorepower.

Solar Controller - what is the indicator that battery is full? Really the only way to know is battery with no draw or charge, resting for a few hours. Turn off the solar controller and see what the battery voltage really is.

At first take, I think you have a battery that is not really charged like you think it is.

[Scalf77]

Your battery is low, If you have been counting on Solar to keep the battery charged, it very possible it has not been up to the task.

[Vndlfsn]

Thanks!

So what kind of charging infrastructure would support running the espar for, say, 8 hrs overnight if needed? More efficient heater? More solar? More batteries?

[1der]

Bummer - missed the battery type being AGM. So, no BMS to shut down but still, a reduced capacity due to cold. Every 1 deg C change below 25C/ 75F is a 1% reduction in capacity on an AGM.

28F =-2.222 °C which means 27% less capacity due to temp.

200w solar on a great sunny winter day contributes maybe 30 amps in total for the day depending on the latitude. So, as Greg says, the solar is probably not covering the charging needs. The last 5% charging of an AGM can take hours by which time the sun has set.

Can you plug the van into shorepower / or add a charger to house battery? Do this overnight/24hrs and give the heater another shot.

[1der]

Very similar thread:
https://www.sportsmobileforum.com/fo...-d5-31022.html

An Espar D5 is going to use around 5A/hr while running, maybe a bit more. Start up will be the heaviest draw for about 5 to 10 minutes. So, overnight use I would guess would be in the 40 to 50 A range.

Low voltage cutoff setting - can you monitor voltage to see what the battery voltage is actually dropping to? Espar D5 Spec says 10.5 is low voltage cutoff but it can be changed. If it it is up at 12 or 12.3, that is too high.

A good condition 200ah AGM should get you through a night maybe two depending on other draws. But, the engine will have to run for a couple of hours to get the battery back up to 90% or so to go to night three. A real battery monitor / shunt such as the Victron Smart shunt properly installed would give you lots of visibility of battery condition/State of Charge/current usage.

You have one of the most efficient heaters albeit a D2 or D4 Airtronic would be even more efficient by eliminating the liquid heat exchanger pump draw and loss of heated water.

More AGM battery capacity? Maybe, if you are not driving/engine running every other day for a few hours, or if not able to plug in for charging. Or switch to Lithium with inside cabin or insulated storage, and then ALL the other mod$ to make Lithium viable. Lith is really nice but it is $2 to $3k pretty quickly.

More solar? - not very practical for winter usage.

[Vndlfsn]

I really appreciate all of your expertise, I’ll spend some more time with this over the next few days.

We are heading to Moab for camping and hiking in March and expect it to be pretty chilly overnight.

We have a 2013 sprinter with a penthouse and my wife really enjoys sleeping up top.

One of the reasons we wanted a sports mobile was due to the penthouse and also the overall build quality and the insulation..

[1der]

We love winter camping in our pop top and the heater makes it cozy. Adding a couple of these to circulate the warm air more evenly throughout took it to another level!

https://a.co/d/cW2NkCy

[JFlo]

These things are very finicky when it comes to power draw. Make sure all connections and grounds are solid. Any resistance will further limit power draw and lead to weird behavior.

[Big_ern_101]

Few suggested course of actions:
Measure voltage at the actual battery with an actual multimeter and use that to determine the state of charge of the battery.

Can read up on that here.
https://sunonbattery.com/agm-battery-voltage-capacity/

If the voltage at the battery is low, either the battery is roached or its not charged/charging as expected

If the voltage at the battery is indicating that it is charged, thats a good step but you are not out of the woods.

Next hook everything back up and measure the voltage you are seeing at the connections to the Espar heater while it is running. You can also measure the voltage across the battery terminals at this time, and see if the values are close. Shouldn't be seeing much more than .1 to .2 volts difference. More than that, check the connections between the Espar heater and the battery, checking voltages along the way, till you identify the bad connection.

Side note are Espars really that inefficient compared to the Chinesium units? I see a lot less than 5A draw on 12V once my Chinesium diesel heater has settled down, it does draw a bit of power during startup and when on full tilt boogie. Dont have the exact numbers but its closer to 2A running moderately high and less than 1A at low.