Help my with my power strategy- 24v espar heater (1 Viewer)

[peteinjp]

So I have my espar heater installed and finally hooked up the wiring last night. I ran it with the blower motor for a good while - say 45 min- and the batteries were just barely able to start the engine. Granted the batteries are getting on in age but still the have been 100% reliable to this point with no signs of being tired.

It's a 24 V truck so there are two batteries. I'm considering going to four smaller 12v batteries batteries- 2 for starting isolated from 2 running the heater. That way I could run a deep cycle pair and a pair of starters keeping them isolated and never have to worry about whether or not my truck is going to start out in the middle of nowhere in a big pile of snow.

This could be totally overkill I have no idea. I could just as easily find the largest batteries it will fit with good specs both in terms of the cold drinking amps as well as amps per hour like a hybrid marine battery.

I'm also open to using any type of battery and just going with whatever has the best specs for the size will fit in my battery tray.

How should I go about figuring out what set up would best suit my needs?

I also like to have some way to lower the power consumption of the blower fan. Espar makes a blower control module that can be used to adjust the amperage to the low side to save electricity. It's not cheap so I was thinking of simply adding a relay as well as some type of control to lower the power consumption.

My third question is about a solar charger. I have a Powerall Goliath 24v lithium jump starterbut in the event that that didn't work I like to have some way to charge the batteries if I'm out in the middle of nowhere even if it takes a day to do it. Put me in the right direction in terms of some type of charging set up it's very simple.

Thanks,

Pete

 

[Bogo]

What is the Amp draw for start-up? It is higher for firing up the glow plug. Also what is the running Amp draw? From that we can figure out roughly how much was used from the batteries. That can then be used for figuring out how large of battery pack may be needed to run the heater per night.

Having a house battery pack that is charged when the engine runs, but disconnects when the engine is off would work. It would then be used to run the heater. There are a variety of different types of disconnecting methods available. Each with it's pluses and minuses.

As for solar, any 24V output solar charger with a high enough voltage input solar array would work. If you used standard solar panels, you'd need two in series. I'd go for a high voltage panel, and use a 24V output MPPT type controller.

 

[peteinjp]

The instruction manual list of power draw has 2 A for 24 V system. I have to measure the starting amperage as well as the amperage that the fan draws and get back with that info.

I probably should've stayed in my intended use as well. I go out and camp in the winter sleeping in the truck. I don't need to keep the heater on the whole time but I'd like to at least set it to come on and heat the cabin in the morning. In fact I'll have a heat the cabin every morning. I'll also see how long takes to get the cabin hot and get back to you with that info as well.

Thx/

P

 

[peteinjp]

So I check the amperage. For two minutes he draws 4a then runs at 2a. The fan also draws 2a on high for a total of 4a.

The batteries measure 24 V but the car won't start or even glow.......

Now for a complete newbie question how should I be measuring my battery to see if they're charged or not? Obviously measuring just the voltage is not enough.

Pete

 

[Bogo]

Espar has a timer unit that can automatically heat the vehicle in the morning. It will shut it off after so many minutes run time.

How long did you run the espar and fan in total? 45 minutes for the first time at 4 Amp draw isn't that much power out of the average starting battery. Double that time should still be handled fine by the batteries. The smallest starting batteries I have are 35 Ah. 3 of them could fit in the space of a Group 31 battery. They should be able to run the espar and fan for 3 hours and still be able to start my truck. It sounds like yours are near death. At roughly 28 volts it is also possible one of your batteries has a shorted cell, but that wouldn't account for the lack of reserve time.

 

[peteinjp]

I have the timer/ 7 day easy start timer and it works great. Yes I think your right about the batteries. So should I just stick with the largest starting batteries I can fit? From what your saying it souknds like that would do the trick.

Pete

 

[Bogo]

That's kinda what I'm thinking too. A solar top off would be good. Consider other uses too. Like compressor based coolers, recharging phones & laptops, etc.

 

[peteinjp]

That's a really good point about other uses. I have been eyeing a refrigerator for a couple years now and haven't pulled the trigger. I suppose with this leave me with is the idea that I should find the biggest starter batteries with the highest amps per hour that I can fit in the trays that I have.

Pete

 

[peteinjp]

So far the most powerful battery I found from a reliable manufacturer is rated for 65 amp hours. For 24 V I would use two of these of course and they fit in a battery trays. They're also very expensive made by odyssey a company I've used before and think it's a very good job of supporting their product. It's a PC 1700. So the question is is this totally overkill?

For example if I expand the size of one battery tray I could fit 2 PC 1100s with 43 a/h each into one tray and that would free up a lot of room in the engine compartment and make my power steering conversion a bit easier. If 43 amp hours times two is more than enough considering that I may add a fridge in the future then of course I want to go that route.


Pete

 

[Bogo]

As for size, you'll have to figure that out. Don't forget about Cold Cranking Amps (CCA). That is the amount of current they can output at 0F. Your new batteries should have an equal or larger CCA than the old ones.

 

[peteinjp]

Bogo- wasn't it optima that had problems after moving manufacturing to Mexico.

From their website:

"ODYSSEY batteries are manufactured to strict quality standards in two facilities globally: Warrensburg, Missouri USA and Newport, Wales United Kingdom."

 

[Bogo]

Oops, my bad..

 

[canman]

I think you have bad batteries. Last year, a couple of my buddies ran their Webastos several times during the night, probably totalling around 45 mins as well, and had no issues starting their trucks (HDJ81 & HJ60) in the morning at around 0C ambient.

 

[e9999]

the Ah rating of the battery should give you a (very) rough idea of what they are capable of delivering when in good shape. For deep cycle ones I think the standard is 20 hrs but only 10 for starting batteries. For the former type, a 43Ah rating would mean you can expect about 2.15 Amps over the 20 hrs before the battery is dead. If you draw it faster you get less energy overall, though, and vv, IIRC. You would still need to figure out at what point you can no longer start the engine, though.

 

[peteinjp]

Yes I do need to figure that out. I have replaced the batteries with 2 pc1200's stuffed into a single homemade tray freeing up the right side engine compartment for a small compressor.

I have the Espar unit set to automatically shut off if the batteries reach 20v but this was too low on my old batteries.

The new units have a 10h amp rating of 40a each. The odyssey batteries are supposedly good in both starting as well as capable of being repeated drained like a deep cell but hopefully they will not be drained often if ever.

No problems running the heater and fan blower for a couple of hours in the morning so you guys were right.

I'll get a shot if the final product when I get back from the holidays.....

Pete

 

[peteinjp]

So this is been working out pretty well. Turned out it was the batteries after all. I'm still interested in getting solar set up to keep this thing running over a longer period of time but for now my car is very warm all day!