FNG - Are my batteries bad? 2020 Interstate GT

[justinshort]

Hey folks - I've had my 2020 Interstate GT for about a month and have primarily been boondocking.. I've got 3500 miles on it so far and have spent about 15 nights in it. I'm still figuring out how to manage my power.. what uses what, etc. and I'm wondering if the braintrust thinks my batteries may be bad.

Yesterday, I drove about 5 hours and stopped around 10:30. When I stopped I was fully charged.. don't remember the volts exactly but it was 13ish. Overnight, I ran the onboard propane furnace.. the inverter with a very small fan, the fridge (no freezer) and left the water pump on. A few little push lights here and there but nothing major there. This morning, just 8 hour later.. I'm at 12.0 volts.

Based on what I'm using.. does this sound right? Is it the furnace that's using that much electricity?

[Bill M.]

My experience is with a trailer. But yes, the furnace uses that much power. And your batteries might not have gotten up to a full charge. Showing over 13 means the converter was still applying power, not that the batteries are fully charged.

Is the fridge electric compressor or is it a propane fridge?

When we boondock in the trailer we pretty much try not to use the furnace.

I expect you need the lithium battery upgrade to be fully functional in a Interstate.

[DKB_SATX]

There are still a few variables unaddressed. What was the state of charge at the beginning of the day? If you started from what should really be 100% charge (e.g. on shore power for 24+ hours) then this MIGHT suggest the battery is marginal, but you didn't really describe getting a good reading on the voltage, either.

a) When you arrived and checked the voltage, had you waited a while after stopping the engine to get "resting" voltage?

b) When you checked the voltage in the morning, was the furnace running? If not, had it been off for more than a few minutes?

Either of those things can affect the apparent voltage. Also, lead-acid batteries are SLOW to charge to 100%. If you were boondocking the night before (or had just been parked for a few days unplugged), the 5-hr drive likely wasn't enough to really get to 100% SoC.

[Al and Missy]

A key might be "Overnight, ... the inverter with a very small fan..."

Al

[turk123]

Originally Posted by Al and Missy

A key might be "Overnight, ... the inverter with a very small fan..."

Al

I agree. Get yourself a USB fan so you don't have to run the inverter.

[DKB_SATX]

Originally Posted by Al and Missy

A key might be "Overnight, ... the inverter with a very small fan..."

Al

Oh, perhaps I misread this... I was thinking the OP meant the fan on the inverter. Yeah, the inverter with a constant 120v motor load (even a small one) is going to chew on the batteries. Mine generally does OK with my CPAP overnight, though, with 2 flooded group24s.

[VT Wanderer]

This may tie into my new search for information. I am thinking about getting a Zamp portable solar system. Although we are not winter campers, (but do early spring in VT), I want to get as much info as possible about solar vs generator (we do have a Honda 3000). I'll be following any new thoughts/ideas that will be posted here.

[nvestysly]

We have a trailer and a van. In both cases, we were just guessing at our power consumption with the factory installed equipment Airstream provided. It was not until we installed a precision shunt and a true battery monitor system that we were able to dial in and see which items used how much power and some of them were surprises.

There's also the problem on new RVs, certainly new Airstream trailers and vans, that they have several parasitic loads.

A precision shunt battery monitor system is not difficult to install and will be worth the time and money. There are several available and to some degree which model you choose is related to future upgrades you might install. Randy at BestConverter.com is a good source for things like this. There are many other reliable retailers but Randy is certainly easy to talk to and has answered the phone for me (and plenty of other customers) on the weekend!

[DKB_SATX]

Originally Posted by VT Wanderer

This may tie into my new search for information. I am thinking about getting a Zamp portable solar system. Although we are not winter campers, (but do early spring in VT), I want to get as much info as possible about solar vs generator (we do have a Honda 3000). I'll be following any new thoughts/ideas that will be posted here.

I have a Zamp suitcase I've used to good effect when the weather's decent. If you're going to be around the campground, it's nice... silent, move the panels a couple times per day and it can stay near peak efficiency, etc. I negotiated it as part of my original purchase of the Flying Cloud, I believe it's a 160-ampwatt suitcase (now the options are 140, 180 and 230 I think.) With stock batteries it can be marginal for me, since I use the CPAP off the trailer's inverter every night, but if it's sunny every day and I can charge all day I can go several days without getting a generator out of the truck.

[Tomfeury]

VT Wanderer
I just added a zamp solar 230 portable to my system and it makes life easier. These are on top of my 160 rooftop stock panels and plugged into the zamp port provided on the hitch.First off, it keeps the batteries fully topped off when parked, so I have not had to plug into shore power yet this winter.

I plan to do some boondocking this summer in Michigan, and hope this added panel, can keep my powered, as some places, such as bear dunes, do not allow a generator to be run at any hour.

[BayouBiker]

Another factor not yet mentioned is the battery internal temperature. If the temperature (of the battery) in the morning was near freezing, then the battery had about 15-20% more residual than if it was 70 degrees reading the same 12V. A lead acid battery looses 0.024 V per ten degrees at the same charge level.

As others mentioned, there was plenty of load being consumed but also as some pointed out, the battery was almost surly not fully charged. 5 hours is not nearly long enough to restore a wet cell that has been sitting for even a little while if some sulfation has occurred. A partially sulfated battery will show a full charge even if capacity is significantly is reduced. It takes about 14 hours at 14.5 volts or so (depending on temperature) to revert to full capacity.

[justinshort]

Originally Posted by turk123

I agree. Get yourself a USB fan so you don't have to run the inverter.

USB fan on order.. thank you folks for the advice.

[Moodywelman]

Originally Posted by DKB_SATX

I have a Zamp suitcase I've used to good effect when the weather's decent. If you're going to be around the campground, it's nice... silent, move the panels a couple times per day and it can stay near peak efficiency, etc. I negotiated it as part of my original purchase of the Flying Cloud, I believe it's a 160-amp suitcase (now the options are 140, 180 and 230 I think.) With stock batteries it can be marginal for me, since I use the CPAP off the trailer's inverter every night, but if it's sunny every day and I can charge all day I can go several days without getting a generator out of the truck.

Re: yourZamp. Are you talking “amps” or “watts”? 160 amps is a whole bunch of power to get out of solar panels.

[DKB_SATX]

Originally Posted by Moodywelman

Re: yourZamp. Are you talking “amps” or “watts”? 160 amps is a whole bunch of power to get out of solar panels.

Sorry, of course it's watts rather than amps. The controller is under 10% of that, in fact, I believe it's a 15A controller.