Micro Minnie Amp Draw

Okay we had our maiden voyage last weekend in our 2018 Micro Minnie 2108DS. On the second night we woke up to dead batteries. Yes, we were running the furnace but still. We have two new Group 24 batteries. We could dry camp in our R-pod for three or four nights in the winter no problem. And that was on one battery not two!

I did not run the generator during the day but I did get batteries back up close to 100% (all four lights on panel) with my 90 watt solar panel. Then at 3am Sunday we woke up to dead batteries. Not good.

Took it to dealer and they tested everything and are saying everything is fine. How can that be? I'm sure you guys dry camp in weather needing the furnace. How do your batteries perform? I guess my real question is could this 22' Micro Minnie be using significantly more battery power than my former 20' R-pod?

Yep, the furnace can kill your batteries just that quick. A lot of folks that dry camp and need heat use catalytic propane heaters. Compared to the R-Pod, the Minnie may take a lot more BTUs to keep at your desired temperature, therefore more furnace run time. The furnace in the Minnie may also be larger, and have a motor that draws more power.

^^ What he said ^^

I would pull your batteries and get them load tested at an auto parts store or you can buy the load tester on-line, they are very inexpensive. If you have the footprint for larger batteries, I would go up as large in physical size as you can. Generally speaking the physically larger batteries have more capacity (with some exceptions.)

I'm a huge fan of Lifeline AGM batteries. AGM chemistry battery will charge faster and have a slower self-discharge rate. I replaced my first set of Lifeline AGMs at seven years of age just because, they will far outlast the run of the mill flooded cell batteries. Also be sure your present batteries are designed for deep discharge but never discharge any battery below about 50% capacity - that will shorten the usable battery life if done routinely.

In addition to the fact that as kdbgoat said the furnace draws more than you might think, my guess is that the batteries were not fully charged at the end of the previous day (notwithstanding having four lights on the panel). Those types of status panels do not give you an accurate state of charge, plus your 90W solar panel is only going to give you about 5-6 amps peak, for about 4-5 hours during midday (you?ll get some charging morning and afternoon but at a lower rate). You could well have started the evening with a 75% state of charge.

Agree with all the comments  above, but still it seems that 2x Group 24 batteries should have lasted just one night. We can only conjecture how many hours the furnace actually ran, but its fan uses around 5A/hour and can easily consume 40-50 AH over a 12 hour period.  That's the entire usable power in one Group 24 battery. Throw in some other power consumption and maybe less than full charge to begin with and I can see getting close to killing both batteries.

Does the Minnie use more power than your RPod? Very likely. Probably a bigger (more btus) furnace, larger interior volume to heat, a slide-out to deploy, and perhaps more lights? And maybe you were a bit more extravagant using power in your exciting new rig?

I think you need to do a more cautious test run, making sure the batteries start out fully charged and paying attention to power usage. It's always difficult to assess what power was actually used after the fact - most of us aren't watching power demand until its too late.

Sun2Retire said:

In addition to the fact that as kdbgoat said the furnace draws more than you might think, my guess is that the batteries were not fully charged at the end of the previous day ...

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That's a good point. If his batteries are flooded cell, he can determine state of charge with a hydrometer.

I'm not believing that the R-Pod would last 3 or 4 nights running the furnace without the batteries being charged daily.

Other than that, this sounds absolutely normal. The batteries were good for the first night, then well into the second night, without being fully charged. A 90-watt panel can only do so much.

Our portable solar panel will keep us going with the fridge and LED lights. I'd never consider trying to run the furnace.

Good info guys. Really appreciate it. And HappyWanderer you may be right. I may have run the generator after day 2 or 3 when we winter camped in the Pod. Can't remember specifics like that but I do remember one night in the Pod and it got down to single digits and that single Group 24 battery made it through the night. Two weeks ago in the White Mountains the low was only in the 30s and both Group 24s in the Winnie were toast by 3am.

I talked to a guy today and learned that the television antenna booster is a large draw and sure enough it was in the on position. Rookie mistake. Another amp draw I learned about today is the heating element in the Dometic fridge. It's function is to prevent condensation build up inside the fridge but dry campers like us can certainly live without it. Older models have a switch inside the fridge to turn the heater off but Dometic did away with the switch - probably to save a buck or two per unit - so now the only way to turn the heater off is to either cut the wire or pull the wire off the terminal and wrap it with tape. The wire feeding the heater is easily accessed inside the removable cover over the interior light. The smaller of the two black wires is the one feeding the heater. Im not a big fan of cutting wires so I decided to pull it off the terminal but the problem with simply pulling the wire is it also disconnects the light inside the fridge but it was a concession I was willing to make. So those two amp draws combined with the fact that we did not start the night with a full charge hopefully explains why we drained both batteries. Or at least I hope so. Again, thanks for all of the good info. This is an excellent forum and I really appreciate the help.

Bill

I'm skeptical that the antenna amp has that much power draw when idle, but every little bit contributes to what is known as "phantom power loss". Any sort of heater, though, is a significant amp draw so the fridge no doubt is a piece of the problem.

Do you have a multi-meter (VOM)?  Measure the amp draw at the batteries when everything you can think of is turned off. Put the VOM in its high amp mode (even cheap meters can handle 10A) and put it in series with the battery ground cable to measure the actual amp flow.  Some rigs have been known to steadily consume more than 1.0A.  These days, few devices or appliances are truly powered off. Their digital circuit boards remain on stand-by and draw tiny amounts of power. The better quality ones use almost zero, but sometimes a sloppy design can pull 150-200 ma. That can add up. You can make further checks by removing DC fuses one at a time to see which one affect the amp draw on through the meter.

How about crimping a bullet-type connector in that heater wire so you can easily reconnect it if needed? Bullet-type splice connectors are slim, so usually fit in small spaces nicely.
https://www.amazon.com/Insulated-Bullet-Connectors-22-18Ga-100pcs/dp/B001HXFW8Y

I don't disagree with anything above. Since it sounds like you enjoy boondocking, I'd emphasize the importance of always being able to determine your battery bank's state of charge (SOC) because it sounds like your batteries aren't getting as fully charged as your panel indicator says they are. Those little panel lights just don't cut it.

Most of us who boondock a lot have installed battery monitors, like the Trimetric 2030 RV. http://www.bogartengineering.com/products/trimetrics.html They display, in percentage, the amount of capacity remaining in your battery bank at any given time. They display a lot of other useful information too. I like to say that boondocking without one is like driving without a fuel gauge.

Kev