Newbie questions about batteries

[Tbrek]

Hello, I have 184BS and headed out for a few days next week. Do folks prefer AGM or Lead acid battery? Is it a good idea to carry a spare batter if boon docking? How do you know when to stop drawing off the battery so as to not overdischarge it?

Thanks!

[Mustang65]

Originally Posted by Tbrek

Hello, I have 184BS and headed out for a few days next week. Do folks prefer AGM or Lead acid battery? Is it a good idea to carry a spare batter if boon docking? How do you know when to stop drawing off the battery so as to not overdischarge it?

Thanks!

We need a little more information. How long do you plan on boon-docking? Weekends, Week, ......? Cold weather.... warm weather?
Using an inverter to power your TV?

The key to batteries are the Amp Hours of the battery. That pretty much decides on how long you will be able to camp using only battery power. The basic Marine/RV battery is about 85Ah, next step up is 100Ah. Either are for very short outings.

How do you plan on charging your battery(s) while boon-docking? You need to replace the power you extract from the battery(s)?

AGM cost a lot more. If your battery(s) are mounted on the outside of your TT go with the regular Marine/RV deep cycle batteries. Since it sounds like you are not used to using battery power, your first battery(s) should be regular Marine/RV deep cycle batteries. Once you learn the limits of the battery power, move on to the REAL deep cycle batteries (6 volt variety). These batteries are about 230Ah's, used for longer boon-docking periods and cost MORE.

12Volt battery systems should not be discharged below 12.2VDC. A dead 12Volt battery is 10.5Volts.

Pick up an inexpensive Digital Voltage display that plugs into the 12Volt Auxiliary power outlet in the TT.

I am sure others will give you more suggestions.
Don

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[jd99336]

Mustang65 brings up all of the right points. Some duplication here but:

1 standard 12V deep cycle battery will be fine for a weekend as long as you are not running the heater (fan motor), tv or other hungry appliances. It will give you some lights and such for a few days.

You charge the battery (hopefully) from your 7 pin plug between the trailer and the tow vehicle. If you run it dead, you would start your tow vehicle and plug in the trailer unless you plan on taking a generator. A small harbor freight generator will allow you to extend your battery life, but you will be running it 2 to 4 hours a day to charge.

2 12V deep cycles will get you a bit more duration...running the heater for nights, etc and if you want to really get duration....2 - 6V golf cart battery as Mustang noted (you have to have two in order to get the requisite 12V in series.

This is a really deep question with lots of bunny trails to go down, so you need to decide what you want from your boondocking, then google the options including generators, solar, etc....

Good Luck

[Tbrek]

Thanks...very helpful. I'm looking at 3-4 days and trying to not run heater at night, no TV. Has anyone used the 100W portable solar panels? Are those able to keep the batter sufficiently charged?

Troy

[DonaandDon]

A quick charge for your RV battery is to remove it from the RV, take it to the truck and use jumper cables to charge it back up. Won't take long to get enough juice to closeup the RV and bring her home.

[jd99336]

Originally Posted by Tbrek

Thanks...very helpful. I'm looking at 3-4 days and trying to not run heater at night, no TV. Has anyone used the 100W portable solar panels? Are those able to keep the batter sufficiently charged?

Troy

I have two grape solar 100W panels that I bought from Costco a few years back. I set them up as "portable" but have hooked them up only one time (usually boondocking is only a day or two and I have two 6v batteries) so can't give you a "for sure" report. BUT, with good sun exposure, I think a 100W panel generates something like 5 to 6 amps (there are formulas for conversion but it is something like watts divided by voltage). That 5 or 6 amps will be charging your battery for likely 5 to 7 hours (average number due to less sunlight in morning and evening), so you will pump 25 to 30 amp hours back into your battery. If you have a 100 amp hour battery, you can see it will return some charge, but the rest depends on your use.

If you are thinking of going solar, go read a couple of the excellent articles on the topic online as some really smart people have broken it down to even my level of understanding.

[Tbrek]

Thanks good idea

[Mustang65]

Originally Posted by Tbrek

Thanks...very helpful. I'm looking at 3-4 days and trying to not run heater at night, no TV. Has anyone used the 100W portable solar panels? Are those able to keep the batter sufficiently charged?

Troy

A 100 watt panel is a GREAT start if you like boon-docking. You can go 2 ways with SOLAR, 1- buy a 100 watt panel kit (expandable to 400 watts - future additions like Renogy) and roof mount it orrrrrr 2- buy a 100 watt portable panel kit.

Both have their pro's/cons.
Roof mounting:
- Mount it and forget about it (just keep it clean, and inspect a few times a year)
- If TT is stored outside in a bright area keeps the battery cleaned each and every sunny day
- No wear and tear on panels and wiring
- If stored or parked in shade the output will be reduced (but in storage there should be enough energy to keep the fully charged batteries topped off

Portable:
- Have to setup and take down each camping trip
- For optimal results they need to be moved throughout the day as the angle of the sun changes
- Possibility of growing legs

Most of the members seem to have gone with the roof mount. Mine has been on the roof since 2012 and is as secure today as it was on day one.

The 2 Trojan 6 volt T145 batteries, installed in 2012 are still supplying power to the TT. The 250 watt residential roof mounted SOLAR pane has been working hard 24/7 since the install which as of this minute has produced 47,448Ah's since the install.

The JAYCO forum has a SOLAR community with a lot of information.

Don
My Registry

RVing with SOLAR

[Mustang65]

Originally Posted by jd99336

I think a 100W panel generates something like 5 to 6 amps (there are formulas for conversion but it is something like watts divided by voltage). That 5 or 6 amps will be charging your battery for likely 5 to 7 hours (average number due to less sunlight in morning and evening), so you will pump 25 to 30 amp hours back into your battery. If you have a 100 amp hour battery, you can see it will return some charge, but the rest depends on your use.

The formula is correct, well sort of. There are 2 types of SOLAR charge controllers PWM and MPPT. The PWM is the inexpensive technology vs the MPPT which is the PERFORMANCE product.

For example (PWM): even though your solar panel is rated at 100 watts, you won't get the full 100 watts unless the battery is at optimum voltage (16.5volts DC).

With a PWM charge controller, if your batteries are low at say 12.4 volts, then your 100 watt solar panel rated at 6 amps at 16.5 volts (6 amps times 16.5 volts = 100 watts) will only charge at 6 amps times 12.4 volts or just 75 watts. You just lost 25% of your capacity! PWM uses the Amps to calculate.

The MPPT controller compensates for the lower battery voltage by delivering closer to 8 amps into the 12.4 volt battery maintaining the full power of the 100 watt solar panel! 100 watts = 12.4 volts times 8 amps = 100 (P=E*I). MPPT uses Watts to calculate.

If your system is producing 5 Amps max, the only time that the 5 amps is feasible is at the peak of SOLAR during the day. Maybe 1 or 2 hours max with a lesser amount of amps as the the time gets farther from the peak sunshine time of the day.

Still, 100 watts is plenty of power to charge (unless you are killing your battery by discharging the battery below 12.2 volts) and keep the batteries topped off.

Don
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[Jagiven]

I posted this on another post today;

There are lots of variables to boondocking. The main issues are how long are you going to be out. Do you need heat? What type of lights do you have, and what functionality do you want from your equipment.

For example when we first got our TT, and my DW was new to glamping, and grew up tent camping. I know with incandescent bulbs we would have power issues on a long 4 day weekend. But I let her use power however she choice, to get the negative experience of running out of power prematurely. We did late on day 2, I had a plan in place to get us through. We can now go for 5 days on a single charge of our cheap OEM group 24 dual purpose battery.

So what we do; 1st I changed out all the incandescent bulbs to LEDs (we have an older camper). We now turn on the wall light switch for all the overhead lights. Then we turn each of them off at the light. When we need light we turn on the one or two that are required. Why light up the other end of the TT, when we are not down there.

When moving the awning and slide out, I keep the truck plugged in. I also keep the truck plugged in until the last moment to help put a tiny bit of charge back into the battery.

The furnace fan can drain a battery in one day. If it is cold out and we need heat. We will turn the furnace on and off thought the trip. For example we may turn it on before bed, to warm up the TT as we settle down for the night. If it is really cold, we may turn it on while one of us goes to the bathroom in the middle of the night. Again turn it on when we first get up. If we know that it will be cold, we often plan a breakfast that requires to use the oven.

The pump and water heater only uses power when it it cycling, so it is no big deal.

I do have a spare deep cycle battery, that I will bring with me on longer or colder boondocking trips. I keep in in a milk crate in the back of the truck. If needed, I made a set of cables that when I disconnect the OEM battery, I can extend to the battery, sitting on the ground next to the TT. I have used it a few times, but not to often.


As others said, you should not drain your battery below 50% charge, which is 12 volts, as you will begin to damage the cells, and shorten its life. A multimeter works great for monitoring your battery charge, and so useful to diagnose other issues too.

Also remember things like 12 volt cell phone chargers, even when plugged in and not being used, pull and waste power, so unplug them, when not in use.

[MontanaRick]

I have a 195RB, so similar demands to your trailer. As others have noted, it depends in how you use your power. On a normal summer trip in the mountains, our demands are lights (all led, so low demand), water pump (almost nothing), fridge ignition (almost nothing), and 1 to 2 hours of heat in the morning. The water heater has a manual pilot, no power needed. We go 3 days and have never dropped to 60%, 5 days without the heater, still above 60%. Or gray water fills up well before our battery gets too low (50%). Oh, and we don't use our awning, but do draw power for our electric jack.

[Mustang65]

Originally Posted by MontanaRick

I have a 195RB, so similar demands to your trailer. As others have noted, it depends in how you use your power. On a normal summer trip in the mountains, our demands are lights (all led, so low demand), water pump (almost nothing), fridge ignition (almost nothing), and 1 to 2 hours of heat in the morning. The water heater has a manual pilot, no power needed. We go 3 days and have never dropped to 60%, 5 days without the heater, still above 60%. Or gray water fills up well before our battery gets too low (50%). Oh, and we don't use our awning, but do draw power for our electric jack.

Do you have a 7 pin plug to the TV? If so, leave your TV running when you put out your awning and electric jack both when you arrive and leave. Saves a LOT of battery power for those other needed things.


Don
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