Ideas with some hypothetical numbers for extended boon docking in RV

[ewarnerusa]

Just to clarify, I'm referring to a soft start kit called Micro Air and not a hard start capacitor. The hard start cap approach is usually to install the SUPCO SPP6 cap. We tried that, too, and it didn't help all that much. The Micro Air did.
We have used our camper microwave one time in 6 years. So I forget we even have that capability. I use ours for storage!
3000 watts / 12V = 250 amps of DC current that you'll have to plan around.

[Treejohnny]

ewarnerusa - I do like to plan!

I have gave a lot of thought as to what will be sustainable for our fulltime adventure, I don't think pulling a generator out every time we want to use the microwave is sustainable. If I had mounted genset with starter, that would be different and I should look into that.

Some of the reasons behind my product decisions are if everything changes these parts could be used off grid at a house. The hybrid inverter can be 'stacked' with another to get 6000 watts or 3000 wats at 240.

I have looked into the capacitors that 'soft start' the air conditioner and that seems like an easy decision.

[Treejohnny]

To save weight, you could look into:
a) energy diet and use smaller batteries
b) Lithium batteries (much lighter weight, and less mature tech)

Mike - I have seen a couple of threads that talk of the LFP batteries but when I search on google the batteries cost more than AGM and that is not including the BMS. Unless I am missing something?

[ewarnerusa]

Well done on the planning. I'll offer some input from the boondocking perspective not necessarily related to your chart - I suggest downsizing the 3000 watt inverter and only using the microwave, hair drier, and toaster off generator power. It takes a lot of battery to make heat and complicates the DC side of your design due to having to accommodate the hundreds of amps that it requires. Your Honda EU2000 can easily handle those loads, although it will have to be one at a time. I would recommend going no larger than 1000 or 1500 watts on the inverter side, that will cover most AC loads you'd want to run from an inverter. You can also probably save some money by avoiding the hybrid inverter/charger unit and just go with a pure sine wave inverter. Recognizing that you'll still want a way to bulk charge quickly using a generator/shore power means you'll want to upgrade the onboard converter to a more boondocker-friendly one. Most new campers seem to come with a WFCO model converter that claims to be a 3-stage smart charger but in practice never actually uses its boost mode (14.4V). It will charge to no more than 13.6V which won't get you charged up quickly at all. Progressive Dynamics and Iota are popular converters that have boost modes that work properly that can also be manually engaged. If you will be driving frequently then consider upgrading the charging capability from your tow vehicle as well.

If you want to run your rooftop air conditioner (likely a 13.5 kBtu unit), your Honda EU2000 may not be strong enough to overcome the startup surge. If you'll always be at low elevations, then maybe it will be to do it but it will be marginal at best. However, there is a product on the market called "Micro Air" that is a soft start kit that you install on your air conditioner that minimizes the start up surge. It costs around $350, but it works. I installed on this year and we can now reliably run our rooftop air conditioner with our Yamaha 2400 gen. There are success stories using the Honda EU2000 as well. I know you mentioned that your plan would be to use the hybrid inverter/charger as a way to deal with the surge and I've read success stories about this as well. I just offer the Micro Air solution as an alternative that is probably cheaper and can also simplify your design.

We strictly boondock camp and get by just fine with 200 ah battery bank (2x6V GC batteries in series) and 280 watts of solar mounted fixed and flat on the camper roof. Mine are 12V nominal panels with a PWM controller. This works for us, but we are long weekend warrior campers so we don't have to necessarily worry about long stretches of poor solar harvest. Having a generator as backup means you wouldn't necessarily have to either. But for your plan I would say twice the battery and solar that we have would be a good plan. MPPT as well.

[max2k]

I believe the wife and I are conservative with electricity and we will get better.
I have looked at lithium batteries and it has an added cost of $5000 from what I could find. At this point I believe I would be better off spending extra money on solar panels and wire to back of travel trailer to AGM battery bank.

what Mike was probably referring to is LFP prismatic cells- they have many advantages, cost is actually comparable to FLA (way cheaper than AGM) and are the safest type among Lithium batteries. They are still capable of starting good fire if not used properly. Many RV- ers use them and posted on this forum- try google those threads, there were few in the past so you can even find updates after few years in use. I'd stay away from other types of Lithium batteries for your application due to their much less forgiving nature often ending in fire.

[Treejohnny]

I believe the wife and I are conservative with electricity and we will get better.
I have looked at lithium batteries and it has an added cost of $5000 from what I could find. At this point I believe I would be better off spending extra money on solar panels and wire to back of travel trailer to AGM battery bank.

[Mike90250]

To save weight, you could look into:
a) energy diet and use smaller batteries
b) Lithium batteries (much lighter weight, and less mature tech)

[Treejohnny]

Thanks for the response Max2k.

Yes you understand the table as it was meant to be! I do like to make sure I spend my money wisely the first time...

When I was researching it looks like most boondockers are happy with 400ah of battery. When I haphazardly through numbers on the wall for my usage I came up with 500ah+. I was hoping my numbers or calculations were off somehow. Is there anyone here that has first hand experience with this type of setup that can say I will need more or less ah in the batter bank?

The main reason for AGM is with a bumper pull trailer the easiest location for the battery bank is a direct addition to the tongue weight and two L16's will weigh 250# with out wires, inverter, charger or temperature control. I can't find travel trailer with the ability to add that much weight to the tongue of empty trailer. So unless I am not understanding something simple I will need to mount the battery bank closer to middle of trailer. AGM should allow for faster charging also, but I have not understood all that I have read about the C rating with regards to charge and discharge. I am sure there is time for that later.

Everything now is hypothetical until I can nail the exact trailer down and figure out the available Real estate on the roof. I have thoughts of panels mounted to top of trailer similar to awning and tipping up to 145 degrees for best angle for where and when I am parked. It would be nice if they were able to be removed and carried inside rv too, maybe someone already makes this type of setup?

[max2k]

you came here more prepared than others

If I understand your table correctly both columns AC watts and DC Watts actually mean Watt-hours so your loads demand 1196 + 1334 = 2530 Wh of energy per day. Now if you take 12V 221Ah battery it would have 12 x 221 = 2652 Wh stored. 'Dc amps' line actually means Ah required from 12V battery. So far so good except AGM is probably poor choice for your application due to costs but they will be less messy for sure.

[Treejohnny]

Hi all,

My first post, been lurking and trying to understand as much as I can, please bear with me. I do not own an RV yet and have not bought anything for this adventure.

I have thoughts of modifying a 25 ish foot bumper pull RV for a one ish year 'walkabout', mostly in southwest. From what I have read I think I would have 400-600ah battery bank.-AGM? A 3000 watt pure sine hybrid inverter/charger with the ability to use mostly generator and battery power for surges.
Honda EU2000 portable generator if I would need to run the air unit or to charge batteries. Solar panels and mppt solar charger and of course battery monitoring system. I am leaning towards Victor equipment for compatibility reasons.

I have done extensive camping in a tent and have never stayed or played in an RV. I don't know much about converting watts to AH and hope I can get some help on here. I know I have left out the water pump and any furnace blower usage. I have guessed at some of the wattage and thought this was good enough to share here. I think without considering any inefficiencies I would use 221ah in a day?

	AC Watts	Hours used
			AC watts	DC Watts
Router	10	6	60
Apple TV	2	6	12
Vornado Fan	44	6	264
2-Fantastic Roof Fans		12		860
Tv	100	4	400
Laptop	100	4
Phones		4		96
Ipad		4		48
Microwave	1500	0.1	150
Hair Dryer	1500	0.1	150
Toaster	800	0.2	160
Radio		5		100
Inverter		6		180
Lights		5		50
			1196	1334
Dc amps			110	111