Back up batteries for boon docking
Haven't purchased FW yet but more than likely be a 35 footer with the standard stuff. We are not air con people ( love the heat) so certainly wouldn't be running a/c while boon docking. Very new to al...
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Our older son is a solar engineer/designer/fabricator and our current rig is autonomous solar: 1.4 kW solar, 9.7 kW-hours of LFP and 4.0 kW PSW inverter. We have tossed the 50 amp cable and only have 1.5 kW (15 amp) battery chargers. We have a backup 1 kW Honda generator. We have had this system since June and have not used line power or generator except to test/monitor system. The forced air heater uses approximately 50 W (0.9 amps at 54 V) so we have enough actual power storage for 150 hours. We generally set the thermostat at 45 to 50 F when it is above freezing and at 60 F when it gets into the teens (worry about freezing holding tanks etc). We use a backup Olympian Wave 8 so the forced air heater is on for 5 to 10 minutes/hour, even last night when it got down to -4 F (-19 C).
The battery suite weighs a total of 160#. Son Cary noted that we had room and space for another 4500 W-hours but 1) we don't need it as we are probably over requirements and 2)and primarily, they are not inexpensive.
5000 kW-hours would have probably sufficed for all purposes by running the a/c on combination of solar/battery suite.
We never liked running the generator we had on last rig (2.5 kW Onan propane which was crushed in our wreck 60 miles east of Puebla, Puebla, Mexico) since it ran off the wildlife and did not endear ourselves to other dispersed camping boondockers.
Had 6" of snow on panels the last two days but we still had 60% of usable power (down -3500 W-hours out of 8200 W-hours availabe = 20% capacity). Sun is out today so I got on a ladder and swept the snow off panels. We were getting 14 amps at 54 v (63 amps at 12 V or about 700 W) before full afternoon insolation.
RV'ing is all about choices made to fit our own particular life style desires. LFP battery technology is greatly improving and the price per W-hours should go down dramatically. There is a lot of misinformation spread about on LFP. The lithium cobalt and lithium polymer have stability and over-hating problems. LFP with proper design and inclusion of Battery Management Systems (which all the fabricators utilize) makes ignition an unlikely proposition. As far as I know, all of the batteries are built in China (they control rare earth production) and the battery suites are fabricated in US and elsewhere = ganging 4 in series is normal to get 12.8 V suite.
Reed Cundiff
The battery suite weighs a total of 160#. Son Cary noted that we had room and space for another 4500 W-hours but 1) we don't need it as we are probably over requirements and 2)and primarily, they are not inexpensive.
5000 kW-hours would have probably sufficed for all purposes by running the a/c on combination of solar/battery suite.
We never liked running the generator we had on last rig (2.5 kW Onan propane which was crushed in our wreck 60 miles east of Puebla, Puebla, Mexico) since it ran off the wildlife and did not endear ourselves to other dispersed camping boondockers.
Had 6" of snow on panels the last two days but we still had 60% of usable power (down -3500 W-hours out of 8200 W-hours availabe = 20% capacity). Sun is out today so I got on a ladder and swept the snow off panels. We were getting 14 amps at 54 v (63 amps at 12 V or about 700 W) before full afternoon insolation.
RV'ing is all about choices made to fit our own particular life style desires. LFP battery technology is greatly improving and the price per W-hours should go down dramatically. There is a lot of misinformation spread about on LFP. The lithium cobalt and lithium polymer have stability and over-hating problems. LFP with proper design and inclusion of Battery Management Systems (which all the fabricators utilize) makes ignition an unlikely proposition. As far as I know, all of the batteries are built in China (they control rare earth production) and the battery suites are fabricated in US and elsewhere = ganging 4 in series is normal to get 12.8 V suite.
Reed Cundiff
