Upgrading converter

BFL13 wrote:

StirCrazy wrote:


I see what your saying. I guess if we stay in that area that skews the numbers the advantage will be on the smaller side but what if we are looking at using the genny from 65-100% how much differentce is there then. this is more where I lived with my GC batteries and solar instead of a genny. I would be at tht 60 to 70% mark in the morning and recharged by 1 to 2 pm to 100% I did drain down my new battery pack by about 45AH in the drive way an did a simulation and it was recharged by 11:38am. hardly scientific but a simular amount that needed to be recharged and a significantly faster time.

I guess I just have a hard time understanding with how cheep solar has gotten why we are still talking generators unless you have to run an AC.

That's easy--for when there is no/not enough solar. Eg we go to Rathtrevor park in the woods for four days in February, temps just above freezing. No solar in the woods. Park rule is two hours gen time morning (we don't do it at night in the dark outside)

460AH bank is about 400AH at those temps. 75 amp charger biggest can carry due to limit of size of portable gen we can carry in the RV spaces so stuck with that 75 amps limit.

75/400 is a 19% charging rate and that means Bulk ends at about 78% SOC before amps taper. After two nights next morning (day 3) we are down about 230 AH so about 43% SOC so fire up the gen for the two hours.

Get 43-78% with constant 75 amps is 140AH at 75 amps = 1 hr 56 min so get 4 minutes with tapering amps, not tapered very much. Heat loss 6%?
So AH restored is say 132 AH (which is close to what the Trimetric says so that works)

If we had LFP we still use the same AH a day. Same two hours limit with same 75 amp charger limit

= 150AH vs 132AH so the LFP gets you 18AH more in the two hours.

In our case 18AH more restored to get us to Day 4 would not make any difference, so no reason to swap to LFP. Absolutely need the gen to go at all whether LFP or FLA or whatever kind of battery.

Happens that four 6s are perfect for that job in our RV. YMMV Haven't worked out how big in AH the LFP bank would have to be to do two nights and 230AH before needing to recharge morning of Day 3 and cost of that compared with cost of four 6s.

In fact if there were sunshine you might still be doing some gen time high amps in the morning and solar low amps but with more time the rest of the day to get to full recharge or as high in SOC as possible that day.

I was always able to find a site with at least 4 hours of sun on the island. don't forget I lived there for 20 years. BC is bad for darker campsites, especialy on the island but you can work it. i bought a genny yeas ago and had solar on my camper thinking I would use the genny for an extra top up but in the 20 years of camping on the island I never had to use it. but I was also changing everything on the trailer I could to maximize battery power. so I think the difference here is in how we use our RV's. I had four 6's for a total of 470AH about 1/2 actualy usable if you want a good life span. my total draw for 24 hours in the winter on the island was under 40AH yes in the winter the solar didnt work verry good but before I installed it I could go about 5 days and just hit that 5% mark, after I could pritty much double that amount of time. in the summer before the pannels I could do about 2 weeks after the install, I never had a issue with power. with my new 5th wheel and the same battery bank just new batteries and more solar it is simular. we do use the inverter now and use the microwave once and a while and the coffee maker. In the summer now power worries , late fall and early spring same thing. if I get stuck in a site that is totaly shaded then I have about 4 days of power then I have to look at moving to some sun or plugging in, no biggy. the camper my length of stay os dramaticly incresed with the LFP. not only did I get my outsize storage back but I decreased the weight by 100 lbs. before on two 6V I could go three days with out sun in the lait fall in alberta and be tickling 50% of my capacity so 104 AH. now if I had that perfect storm again I could wait it out for 10 days if I had to. with the solar in the camper I never have to worry about power in the summer, when the sun is out it used to be full by about 1pm now before lunch I am back at 100%.

I guess it all boils down to how much power you use and what you want to do to maximize that lenght of stay factor. some people like gennys , I personaly cant stand them. nothing worse than drinking a coffee by the lake in the morning as the sun rises listing to the birds , watching the fish jump .... then the drone of a genny starts up...