The battery that came in my new adventure toy hauler (InTech) was crap, was a interstate 60aH RV battery the dealer slapped in, literally the cheapest thing you can get.. In our first few boondocking weekends it hardly lasted a day before I had to fire up the generator (Honda 2200i) for hours to get it back to 100% so we could go through the night.. Pretty much every time we went out we deep discharged the poor bastard and it was shedding amp hours quickly.. this was not going to last even our first season and I just started wiring up my gmrs repeater and vhf radios knowing I didnt have the capability to use em.
We dont have very large energy needs, I had a 100ah AGM battery in a milk crate I used with a 100w solar panel to keep my ARB fridge going throughout or adventures w/my lil tent trailer.. it'd last for days without energy input, but it didnt last long with the abuse we gave it.. after 3 seasons it was done.. Now I just plan on adding an efficient propane heater as a critical load with that same fridge, they are nearly diametrically opposed, when fridge has to cycle often im likely not using heater, and if heater has to cycle often I can put fridge outside where it likely wont cycle much at all..
I do have extra secondary loads like lights/fans/radios/numerous battery chargers that will gladly use any excess energy I happen to collect.. but I had those before and managed consumption just fine with the help of an accurate energy meter.
I was planning on ponying up $400 for 150lb of lead batteries (Trojan 6v) to get 110ah of usable capacity, but instead opted to spend a little more than twice that on lithium, If it lasts 2x as long its a bargain for all the extra benefits I'll receive, if not its still likely worth it if you can afford it IMO.. I am just really starting to outfit this rig and being able to not only save a bunch of weight on the tongue but reduce it from this crap I got it with was worth a lot to me.. Ive got room for a ton of unobstructed solar over the axles.
It weighs in at only 30lbs, being 99% efficient on energy input and output means less losses charging it, and being able to bulk charge to 100% is greatly reducing the amount of sunlight or generator time needed, it gladly takes 30A even when its 95% charged, and with an internal BMS they can give you 100% capacity without the kind of abuse that would do to lead..
I'm going with fixed solar panels on roof, 350 watts worth.. Should be able to recharge from cut off to full in a few hours of direct sunlight, and with as much time as we spend in forest environments thats about the best we can hope for.. with oversized solar setup and a battery that can recharge in a fraction of the time, I hope to avoid the need for alot of battery capacity or using the generator frequently.. When I do need to use the generator, I wont feel as guilty for making noise and burning gas since I can get it done in a few hours instead of all friggin day.
I got lucky and had a manufacturer defect with the 35amp Progressive Dynamics fuse box in my camper, they were easy to work with and when I asked them if I could take the opportunity to upgrade to the 45amp Lithium power center they had they said sure, no problem and upgraded me for free.. wow totally ************, thanks PD! I really like the new fuse box over the old one, for starters it has 12 circuits instead of 5.. most are unused right now but that wont last long.. it also has support for an external DC cut off switch that made wiring up to an external LVD (100A Victron Battery Protect) a piece of cake, otherwise if the charger is cut off from the battery when voltage gets low there'd be no way to charge it back up w/the generator. I also needed the extra space for a breaker so I could hardwire my fridge in separately from outlets, this way when I run the inverter it wont be powering the fridge with AC when there is no shore power.
Sadly the new fuse box didnt fit w/out modification, the hole needed to be about half an inch taller, that was easy few mins w/a jig saw, but unfortunately it made contact with my power cable box that was directly behind it.. well this was nothing a bit more sawing could not work around:
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also without any internal power, there's also no ventilation, lighting and of course air conditioning.. but we keep on working through the heatstroke sporting our headlamp.
I also install a master disconnect switch, so I can ensure there are no loads on the battery when I have it in storage.. in the end everything looked nice and clean. I decided to install a green 120v led into the top of the fuse box, as an indicator we have shore/generator power.
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In the battery compartment I put a new battery box in and move it to a new location, it dont need ventilated anymore so I get to reclaim a bunch of storage space.. I chose BattleBorn because they were well reviewed, warrantied and price was fair IMO (could save a couple hundred and import one from china, with no warranty and lower output ratings). I also way oversized the cabling for a couple of reasons, first of all the main connection points for power/ground would be on the other ends of the Battery Monitor (Ground Shunt) and the Battery Protect (Solid State LVD) so I wanted absolutely minimal voltage drop so these connection points would be just as good as the points on the battery.. Secondly because I soon intend to wire in a 1200VA Inverter that can handle surges more than 2x that, so it needs to be capable of delivering 200A of power for up to 30s, and 100A continuously. A 200A inline fuse was installed directly to the battery terminal, even though the battery's BMS will supposedly stop a short circuit in 1/2 a second, a fuse will react even faster.
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I still need to run a wire from the relay output of the battery monitor to the power switch on the battery protect, this way I can have the battery monitor shut down the power once its 80% discharged.. Lithium does not start shedding voltage until its almost discharged, so even though the battery protect is programmed to cut off at 12v, the lithium battery will still be mostly discharged at that point.. I'll keep 20% in reserve to prolong the lithium battery, and if push comes to shove and I need that extra 20% (say it cuts off heat in middle of night) its a few clicks on the battery monitor to turn the LVD back on.. then it'll keep running til it hits that 12v and the battery protect decides the reserves are gone.
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Now that this rather expensive project is complete, I'll move on to installing a Propex 9k btu heater to extend the season.. then I'll probably put the solar panels up and then get the inverter so I can make coffee in the morning without going out operating machinery (firing up genny)
I've done a bit of dry run testing here at home and have been very impressed, with typical loads the battery monitor says I have several days of capacity left instead of several hours.. I'm taking it out this weekend for first real run but I expect it to still have plenty of charge on our way home after a weekend @ sand dunes, finally..
