https://rvwiki.mousetrap.net/ 2026-04-13T10:27:52+00:00 https://rvwiki.mousetrap.net/ https://rvwiki.mousetrap.net/lib/tpl/dokuwiki/images/favicon.ico text/html 2025-12-24T22:58:34+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:alt_and_solar&rev=1766617114&do=diff Note: although this page was written with alternator-augmented solar charging in mind, the general principles also apply to solar+shore power charging and solar+generator charging. Also see Deciding on a Power Mix. " Solar and DC-DC alternator charging are going to be the best practices for maintaining charge in one's battery bank. It only requires a little math, a little discipline to stick with the math, and the right expectations about solar intake. text/html 2025-12-24T22:58:34+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:alternator&rev=1766617114&do=diff Words of Wisdom: With a isolator you would run the truck early to get a fair amount of the bulk charging done and let the solar finish it off the rest of the day. -- jimindenver Alternator charging Note: this is a basic overview. More details available on the text/html 2025-12-24T22:58:34+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:alternator_charging_hvd&rev=1766617114&do=diff Disconnecting alternator charging at a voltage setpoint There are scenarios where one might want to prevent a battery isolator from combining the house and chassis 12v systems: * the house battery might be a chemistry that could get overcharged by the alternator (lithium, for example) text/html 2025-12-24T22:58:34+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:alternator_charging_rates&rev=1766617114&do=diff DRAFT How much will my battery charge by alternator? This should be easy, right? time charging x charge rate in A = Ah replaced in the bank We know the time part because we're the ones driving. But the charge rate part can be hard to predict with any certainty; this is especially true for combiner ( text/html 2025-12-24T22:58:34+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:alternator_details&rev=1766617114&do=diff Alternator details Also see the alternator charging overview article. theory of operation An oversimplified overview will help us understand the challenges and approaches to overcoming them. * An alternator makes alternating current (“AC”, hence alternator) by rotating an electromagnetic - field through stationary wires ( text/html 2025-12-24T22:58:34+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:b2b&rev=1766617114&do=diff Battery to battery chargers TL;DR <https://amzn.to/2RY2GNQ> * A DC-DC (or b2b) charger is a type of isolator that converts alternator voltage to specific charging voltage setpoints and limits current instead of just passing it through as a relay might. * they are usually rated on their charging text/html 2025-12-24T22:58:34+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:batteries&rev=1766617114&do=diff High-level battery overview Batteries used in your "house" setup have markedly different needs than the battery that's already under the hood of your car. Not that there aren't similarities, but understanding the differences can help you right-size the batteries for your need and avoid text/html 2025-12-24T22:58:34+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:battery_capacity&rev=1766617114&do=diff C notation C notation is used to express the relationship of a bank's capacity to charge/discharge current. Example: a 20A current into or out of a 100Ah bank is 0.2C (20A / 100Ah). The same calculation could be made with W/Wh since it's about the relationship between the two and not any specific unit of measurement. text/html 2025-12-24T22:58:34+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:battery_monitor&rev=1766617114&do=diff Battery monitors TL;DR <https://amzn.to/4bxDjw8> * Battery monitors start from a known State of Charge then count every Amp going into or out of the battery bank * the shunt can be internal to the battery (lithium batts with BMS comms) or external to the bank * the current acceptance of the battery bank in Absorption can tell you how close to fully charged a lead battery is text/html 2025-12-24T22:58:34+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:bms&rev=1766617114&do=diff BMS BMS The term Battery Monitoring (or Management) System is used in at least two different ways regarding LiFePO4 battery banks: * cell-level monitoring and cutoff for overvoltage or undervoltage; these are intended to maintain balance between cells of fast, high-current charging, as found in electric vehicles (EVs). text/html 2025-12-24T22:58:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:car&rev=1766617116&do=diff if you are just running a fan and charging phones/tablets a small solar generator power pack thingy could work. You could charge it from the CRV's alternator while driving, plug it in when you are around an outlet, or charge it from a small solar config suitable for vehicles. Alternator-only charging would work best with packs based on lithium cells rather than lead-acid cells since the latter doesn't like incomplete charges. text/html 2025-12-24T22:58:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:charging&rev=1766617116&do=diff Words of wisdom " “Three stage chargers are easier on your batteries, charge them faster, fuller and help you use less water” – HandyBob" " A [ shore power ] charger is a stiff source with unlimited energy and time. Your solar is a very soft source of unknown power and only a few hours to get the job done. - sunking text/html 2025-12-24T22:58:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:chassis_power&rev=1766617116&do=diff Chassis power Chassis power is the 12v system used to start and run the vehicle. Generally this system is completely separate from house power unless the alternator is used to charge the house batteries. For our purposes the main components of the chassis power system are: * the starting battery - a “ text/html 2025-12-24T22:58:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:dailypowerrequirements&rev=1766617116&do=diff DRAFT How much power do I need to run stuff? It may seem overwhelming at first, but all we really need are * a list of things you intend to run in the van. Be specific and thorough. <- the hardest part. * reading the product labels on the above items text/html 2025-12-24T22:58:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:deep_cycle_battery&rev=1766617116&do=diff Words of Wisdom: “if [you're] the type to park the rig, let the batteries die and boost them for the next time [you're] using it, get the cheapest batteries out there. [You're] killing them anyway.” -- twinboat Deep cycle batteries Deep cycle batteries are batteries which are designed to have an extreme text/html 2025-12-24T22:58:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:directcharginglfp&rev=1766617116&do=diff DRAFT Words of Wisdom: “With a few basic design considerations, and an alternator design newer than 25 years old, a direct charging system [for LiFePO4] can be safe, effective, and provide significant benefits. - midwestdrifter Direct charging LiFePO4 banks There is an text/html 2025-12-24T22:58:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:diysmartpass&rev=1766617116&do=diff DRAFT / EXPERIMENTAL / OPINION DIY Ctek D250 + Smartpass setup This article is about the 1st-gen Ctek combo and possible approaches to duplicating the major functionality for less money and/or better specs. This article assumes you want and the bank will accept >20A of alternator charging, and that your alternator can handle it. If you only have a 80Ah AGM then the combo setup is massive overkill. The bare D250 would handle that with ease. text/html 2026-01-31T17:42:51+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:drop-in_lifepo4&rev=1769881371&do=diff Drop-in Lithium (LiFePO4) TL;DR * the most common lithium chemistry for 'dwellers is LiFePO4 (LFP hereafter), an extremely stable version of Li-Ion. * there are two basic types of LFP batteries: drop-in (pre-made retail batteries) and DIY (built from components by the user) text/html 2025-12-24T22:58:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:electrical_notation&rev=1766617116&do=diff Electrical terms often seen with solar * I - current in Amps. The I comes from the archaic term intensity. * Imp current at the panel's maximum power output (see Vmp) * Isc - Amps when short circuited; this is when your solar panels are connected only to themselves. This is the highest current your panels can theoretically produce. text/html 2025-12-24T22:58:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:eternal_absorption&rev=1766617116&do=diff Note: this is for deep cycle lead chemistries only! Lithium batteries should not be held at full voltage. Words of wisdom: " “As long as... you cycle the battery daily, you could set float voltage to [Vabs] too without worry. Only when you stop cycling the battery do you need to return float voltage to more regular 13.2v levels. text/html 2025-12-24T22:58:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:hvd&rev=1766617116&do=diff High Voltage Disconnect <https://amzn.to/3LaoTqD> A high voltage disconnect (HVD) is the opposite of a low voltage disconnect. When the voltage reaches a given setpoint (Vhvd) the circuit is opened and any related loads are disconnected. Such HVDs can be complicated, or cheap and simple like text/html 2025-12-24T22:58:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:intro&rev=1766617116&do=diff Powering your vanlife TL;DR * There is chassis power (your van's electrical system) and house power (your power setup for charging and running things). They are separate except when intentionally combined, as when charging from the alternator. * text/html 2025-12-24T22:58:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:laptop&rev=1766617116&do=diff Charging and powering laptops Laptops are the most power-hungry of the nomad's communications devices; phones and tablets require much less power. Pretty much the only communication device that will consume more power would be a Starlink dish. There are two basic approaches to keeping your laptop charged on the road: text/html 2025-12-24T22:58:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:lifepo4_batteries_thread&rev=1766617116&do=diff Words of Wisdom: " “LFP batteries do not need to get back to 100% SOC, ever” -- Maine Sail" " “Others will likely say you should read a few of the previous pages in this thread and a lot of your questions will be answered. I'd suggest you pick and random number between text/html 2025-12-24T22:58:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:loads&rev=1766617116&do=diff Loads Loads are electrical burdens placed on an electrical system. When vandwellers talk about loads they usually mean user loads like lighting, running a laptop or microwave. Technically, though, it also includes system loads like charging the bank. Understanding this last part will help make text/html 2025-12-24T22:58:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:lvd&rev=1766617116&do=diff Low Voltage Disconnect (LVD) A low voltage disconnect is used to stop loads from dragging a battery bank below a given voltage (Vlvd). examples <https://amzn.to/3Ri94RY> * Victron Battery Protect * Blue Sea 7635 m-LVD * various amazon listings One can also DIY a low voltage disconnect. In theory the simplest way to implement an LVD would be to wire all loads go through the text/html 2025-12-24T22:58:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:maintaining_starter_battery&rev=1766617116&do=diff [also see self-jumpstarting] maintaining starter batteries * Some combo DC-DC chargers contain logic to maintain the starter battery when solar power is present. For specifics see the starter battery maintenance behavior section in each listing. * the Ecoflow 800w alternator charger (DC-DC) has a starter battery maintenance function. text/html 2025-12-24T22:58:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:mandatory_dcdc&rev=1766617116&do=diff Note this is a companion to the Is Solar Mandatory? article Is DC-DC charging mandatory? Death and taxes are mandatory. Gravity is mandatory. Are DC-DC chargers mandatory? Ehh... In many/most situations, direct-charging the house bank with a combiner (relay, isolator, VSR) is both effective and inexpensive. Even text/html 2025-12-24T22:58:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:mandatory_solar&rev=1766617116&do=diff Is solar mandatory? Solar isn't mandatory. Here are some cases where it might not be worth the trouble: * the camper has Lithium, carbon-foam, or similar battery chemistries that are not bothered by sitting at partial state of charge and there is enough charging capacity to meet needs. text/html 2025-12-24T22:58:38+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:multipoint_charging&rev=1766617118&do=diff Words of Wisdom: “Think of the batteries as a bucket of electricity. It's possible to pour water from multiple sources into a bucket at the same time, and also to do that while water is leaking out of the bucket.” -- MarkSF Charging from multiple sources It is common for a camper to have different text/html 2025-12-24T22:58:38+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:parallel_serial&rev=1766617118&do=diff parallel-serial Electrical components like batteries and solar panels can be used independently or combined. If combined, they are connected in series or in parallel. For the following examples we will consider two items -- batteries, solar panels, etc. Series connections text/html 2025-12-24T22:58:38+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:phone_charging&rev=1766617118&do=diff charging your phone Keeping a phone or tablet charged is an essential task for vehicle dwellers. It's more an issue of resource management (taking advantage of charging opportunities, carrying the chargers/cords) rather than spending money on special gear. text/html 2025-12-24T22:58:38+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:ports&rev=1766617118&do=diff 12v house power outlets Full-timers and those with more robust system will likely want to install 12v power outlets in their van. Doing this means one can move electrical items around and plug them in where you want them. the cigarette outlet <https://amzn.to/3efQlRr> The most common 12v outlet is the cigarette lighter outlet. Some are text/html 2025-12-24T22:58:38+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:power_mix&rev=1766617118&do=diff DRAFT Power mix Having a mix of power generation approaches will usually be more dependable and less expensive than relying on only one. For example, it is expensive (and maybe impossible) get Big Current with solar alone and difficult (or even impossible) to complete charging on alternator alone. But text/html 2025-12-24T22:58:38+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:psoc&rev=1766617118&do=diff Partial State of Charge Partial state of charge (PSoC) refers to the state of a lead-chemistry battery when it is left below 100% State of Charge (partially discharged), which lead-chemistry batteries do not like. Since state of charge is measured “on the way down text/html 2025-12-24T22:58:38+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:relay&rev=1766617118&do=diff this page has moved text/html 2025-12-24T22:58:38+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:renogy_dip_switches&rev=1766617118&do=diff DRAFT - please report errors DIP switches on Renogy DC-DC chargers TL;DR * the DIP configuration tables and nomenclature in the 20-40A-60A DCC1212 series manual are needlessly confusing. The tables below intend to correct that * the DIP switch area has indicator that shows ON↓ text/html 2025-12-24T22:58:38+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:self-jumpstarting&rev=1766617118&do=diff Self-jumpstarting Self-jumpstarting means jumpstarting one's own vehicle without the use of another vehicle. It's done by combining house and chassis batteries by one of several methods discussed below. Note: regardless of specific method used, it will be gentlest on the system to text/html 2025-12-24T22:58:38+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:thermal_switch&rev=1766617118&do=diff Thermal switches TL;DR * thermal switches are simple and expensive devices used to activate or deactivate an electrical circuit at a set temperature. * they are commonly used to activate cooling fans or to deactivate a device that is running hot * the switch body is affixed to the object text/html 2025-12-24T22:58:38+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:voltage_sag&rev=1766617118&do=diff Voltage sag TL;DR * resistance in the circuit causes apparent voltage to sag when discharging * likewise, resistance causes apparent voltage to rise when charging * some sag/rise is normal. Circuits with excess resistance (undersized wiring, iffy connections) can cause apparent voltage to deviate enough to affect system performance text/html 2025-12-24T22:58:38+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:voltage_sensing&rev=1766617118&do=diff Chargers with voltage sensing Higher charge/discharge current can distort the voltage the charging source “sees” at that source's BATT terminals. For example, if the battery battery bank is actually 13.0v and the charger is putting out a lot of current the battery voltage might appear (to the charger) to be 13.4v. From the bank's point of view it's voltage text/html 2025-12-24T22:58:38+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:voltage_sensing_delay&rev=1766617118&do=diff Adding voltage-sensing to an ignition-triggered device <https://amzn.to/2RubQqw> Solenoids and some DC-DC chargers use a circuit powered when the ignition is on (IGN) to start their operation. Voltage-Sensing Relays (VSR) do this by reading voltage to know when alternator charging is occurring. Voltage-sensing can be added to devices that lack it by adding a text/html 2025-12-24T22:58:38+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:wallwart&rev=1766617118&do=diff Devices with power adapters It is a common misconception that inverters are needed to run devices with wall adapters. That is usually not the case. Devices that have a plug that has a block at the end (or elsewhere) are typically using DC power, which is what is already in your car. No inverter needed. The adapter is there only to change 120vac to the required amount of DC voltage. text/html 2025-12-24T22:58:38+00:00 Anonymous (anonymous@undisclosed.example.com) https://rvwiki.mousetrap.net/doku.php?id=electrical:12v:wiring&rev=1766617118&do=diff Wiring the van basic principles * wire * wire runs are typically sized for critical vs noncritical applications. Factors include both the amount of current and the total length of the circuit (POS and NEG sides combined). See below. * stranded wire