Battery Charging

[monkey44]

2008 Lance Camper 845 - bought new in 2009 ...   If I'm driving down the road, does the truck alternator charge my house battery just as it does my truck starting battery.   OR, it there a separate battery charger it passes the current thru before the current reaches the house battery?     And, if I plug in at campground, does the 110v current change to 12v thru an inverter in the truck camper?

I'm changing to AGM battery for house battery next week.  Does that affect my charging system, and harm an AGM battery in any way.   If so, what do I change in the charging system.  Every thing in the charging system is from factory, haven't add or subtracted anything that is not OME...  Thanks Guys.

[nstaron]

When your truck is running, the alternator produces electricity which is used to power your truck and charge its starting battery. However, the process of charging the house battery is a bit different.

Generally speaking, most modern trucks do not have an auxiliary battery charger built in for charging their house batteries. Instead, they rely on a "leeching" method where the house battery draws from the starting battery while driving. This means that as long as your starting battery has enough energy to start your truck after powering any accessories or electronics you may be using, it should also have enough energy left over to trickle charge your house battery.

However, this method can sometimes cause issues if you're draining both batteries at an equal rate (for example if you are using a lot of electronics in the camper while driving). In these cases, it's always best to use a separate charger specifically designed for AGM batteries before connecting them to ensure proper charging.

Now let's talk about plugging in at campgrounds. When you plug into 110v shore power at a campground with an AC-DC converter (also known as an "inverter"), it converts the 110v AC power into 12v DC power before reaching your camper's electrical system and ultimately charging both your truck starting battery and house AGM battery through their respective chargers.

As for switching from a traditional lead-acid house battery to an AGM one, there shouldn't be much difference in terms of how they are charged by your factory-installed system. Most modern systems can handle both types of batteries without any modifications necessary. However, before making any changes it would still be wise to consult with someone who knows more about the specifics of your particular setup just to be sure.

Make sure to keep an eye on your battery levels while driving and use a separate charger when necessary to ensure proper charging. And don't worry about causing any harm to your new AGM battery, as long as it is being charged correctly it should last you for many trips to come.

Safe travels!

[StirCrazy]

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@nstaron wrote:

Now let's talk about plugging in at campgrounds. When you plug into 110v shore power at a campground with an AC-DC converter (also known as an "inverter"), it converts the 110v AC power into 12v DC t modern systems can handle both types of batteries without any modifications necessary. However, before making any changes it would still be wise to consult with someone who knows more about the specifics of your particular setup just to be sure.

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Don't follow this, an inverter does not covert 110 to 12V that is the normal converter of your rv unit (tyhe part you see people saying to upgrade if you go to LFP batteries.  what give you 110 power from your battery when you don't have short power is the Inverter

[monkey44]

Talked to Battery guy - bought a 90Ah SLA battery.  Seems the cost for AGM or other options made it the best option.  We're retired and don't boon-dock nearly as much as we once did - and most Florida and SE-USA campgrounds have WE ... so less likely we will need the extra power supply.   We use very limited power at this point (all LED) and we do not watch TV or use much E-power except charging phones - laptops - camera batteries.  We usually hit the sack shortly after dark, and up with the sun. I was just exploring options to see what is out there - equipment changes so frequently, we like to keep track.   Thanks for the info y'all ...     M44 & Genie

[Grit_dog]

SLAs are good compact options for TCs. Only way to get 2-6v in our old TC without removing the tray. Worked great. 
As far as your truck charging it, just check. Yes it should thru the 12v trailer pin. 
Either when truck is on or constant power. 
check your battery V unhooked from truck. Sb like 12.6v

 start truck and check it. You should see immediate voltage rise 

but also see if it’s always hot. If so remember you could drain your truck battery if you run everything down. 

[monkey44]

Yeah, I disconnect camper wire from the truck whether we have 110v or not.  So, it only drains the camper battery for camper use.  Propane Fridge, propane stove, propane heater (Two tanks - we hardly every use it all).  All lights are LED, and we shut down for sleep fairly soon when dark arrives, and we wake up when daylight arrives.  We've been truck camping since 2002, so have it down pretty well.  Crossed the country five or six times, a few months trip at a time, mostly shoulder seasons, and summer in out of the way campgrounds - not crowded

[joebedford]

"an AC-DC converter (also known as an "inverter")" A converter is never known as an inverter. A converter converts AC to DC and an inverter converts DC to AC - always. You could also have an inverter charger but that's a different beast.

[jetalkington]

If you do not do much boondocking the cost of going to lithium is likely not worth it.  I have a Northern Lite truck camper and boondock most of the time. So, I went to lithium. If you spend most of your time in campgrounds, your AGM will suit you fine.  To answer your questions, your 7 pin plug has a charge line from your truck battery to the house battery.  It may not put a lot back there, but it does charge. When your plugged in your power center should be charging your battery as well. 

[monkey44]

Yeah, if we were still boondocking a lot, or camping back-country with no hookups, we'd go lithium and retrofit for charging it.  But we're off the road a lot now, and camping more w/hook-ups, so not as critical for long-term battery power.  I was more concerned with going AGM and not having proper in-house charger for it.  I didn't want to damage it.  But apparently, we can get away with SLA sealed, and get a week or so out of 100Ah battery.  We do mostly day stuff, and early bed then up and greet the sun.  We have no TV or E-stuff except Cameras, Laptop and phone charging, and propane cooking. In cooler weather, we heat up the Camper - shut heat off - and curl up in our sleeping bags.  We can fit only one battery (group 27) in the Lance.  Been Lance TC camping for over twenty years with no generator, and about 50% HU and 50% none ... We need a new battery, so exploring options, and don't want to upgrade the battery if our inhouse charger might damage it.   We're aging out of long-term cross-country camping, but will never age out of camping completely.  We live in Florida now, but spent plenty of time on the west coast, the Sierras and Rockies, and pretty much everywhere in between.  

[StirCrazy]

ya, you camp kind of the same as I do, but I leave the heater going all night as the wife would shoot me if I turend it off haha, I could go about 3 days on 100ish AH if the solar died which is why I looked at the LiFePo4.  it is a little smaller than a group 27 (about the same size with the BMS) and has 304AH.  I ended up buying the cells and bms and building it myself as at the time the permade were quite expensive.  now the price of Lfp cells has been droping even more a persona could do this build for about 500.00US.   I know building one isn't for eveyone so a 100AH LiFePo4 can be had as low as  250 US and that one battery will double your "usable" over a group 27 deep cycle.

One more thing I will point out is that, like LiFePo4, an AGM isn't compatable with a normal charger also.  while they may both work, they won't get the optimal charge, or in the case of AGM a charger with out a AGM or Adsorbed setting can dammage the battery from to high of voltage being put to the battery.  so for me if your getting away from a normal flooded battery you realy should concider changing the charging section of your converter to one that suports the charge you need.  most newer ones have and AGM setting and the real new ones also have a Li setting.  

[jetalkington]

My wife and I have been camping over 30 years and this is the first camper we do mostly boondocking with.  Our previous campers had solar, but we used AGM batteries.  Even with the AGM we could go 4-5 days without plugging in due to the solar. We didn't have a bunch of electronics and used our laptop if we wanted to watch Netflix.  I am a photographer so we would watch our electricity and do our charging in our vehicle before came in for the night.  We would wake up with batteries around 60%.  Turn everything off and the furnace down, then go hiking.  We always came back to full battery.  The lithiums allow us to go 3 weeks or more and still have 100% when we get home, due the charging system we put in.  We could probably go longer, just haven't needed to. I have had good luck with AGM from battery plus.  I use the Duracell brand and their house brand. They all made by East Penn battery; a solid USA made battery. I have also gotten the Duracell from Sam's Club. The big thing is not to take them below 50% very often. So, if you do a quick calculation on your energy needs then you have an idea of what you need.  Just double your calculation and get at least that many amp Hour battery.  I am pretty sure your 2009 Lance will have a converter/charger built into the power center. So, being plugged in you would be good and charging.   If you traveling and want to be sure your alternator is charging your house you can check the size of your alternator and install a Blue Sea Automatic charge relay. They are a straight forward install.  It will monitor your vehicle battery and when it is a full charge send everything from the alternator to your house battery.   On your vehicle I would check to see if the truck cuts off the power in the 7 way plug.  I have a Ford truck and it cuts power to the 7 way with ignition off.  I know some Cheverolet do not and can drain your truck battery if you camp to long. I am not sure about Dodge.  This is important on truck campers as they are connected all the time.

[StirCrazy]

probably would have got a faster answer int he truck camper forum, but yes you need to do somthing different.  I don't use any charging from the truck with my camper and 5th wheel as I have solar to do that, but even if I didn't I wouldnt anyways unless it was through a dc to dc charger.   the factory lines that are run to the 7pin are just to small to keep up the voltage over that distance.  I used to have 6V GC batteries in the camper now I have a 300AH LiFePo4 and I just bought a dc to dc charger to use in emergencys as I don't like generators if I can help it haha. 

what made you decide on AGM batteries?  (just curious not pushing one or another, its just they are by far the most expensive option for the lowest increase in benifits)

AGM, GC2, LFP heck any battery that isn't a car starting battery need different charging profiles that your altanator and truck charging system cannot meet exactly..  so in all cases it won't charge properly, in few it may harm it from overcharging or charging to a wrong voltage ect..  a dc to dc charge lets you limit the charge the truck can put out so you don't dammage anything and also customize the charge profile for your house batteries.  

[monkey44]

I thought AGM will last longer and can safely go below 50% discharge.  I'm weak on electrical knowledge so like to get info from RV folks, and not always listen to advertising that's trying to sell me a product..  We do boondock some still, but less than in past years.  We do not carry a generator and never have in over twenty years with Truck Campers.  We've usually bought an Interstate battery and just used up the last one and now need another - so have been exploring the options a bit. So  it doesn't make much difference if we buy AGM or a standard battery.  I do like the idea of a sealed battery because it's a little difficult to watch the water in the Lance battery case.  We most often recharge in a W/E campground during our trips and boondock for shorter periods than in the past as well. Do you have  a recommendation for the best battery choice in this case??  Cost is less a concern than quality.

[StirCrazy]

I tend to sway towares LFP(lithium iron phosphate) , but I mostly boon dock, if you are not having capacity issue for how you use it now then the only advantage of a LFP would weight and space savings and sence you plug in a fair bit you would need to change your converter to a Li compatable one if it isn't already.  Like I said I went from two 6V GC2 batteries rated at 208AH each but as with flooded batteries you have to stay under that 50% so I had 104AH I could use and they took up my entire outside storage and weights 158ish lbs.. now I have a 304AH LFP battery that is the size of a normal car battery and livens in the closet (freed up my outer storage) and only weighs 48lbs and I can use 100%.   if you going on cost, then you have to look at the cycle life of a battery and how much power it can deliver on each cycle.  so a LFP battery is usaly rated for 3000-4000 cycles at 100% discharge, so like I say if we take the average of 3500, and  you fully cycle a battery twice every weekend that would last for 33 years before you need a new battery as long as you don't abuse it.  as far as abusing its actualy hard to do except for charging whent he internal battery temp is below 0C .  which is why I put mine in the closet as it gets heat from the furnace and I do a lot of early spring/lait fall camping where the temp is down at -5 to -10C.  now you can discharge them to -20C and newer ones to -30C but just cant charge them.  

I am not sure how many AH you have now, but 100AH LFP batteries can be had cheeper than AGM well for me up here, and even cheeper than good quality 6V batteries.  but, if your converter isn't Li capable you have to factor that in.  but if  you are runing two say 80AH batteries right now and you switch to two 100Ah LFP batteries you have increased the AH available to you by around 2.5x and cut your battery eright in half aproximatly.