Has anyone had experience with a battery to battery charger

[ris]

We are building a camper out of a cargo enclosed trailer. We are setting it up using a lot of the stuff from the 26X. The natures head, batteries, engel fridge, and stove. We can swap the stuff back and forth with little effort. The trailer will be set up like the boat with everything being 12 volt or propane. To charge the batteries with the truck as we travel it seems a battery to battery charger is the best way. Just wondering if anyone had used one.

[Ponaldpe]

All of my trailers that have a battery , I have a charge line in the trailer light plug. It will charge the trailer battery as long as the trailer light plug is plugged in and tow vehicle is running.

[1st Sail]

I spent the weekend reading multiple articles and lab results in practical-sailor about smart chargers. The one takeaway is building an effective charge system is a very challenging task. I just replaced my 2 AGM's this spring. Previously I had a $30 battery maintainer which I switched between batteries in the off season every 15-30 day. I got 9yrs out of both batteries. In year 9 one was marginal at best the other still satisfied my day sailing needs. The operative questions is do you spend $ on a smart charger to improve long term battery life or little $ on a maintainer and just replace batteries more often. The real issue for smart chargers is they are essentially useless for day sailing and occasional use/drawdown. Smart chargers need to learn in that they are software driven to monitor draw, charge and recovery. From those data points they build a profile to control charge rate, improve battery performance, charge recovery, and optimum float voltage. Several smart chargers called for an annual drawdown to 50% and charge back to learn the dynamic characteristics of the battery bank. For occasional travel and limited use charging from the tow beast may be your best bet. If you are dry camping and plan to use the batteries with high drawdown/ charge back then I would do my research. Having a smart charger between the battery bank and charge source,(tow beast, portable genset, shore/campsite power) may be worth the time and investment. All the articles emphasized use. The more a battery system is used discharged/charged back the more effective the charger becomes.

[dlandersson]

Honestly, if you got 9 years out of your batteries, your system woulds seem to be working. I replace my batteries every 3-4 years.

I spent the weekend reading multiple articles and lab results in practical-sailor about smart chargers. The one takeaway is building an effective charge system is a very challenging task. I just replaced my 2 AGM's this spring. Previously I had a $30 battery maintainer which I switched between batteries in the off season every 15-30 day. I got 9yrs out of both batteries. In year 9 one was marginal at best the other still satisfied my day sailing needs. The operative questions is do you spend $ on a smart charger to improve long term battery life or little $ on a maintainer and just replace batteries more often. The real issue for smart chargers is they are essentially useless for day sailing and occasional use/drawdown. Smart chargers need to learn in that they are software driven to monitor draw, charge and recovery. From those data points they build a profile to control charge rate, improve battery performance, charge recovery, and optimum float voltage. Several smart chargers called for an annual drawdown to 50% and charge back to learn the dynamic characteristics of the battery bank. For occasional travel and limited use charging from the tow beast may be your best bet. If you are dry camping and plan to use the batteries with high drawdown/ charge back then I would do my research. Having a smart charger between the battery bank and charge source,(tow beast, portable genset, shore/campsite power) may be worth the time and investment. All the articles emphasized use. The more a battery system is used discharged/charged back the more effective the charger becomes.

[Catigale]

If you have room in your engine bay, think about a simple Solution of mounting an aux battery and charging with the alternator , then swapping it into the camper as needed

Having a 5-10 amp charge cord running from car to camper while underway seems complicated.

Do match battery types....trying to charge wet and AGM batteries on one system is hull.

People tend to grossly over-engineer battery systems on boats, cars, planes, and space ships.

First step should be calculating all your loads, then your usage, then drawing up a watt your budget for your camping needs. Then size batteries and chargers to fit, remembering that 50 % is the target maximum trip discharge.


Once you start pricing stuff out, remember you can get a Honda 1000 EU generator on eBay for $500

[KonstantinAtHouston]

To charge the batteries with the truck as we travel it seems a battery to battery charger is the best way.

DC-DC (battery-to-battery) charger is needed in order to limit charging current, thus protecting the alternator from overheating, when charging LiFePO4 battery with regular alternator. If your batteries are lead-acid, I wouldn't bother and would charge them directly from the towing truck electrical system, running additional thick wire from truck to camper, if there is no dedicated charging wire installed. First 15-30-60 minutes of running this scheme I would stop and check the alternator temperature. If it starts overheating then I would know I need to upgrade to more powerful alternator (still cheaper and makes more sense than DC-DC charger).

Update: Drat... Didn't look at the dates...