Quote:
Originally Posted by Johnynorthland
Op here, I have another question or 2 or 3!
So looking into this further, does an alternator work harder to charge an AGM because it’s charging voltage is a little higher than a regular lead acid battery? No Is there any harm to the alternator because I Have mixed chemistry, having one AGM for house battery and one lead acid for a starting battery?No
Am I way better off just installing a DC to DC 20 amp charger and get rid of my isolation solenoid?No
Is there any benefit to either of my charging systems if I had two AGM batteries?, (One for starting and one for the house)No
|
To add more content, the alternator you have in yours doesn't know or care if you have an AGM or Lead Acid battery and will charge the battery in the same regulated manner. While this is true for all E450's up to 2020, in 2020 (could be 2021) the alternator charge control was changed to a computerized module and I suspect the ford dealer could change the program to be optimal for an AGM or Lead Acid (LA) battery however, without any programming change the alternator would still charge the battery the same for a lead acid or agm battery. For the newer vehicles with the battery computer controlled charging setup, I would stay with what the vehicle shipped with, likely LA on the newer E450's however some new vehicles (not E450's) may have an OEM AGM battery.
There would not be any harm to the charging circuit whether you used an AGM or LA battery (or a combination). However, due to the slight voltage differences, it would be best to have the same battery type for any multi battery setups where the batteries are connected in parallel (or serial). This isn't a big issue when having a chassis with LA or AGM and the coach with the opposite. While not in your questions, the more concerning aspect would be with having LifePo4 and either AGM or LA in parallel for any extended period of time.
I wouldn't be concerned with installing a DC2DC charger for the use of AGM\LA batteries (both or in combination) as the voltage difference is very little. However, I would suggest the setup would be better off with a DC2DC charger vs without, I answered "No" above though to that question as you added the word "way" in front of better off, and while the DC2DC charger would be better, it wouldn't be "way" better, just a little better if even that.
If I remember correctly there is somewhere around .1 volt difference in the recommended "float" charge state for AGM vs LA. Also, if you did choose to install a DC2DC charger, you can still do so while maintaining the isolation relay. Somewhere here in the forums I shared a modified wiring diagram showing how to optimally wire a DC2DC charger while keeping the solenoid in place for the AUX start ability.
All in all, there is little difference in AGM and LA voltages and I wouldn't replace a good battery of either type just to match the coach to the chassis. However, I wouldn't mix AGM and LA in the same bank of batteries for example when\if you have multiple coach batteries.
Not to go too deep for other thoughts, most newer RV's power converter (charge controller) has a profile that is battery type specific and can be user set for the optimal profile (agm or la and some also have LifePo4 settings). However, even that is not a perfect solution because the charge voltage should be "battery" temperature compensated (agm and la). While some RV power converters and many smart chargers (and the engine alternator itself) are temperature compensated for the charge voltage, most do not actually measure the battery temperature (some of the better ones do have a battery temp sensor). So what that means is if the battery is colder than the charger (like my coach battery would be in the winter time or even the opposite in the summer time), then the charge voltage would not be optimal anyway as the voltage needs to be increased as the battery gets colder and decreased as the battery gets warmer. Therefore regardless of what you decide, it would be best to use a smart charger once in a while (perhaps monthly or maybe every 3 months) that is temperature compensated (many of them are now) and have that charger at the same temperature as the battery or as close as possible. During the bulk and absorption charge stage, the battery(s) will be a bit warmer than ambient air temp, but at the float stage the battery should be very close to the ambient temp (once cooled off from the faster charge stages). Most all new smart chargers (the portable ones) allow you to choose the battery type and I would choose the correct type and charge the coach batteries once in a while and also choose the correct type and charge the chassis battery once in a while with a quality external charger.
Just for example and not necessarily a recommendation, this is a temperature compensated charger. If the charger was in the warm RV and the battery was in the cold outside, then the temp compensation would prevent the battery from being fully charged. What needs to occur is that the charger should be located where the battery is (such as under the hood next to the chassis battery).
https://www.amazon.com/NOCO-GENIUS10...d670b6bc&psc=1
Short answer, now that you have read all of this,
I wouldn't worry with mixing LA and AGM batteries between the coach and chassis but I would keep all the coach batteries the same and if (which our Jayco E450's don't have) there were two chassis batteries, they need to be the same type as well.
~CA
Linear Mode
