Lazy Daze Owners' Group

Hi Everyone!

Needing to replace our house batteries (we were warned about that from the RV inspector after he "tested" them) and thinking of making some selected upgrades at the same time for better battery usage/life. I've read through alot of threads on this topic. I'm listing my plan below so that I can request some advice/shared wisdom in case I've misunderstood or am missing something important etc.

We don’t boondock very much if at all at this point but may in the future -- which I think would require making further upgrades than what I'm listing below (like adding solar). I want to be relatively cost-conscious right now. We mostly stay in state or county parks with shore power -- or sometimes private parks for one-night layovers.

Here's my current plan. I'd be grateful for any feedback/corrections as needed.

1. Replacing the current Trojan T-105s with something equivalent. If I can find those locally, great. If not, probably a "Duracell" branded whatever from Batteries Plus. Costco is 2 hours away, and Sam's has very limited options and they're not much cheaper than BP anyway.

2.  Replace functioning Parallax with PD4645 (without need to upgrade wiring) – reason: allowing me to remain plugged in to shore power in storage without overcharging house batteries.
 -- Anything more powerful than the PD4645 (like a PD4655 or more) would require rewiring (and/or upgrading fuses) to handle current going to the battery, correct?
 -- Should I replace the entire 20-year-old power center (what I mean by that is the breakers and fuse panel etc) AND the perfectly functioning Auto Transfer Switch pre-emptively at the same time?

3.  Replace diode/isolator with Victron Cyrix battery combiner. Reason: hoping this will allow me to maintain charge of starting battery while connected to shore power in storage. (this is the thread where you all discussed this somewhat: Should the battery isolation manager be replaced when updating to lithium?)
 -- This just replaces the blue-finned isolator I have, right?
 -- This doesn’t have an alternator connection, correct? Unlike the isolator? Is that an issue?
 -- What about the threads where people mention replacing the isolator with a mechanical relay? Is that what the Cyrix is?

4.  Adding proper battery monitoring -- something like this: Amazon.com: CDI Electronics SG200 Battery Monitor Kit, 12V-48V : Electronics

Not adding solar (RV has never had solar on it – don’t think they solar-prepped in 2003 either?) or Lithium right now, but happy to replace old/worn/inefficient parts with something generally compatible with solar/lithium upgrades in the future.

Future plans: adding solar, upgrading to Li, replacing a tired fridge with either a 12v compressor fridge or new 2-way (if they will still be making those when it’s time to pull the trigger -- what I'd really like to do is replace circuit and eyebrow boards, and cooling unit to keep the current one going -- it's plastics are fine and it fits the spot).

Thank you for any advice!
Jason

Hi Jason;  One by one: #1)  get two 6 v deep cycle batteries, just like what you have now.  AGM are too expensive. For two AGM, you could go LiFePO4. One of those at 13 Volts, would give you more usable Watts than two AGM's.
      2)  Get a Progressive Dynamics 4655VL with the jumper to upgrade to Li in the future. (the 4675 fans run continuously, maybe you don't want that)  PD 4655VL 55 Amp Converter Upgrade, Optional Remote Pendant  The VL option is fo Li.  It is what I got. Don't get the optional remote. That is for RV's where the converter isn't out in the open.  With a new fuse panel (it comes with that).
I didn't upgrade the wiring. I changed the 50Amp 'breaker' for a 60Amp better unit.  Amazon.com: Young Marine Circuit Breaker for Boat Trolling with Manual...  (some profits from Amazon goes to the LDOG) This breaker has a switch to intentionally disconnect the power if you want.
     3) Leave the blue finned isolator alone.  It is a good unit and works even with a conversion to Lithium. (check Steve out).   Get a Trik-L-Start and hook it up across the isolator. It will charge the chassis battery when plugged into shore power. (it's a trickle charger, not too effective if you are running the generator).. It will not overcharge the chassis battery. The new PD converter (#2 above) has a microprocessor controlled charger with bulk, absorb and float. (and equalize if you want to).  The Trik-L-Start wont work with Lithium,but  an upgraded Amp-L-Start does. Without clips (use the ring terminals) $55 + shipping Mega TRIK-L-START Starting Battery Charger/Maintainer
    General comments.  My original 1999 Dometic still works fine. Leave it alone for now. ( my freezer was two degrees yesterday at Doheny Beach CaSP, not quite leveled, in the full sun.)  While it can fail anytime without much notice at this advanced age, even much newer ones can do that trick also. I think the older ones were built better.  You can cross that bridge when you get to it. 12V motor/compressors may be much better in the future, but you will need LiF batteries and solar for a compressor anyway.
    My '99 TK coach wasn't 'prepped' for solar. But it was easy to put in 3 x 48 Watt panels at 14% efficiency in 2000. Cheaper now, I upgraded to 4 x100 W. and one 50W Renogy panels at 21% efficiency. ($600) And I upgraded from a Solar Boost 2000 (20A) to a Solar Boost 3000 (30A) same size cutout hole/wires.  Both MPPT type.  (thanks to Kent who went to a much bigger solar array and controller.)  I got his used LD supplied controller, and with a little (user) simple reprogramming to a higher voltage for the Lithium batteries in your future.
    The Cyrix is meant for a way to charge the LiF batteries. I wasn't impressed! Just a more involved mechanical relay.   I feel that a better solution is with a Renogy DC to DC converter. 20Amp for your older alternator. It takes whatever the Ford can supply, 8 to 14.8 volts, totally isolated,  and converts it to 14.4 or 14.6 volts with a Lithium battery charge profile. That is: more current measured than voltage determined. It will also work well with your lead acid batteries by DIP switch selection, but it needs an optional temperature probe, that LiF doesn't need.  I have a 60A version that is so far throttled down to 30A by the LC (low current) input.   Amazon.com: Renogy 12V 20A DC to DC On-Board Battery Charger for Flooded,...
   If you do add solar, stay with 12V optimized panels in parallel, mostly to minimize shading problems. Unlike a house everything on an RV is native 12v. operation. Going to higher voltage just involves losses to switch voltage around. Use 10 gauge wiring in parallel into a combiner box. Easy upgrades, etc. 
    I have the BalMar battery meter. (SG-200) Balmar Sg200 Battery Monitor Kit W/Display Shunt & 10m Cable - 12-48 Vdc      It can be configured for Lead Acid or Lithium. I'm really pleased with it. I used it last year and it told me that my Lead Acid batteries weren't in good shape. (SOHealth)  was about 72%. When Kent told me about the SOK 206 LiFePO4 batteries about the size of T-125's with 206 AH, I sprang for two of those. Will Prowse has an evaluation of the metal cased ones on YouTube.  So far they have been working well. They and an electric 12v. heater for below 32 degree weather fit in my original battery box.    RonB

When I changed out my  Parallax converter for the PD4655 I considered changing out the DC fuse board but saw that, due to the very short LD wires it would be a major PIA. I checked with a Progressive tech and asked how important it was to have their board as opposed to continuing using the Parallax fuse board and he said it would be just fine to use the Parallax board which I did. My PD4655 is set up for charging my lithium battery bank and works just fine.