Hello Groover,
I’ve been running Lifepo4’s for 7 years and have helped friends install or been involved with the install of various other Lifepo4 systems for the last 6 years. Below will be the things we have learned in that time. In other words “real world experience” which is I think what you are after.
The first argument for the B-B charger is that it helps prevent alternator burnout from overload. I am thinking that a class A with a significant house battery pack of any sort should be prepared for a heavy load and that this reason doesn't really apply to newer class A's. Besides being expensive the B-B charger reduces efficiency and impedes charging, at least up to the voltage that the alternator produces.
On Coach #1- I installed Po4’s for the house and left the couple year old AGM’s for the chassis. Installed a Balmer programmable regulator to de-rate the “alternator” by half to avoid burnout. Set the “alternator” to the suggested charge profile for the Po4’s. All good. 7 years later both the AGM’s and the Po4’s are doing fine. Of note is that we played around will all types of various charge profiles and they all worked, additionally this coach has been used full time with over half of that time boondocking and they drive it 10k miles each year.
Coaches #2 and #3- Same as coach #1. Doing fine.
Coach #4- Used existing “alternator” controlled by 25yr. old original external controller. Doing fine 4 years later. BUT, these coaches, except for #3, all have oil cooled “alternators” or as my friend corrected me we actually have “generators”. The owner of this coach told me he just starts it up and the alt/gen pumps out 250amps, the PO4’s fill up and the current backs off.
Coach #5- Used air-cooled alternator with original internal regulator. He installed dash mounted switch allowing him to turn alt. on and off manually every 15 minutes or so to avoid over heating it. Well, he forgot to turn it off once and the alt. did indeed burnout.
Coach #6- Just finished Po’4 install and I am thinking I’ll go the DC-DC charger route. In the overall scheme of things it is not that large an expense and I like the simplicity.
The second argument for the B-B charger is that the engine alternator will not fully charge the lithium battery. I don't expect that to be an issue very often and if it looks like it may be an issue I can always fire up the generator and use its charger to top of the lithium batteries. In the summer it will probably be running anyway plus the solar panels that I plan to install will have a controller that will allow a full charge.
Hmmm…well they are plenty full for us. I have set various controllers to all types of voltages and they never fail to fill up the Po4’s. You guys got me thinking so I’ll set my solar to 14.0v today and see if it fills’m to the top. There is no need to fill Po4’s to the top though. The only “need” to do so is if you need those last few amps to get you thru till the next charge.
Hope this helps.
