Question Lithium Upgrade Simple Answer
I have a 2015 C Class on the E450 chassis with a single 12V group 27 lead acid battery and I would like to upgrade to a single lithium equivalent, to draw, as a minimum, 3 amp-hours for 24 hours before recharging.
I currently have the Progressive Dynamics PD4060K multistage charger converter and would like to know if it will recharge lithium and also would the chassis charging system be good enough for a single lithium battery or would I need to add a DC/DC converter.
My background is in electronics engineering technology with 30+ years in the aircraft electrical/electronics industry, I say this because after extensive searches for straight answers, I grow annoyed at all the extensive lecturing about the “must have” and “absolutely need” sales pitch nonsense.
Any subject specific information you can provide would be greatly appreciated as I don’t want to pay for equipment I don’t need or electrical “lessons” that waste my time.
Keep up the good work that you and the folks at RVTravel.com do for RV’ers who are looking for unbiased information for our community. Thank you.
From the PD site…
I noticed Mike missed your second question (charging the LFP from the alternator). The answer is absolutely yes, you do need a DC-DC charger. A 20A should be adequate. Your 2015 chassis almost certainly has a variable voltage alternator that is focused on fuel economy and will rarely produce enough voltage for any length of time to provide charging to your house batteries (lithium or otherwise). The higher charging voltage of LFP will make it even more difficult. It also probably does a poor job of charging your house battery now.
Your 2015 converter does not have any provisions for lithium charging. All current converter sections are built with a switch to provide a constant 14.6 VDC output for lithium charging Your converter replacement is a PD4060CSV.
When you are charging from the alternator you will definitely want a DC -DC converter.
This will allow you to charge at the proper voltage as well as limit the current draw from the alternator. Excessive current draw can cause the alternator to overheat and cause permanent damage.