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Idle-Up's avatar
Idle-Up
Explorer
Apr 04, 2019

Lithium & 2nd Alternators Verses Onan Generators - Mike Mas

Greetings - I have a great In-Depth RV article on the integration of Lithium Batteries and 2nd Alternators in our RV’s and how they stack up compared to our Onan generators. Aside from talking about lithium batteries, we’ll discuss diesel engines and how temperature affects the engines oil shear abilities and viscosity. I’ll also cover cold weather idling which causes “Wet Stacking”.

We’ll also look at the many advantages of lithium over flooded or AGM packs, where just one 600 amp/hr lithium battery about the size of one 8D battery, can operate our RV’s roof top AC (50% cycle), lights and TV for 6-8 hours on just one charge. There is also major weight and space saving advantages with lithium, where the same 600 amp/hr lithium battery weighing just 150 lbs. can replaces 4-5 flooded D size batteries, weighing 500-650 lbs, or 2-4 AGM D batteries for weight saving of 300-600 lbs. This is big news when considering some smaller RV’s like type B’s have limited space and weight carrying capabilities.

We’ll also compare how an RV equipped with lithium batteries and 2nd alternator stacks up to a RV with just one 8D AGM battery a few solar panels and propane generator. I guarantee you’ll be surprised when you find out the Onan generator RV, actually provides more “off the grid” time than a lithium powered coach.

Most important, we’ll also look at the damaging effects of extended idling to a diesel engine, turbo and diesel particulate filter. We’ll also talk about how cold weather and hot temperature idling has a major effect on the Sprinter’s engine.

We’ll also look at other RV applications where lithium companies are taking out big 10kw diesel generators from 45’ Type A’ coaches and equipping them with massive lithium 136 KW packs using three inverters to run the coach. I’ll also provide information on companies and vendors so owners looking to upgrade their existing coach, can consider if lithium will be part of their future in RV’s.

Please click on the link below for the Story

http://www.rotory.com/sprinter/lithium/

Enjoy - Mike Mas
Class B

6 Replies

  • Shearwater's avatar
    Shearwater
    Explorer
    Apr 05, 2019
    c/20 is a charging parameter for lead acid batteries. One of the advantages of Li batteries is that they can be charged and discharged at a much higher rate.
  • noteven's avatar
    noteven
    Explorer III
    Apr 05, 2019
    What if a guy set up a generator and controls using the pto provision on a Ford 6R or Allison auto trans?

    An idling 6.2 gasohol V8 has a less irritating sound than a 100cc “quiet” generator fast charging LiFe04.
  • theoldwizard1's avatar
    theoldwizard1
    Explorer II
    Apr 05, 2019
    IMHO, using the vehicle engine to re-charge a 600 amp-hour battery bank (regardless of its chemistry) while PARKED is not a good plan ! If you are charging at capacity divided by 20 (C20), a common rate, would be 30A. For a LiFePO4 600 AH battery bank, which can be discharged to near 0% SOC, that would take 20 hr to recharge. For a lead acid battery bank, which should not be discharged past 50%, it would still take 10 hrs.

    First, solar is you friend. Not cheap but silent and it works whenever the sun is shining.

    Second, high current (50A ?) fully automatic chargers are not common.

    Third, automotive alternators do a poor job of charging deep discharge batteries, irregardless of the chemistry. They are not "smart" enough by themselves. Read this DC-DC battery charging

    Forth, if it was me, I would take a multi-prong "attack" at your problem.
    • Use a DC-DC battery charger while driving.
    •Us e a small (< 3000W) portable gasoline/diesel generator for bulk recharging when no shore power is available.
    •Use a 100A 12V power supply and timer for "bulk" recharging (a pair of MegaWatt S-700 would work. The mechanical timer is very important. If that power is applied for too long you will ruin the battery bank.
    • Follow up with a "smart" multi-stage battery charger.

    OR

    Use a CTEK D250SA in combination with a CTEK SMARTPASS 120 from the engine alternator. This of course does mean the vehicle engine will have run for many hours when boondocking.


    Regardless of what you decide to do, make sure your battery bank charging system will provide the correct voltages and current to your batteries if you want then to live a long life !
  • DownTheAvenue's avatar
    DownTheAvenue
    Explorer
    Apr 05, 2019
    A long article that is well written from an amateur's perspective. It is merely written by someone without any credentials to back up the statements.
  • Shearwater's avatar
    Shearwater
    Explorer
    Apr 05, 2019
    I read his article mostly because we have a Sprinter with a lithium battery, 2nd alternator, and auto-start function with a high idle set up. Some comments in no particular order -
    1. Our previous B van had propane for cooking, heating and a water heater. We had 2 serious propane leaks in 110,000 miles and we never used the water heater because it was too slow. I wanted to avoid the hazards of propane leaks and carbon monoxide.
    2. We have the autostart feature set up but it has never been necessary. If it is activated it only needs to run for either 60 or 90 minutes (I forget which) not the 3-6 hours claimed.
    3. The Li battery runs all functions including cooking for days without requiring charging. I suppose if you are boondocking for long periods of time or if you need AC or some other power hungry appliance, a generator would be useful. OTOH, a generator is just another engine that takes up space and requires monthly maintenance all year long.
    4. His sound level tests were measured with the detector set up right in front of the vehicle's grill, hardly a fair comparison.
    5. In one part of the article, he complains that the engine doesn't warm up enough while idling and in another he complains about overheating.

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