Thread: Lithium Battery

I think you will be losing some of the capacity of the lithium pack if you do this, as it's fully charged voltage is higher than a standard 12v battery, although to be honest it is not a huge percentage of charge your losing from not fully charging it.

I have run standard lithium cells without any BMS in my racecar for years now and the only problem I have had is over discharging them. They do not tolerate this at all. So as a second battery as long as you had a low voltage cut off on anything plugged into it I think it would be okay.

I very nearly did this setup myself when I last replaced the batteries in my defender also, but I got a good deal on 2 marine lead acids that fit in space I had so I didn't, but I can't see any particular reason it would not work.

I think i worked it out from the cells I was looking about using (Headway) you would lose only about 15% capacity by only charging them up to ~14 volts rather than fully charging them to ~14.6 volts.

Tim (Traxide) can set his gear to suit Lithium aux batteries. Give him a yell - Drivesafe on this forum!

Hi Brad and here is some info relating to your questions.

1. Can I install a Lithium deep cycle as my 2nd battery with my current setup of a Traxide D4-5U? - NO

2. Would i need to run a specific lithium BMS? - YES

3. Can i run the Traxide and lithium charger in tandem? YES but the two battery types must be isolated from each other once the motor is off.

From experience gained from a number of D4 lithium battery installs, IMO, at this time, it is still more advantageous to stay with conventional battery type setups and they work out a lot cheaper.

Originally Posted by mattims

I think i worked it out from the cells I was looking about using (Headway) you would lose only about 15% capacity by only charging them up to ~14 volts rather than fully charging them to ~14.6 volts.

Hi Matt and unfortunately it is not a small capacity lose.

While a lithium battery is connected to any form of lead acid battery, the lithium acts as a low current trickle charger for the lead acid battery and is continually being discharged by the lead acid battery.

Thanks again all. Useful information as always.

Tim,

If i decided to use Lithium batteries in my Camper Trailer that will come with a recommended BMS, the Traxide kit i have installed in my D4 will still supply power through the Anderson plug to charge the camper trailer batteries?

Thanks
Brad

Hi again Brad and yes, the Traxide system you have is fine.

As for charging the Lithiums, there are a number of ways, with DC/DC being the most common.

BUT, you can actually set up a much better system by using a 12v to 240vac inverter and a good quality battery charger, preferably one with a LITHIUM setting.

You then have your on the road charging, plus a 240vac power supply while free camping and a decent battery charger while on mains.

Originally Posted by Bradmc

.........If i decided to use Lithium batteries in my Camper Trailer ........

Thanks
Brad

Hi Brad, I am just in the process of changing my caravan over to Lithium (Lithium Ferrous Phosphate - LiFeP04, or LFP) and I have been researching this upgrade for two years, my strongest possible advice is to do some serious home work before you put your hand in your pocket. There are plenty of people selling LFP batteries with so called BMS systems as drop in replacements for Lead Acid (FLA) if this is what you are considering, I strongly urge you to be very cautious with this approach. At the least just go and look at web sites of Mastervolt or Victron Energy, they sell properly configured systems, then ask yourself, how does the "drop in" work compared to these engineered systems?

Yes, LFP has some excellent advantages over FLA but other than the fact that it is a device to store electrical energy they have nothing much in common. You need a complete, and I mean complete paradigm change in the way you use these batteries if you want them to last and give the type of performance that they are capable of delivering. IMOH, peolpe and their "lead acid" programmed brains are the biggest problem.
You also need equipment that is specifically designed to manage them, do not buy the sales speak when a manufacturer tells you it has a "Lithium" charge profile. The question to ask is "can I customise the charge profile" if the answer is "no" shop somewhere else.

The BMS on a good Li system is not there to control the charge/discharge process, it is there as an insurance policy, to protect at cell level against high and low voltage events and stop cell imbalance buy cutting loads if a cell drifts.

Food for thought................................Peter

Originally Posted by PeterJ

You also need equipment that is specifically designed to manage them, do not buy the sales speak when a manufacturer tells you it has a "Lithium" charge profile. The question to ask is "can I customise the charge profile" if the answer is "no" shop somewhere else.

And this is why I only use and recommend Sterling or Promariner battery charges.

They come with 12 different user settings including two dedicated Lithium charge setting and can also be setup in a user programmable custom setting.

I have been using these chargers and supplying them to customers, including quite a few lithium battery owners, for over 6 years now, and never had a problem with lithium battery charging.

In fact, one of my D4 customers bought some lithium batteries from a well known supplier and bought one of their recommended battery charges, which did not charge the lithium batteries properly.

After he had a few different chargers from the battery supplier, with out success, he bought both an Sterling inverter and Promariner ProNautic charger from me and finally, his system worked as it should, and5 years later, still is.

Both the Sterling and ProNautic charges are designed for the marine industry and have long established track record of successfully charging lithium battery banks for years before anyone else came up with anything comparable.

And again, by my customers having a separate inverter/charger setup, they have a far more versatile system, and usually at a much better setup cost.