Electrical Charging lithium batteries with tug alternator

[Boots in Action]

For all of those members who have or are considering fitting lithium batteries to their van to replace AGMs, here is some information on what happens to the tug alternator at slow to medium speeds. All the equipment used is Victron (quality stuff), but because Lithium batteries can accept a very high charge- in fact demand it- the tug alternator is placed under a very high load, gets hot and may even burn out the alternator wiring. Just another thing to check on in this fast moving technological world besides "smart" alternators.

 

[Drover]

Certainly the best reason to have a DC/DC charger no matter what battery isnt it ... If you spent all that money on a van lithium set up you would be doing off grid big time so no reason really for tug charge set up.....

When my alternator went up my fire extinguisher earned its keep..

 

[jazzeddie1234]

Useful video as it's easily overlooked when 'dropping in' that new lithium battery. A setec charger (if fitted) also has no current limit on the aux-in that jayco uses to charge the van battery - which is why they require a fuse on the tug side. Have they improved that with the newer setup?

And lastly don't forget to add up all the amps consumed by the tug and caravan and provided by the altenator (at idle) before selecting a dc dc! Eg headlights 10amps, van fridge 20 amps, tug fridge 5 amps, tug second battery 10 amps, engine operation 10 amps (?) , tug battery ... Thats getting near the limit

 

[Boots in Action]

Useful video as it's easily overlooked when 'dropping in' that new lithium battery. A setec charger (if fitted) also has no current limit on the aux-in that jayco uses to charge the van battery - which is why they require a fuse on the tug side. Have they improved that with the newer setup?

And lastly don't forget to add up all the amps consumed by the tug and caravan and provided by the altenator (at idle) before selecting a dc dc! Eg headlights 10amps, van fridge 20 amps, tug fridge 5 amps, tug second battery 10 amps, engine operation 10 amps (?) , tug battery ... Thats getting near the limit

@jazzeddie1234 , that would certainly be a consideration whilst traveling at anything less than highway speed of 100kph. Even at that speed, my tug is only at 1800rpm. With a high electrical load, even without headlights (I always run with parkers/running lights) and if I had two 100ah lithium batteries in a low condition, that will really have the alternator working hard under the bonnet with all the other hot parts. Yeah, would definitely be pushing the limits. Although some alternators have very high outputs (200amps?) , it is only at high rpm and the amount of heat generated at that high output for even a short period is likely to fry something.

 

[Drover]

and in modern rigs with everything electric the poor old alternator is already getting a flogging, check out the loads with electric steering normally let alone on a winding road and if you added lights and wipers, no wonder they fail or cook up............ I'm not all that happy having the van fridge hanging off mine.

 

[DRW]

Most modern alternators are at almost full capacity at 2,000RPM being as they are geared at around 3 to 1 of engine revs this means just above idle for most vehicles. I wish this was the case years ago as I might still have my hearing after revving engines to set voltage regulators for years.

 

[Boots in Action]

Most modern alternators are at almost full capacity at 2,000RPM being as they are geared at around 3 to 1 of engine revs this means just above idle for most vehicles. I wish this was the case years ago as I might still have my hearing after revving engines to set voltage regulators for years.

You mean with temp gauge in one hand and small screwdriver/needle-nosed pliers in the other and throttle blocked open at 3000 rpm. Yeah, them's were the days, and very fiddly. I can't hear that well either, but not caused by close encounters with revving engines!

 

[yabbietol]

Good informative video thanks for posting.

Recently a friend told me he was looking at a Lithium Battery for his caravan. I recommended Enedrive battery set up (AC charger, DC-DC, BMS) which is what I have had for 5½ years and still working well. I also said he needs to get a DC-DC converter and Battery Management System (BMS). He rang me and said he had spoken to a sales person who said he did not need a DC- DC converter and BMS. I was skeptical of the sales person advice. I warned him he really needs a DC-DC converter and a BMS (although some batteries now have internal BMS).

The DC-DC converter to ensure correct charging voltage for Lithium Battery and BMS to ensure all the battery cells are balanced in charge and voltage levels. Thanks for the video which I have emailed to him. Hopefully, it will inform his purchase.

Also an aside is that though a bit heavier I recommend Lithium Iron Phosphate (LiFePO4) batteries over Lithium Ion. We own 3 LiFePo4 batteries and they seem very reliable and have many more charging cycles (than Lithium Ion), they are also more fire resistant and do not mind been charged to 100% (though they do not like been discharged below 10-15%), so more useful capacity.

The caravan battery is 200Ah (equivalent to 320Ah lead acid) 5½ years old; house battery 10kWh 3½ years old and car battery ~55KWh (4 mths). They all perform well and the older ones appear to have lost little capacity and still charge nicely to 100%. I am a fan of LiFePO4 batteries, but they need to be looked after with good BMS and purpose designed chargers. The caravan (battery) is stored with a 100W solar panel on outside of its shed, keeping it charged to 100% ready to go and preventing the LiFePO4 discharging too low (<20% soc) which is not good for battery health. House and car battery are charged with house solar.