Alternators burning out charging lithium

[JayGuevara]

I saw a video on the Victron Energy YouTube channel where they showed alternators burning out when charging lithium at low speeds due to the high draw but low cooling effect from the internal alternator fan.

If I run a split charge via the van lead acid battery I assume the internal resistance of the lead acid battery will negate this?

Obviously, I’d like to charge as quickly a possible. I have 300 watts of solar and am planning to add 300ah of lithium.
Solar is pretty useless here in the UK in winter and I want to power a house fridge/freezer via an efficient inverter all year.

I drive around an hour a day so I don’t want to waste the ‘free’ charging.

 

[grizzzman]

You need a DC to DC charger to keep the Alt. safe. Renogy has a good price 20 or 40 amp units They also have one with a solar charger.

 

[KG6S]

I chose this method to charge my 12v LFP from my tow vehicle. The tow vehicle charge is fuse limited to 25A, and you are right, an SLA has high enough resistance to not cause excessive current draw, but the LFP will suck power like a ....never mind... a lot. Cheap insurance to not have to blow the charge circuit fuse, or worse, damage the alternator.

The Renogy works good for the intended purpose. A little goofy design, but it works as advertised.

 

[tictag]

If I run a split charge via the van lead acid battery I assume the internal resistance of the lead acid battery will negate this?

No. Your alternator will simply (attempt to) dump current as is required by the load (until something blows, that is). The safest methods of charging a lithium-ion battery from an alternator is either:

1. Fit a 'smart alternator', that limits the current it provides to safe levels (i.e. revs dependant).
2. Charge via a DC-DC charger e.g. Victron.

 

[peallen]

nations alternators has a 12v, 24v, and 48v 2nd alternator with balmer regulators. dual alternators.
also this relay: link