Aux. Alternator for charging Lithium batteries

[John Plyler]

I am setting up a new 400Ah lithium battery 12V system and need an aux. alternator for charging it.


I am new at this and the only alternator I have found is the Nation's 280 amp.



Has anyone had any experience with this alternator for charging a lithium battery bank or have another recommendation? I was thinking of using the Wakespeed WS500 regulator with it, and since it is a DIY build the REC-Active BMS.


I should mention that this is to go in a Sprinter Van. The reason I am at a marine forum is because I believe this group really has more knowledge!


Many Thanks

[a64pilot]

Many ways to skin this Cat.
Depending on money available, but a Leece Neville school bus alternator is a good option, or if you can live with 24V, a used Humvee alternator is good.

If money is no object then go with a special aftermarket alternator. But be advised that especially any of the highly modified small frame ones can’t put out their rated power for very long at all before they burn up.
Think of them as a highly modified hot rod engine, will make enormous power, but if you try to use it to pull a heavy trailer, soon it will overheat and blow up. Charging lithium is pulling a heavy trailer, up a hill.

Good thing with Lithium is it will accept enormous amounts of power greatly reducing charge times, bad thing with Lithium is it will accept so much power that it will easily burn up most alternators.

I usually pitch a Honda 2200, using the AC charger a Honda will easily charge 100+ amps continuously, and will do so for $1,000 and of course doesn’t require the big motor to be run just to charge batteries, besides the Honda can be used for so many uses that require AC power that they are just useful things.
it’s not hard at all to drop a couple of grand into an alternator set up by the time you buy one, fab mounts and buy a good regulator.

On edit shop for an ambulance alternator and or a school bus one, they are big and may be a challenge to fit, but any small alternator just can’t cool itself to make big power for long, see an alternator is actually an AC generator that rectifies AC power to pulsating DC using diodes and that produces lots of heat. A modern “shore power” charger does it much more efficiently by not producing much waste heat.
I would investigate a good shorepower charger and a Honda myself as opposed to a big alternator, unless you do a lot of driving and have the skills to fit one, or they money to pay to have it done.

Some vehicles may have provisions for a second alternator, my Duramax Diesel could I believe run dual 200 amp alternators with factory parts, a dual alternator was an option.

[rgleason]

https://www.cruisersforum.com/forums...o4-209089.html

One issue is BMS overvoltage disconnect of LFP leaving the alternator charging and causing diodes to fry. This has to be addressed somehow.See this thread and links

Configuration: Hybrid LA/LFP Frans' take on a hybrid LA/LiFePO4 system
which uses a smaller FLA battery in parallel to protect the Alternator when the BMS cuts off the LFP Batteries.

Nordkyndesign Lithium Dual Bus and Hybrid LFP
At the bottom after Dual Bus section, excellent wiring and configuration information about Hybrid LFP

[John Plyler]

I am told that this new Wakespeed regulator will totally control the Nation's alternator so that the current draw and heat generated will be controlled to keep everything in check!



This is such a new product no reviews seem to be out there!

[rgleason]

Wakespeed is sold by Ocean Planet Energy and APS, targeting miltary, they sell only the best equipment in my opinion. I got to know Al Thomaston who completed the Wakespeed development after the original developer died unexpectedly. Al had developed a Smart Regulator that also measured current as well as voltage and was developed as an improved regulator, very much like the Wakespeed. I happen to have one of the Gen3 versions of that regulator.

Balmar sells the 614 External Regulator which had a predefined program for LFP (also can be user programmed) and it will also work with LFP very well, but it does not sense current. It is less expensive.

See this note: https://www.cruisersforum.com/forums...ml#post3273812

[John Plyler]

Thanks you very, very much! It is so nice to finally hear some good feedback.

[rgleason]

John,

Since you've picked a nice set of components, I would love to see a good diagram of your system if you can do it, even just a hand drawing at first.

I just mention, since you are already involved in this, that I found this hybrid writeup and configuration very interesting Perfect Switch Marine-Lifepo4-Lithium Ion on Mai Tai , because when the LFP is disconnected a Perfect Switch (mosfet) automatically connects an LFP battery to protect the alternator.

I believe the WS500 will cut the alternator field automatically when the BMS cuts off the LFP, with its Canbus connection to the BMS, to protect the alternator, but hopefully your configuration will have a charge bus and load/discharge bus with relays so that your nav equipment remains powered. You might also be able to use one or two of these solid state Mosfet switches from Perfect Switch which use very little power.

Originally Posted by John Plyler

Thanks you very, very much! It is so nice to finally hear some good feedback.

[John Plyler]

I am just buying the parts right now, but I plan to set it up similar to this one. Thanks again.

https://www.youtube.com/watch?v=JMqt...ature=youtu.be