2004 Cat C7 Charging LifePo4 battery bank

[map40]

I am upgrading my battery bank to a hell of a lot of capacity (Around 1200 amps). I know that if this was a gasser, the alternator will die young if it has to charge the bank. How good is the alternator in the Caterpillar? Will it take sustain maximun capacity constant? Otherwise I need to find a way to regulate power or connect and disconnect the banlk ontermitently.
Thanks!

[MEXICOWANDERER]

What would you suggest with my Lombardini driving a 385 ampere 50 DN? Distance around thirteen feet if I remember correctly. 330MCM gives me .34 vdc at 28.3 volts and 385 amps. I had to bend this wire using a 1-1/4" EMT bender.

An amp is an amp is an amp DC.

# 6 AWG is good for twenty feet total.

[wa8yxm]

2oldman wrote:
The charging rate will likely be determined by the size of the charging wire. Congrats on the 1200ah.

And there is your answer. a few more feet of wire (how many depends on what gauge) and the charge current is limited to alternator*50%

[MEXICOWANDERER]

Drive belt power capacity is the #1 factor to muse. A 100 amp 24 volt unit requires the same power as a 200 amp 12 volt alternator. So pulley feasibility is top importance. Best to drive 2nd alt alongside the engine which involves one added engine pulley. Use a spring loaded belt tensioner. Use only an alternator that has a ?" diam shaft.

[Dirtyrhoades77]

Could anyone ballpark estimate a the price on a 24v 100a alternator for a gas class C? It would be serve as a backup charger for a 24v 7200w lifepo4 battery on the rare occasion the solar panels have been without sun for a few days. The batterie's BMS indicates a 100a continuous charge.

I'm not sure the ones I see on amazon are compatible with a gas engine, they all seem to be diesel. Is this a bad idea? I'd prefer to dump the generator as I would very rarely need it.

[MEXICOWANDERER]

The main issue with the square wire hairpin 50 DN is the wire leads get brittle and break. I mounted an air cooled 50 DN to the Lombardini chassis frame and used belt tensioner to reduce vibration. These alternators use 125-amp 200 PIV Rectifiers. They have 1? keyed shaft. Good alts.

[SV_K]

Our 50dn's have no problems in various coaches feeding 700amp, 1000amp and a 1200amp Lifepo4 batts using the stock controller. Outputs approx. constant 250amps till target voltage is hit and then drops to maintenance amps.

[MEXICOWANDERER]

Output voltage is determined by the voltage regulator, but the stator has to be wound specifically to allow lower speed charging. I like 5/4 wye windings for 32 volts.

The rotor should be full spool wound. Right to the lip. 8-10 ohms. For 24 volts and add two more ohms for 32 volt operation.

48 volts needs 14 x 4 specs. Another 2 ohms. Magnet wire is available in 1/4 AWG increments like stator wire. A spool however is 10M feet.

It's getting harder and harder to source discrete voltage regulator components to build tough systems. The design of a 200 volt 200 ampere MOSFET power transistor heat sink is a nightmare. It cannot be done on substrate without great cost.

I used scrap stripped 70 amp battery isolators for regulator heat sinks. I built 48 volt alternators for alternate energy systems that used the 5548 Trace Inverters. Mid-fifties working voltage was the norm.

As far as I know the building of high voltage alternator art form is dead.

Today if I had to start somewhere with an alternator model for 48 volt conversion it would be with a Motorola

8SC 4006 U

Originally 100 amps at 37.5 volts
Converted and rewound 70 amperes at 56 volts.

56 volts is enough to stop a human heart.

[pianotuna]

While the alternator may be full load capable--how does it determine the out put voltage?

There are 48 volt dc air conditioners available as a mini split. I would go that route.

Have you considered providing for 12 volt needs via a DC to dc device (i.e. 48 volts in, 12 volts out)?

It would seem to me to be more efficient to use either 48 volts or 12 volts, but not both. The first thing that comes to mind is having two inverters, when one would do.

How much solar wattage is planned for?

[ScottG]

You should have a large frame alt. and it will happily pump out it's max current all day long.

[MEXICOWANDERER]

Detroit uses the 50DN oil cooled alt.

[SV_K]

Is your alternator air or oil cooled?

[MEXICOWANDERER]

6?" or 8?/¹?" alternators can sustain 100% load.
Google DELCO, MOTOROLA, LEECE NEVILLE IMAGES and state which one you have.

[2oldman]

I think CA is referring to the designation of amp-hours, not amps. Running ACs with 12v is going to require some big cabling. I think I'd prefer doing that with the 48v side.

[map40]

CA Traveler wrote:
Not an expert but there have been prior posts that typically alternators will not sustian their maximum ratings without damage which is basically what you want with that amount of Ah.

But not sure what you mean by 1200A - Are you planning for 1200 Ah?

Suggest you get the model number and contact the mfg.

Well, by 1200 amps I meant 1200 usable amps. 6 280 amps batteries. 15kw in the 12v system. I also have 28kw in a 48V system to run all the 110-220 with a split phase.
This 12v battery bank will be for storing the solar and running the 12V side of the house. If needed, I can run 110V through the inverter (which I might be upgrading to a low frequency inverter so I can run ACs with the 12v batteries).
I have a 6kw inverter generator that I can use to recharge both banks at a 90% efficiency, if I ever need it, wich I don{t believe I ever will.
I am getting rid of my diesel generator. I am done with the smell, noise, maintenance and ineficiency. With what I get from selling the generators I can do all of this and more.
Now I have to find a way to control the flow from the alternator or install a timer on the batteries so the charge intermitently.