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Open Roads Forum  >  Tech Issues

 > 2004 Cat C7 Charging LifePo4 battery bank

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MEXICOWANDERER

las peñas, michoacan, mexico

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Posted: 03/03/21 05:43pm Link  |  Quote  |  Print  |  Notify Moderator

Detroit uses the 50DN oil cooled alt.

ScottG

Bothell Wa.

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Posted: 03/03/21 07:48pm Link  |  Quote  |  Print  |  Notify Moderator

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

pianotuna

Regina, SK, Canada

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Posted: 03/04/21 08:22am Link  |  Quote  |  Print  |  Notify Moderator

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?

* This post was edited 03/04/21 08:29am by pianotuna *


Regards, Don
My ride is a 28 foot Class C, 256 watts solar, soon to have SiO2 batteries, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

MEXICOWANDERER

las peñas, michoacan, mexico

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Posted: 03/04/21 11:25am Link  |  Quote  |  Print  |  Notify Moderator

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.

SV K

Varied

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Posted: 03/04/21 01:46pm Link  |  Quote  |  Print  |  Notify Moderator

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

las peñas, michoacan, mexico

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Posted: 03/04/21 06:37pm Link  |  Quote  |  Print  |  Notify Moderator

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.

Dirtyrhoades77

Tucson

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Posted: 03/05/21 06:15pm Link  |  Quote  |  Print  |  Notify Moderator

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

las peñas, michoacan, mexico

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Posted: 03/06/21 02:55am Link  |  Quote  |  Print  |  Notify Moderator

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.

wa8yxm

Davison Michigan (East of Flint)

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Posted: 03/06/21 04:51am Link  |  Quote  |  Print  |  Notify Moderator

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%


Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times


MEXICOWANDERER

las peñas, michoacan, mexico

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Posted: 03/06/21 02:06pm Link  |  Quote  |  Print  |  Notify Moderator

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.

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