Empathy List Archives

SH

Scott H.E. Welch

Thu, Nov 6, 2008 2:04 AM

a tech question, is it possible to run the intelligent battery charger,
using the generator and at the same time put charge into the batteries from
the alternator as the main engine is running?

Yes. One caveat, you might want to double-check the sizing of your primary
battery wiring and your main disconnect. When I run my main engine alternator
(140 amps) plus my Xantrex inverter in charge mode (another 150 amps) the 3/0
cable and switch get warm to the touch. This winter I'm switching to the
biggest Blue Sea switch and 4/0 cable.

We have one huge double bank of 6 volt wet cells that provides about 1400
amp hours. Because we have been anchoring a lot we are having a hard time
putting back the amps that the frig and freezer relentlessly eat every night.

Yes, I noticed this as well. The problem for me is that my charger (150 amp)
is just not big enough. You might want to investigate a bigger charger.
Ideally you want to absorb as much of the genset output as possible, to
minimize genset run time.

Scott Welch
FirstClass Product Manager
www.firstclass.com

"Things turn out best for people who make the best of the way things turn
out." - John Wooden

astonj@rogers.com writes: >a tech question, is it possible to run the intelligent battery charger, >using the generator and at the same time put charge into the batteries from >the alternator as the main engine is running? Yes. One caveat, you might want to double-check the sizing of your primary battery wiring and your main disconnect. When I run my main engine alternator (140 amps) plus my Xantrex inverter in charge mode (another 150 amps) the 3/0 cable and switch get warm to the touch. This winter I'm switching to the biggest Blue Sea switch and 4/0 cable. > >We have one huge double bank of 6 volt wet cells that provides about 1400 >amp hours. Because we have been anchoring a lot we are having a hard time >putting back the amps that the frig and freezer relentlessly eat every night. Yes, I noticed this as well. The problem for me is that my charger (150 amp) is just not big enough. You might want to investigate a bigger charger. Ideally you want to absorb as much of the genset output as possible, to minimize genset run time. Scott Welch FirstClass Product Manager www.firstclass.com "Things turn out best for people who make the best of the way things turn out." - John Wooden

RT

Richard Tomkinson

Thu, Nov 6, 2008 3:55 AM

Yes. One caveat, you might want to double-check the sizing of your primary
battery wiring and your main disconnect.

Also check the shunt capacity.The shunt should be rated for 150% of the max
amps. So if you are putting 300 amps through, you should have a 500a shunt.
Also be sure the shunt studs are up to carrying the wire weight or better,
that wire weight is supported by strain relief at the stud. Otherwise the
stud may weaken and separate under high amp load. A symptom is heat transfer
through the wires tripping a nearby thermal breaker. This looks like a
breaker failure at first but can turn out to be the resistance of a weak
stud generating the heat.
Richard

> Yes. One caveat, you might want to double-check the sizing of your primary > battery wiring and your main disconnect. Also check the shunt capacity.The shunt should be rated for 150% of the max amps. So if you are putting 300 amps through, you should have a 500a shunt. Also be sure the shunt studs are up to carrying the wire weight or better, that wire weight is supported by strain relief at the stud. Otherwise the stud may weaken and separate under high amp load. A symptom is heat transfer through the wires tripping a nearby thermal breaker. This looks like a breaker failure at first but can turn out to be the resistance of a weak stud generating the heat. Richard

MR

Mark Richter

Fri, Nov 7, 2008 11:01 PM

<<When I run my main engine alternator
(140 amps) plus my Xantrex inverter in charge mode (another 150 amps) the
3/0
cable and switch get warm to the touch. This winter I'm switching to the
biggest Blue Sea switch and 4/0 cable.>>

The best marine cable insulation is rated at 105C, or 121 degrees F. Some
cheaper cable may only be rated for 75C. So I wouldn't worry about the
cable feeling warm to the touch, that's normal for cables carrying heavy
currents.

Mark Richter, m/v Winnie the Pooh, homeport Ortona, FL
Lying Ortona, FL, on the Okeechobee Waterway, finally.
Mark's Mobile Marine, electrical system design, installation and repair

<<When I run my main engine alternator (140 amps) plus my Xantrex inverter in charge mode (another 150 amps) the 3/0 cable and switch get warm to the touch. This winter I'm switching to the biggest Blue Sea switch and 4/0 cable.>> The best marine cable insulation is rated at 105C, or 121 degrees F. Some cheaper cable may only be rated for 75C. So I wouldn't worry about the cable feeling warm to the touch, that's normal for cables carrying heavy currents. Mark Richter, m/v Winnie the Pooh, homeport Ortona, FL Lying Ortona, FL, on the Okeechobee Waterway, finally. Mark's Mobile Marine, electrical system design, installation and repair

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