Community Forums

Unicorn Driver · 06-07-2018, 09:51 PM

Hi,

How many amps will a UFO alternator send to the house batteries?

Thanks,

Skip426 · 06-07-2018, 10:06 PM

I can't say what the design output of the alternator is , but I doubt that it could ever deliver max output to the coach batteries, there could be limitations built into the interconnect system installed by the coach manufacturer .
Another factor in max alternator output is what the internal regulator sees for battery state of charge , e.g. if the coach batteries are low on charge and the chassis batteries are fully charged , the regulator will react to the fully charged batteries or a blend of the two battery banks condition so charge rate would be lower than if both battery banks were low on charge.

Do you have a specific problem ?

Unicorn Driver · 06-07-2018, 10:10 PM

Hi Skip,

No problem at all.

Just new to me coach questions and what ifs ;-)

twinboat · 06-08-2018, 03:44 AM

In most applications, the alternator sends all of its output to the chassis battery.

Connecting the charging, chassis battery to the depleted, house battery causes the current to move from high to low.

How many amps move, depends on the voltages of each battery. A battery monitor on the house battery will answer that question.

Some MHs, with voltage sensing isolation controls, will cut the house battery charging if the chassis battery volts drop too low. That is to preserve the chassis systems from low voltage and overheating the alternator.

Unicorn Driver · 06-08-2018, 04:22 AM

Thanks Twinboat,

So after a boon docking trip I may beed to run my generator to charge my batteries.

twinboat · 06-08-2018, 04:50 AM

Quote:

Originally Posted by 1stmh

Thanks Twinboat,

So after a boon docking trip I may beed to run my generator to charge my batteries.

That depends on how low you discharged them and how long you'll be driving before the next stop.
Many folks do run the generator to get the bulk charging done on large battery banks.

l1v3fr33ord1 · 06-08-2018, 06:05 AM

1stmh-

According to the brochure, your coach has a 145-amp alternator.

According to the wiring diagrams, your coach has a solenoid to connect the chassis and house batteries, but no other components (such as a Intelligent Relay Delay, or IRD) to regulate the charging across the solenoid from chassis to house. The coach was built with a Trik-L-Start to regulate charging between house and chassis, for when the coach is on shore power or the generator is running.

Assuming the solenoid is working as designed, the chassis and house battery banks are joined (through the solenoid) if the ignition switch is on. The alternator will attempt to charge the joined battery banks. The alternator output could be overloaded if the joined battery bank voltage is too low.

As "twinboat" recommends, check house battery state with your Trimetric monitor and, if needed, run the generator to charge the house batteries to a reasonable state of charge before starting the coach.