Mixed battery types on same charger?

[richard5933]

are you saying your generator has no alternator ?

Correct. There is a charging circuit in the generator, but it is single stage and will keep charging after the battery no longer needs. Seems to be a battery boiler. No alternator and no way way to add one.

Richard
1974 GMC P8M4108A-125 (Current bus)
1964 GM PD4106-2412 (totalled Sept 2017)
Located in beautiful Wisconsin
KD9GRB

[TomC]

At least with my Powertech 10kw with 4 cylinder Kubota, it too has an electric fuel pump and fuel solenoid. The gen is attached to the 2-31 starting batteries. I've dry camped 4 days and still the big engine started just fine (no charging on the generator-12v alternator is disconnected). Good Luck, TomC

[buswarrior]

Any of these non-alternator "charging circuits" I've seen have poor voltage levels for charging, often below 13 volts.

Put a meter onto that charge source before you dismiss it, you may already have a solution for underway, and then a simple trickle charger is all the gen battery needs for between times?

That relatively well charged 8D, if inter-connected, can contribute to fooling your charging devices into lowering the charge sooner,  on the rest of the depleted bank, extending charge times.

As usual, there are the different scenarios. Everything is in storage, all the batteries are sufficiently charged, it doesn't really matter what you do... out camping, pulled the house bank down overnight, a quiet venue, a short 100 mile re-locate...

Lots of busnuts unwittingly have sufficient hardware for happy daily 100% charging, but connect stuff up and deploy it in ways that makes far less.

Adding more fancy hardware does not necessarily fix the problem? But it sure is fun messing around with, both in thought process and application!

Don't tell the Admiral what it all costs...

happy coaching!
buswarrior

[brmax]

I think there may be more use from the 8D than just starting, not sure what yet.  Though im interested really lately to why you, TomC needed to disconnnect the genie alternator. If you could please explain a bit more if ya can.  

Good day
Floyd

[thomasinnv]

I think there may be more use from the 8D than just starting, not sure what yet.  Though im interested really lately to why you, TomC needed to disconnnect the genie alternator. If you could please explain a bit more if ya can.  

Good day
Floyd

My guess would be that since he is connected to the chassis batts for generator starting, that while running down the road with both the big engine alternator going and the genny alternator going he was having a battle going on between the two resulting in less than optimal charging performance. My genny is connected to my house bank and i too had to disconnect the alternator on the genny becuase my inverter smart charger and the alternator were not playing nicely together.

Sent from my SM-G920T using Tapatalk

[sledhead]

I use this type of charger maintainer to keep my house back up geni charged and had 2 separate units on each of the start batteries ( mci 24 volt system ) all on a switch for each unit  so I could control when I wanted them on or off . this way you do not boil the batteries .

http://www.canadiantire.ca/en/pdp/motomaster-eliminator-intelligent-battery-charger-2a-0111506p.html#srp 

dave

[richard5933]

Charging circuit on the generator brings the battery voltage up to about 12.8 which is not enough to charge properly. It also doesn't automatically shut off and will eventually boil the battery.

My plan at this point is to use the Echo Charger to keep the generator start battery topped off. If I find that the generator fuel pump and fuel solenoid draw more than 15 amps, I'll move their feed so that they run off the house batteries (which are being charged by the PD 9270). That would leave the 8D strictly to start the generator, and it would be isolated from the house system - if one of us accidentally runs down the house batteries we can still start the generator. I guess it will be nice to have the 'extra' 8D in case one of the chassis batteries craps out on us while on the road.

Maybe one day I'll get a new Wrico generator and all this will be moot. Till then I will work with what I have.

Got to say though, overall this coach is in great shape and I'm thrilled that I'm only having to refresh and update a few of the house/RV systems. The techs at the shop didn't really believe me when I made the appointment for maintenance and inspections as I told them what I was bringing in. Once they got their hands on it they said it was in better shape than many of the charter coaches they maintain for the local company, even their newer ones.

Now I just have to figure out how to be patient until spring arrives...

[buswarrior]

There is nothing wrong with using that existing charge source at 12.8. You'll never "boil" a battery with that.

Remember, the generator battery is in a perpetually fully charged condition, starting the generator is meaningless to an 8D battery, it needs hardly a handful of electrons to replace what starting the generator took out.

A lead acid battery at rest, fully charged, surface voltage gone, is commonly said to be 12.6 volts.

The fuel pump and solenoid will run just fine off the existing charging circuit, that's why it's there!
Moving them to the house battery, and then killing the house bank... you get no generator either.

The principle of redundant/isolated systems, is to keep them isolated.

The charge circuit shuts off when the generator does, and won't do any harm to your generator battery.

Just like a garden tractor, outboard motor, and countless other applications with a magneto style "charger", an occasional treatment with a battery tender will put any fears to rest about being a battery murderer, if you can even get one to engage the charge when connected.

The fewer pieces of equipment, the fewer failure points, the fewer things to inspect, the fewer things to remember?

happy coaching!
buswarrior