What do u mean wen u say house batterys? inverter or engine start batterys

[johnjem]

please sort out my confusion   lmao???!??!!!

[Tenor]

House Batteries usually refers to the batteries used to supply an inverter or take power from a converter.  House referring to your "house" systems vs chassis systems.

Glenn

[belfert]

House batteries are for the inverter and for stuff one might typically have in a house like interior lights and such.  That is why people call them house batteries.

[Utahclaimjumper]

"House batteries" as opposed to "Chassis" batteries are distinctly different animals,, if they are not separated in your system you will have a very unpleasant surprise one day.>>>Dan

[Dave Siegel]

Hi John, I think what they are trying to say is: House batteries are a battery or series of batteries that are used to power 12 volt items in your coach like lights and some 12 appliances. (Usually you would use these items when you are boondocking or not plugged into a wall outlet or genset.) The chassis batteries are used to start your coach and run your headlights and signals,etc.

It is a good idea to have these as two separate systems so that if you use too much power while boondocking you don't run down your starting batteries.

Is that as clear as mud?

Dave

[bobofthenorth]

This will further muddy the waters but I think its timely.  When we bought our boat I was surprised to discover that my house/start bank was one and the same but I've grown to think that is a very good idea for our bus application as well.  When I next replace batteries on the frenchy-bus I will combine the two banks.  Here's the logic:

Right now I'm carrying 2 x 8D wet cell batteries to start the bus and 3 x 8D AGM deep cycle batteries for a house bank.  The start batteries get used briefly to start the bus maybe one morning out of 10 and maybe I buy fuel or stop for lunch but really they don't get used at all relative to the amount of amps we're carrying around.  We're paranoid about never drawing the house bank below about 60% SOC.  So we're hauling around close to 200# of battery that would almost double our battery time if we had the 2 banks combined.  I've never run the house bank down to the point where it wouldn't have started the engine but anything is possible so to avoid that possibility when I combine the banks I will add a single Group 31 battery as a generator start battery.  Currently the genset starts off the engine bank.  Deep cycle batteries don't make good start batteries because they can't deliver the rush of current necessary for starting but I think 5 X 8Ds will be adequate even if they are deep cycle.

I just want to throw this out there as an option.  If you're marginal on your start bank capacity already or if you typically draw your house bank down to 25% then this idea won't make sense to you.  OTOH if you are carrying around big batteries to start the noisemaker in addition to big house batteries then you may want to consider combining the banks. 

[Oonrahnjay]

(snip) I will add a single Group 31 battery as a generator start battery.  

      Bob, why do this?  If you're going to carry a separate generator-start battery (and I think that this is an excellent idea), why not a small battery that's big enough to start the generator.  You could arrange a generator-start battery that's kept fully charged (either by the built-in alternator on the genset, or by a separate "smart charger") but completely separate from the house/start bank.  No matter if something went wrong and drained your house-start batteries, you could always atart the generator from that separate battery but there would be no way that that the generator battery could get drawn down with the others.  Once the generator is running, you could do a charge off of it to get the engine started (if you're ready to go right then) or a battery charge through your inverter/charger is you are not in a hurry to get on the road but want to bring the other batteries up.

     And if the very worse should happen and *every* battery was flat, you could jump your generator off with jumper cables and something as small as a lawn tractor (or your toad). 

      But my main point is that there's no need to run a battery as big or as $$$$pendy as a G-31 for your generator, if it's totally separate from your house/start batteries.  You get enough redundancy to take care of almost every possible problem with a small battery.

Bruce H  NC   USa

[bobofthenorth]

Fair enough - let's agree I need enough battery to start my antique Onan in cold weather and leave it there.  Maybe I could get away with less battery on the generator but the point is that people don't need to run big 8D banks for separate house and start systems and they in fact lose some functionality by doing that.

[Oonrahnjay]

(snip) people don't need to run big 8D banks for separate house and start systems and they in fact lose some functionality by doing that. 

     Agreed!

[belfert]

If one decides to have a single house/starting bank with deep cycle batteries it would be prudent to replace the alternator regulator with a three stage one that will handle deep cycle batteries.  Sean would tell you that deep cycle batteries won't handle starting the main motor without damage.

I think I would ask a battery distributor before using deep cycle batteries to start my main engine.  If you're never in freezing weather it would probably work fine, but you never know.

[bobofthenorth]

I won't presume to speak for Sean Brian but if I had one 8D deep cycle I'd agree with you.  In my case I'll have 5 and there's no way any of them will be damaged under normal starting conditions. 

[Sean]

Hmm.  Before anyone else speaks for me, I'll speak for myself:

If I were doing Odyssey over again, one of the very few things I would change would be to eliminate the chassis/start batteries altogether and go with a single bank, just as Bob suggests, with the proviso that the generator has its own separate start battery.  The generator, of course, can charge the main bank via a charger once it's started.

My "deep cycle" batteries happen to also carry cranking ratings (Trojan 8D-AGM), which technically makes them hybrid type, but almost all deep cycle batteries have some cranking ability, and if you press hard on the manufacturer they can tell you what the rating is.

Some deep cycle batteries should not be used to crank an engine alone.  But in very large banks, an engine starter is just another load.  Note that a Trace SW4024 can draw well over 300 amps when operating in surge mode, and that's easily handled by just a single pair of 8D batteries.  Typical Delco 24v starter draw is around 800 amps, easily handled by two or three pairs of batteries.

BTW, my Trojan AGMs are rated 1850 CA or 1450 CCA each, so even a single pair can spin the big Detroit without any ill effects, and I would guess that most other 8D size AGM batteries are about the same.

In my case, the house batteries are simply too far away from the starter for me to implement the single-bank system now.  (The location was chosen for weight and balance reasons.)  So I continue to use separate starting batteries (a pair of Group 65s) for cranking purposes, and the two banks get bridged 30 seconds after the alternator comes on line.

-Sean
http://OurOdyssey.BlogSpot.com

[rip]

For nine years I have been using four 8d batteries for starting and house use.I have one separate battery for starting my gen-set.I have not had any problems with this set up.My 8D's are from NAPA and have five years on them.
   Don

[Oonrahnjay]

  For nine years I have been using four 8d batteries for starting and house use.I have one separate battery for starting my gen-set.I have not had any problems with this set up.My 8D's are from NAPA and have five years on them.       Don   

    Are your house batteries 8D "deep cycle" batteries, Don?   Two 8D's fit just about perfect in the one location that I had for my batteries but I had a hard time finding the deep cycle ones.

[Don Fairchild]

So if you went to a single bank of Batt's would you run every thing to a bus bar and then feed the inverter and start circuit or would you run thru a relay to start the road engine ( and remove the isolator I take it). If you run to a bus bar would you place the 300amp fuse that is now in the system after the bus bar?. I have been thinking about doing this for some time. I always seam to have one bad 8D in the group every time I get ready to go on a trip. I replaced them all at the same time three years ago and have had to replace two of them one each year (They have a bad cell) and now have another one with a bad cell. I keep a batt tender on them when not in use and still will lose one a year. whats up with that.

Don