Forza 34T Additional Coach Batteries

Gormleys · 04-16-2015, 01:13 PM

I am planning to add a couple of additional 12v RV Batteries to my new Forza. I think they are NAPA RV/Marine batteries Type 31, equivalent from Napa as their battery 8231.

1) Where do I get the long screw and hold down "straps" to match what is on the existing batteries?
2) What gauge are the connecting wires? Are they generic?
3) Do I need to lengthen the positive wire to run to the last battery in the parallel "chain" or can it stay on the current battery?
4) Do I need to change any settings on the battery/inverter monitor?

Thanks!

PeaceOwl · 04-17-2015, 12:22 AM

How many total? We have 4 and want two more, but it doesn't look quite big enough left in the tray area for a total of 6. It would be tight. Sorry I don't have answers to your other questions, but call your local RV repair shop, they'd know.

Gormleys · 04-17-2015, 07:21 AM

Yes, six total. There are two holes drilled to put the mounting Screws in for two additional, so I know that they fit. NAPA has the Screws and a plastic covered Wire that would replace the holding straps. I might just try it and see if it all goes together over the weekend.

Gormleys · 04-17-2015, 03:56 PM

So I went ahead and purchased two additional NAPA batteries and their retaining Screws and Plastic covered holding "straps". They fit perfectly. I also got 12" attachment wiring to put them in parallel (the existing wiring is a bit heavier gauge and is ~9" in length). I left the existing Wiring in place and did not extend the main positive wire run to the last battery. Now the question is the Inverter settings.

The book says to update the inverter based on the total number of Amp Hours to control the charge rate. The inverter offers 200Ah, 400Ah and 800Ah. Each Type 31 is 110Ah, so four was 440Ah and the Inverter was set to 400Ah. Six is 660Ah.

Do I set the Inverter to 400Ah or 800Ah?

grtharris · 04-17-2015, 08:03 PM

Gormleys, 400 would be a litter easier on the batteries or set it a 800 and keep an eye on the batteries for over heating.

jrobnett · 04-17-2015, 08:30 PM

Will setting it on 400 completely charge the batteries? My journey came with 6 batteries and was set to 400. I changed it to 800. So far so good.

InverterServ · 04-20-2015, 11:23 AM

What type inverter do you have? Is there a battery temp sensor connected from the batteries to the inverter?

twinboat · 04-20-2015, 12:18 PM

The AH setting has nothing to do with the charging, it is to let you monitor the state of charge.

The charger will not overcharge your batteries, it reads volts, not amp hours.

With the wrong settings, you could under charge, your batteries, if you actually turn your charger off, based on the AH reading.

Since batteries are tested in perfect conditions and we aren't perfect, use the lower AH setting.

This can all be explained in the instructions of a battery monitor.

If you have an inverter/ charger, with a monitor, your manual should explain it.

InverterServ · 04-21-2015, 06:56 AM

Quote:

Originally Posted by twinboat

The AH setting has nothing to do with the charging, it is to let you monitor the state of charge.

The charger will not overcharge your batteries, it reads volts, not amp hours.

With the wrong settings, you could under charge, your batteries, if you actually turn your charger off, based on the AH reading.

Since batteries are tested in perfect conditions and we aren't perfect, use the lower AH setting.

This can all be explained in the instructions of a battery monitor.

If you have an inverter/ charger, with a monitor, your manual should explain it.

The Amp Hour setting does have to do with charging. It tells your charger how long to stay in absorb charge. It's really described well in this article here the importance of choosing this right. If you do not your batteries will not last near as long as they could be cause they could be getting under charged. http://www.energy1batteries.com/Tech...cteristics.pdf

Gormleys · 04-21-2015, 09:21 AM

Quote:

Originally Posted by InverterServ

What type inverter do you have? Is there a battery temp sensor connected from the batteries to the inverter?

The Forza has a Magnum Energy Model MS2000 Inverter/Charger installed. It does have a Battery Temperature probe included.

My question still stands. Is it better to set it to 400Ah or 800Ah when 6pc of Type 31 110Ah batteries are installed?

Thanks!

twinboat · 04-21-2015, 11:35 AM

My Tri Metric battery monitor suggests you use a Lower setting then the actual calculation.

I am limited in my internet access, right now but I have not found any information , stating that the AH setting will effect the absorption time.

InverterServ,
your paper explains the need to lengthen absorption times, on large banks, but not that any units do it, by battery bank size settings.

Gormleys · 04-21-2015, 02:46 PM

Besides my open question about whether it is better to have the Inverter set to 400Ah or 800Ah to charge the 600Ah of House batteries, what about the Engine batteries? I think that they are also charged off of the Inverter when plugged into shore power. Should they be included in the consideration?

twinboat · 04-21-2015, 03:17 PM

I wouldn't, engine batteries are usually sitting charged up.

The only time they would be run down , would be after starting the engine. The alternator would take care of that.

grtharris · 04-21-2015, 04:46 PM

Gormleys, after much digging and then actually fining the answer in the Magnum Energy manuals here is my $.02. The picture below is from the manual for your remote and shows AH ratings and Absorb times. In the manual for the newer remote they show setting absorb time basic on battery AH with a lot more ranges. In that chart the absorb time for your 660 AH would be 114 Minutes. So with that information I would set the Battery AmpHrs to 800 AH which is only 6 minutes over the ideal setting.
As stated above, do not worry about the chassis batteries as they are only used for starting and do not get discharged much.

Gormleys · 04-22-2015, 04:10 PM

Great! Thanks for digging that up!

Gormleys · 04-23-2015, 10:26 AM

I did finally get an answer back from Magnum (the inverter manufacturer) on their recommended setting. They say with 660Ah of batteries, leave it at 400Ah if we mostly are hooked up to shore power, but set it to 800Ah if we mostly boondock. It sounds like their impression is that the setting has more to do with the depth of discharge. The Engine batteries are also trickle charged off of the inverter, but should not be considered.