Would like some input from someone experienced with this setup. All seems to be working ok. Maybe system could be better. Have 2004 Volvo 670. Has three start batteries and I have added an isolator and 2 6 volt deep cycle batteries with 5000 watt inverter. Deep cycle batteries kept charged thru truck altenator. Deep cycle batteries seem to be charging ok. I use hydrometer to check battery charge. Charge stays at blue to green line on hydrometer. I usually put on battery charger when at home to top off deep cycles. Would like to add 2 more deep cycles. Will the truck altenator keep up ok? Any advise appreciated.

 

:shock:

You want to charge SEVEN batteries off your alternator?

 

I guess that's what i'm asking. Checking with meter, reads 13.8 volts all the time. Been using this setup about 6 months with no problems so far. Currently running fridge, microwave, tv and coffee maker, would like to run electric heater thus the need for the extra batteries.

 

Wait for the new battery to come out:

www.fireflyenergy.com

With this battery you might be able to get away with 4-5 in one bank, they're starting and deep cycle.

Much more energy density as well.

 

So the Truck runs on 12V batteries?- the altn puts out 12-14volts?- and you're trying to tie in 2 6volt batteries---in series? or parallel?

my setup for my truck- you have to stick with same voltage batteries and connect the extra (isolated) ones in parallel.

Now, it might be possible to set up the 2 6volt(in series)=12volt, then connect these(to the isolator) then connect all in parallel to the car battery---
but you're still going to have 12volts running into one 6 volt battery(bad idea)

 

You could also replace your alternator with one that's used in EMT vehicles. They use a large rack of batteries and I think the alternator is 200 amp.

 

Thanks for all the replys. I would prefer to keep the starting and deep cycle seperate. I know the electonics on this truck require alot of battery power. The deep cycle 6 volts are connect in parallel for 12 volt to the inverter. I can just get alot more amp hours out of 2 6 volt batteries. I figured the stock altenator was at least 110 to 115 amp. Figured that was enough since starting batteries don't require that big of a charge. Wondering if a 200 amp altenator would be big enough to keep the deep cycles charged. Future plans to run electric heater will draw about 400 watts. I usually turn off inverter when driving and let deep cycles charge up, just not sure 4 deep cycles will charge enough between down times. Anybody know how to measure amp charge to batteries from altenator?

 

Yeah! I saw it. Wondering on a price tho.... :roll:

 

First thing I'd recommend when charging deep cycle batteries is a charge controller. When your batteries are deeply discharged, your alternator will be only too happy to try to replace the charge as quickly as possible. To the point of overheating and burning itself up! The charge controller uses input from heat sensors on the batteries and alternator to regulate the amount of current the alternator outputs (and prevent it overheating). It also uses a 3 stage charge process that helps the deep cycle batteries last longer.

Xantrex makes a control panel with charge controller, battery voltage readout, amps and more. It's pricey! Balmar's is less costly but has a readout that shows codes and you have to look them up. Here's some links:

http://www.xantrex.com/web/id/99/p/1/pt/7/product.asp
http://www.balmar.net/page15-maxchargemain.html

Depending on the load on the batteries, you'd need at least the 200 amp alternator unless you're going to leave the engine running 20+ hours a day. This is assuming you'll be putting a fairly deep discharge on the batteries overnight. A 1000 watt space heater would draw about 90-100A per hour depending on the inverter's efficiency etc.

I've seen 200A alternators for trucks for $299 + shipping. A 270A jumps to $799! 270 is the limit I've found using the stock alternator dimensions. The more amps the thicker the wires etc. Here's a link about choosing a high out alternator. Note the part about engines with computer controls (ECMs).

http://www.zena.net/htdocs/alternato...inf2.shtml#Top

I'd also recommend using a battery separator instead of isolator. The isolators are known for excessive voltage drop which prevents the deep cycle batteries from fully charging.

And last but not least, batteries lose a lot of the charge they're rated for as temperature drops. At 32F, a 250AH battery might only be able to produce 180AH at the 20AH rate (i.e. your inverter won't be able to put out near as long in winter as in summer). To overcome this, I'd consider using AGM deep cycle batteries and put them inside the truck, like under the bed. The AGMs aren't subject to spilling nor will you get fumes.

I've been researching this subject for awhile, especially using the deep cycle battery bank for cooling in the summer. Let me know if you have any questions I can help with. I'd also be interested in reading about your results as you continue with your project!

 

THANKS NCNEWBIE Thats the information I have been looking for. Not much information out there about what I would like to set up. I will try your suggestions as I have some down time right now. I will let you know the setup and how it performs.