2 coach batteries???

[jocko]

I'd like to know if I can add a second coach batttery. Could I put it behind the driver's or passenger's seat as there is no room under the hood. Will my alternator be strong enough to charge all three batteries? I have a stock isolator solenoid type I guess it is . Should I upgade? Would appreciate the help.

Jocko

[gmichaelz]

Hello Jocko: On my ToyHome, a 1987 Gulfstream Conquest, the coach battery is stored under my pull out sofa / bed. I have the necessary extra storage room to install another 12 volt DC coach battery by using a parallel battery setup. But, I would need to purchase two identical deep cycle 12 volt DC batteries at the time of conversion. My single coach battery still services me well, I have no desire to increase my weight.

Have you considered installing a single, larger, deep cycle battery to replace your existing coach battery to achieve more amp hours?

[Skipmeister]

Hello Jocko: There is quite a bit to know when it comes to batteries...I highly recommend that you pick up a book by Harold Barre called "Managing 12 Volts": Written specifically for RV owners it will absolutely answer all of your questions...but more importantly it will answer the questions you haven't begun to think about: I would rank this book as a must read for all RV'ers:

[Maineah]

I'd like to know if I can add a second coach batttery. Could I put it behind the driver's or passenger's seat as there is no room under the hood. Will my alternator be strong enough to charge all three batteries? I have a stock isolator solenoid type I guess it is . Should I upgade? Would appreciate the help.

Jocko

Yes you can add a battery and yes the alternator will charge it and the isolator should not be an issue. If you are not running inverters there should be not need to add batteries just running lights and the water pump your battery should last a week or more. Like some one else said replace the coach battery with a 120 amp hour deep cycle that should be more then enough. If you need more power be sure you have some method of venting an add on battery they produce hydrogen gas and can go boom I would not put it in the cab.

[nibs]

Hello Jocko:

As Maineah says adding a second coach battery is no problem, I did, but now having changed all my interior coach lighting to LED's I doubt if it is necessary. We use a lot of light, we are readers with no tv. We often skip shore power cause it is too much bother to plug in, even if we have paid for it.

[wetboy]

I currently run 5-120 Amp/hr batteries in my 85 Toyo New Horizon. I spend alot of time boondocking as a full-timer and I run an inverter. If you add more than two batteries to the coach, I'd recommend upgrading to a more powerful alternator. I just installed an 140 Amp Delco using a mod I found online. With two batteries, a 60 amp should charge just fine. After pulling my original, I found it was a piddly 30 amp Nippondenso. When I hooked it to an amp meter with near dead coach battery, it was barely putting out 5 amps!

Now I can run my engine for an hour or so and charge my batteries daily. Make a run to the store... that usually tops of the battery bank pretty well. I got rid of my Generator as my new Alt combined with my pop-up wind generator provides all the juice I need. Esp out at the beach where there is constant wind. So...YES! You can add batteries, you just have to size the alt to match. if your stock alt id charging your coach battery now, you should be fine with one more. After that, try to upgrade your alt by 20 amps or so per battery at least so it can recharge the bank by the time you reach your next destination, or if you just need a recharge at a remote location.

Also, I have a 40 amp Smart Charger that charges my batteries properly whenever I am hooked to shore power. This is important as Alternator and older converters don't "top off" batteries properly, and this is critical to long battery life. Esp if you're a heavy user like me...( I used to build and drive electric cars, so batteries are a passion of mine)

Also, VERY IMPORTANT...make sure the coach batteries are the same amp hour rating, and the same brand and batch if possible. If not, one will always reach full charge before the other and you will quickly destroy the unbalanced pack, cooking one and undercharging the other. I use wal-mart deep cycle trolling motors, and rarely let them fall below 70% state of charge. They usually last me 3-5 years easily. Drain your coach batteries regularly, don't recharge them fully,and they will die within a year.

Hope that helps

[Gulfstream Greg]

Also, VERY IMPORTANT...make sure the coach batteries are the same amp hour rating, and the same brand and batch if possible. If not, one will always reach full charge before the other and you will quickly destroy the unbalanced pack, cooking one and undercharging the other.

Yes, dual batteries must be purchased at the same time and hopefully with the same lot numbers. Never run different makes, years or types together in parallel. Sure it will work, for awhile but one or both and or all three* will die prematurely. Batteries have whats called internal resistance and therefore accept charging and discharging at different rates. Age is a factor here.

*That point made, is exactly why the old style solenoid isolators are bad for batteries. Your starting battery usually is a different type, size, year etc and the coach battery is on a long wire run creating a slight voltage drop from the alternator at the battery when charging. The old style solenoid isolators effectively connect the batteries in parallel when the ignition switch is on and the engine running. So here is your starting battery within a couple of feet of the alternator. And here is the coach battery maybe 10 feet of wire away and its a different type battery with a different internal resistance. Ya it all still works but if you are running an AGM battery in the coach you are asking for trouble, expensive trouble. My 2 cents worth.

[tlava]

Hi GUys--

Here's a way around the incompatible batteries issue: I installed 2 bats, an also a Perko battery selector switch (thee type used in boats), which has a 1, 2, or All position settings, so that when one runs down, I simply switch to batt 2--they can run in parallel by selecting "ALL," but I only use that selection when in charging mode (i.e., when plugged to shore power, in which case my converter takes over and sends a charge to the batteries, but does not draw from them).

[jocko]

Yes, dual batteries must be purchased at the same time and hopefully with the same lot numbers. Never run different makes, years or types together in parallel. Sure it will work, for awhile but one or both and or all three* will die prematurely. Batteries have whats called internal resistance and therefore accept charging and discharging at different rates. Age is a factor here.

*That point made, is exactly why the old style solenoid isolators are bad for batteries. Your starting battery usually is a different type, size, year etc and the coach battery is on a long wire run creating a slight voltage drop from the alternator at the battery when charging. The old style solenoid isolators effectively connect the batteries in parallel when the ignition switch is on and the engine running. So here is your starting battery within a couple of feet of the alternator. And here is the coach battery maybe 10 feet of wire away and its a different type battery with a different internal resistance. Ya it all still works but if you are running an AGM battery in the coach you are asking for trouble, expensive trouble. My 2 cents worth.

So then would a new stlye isolator solve that problem. I now have two deep cycle batteries running in parellel and do not want to wear them out unecessarily