| Author | Message | ||
| Frank Allen (Frank66)
Registered Member Username: Frank66 Post Number: 75 Registered: 10-2005 Posted From: 205.188.117.73 Rating: N/A |
one of my 8 d batteries in my 06 is bad, going to replace it with a group 31 and levae the other 8 D in place tell it goes bad, will two group 31 s be ok?? or do i need three?? will the group 31 run ok in paralell with the 8 D ????? Thanks waiting for my stimulous check so i can buy a half a tank of fuel. Thanks Frank Allen | ||
| Pete/RTS Daytona (Pete_rtsdaytona)
Registered Member Username: Pete_rtsdaytona Post Number: 475 Registered: 1-2005 Posted From: 72.189.66.170  Rating: N/A |
Go FIND the INTERSTATE "SUPPLIER" in your area - not just a dealer ---***the SUPPLIER***--- Just look in your phone book and look for thge INTERSTATE STORE - Go to thier sales counter - he'll have group 31 "BLEMS" for about 30 bucks each - the catch - 30 day garentee & they are over 1 year old and can not be sold as new - WHAT A DEAL - Never got a bad deal from them yet | ||
| Laryn Christley (Barn_owl)
Registered Member Username: Barn_owl Post Number: 420 Registered: 10-2006 Posted From: 72.66.162.33  Rating: N/A |
I would not mix used with new batteries. The old batteries will be a drain on the new. They don’t charge at the same rate, same for discharge. There are other variables that will also cause problems. You don’t save enough to make it worth it. | ||
| Glenn Williams (Glenn)
Registered Member Username: Glenn Post Number: 159 Registered: 6-2006 Posted From: 216.163.57.205  Rating: N/A |
Frank, 2 group 31's will be plenty to use as start batteries, as long as you use a block heater in the cold. I agree with Laryn about mixing them, and I got mine just like Pete described. You could use your remainig 8D for a house battery. Good Luck! Glenn | ||
| larry currier (Larryc)
Registered Member Username: Larryc Post Number: 170 Registered: 2-2007 Posted From: 207.200.116.13 Rating: N/A |
If you hook a small battery and a big battery togather it will cook all the water out of the smaller battery. It smells bad while its doing it too! | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 275 Registered: 7-2006 Posted From: 4.240.213.149 Rating: N/A |
Thanx for the "heads up", Pete! RCB | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 437 Registered: 8-2006 Posted From: 76.91.197.153 Rating: N/A |
Frank, Two group 31s will start your bus just fine, in other than very cold weather. Two group 27s out of my pickup started my 12V71 very well. I must respectfully disagree with the above post about "hooking up a small & a big battery." In PARALLEL, you could hook up a 12V flashlight size battery next to an 8D, and they would work well. Your total ampere hours would be the total of the two, (which wouldn't be much more than the 8D) but you knew that already. Two different sized batteries in SERIES won't work well together. G | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 653 Registered: 11-2005 Posted From: 208.54.200.196 Rating: N/A |
FRANK, I have two each Gp 31s in my 4104, two each for start and house but my house load is very small and those two are deep cycle. Never had any problems starting the 671 even after the alt not working for a couple of days. | ||
| larry currier (Larryc)
Registered Member Username: Larryc Post Number: 171 Registered: 2-2007 Posted From: 207.200.116.13 Rating: N/A |
George, the problem I had was with charging. If you put an 8D and a flashlite battery togather and let the bus alternator charge them togather, I bet the flashlite battery will get real hot before the 8D takes enough charge to get the regulator to drop the amps. | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 438 Registered: 8-2006 Posted From: 76.91.197.153 Rating: N/A |
Larry, In parallel, both batteries are exposed to exactly the same charging voltage. Think about it this way, the positive terminals of both batteries are connected together, and to the output terminal of the alternator. The negative terminals are also connected together, and to the frame of the bus. As they are side by side, electrically speaking, they have no effect on each other. Regulators do not control amperage, only voltage, so charging current depends solely upon the state of charge of the batterie(s). A discharged battery will accept a lot of current, while a charged battery will accept essentially none. A 12 Volt bus or car will have the regulator set for between 14 and about 14.2 Volts. This voltage is applied to the batteries as long as the engine is running, and when the batteries are fully charged, current simply ceases to flow, due to the incresed resistance in the batteries. Voltage regulators have no idea what the state of charge of the batteries is, they just keep the voltage at its setting, and the current flows into the batteries depending on the charge. A small battery will take less current to fully charge than a large one, and the small battery will indeed be fully charged before the large one next to it, but as its resistance increases faster, it will not overcharge. This is NOT the case in a SERIES circuit, or in other words, either a 24 Volt bus, or a 12 Volt bus with two 6 Volt batteries. Then, as you say, the smaller, or more charged battery in SERIES with a larger or more discharged battery will be overcharged, because the TOTAL resistance of the two batteries is low enough to allow current flow through the charged battery, which will indeed boil it. I hope this clears it up, as I need a charge now! George | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 329 Registered: 10-2006 Posted From: 208.100.193.249 Rating: N/A |
My solution to the batt question was to install 2 ser 31 and 4 6V deep cycles, and a disconnect. The set fits in the Sportscar where the 8D's were. The coach is seldom boondocked so all charge together, BUT, when a few days in the woods calls the disconnect seperates the house and starts. An 85W solar panel keeps everything happy when the coach is just parked. Beware , ONLY a real coach disconnect is robust enough to start a cold 8V-71 with , the boat rotaries will not handle the amps. FF |