6V bank charging questions

[Tippyman]

I plan on having a bank of four 6v golf cart batteries (wired to be 12V obviously) to use as house batteries. I don't really want to use the alternator to charge them because I've heard a three stage smart charger is much better for battery longevity.

I planned on having the smart charger running off of my house power before I left for a trip, and running whenever the generator is on powering the A/C unit.

When I'm driving the bus, however, I was wondering if it were possible to have the smart charger plugged into a DC to AC inverter. I know that seems kind of weird, just wondering if it's doable or a bad idea?

[charles_m]

Its totallu doable, but it will be a lot less efficient use of your alternators output. How many amps is the smart charger? Ive never heard anythinv about alternators being bad for batteries. They're built to charge them! Maybe they're not 'smart' but they've beeb reliably charging lead acid batteries for ages.

If you dont want to connect your buses alternator to.your house batteries, why not run 24V? It would be less strings and that would help keep your batteries balanced and lasting longer. Probably more than trying to use something instead of an alternator to charge them.

Keep em watered, and watch the d.o.d. and i bet dollars to doughnuts they'll serve you well!

My .02

Just my .02

[Tippyman]

Maybe I'm over analyzing. I've been researching on a lot of RV forums, perhaps I need to quit going to such fancy-pants corners of the internet haha.

[charles_m]

HA! The wormhole.
The good news is that if you research long enough on the internet you can prove almost anything, or disprove!

I've got 8, 6V batteries wired in 2, 24V strings of 4 each for my house batteries. That system is 24V and solar charged. The bus is still 12V but also has its own small solar panel just for good measure. My systems are not interconnected, but I might down the road pickup a 24V to 12V converter for just in case moments.

A lot of those RV forums don't impress me. Not to offend, but there are some really smart people on here. We're a different breed.

I will say this, however, if you use your bus alternator to charge your house and chassis batteries at the same time, make sure that if one has a dead cell or is older than the other or whatever, that they charge evenly. Maybe this is what they were talking to on the rv forum. If you just wire up several different makes and kinds of battery to an alternator and try to fully charge them all, over and over, the liklihood that the weakest battery will pull down the others increases. This isn't really the alternators fault. If multiple, different kind battery banks are going to be charged, they need to be isolated from each other as a general rule for best results. This isn't to say that a lot of people dont listen to this advice and get on just fine.

Something like this is pretty clever
1315 Sure Power Battery Separator | Connector Concepts, Inc.

[Tippyman]

If i charge via the alternator, then it'll definitely have an isolator. My jeep is wired up with a backup battery and isolator from Hellroaring technologies so I'm well versed in that. My concern was the way the alternator charges. People were saying it isnt a good three stage charge like a deep cycle should have. Alternators are good for starting batteries but not deep cycles, basically. Alternators will work, but its quick and dirty.

[charles_m]

It's an interesting point, but I've never experienced problems myself with just a plain jane alternator on batteries. I'd love to see some tests! I'd use an isolator and wouldn't worry about it.

[bubb, the real one]

Originally Posted by Tippyman

I plan on having a bank of four 6v golf cart batteries (wired to be 12V obviously) to use as house batteries. I don't really want to use the alternator to charge them because I've heard a three stage smart charger is much better for battery longevity.

I planned on having the smart charger running off of my house power before I left for a trip, and running whenever the generator is on powering the A/C unit.

When I'm driving the bus, however, I was wondering if it were possible to have the smart charger plugged into a DC to AC inverter. I know that seems kind of weird, just wondering if it's doable or a bad idea?

in the short term the alternator will not damage the batteries, it is because it is not a 3 stage charger that it will never fully charge the batteries, depending upon the manufacturer of the battery but most deep cycle batteries (wet lead acid) need 14.8v at the battery post to fully charge the battery and most alternators dont go above 14.0 or 14.2 and that is at the alternator not at the battery post.

most DC plugs can only pull 5 or perhaps 10 amps without overheating so if you use a battery charger it would have to be a small one that would not charge them well.

most alternators are not designed to run continuously so if you did use the alternator to charge a lot it would also damage the alternator.

[charles_m]

I mean, if the lights and heaters are on, it's running continuously. I know most arent designed to deliver their full rated current continuously, but at least a couple dozen amps continuous shouldnt be a problem.