Batteries and Inverter Installed

pianotuna wrote:

Lantley wrote:

I'm not challenging the install, I'm asking for my own benefit.
Would this be a rreason to use AGM batteries?
Checking once a week seems like a lot? Would AGM's require minimal water checks?

There is no way to check water in an AGM.

With that in mind what is the down side of using AGM'S Price?

Lantley wrote:
With that in mind what is the down side of using AGM'S Price?

A properly cared for flooded bank may outlast an AGM. It is hard to beat six volt golf cart batteries wired in series.

However the "properly cared for" means checking water levels regularly, always cycling to 100% state of charge, and keeping corrosion at bay.

AGM are more expensive than flooded. Like flooded, they should be recharged to 100% on every cycle.

I chose to move to reconditioned telcom batteries which are an AGM format.

My favorite battery is SiO2 which are a subset of AGM. That particular format does NOT have to be recharged to 100%, but should be fully recharged once every 30 cycles.

Lwiddis wrote:
Using #4 wire should mean close to no loss.

For a 600W inverter #4 is the minimum size. The Xantrex ProWatt 600 manual recommends 0 AWG (1/0) wire.

OP, what breaker/fuse are you using between the batteries and inverter?

Costco use to carry us battery 6 volters which were excellent. Not sure who makes the ones they sell now but they have terrible reviews. If you go to there site you will notice there are no reviews now but last time I checked there where plenty and none were good.

Sam

I guess the downside of AGMs is the price however there are plenty of upsides starting with the length of service life which should be 2-3 times that of wet cells. There is NO checking for levels on an AGM. There is no concern about venting. The only checking to be done is perhaps connections at the battery. You can locate an AGM anywhere you please. They don't even have to be mounted upright. Mount them INSIDE if you wish. In boats it is not uncommon to find AGMs located in spaces inside the cabin. They can withstand a deeper discharge, & recover, than a wet cell. They accept a bulk charge rate better than a wet cell. They lose less charge in storage than wet cells.

Yes, the wet cells are cheap on the initial setup but over time are they a better way to go? My first AGM, a 4D case size, had a 215AH rating & gave a service life of 9 years. Every year it sat in storage for over six months with NO trickle charge or top up charge.

Unless you have a faulty charger or abnormally hot weather, I think you'll find that you'll only need to add water every three to six months. Mine stays on solar 365 days a year and I add water at the beginning of the season and just before it goes to storage for the winter. Check more often until you are confident of the interval.

Lantley wrote:

With that in mind what is the down side of using AGM'S Price?

IMO, yes, that's the only downside.
I'm not one to be terribly OCD about batteries. I probably do a better than average job maintaining batteries than alot of people, but not interested in treating them like your first newborn child!
AGMs just eliminate a maintenance issue, which in turn also makes them a better fit sometimes for "custom" applications.

I'm no battery guru and I'm not challenging the advice given.
However, checking battery level weekly seems like a lot to go through.
In reality I can never see ME checking the battery level that often.
For that reason alone I would opt for AGM's.

theoldwizard1 wrote:
You need to check the water in the batteries at least once a week. Hot weather and multiple discharge/charge cycle will cause evaporation. Depending on how much you use your RV, you probably need to clean the batteries every 3 - 6 months.

Our four FLA 6 volt golf cart batteries only use one pint each per year. We use our trailer 120 -150 days a year. They are seven years old and there is no corrosion on the terminals at all.

TechWriter wrote:
OP, what breaker/fuse are you using between the batteries and inverter?

I have a 60a circuit breaker on the positive lead between the battery bank and the inverter. A #4 wire can actually handle more than 60a, but 60a @ 12v = 720W which is more than the inverter is rated for, so the inverter will shut down before the breaker pops in case of overload. The breaker is there to protect the wire in the event that the inverter malfunctions.

Xantrex states that #0 wire is recommended to minimize voltage loss over distance. They also have the same install guide for the 600w, 1000w, and 2000w models. Being that the inverter is ~3' from the batteries, voltage drop over distance was not a concern.

Lantley, the advantage to AGM is that they don't need to be vented, but also cost about double what you pay for a 6v GC2. The install worked out good for me because there was already accommodation for an external battery vent that I could connect to. Keeping the batteries in a storage bin not only supports venting but also keeps anything from accidentally contacting the battery terminals. I can store stuiff on top of the bin, it has a sturdy lid.