# Need battery advice....just bought a 16KW generator



## TxGypsy (Nov 23, 2006)

I just bought a generac 16 KW propane generator. I'll be using it to power the shop and using solar panels to power the house. I'll be using the generator to top up the battery bank while it's running. No sense in wasting fuel. My question to ya'll is in 3 parts.

1. How many batteries would you recommend I start out with? I know there are sizing sheets but I don't really fit any of them. I won't be using as much as a conventional house would. I will have a small, very energy efficient house with as many gas appliances as possible. I'd like to start out with the minimum number of batteries and add to them until I find what is right for me. What would you suggest as the minimum?

2. From my research it looks like sealed gel batteries are the way to go. I have found one place that has a 12 volt 90 amp gel battery for $169.95 with free shipping(lol....I know the shipping isn't free...it's figured in). Is this a good deal? Can you recommend a better deal?

3. How would you hook up the batteries to the generator to keep them charging while the generator is running? I know I will need a volt regulator. My 'significant other' says that you should just plug in a 110 battery charger to the generator and charge the battery bank that way. Doesn't make sense to me....plug the charger into the interter so that the charger can turn AC back into DC. Kind of one of those....here's your sign type things. Any links you could send my way with scematics would be appreciate. I tend to get that deer in the headlight look when I start reading about all the technical aspects. Pictures are good! Thanks!

PS.....I'm really hoping that the solar panels will keep the battery bank topped up and this won't even be a problem.


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## Ed_Stanton (Dec 28, 2004)

I'm not sure that I understand your needs, but I'd think that you either need to do an electrical needs audit (how much power you need your batteries to provide to power the things in your house for how long), or you need to provide a financial budget? There are too many options as to how many batteries you can use and their costs. Is your inverter 12 volt, 24 volt or 48 volt? Does your inverter have a charge controller installed as part of it? What brand of inverter do you have, just out of interest?

You cannot simply plug a 110 v battery charger connected to your batteries and then into your generator. It doesn't quite work that way. Also, YOU MUST have a seperate charge controller (than as part of the inverter) coming from your solar panels to your batteries. So to use the generator and the solar panels connected to the batteries, you'll need 2 seperate charge controllers, one of which can be part of the inverter. 

So, along with batteries, you'll need a solar charge controller, a generator charge controller/inverter sized to how your batteries are to be configured 12v, 24, 48v. You'll also need a DC disconnect box, an AC disconnect box, correct sized cables and you'll need to wire the batteries to each other correctly as in series, parallel or a combo of both to meet your needs. Also, you could do with a meter, such as some charge controllers provide, or get a seperate meter, such as the Tri-metric. Otherwise, you'll have a tougher time figuring out the state of charge and discharge of your batteries.

Please see other battery / generator threads in this forum for links to further info to explore, but without an energy budget or financial budget, it's pretty hard to advise you. www.homepower.com is an excellent site and magazine for you to explore and perhaps subscribe to. Your library may have the magazines too.

To me it seems like an awful waste of energy to power lights via gas when you have a HUGE 16 KW generator and also solar panels that can provide power to as few or as many batteries as you can afford. At minimum, a few, lets say 4-6 or as many as 12, 6 volt lead acid deeps cycle batteries about $80 each, plus a used 24 volt inverter / charge controller, such as the Trace 2424SW or 3624SW or their DW series, and a Trace C40 charge controller for your solar panels, a DC disconnect box to run between your batteries and the inverter can all be found for pretty low costs used these days, and could be a good basic combination to power compact flourescent lights and a few other things for a few days to a week between charges and would be more economical and safer perhaps than burning propane lights? Get fewer batteries say 4 if you run your generator more often anyway and can keep the batteries topped up. But overall you'll need more than just batteries and you can't use a 110 v battery charger, so the initial set up cost is going to be probably more than you expect.

Sealed gel cell batteries are not ideal for home applications and more problematic for maintenance but they can work. They are also more expensive. From what I've read, I would not recommend them to you. A single 220 Amp Hour 6 volt deep cycle battery costs only $80-90, vs. the $169 for your 90 AH gel cell. Much more capacity for a lot less money.


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## Jim-mi (May 15, 2002)

Mr Stanton has a lot of good words there.

With all due respect, you need to sit down with a system designer to put the BOS (ballance of system) componets together for you.
In the long run you will be far better off doing so.


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## Explorer (Dec 2, 2003)

Be very careful with Gel cell as the charging voltage is lower. My local dealer said Interstate no longer makes Gel cell as they explode when charged with to high a voltage and amps also need to be limited (charge rate).


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