House battery types

[ralley]

After one of those interesting trips home in a new (to me) AS 350, I discovered that the battery capacity consisted of one side post 100AH cranking battery, and, for the house, one marine cranking series 24 (in a series 27 slot) and one marine RV deep cycle series 24 (again, in a series 27 slot). Aside from the system being woefully inadequate for a 350 with way too many bells and whistles, is there a reason to use a marine CRANKING battery as a house battery (a previous owner's peccadilloe, perhaps)?

Time to look for a solar panel system.....

[mello mike]

If I understand your post, I would ditch both size 24 batteries and upgrade both to deep cycle size 27s. It's always best two buy groups of batteries together. Why? Because if you have an old battery and a new one, the new battery will attempt to recharge the other.

Another alternative is two buy two 6-volt batteries and wire them in series.

The choice is yours.

[davidz71]

Originally Posted by ralley

After one of those interesting trips home in a new (to me) AS 350, I discovered that the battery capacity consisted of one side post 100AH cranking battery, and, for the house, one marine cranking series 24 (in a series 27 slot) and one marine RV deep cycle series 24 (again, in a series 27 slot). Aside from the system being woefully inadequate for a 350 with way too many bells and whistles, is there a reason to use a marine CRANKING battery as a house battery (a previous owner's peccadilloe, perhaps)?

Time to look for a solar panel system.....

I'd say someone sold them a Marine type battery and the person didn't know the difference. Ditch the grp 24's and get grp 27 deep cycle RV batteries.

[markdoane]

I suppose the P.O. was upgrading the batteries in his boat, and you got stuck with the left-overs.

Tough bounce.

[Chaplain Kent]

You have three batteries, am I correct? One for cranking and two for the "house." If one of the three can be used as a cranking battery use it and replace the other two. It is expensive to replace three at a time and would be nice to get on a schedule of one and two. So next time you are buying just one battery or two batteries. But I do not think that marine deep cycle would be a good choice for your cranking battery.

[davidz71]

Originally Posted by Chaplain Kent

You have three batteries, am I correct? One for cranking and two for the "house." If one of the three can be used as a cranking battery use it and replace the other two. It is expensive to replace three at a time and would be nice to get on a schedule of one and two. So next time you are buying just one battery or two batteries. But I do not think that marine deep cycle would be a good choice for your cranking battery.

You are definately correct in your statement. After I posted my comment I thought it might be taken the wrong way. A Marine Cranking battery can be used as the cranking battery for the engine starter but you are better off going with a high CCA rated auto battery for that purpose. Use true deep cycle batteries in grp 27 around 105-115 amp hour rating for the house batteries.

[ralley]

Originally Posted by mello mike

If I understand your post, I would ditch both size 24 batteries and upgrade both to deep cycle size 27s. It's always best two buy groups of batteries together. Why? Because if you have an old battery and a new one, the new battery will attempt to recharge the other.

Another alternative is two buy two 6-volt batteries and wire them in series.

The choice is yours.

Thanks, Chief. I had come to that conclusion already, but was curious why someone would mix cranking and deep cycle batteries in a house battery bank. I think eventually I will rebuild the battery box and resize to 4D or 8D batteries, which should give me more time off the grid....and reduce the household discussions about leaving the (lights, radio, TV, etc, etc, etc) on when not in use.

Thanks,
Best,
Rob Alley
1991 AS 350
Presently snowed in.

[ralley]

All: Thanks for your replies. Our "Family Discussions" have resulted in the requirement to buy new Series 27's this weekend as the most prudent course of action, as it provides a known baseline and a known quantity, not to say a warranty of sorts.

I am planning to increase the depth of the battery boxes a few inches to make it possible to use larger batteries than the series 27's in the future, and may have to move the starting battery to the engine compartment, but there seems to be plenty of room in front of the radiator.

Best,

Thanks,

Rob Alley

[Pat370]

I own a AS 370 with the same battery set up. My unit is
equipped with a 2500 watt inverter. What I have found to
work the best is one 850+ cranking battery and two 6 volt
golf car batteries set up in series. You can buy all of these
batteries at very low cost from Sams Club.






Have a great day, Pat370

[lewster]

Pat,

Your idea of using 6VDC golf cart batteries is a good one (I am currently changing the group 24's in my 19CCD to a pair of 6 volt AGM's), but the cranking battery is a poor choice as a mate for them. A cranking battery is designed to put out a savage burst of energy that starting a motor requires and it should not be discharged more than 20% on a regular basis.

OTOH, golf cart and other deep cycle batteries are meant to be drawn down regularly to 50% and ocassionally to 80% in 'house use'. This type of discharge will kill a cranking battery quickly as the plate structure is not designed for this, and can possibly damage your other batteries as well. There is a lot of bad information out there about batteries and combinations of them.

This information is provided solely as a guide for you to use. I hope you don't find this intrusive in any way.

[Pat370]

Lew, The two 6 volt batteries and the cranking 12 volt
battery in my coach are on different systems. The only
time that the two systems are together is when the
battery parallel switch is applied manually.
Other that that Lew you are correct about the difference
in the two types of batteries.

Thanks again Lew,
Pat370

[lewster]

Got-cha!

Does the switch allow you to use the house batteries in an emergency situation if your start battery is low so you then join the two systems to have enough 'juice' to get the engine running?

Thanks for the clarification.

[Pat370]

Lew, Yes it does. In the front glove box is a push button switch. When pushed in it activates an electric soloinod
that connects all the batteries together and disconects
when the button is released.

Thanks for responding,
Pat370