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Topic: Battery Selection for Engine 3xG34 or 1x8D? (Read 740 times) previous topic - next topic

Battery Selection for Engine 3xG34 or 1x8D?

For my previous FT (94-U225) the best thing I had done was converting one engine 12v 8D to 6x6v Golf cart Batteries.
I also have a golf cart that we use everyday up&down our property 10-20 times a day. The golf cart and its batteries are almost 3 years old.  I just check the batteries every 5-6 weeks, add some distilled water, good to go. Of course it is plugged into the charger when not in use.
On my current 03-FT, I am on my second set of 3xG34 AGM Duracell Engine batteries. They are not good. About 7 years ago I purchased the set from Batteries Plus Bulbs store. All 3 batteries went bad/not holding charge in a bit under 36 months. So the store manager replaced 2 of them and had me pay for 1.  That set just went all bad. I always keep the batteries charged. For the first time for about 5-6 weeks I forgot to plug in the charger :-(. After we got back home from Christmas trip, for what ever reason I forgot to plug in the charger for the Engine batteries. When I did remember to do it, too late. I charged them, charged them 1 by 1, etc. They are not holding charge.
I hear good things about Walmart EverStar batteries and I am thinking to get 3xG34 Lead Acid EverStar batteries or 1x8D wet cell (like my golf cart batteries I can maintain it ) or Duracell AGM Deep Cycle Marine and RV Battery, Group Size 34M

I know in the past I spoke about Odyssey batteries, which I still like the most. But this time around I want to get locally available relatively inexpensive engine batteries and see how that goes. What do you suggest?

How do 3 batteries work together, as far as CCA goes? If each has a 800 CCA, do they provide 2400 CCA? If so then 1x8D battery by itself provide, in this case a 1400 CCA. If so 3 batteries preferred? Engine is. ISL 400.  Thank you,
Al
Former 2003 GV U295 (6230) (2015 - 2025)
Former 94 GV U225 (2013-2016)

Re: Battery Selection for Engine 3xG34 or 1x8D?

Reply #1 –
Yes, you have it correct. 3 x 800 is 2400 CCA. OR, Autozone, WM, all have good batteries and I think most are made by Johnson Controls. Our AZs usually last 8 years minimum. Our Progressive Dynamics converter along with my lighter plug to lighter plug jumper keeps batteries at almost exactly the 13.2 volts advertised. You have probably seen my twin voltmeters. One bank is three maintenace free conventional and the house is six AGMs. It's a good mix for keeping both banks charged for max life. If you let the battery go flat, a failure is not the battery's fault.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Battery Selection for Engine 3xG34 or 1x8D?

Reply #2 –
I replaced all three start batteries last fall. The ones that were there came from O'Reilly's, so that's what I went with again.

Re: Battery Selection for Engine 3xG34 or 1x8D?

Reply #3 –
O'Rileys and 10% for being a veteran!
Joe & Dottie Allen
Sold!  December 2023.      2000 U320; build # 5645
Our coach " Maxine"
Motorcade #  15922;  Escapee 150950; FMCA F330833; Boondockers Welcome;  Harvest Hosts;  Thousand Trails
'98 U320 from 2000-'06
USAF '62-'66

"Do not spoil what you have by desiring what you have not; remember that what you now have was once among the things you only hoped for." ―Epicurus

Re: Battery Selection for Engine 3xG34 or 1x8D?

Reply #4 –
Costco Sells a group 24 AGM with impressive CCA and MCA for 169.99 ea.
Just bought 3 of these Costco batteries to replace 3 flooded cell group 27's for "Das Boat". (Starts two two cycle Detroit's, 6V71 if memory serves me right. They start super duper fast, current start batteries have 2013 dates on them) Going with 6 new  AGM L-16 house batteries as well. replaced 400 watts solar  with 600 watts on Bimini above flybridge. and making the alternators external regulated with a cool new balancer to set up for AGM  Resetting  the magnum inverter/charger settings to AGM.
Maybe take a look at those Costco group 24 AGM's for your coach? May not have as many CCA's to as your  3 x group 27 AGM's, and of course smaller in size by a bit.
Costco currently doesn't sell group 27 or 31 in AGM (yet?)
Tim Fiedler    2025 LTV Unity MBL on Order
2000 Chevy Tracker 2 Door Convertible 4WD Now lifted 4.5"
1985 Citroen 2CV6 Charleston
Murphy Rebel on wheels with 175HP Titan
Cessna P337
1980 48' Westport MY (!/4 Share)

Re: Battery Selection for Engine 3xG34 or 1x8D?

Reply #5 –
Iv'e been going thru the same problem this last week with deciding what to do about replacing my 3 Yellow Top Optima's that didn't make it 3 years, They were purchased 04/2019 they were subjected to last year's deep freeze in Texas but I still felt they should have held up better than 30 month's, so after much thought and discussion, I decided to go a different route than AGM"s, I purchased 3 - Continental - Group 31 Commercial Maintenance Free Batterie's rated at 1000 CCA ea. from the supplier that supply's the batteries to FOT here in Lufkin, on my coach a 2003-295 there were 2- board's on each side of the 3 - group 34 Optima's I removed the board's and the group 31 batterie's fit like a glove, the group 31 batterie's have higher cranking amps than most group 34 batterie's, I also purchased a NOCO Genius Gen 5 X 3 battery charger/maintainer that's good for all type's of batterie's so for less than $600 I have 3 new 1000 CCA batterie's and new smart charger. I'm going to see how this play's out, time will tell.
Mike & Donna Mariana + Angel & Rusty
2003 U295 3620
Build# 6118
2021 Jeep Wrangler 392

Re: Battery Selection for Engine 3xG34 or 1x8D?

Reply #6 –
Group 31 batteries are a lot larger and heavier than group 34s and have 15% to 20% more CCA. As I remember, our 31 series weight about 66 lbs each. For lead acid batteries, heavier is always better. Seems to me 34 series are 45 to 50 lbs.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Battery Selection for Engine 3xG34 or 1x8D?

Reply #7 –
Concur.

In Das boat case the group 31 Costco flooded cells were less CCA (675) than the group 24 AGM, (710 CCA) so in our case we improved CCA despite smaller batteries Yes Group 31 AGM would be more CCA than group 24 for sure. We just needed AGM technology and these group 24 fit the capacity, technology and price point for us
Tim Fiedler    2025 LTV Unity MBL on Order
2000 Chevy Tracker 2 Door Convertible 4WD Now lifted 4.5"
1985 Citroen 2CV6 Charleston
Murphy Rebel on wheels with 175HP Titan
Cessna P337
1980 48' Westport MY (!/4 Share)

Re: Battery Selection for Engine 3xG34 or 1x8D?

Reply #8 –
Our start batteries are flooded batteries and 850 CCA. They were just over $300 for all three at AZ with discount for buying three. The Walmart/Costco variety were about 5 lbs lighter. For a bit more $$, 31s were available at 1000 CCA. The 34 series could not come anywhere near this amount of CCA. They had been working fine but when one was a bit weak at about 8 years, I decided that for less $$, I would go with the commercial 31 series. I had to build a larger rack as while the width is the same, the 31s are much longer. While a total of 2850 CCA is overkill for the Detroit, cold weather combined with high altitude make the extra CCA an added margin and especially when they were less expansive. Note that commercial 31 series may not have the same warranty as the 34 series. In fact, our Duralast 31s are only warranted for one year. Long past that now.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Battery Selection for Engine 3xG34 or 1x8D?

Reply #9 –
With an 8D if one cell goes bad it's an easy decision, you get a new battery. But if one cell goes bad in a two or three battery set up it's up to you. Buy one or two or three.
I know you shouldn't mix batteries but now you do have an option.
John Duld
1995 U320C SE 40'

Re: Battery Selection for Engine 3xG34 or 1x8D?

Reply #10 –
I ended up getting EverStart 3xG34 batteriers for engine start. Installed them and connected the NOCO charger.
I wanted to get your opinion about BEP DVSR (Digital Voltage Sense Relay). It came with my FT but I disconnected it sometime ago. I did that because my 3 house batteries are GEL 8D, different than the engine start batteries. My thinking was to keep a dedicated charger for the engine batteries and I do that all the time (except I did not for 5-6 weeks, as I mentioned earlier)
My FT is always connected to a 50 amp shore power.
Former 2003 GV U295 (6230) (2015 - 2025)
Former 94 GV U225 (2013-2016)

Re: Battery Selection for Engine 3xG34 or 1x8D?

Reply #11 –
Our engine batteries are also conventional and the house AGMs. With the jumper, they are almost exactly the same voltage.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Battery Selection for Engine 3xG34 or 1x8D?

Reply #12 –
I like Marinco components.  You might want to make sure this is rated high enough for the alternator you are using. The attached document mentions 140 amp alternator max.

It appears that it is bidirectional. In this case charging the house batteries from your charger or from solar at greater than 13.4v with turns it on and joins the house batteries with the start batteries.  While driving when the start batteries see charge voltages greater than 13.4v it will turn on and join them with the house batteries.  If both battery sets are above 12.8v they remain connected until one or the other falls below 12.8v.

This would not work well with lithium batteries but a mix of GEL and AGM should be OK.

It would be a good idea to add in a manual enable/disable switch. 
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN
 

Re: Battery Selection for Engine 3xG34 or 1x8D?

Reply #13 –
Quote from: Roger & Susan in Home2 –
I like Marinco components.  You might want to make sure this is rated high enough for the alternator you are using. The attached document mentions 140 amp alternator max.

It appears that it is bidirectional. In this case charging the house batteries from your charger or from solar at greater than 13.4v with turns it on and joins the house batteries with the start batteries.  While driving when the start batteries see charge voltages greater than 13.4v it will turn on and join them with the house batteries.  If both battery sets are above 12.8v they remain connected until one or the other falls below 12.8v.

This would not work well with lithium batteries but a mix of GEL and AGM should be OK.

It would be a good idea to add in a manual enable/disable switch. 
I think it is only useful with a "manual enable/disable switch." used "enabled" when parked and "disabled" when on the road. I have to check to make sure but I think my alternator is at least a 160 amp. The way I operate using a dedicated charger for the engine batteries will keep it simple for me. Just as long as I don't forget to do it :-)  Thank you, AL
Former 2003 GV U295 (6230) (2015 - 2025)
Former 94 GV U225 (2013-2016)