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Replacing house batteries in our new motorhome with AGM

mark52
Explorer
Explorer
The house batteries in our new motorhome need to power a 2000w inverter and allow us to boondock for several days at a time. Against our better wishes, it cam furnished with a full size residential refrigerator that must be kept going while in the boonies. It came furnished with 4 6v Harris Professional Plus golf cart batteries. I think that the dealer let them discharge badly before the motorhome was sold to us. Anyway, time for new ones! After a little research and some prodding from a local dealer where we are having our warrantee work done, they are recommending 4 new Centennial CB6-250 GC2H sealed lead acid AGM Batteries. They seem pretty top notch when looking at the specs. 250 AH @20 Hr rate, reserve capacity of 570 min @25 amp draw. I can get them locally for $320 each + 30 core charge. Has anyone used these batteries or anything similar? Any thoughts? Thanks!!
2018 Holiday Rambler Vacationer 35K "The moose"
The toad: 2006 Jeep Unlimited Rubicon lifted 4" with 33" tires
26 REPLIES 26

time2roll
Nomad
Nomad
The OP nor that link give enough information to expand the comments.

BFL13
Explorer II
Explorer II
time2roll wrote:
I assume the 2000w inverter will charge at 80+ amps and should be adequate.


This says it has a converter. OP could give some more details on how he will recharge his batteries.

https://www.rvusa.com/rv-guide/2018-holiday-rambler-vacationer-class-a-floorplan-35k-tr36691
1. 1991 Oakland 28DB Class C
on Ford E350-460-7.5 Gas EFI
Photo in Profile
2. 1991 Bighorn 9.5ft Truck Camper on 2003 Chev 2500HD 6.0 Gas
See Profile for Electronic set-ups for 1. and 2.

time2roll
Nomad
Nomad
I assume the 2000w inverter will charge at 80+ amps and should be adequate.

Ivylog
Explorer III
Explorer III
Adding a 100amp charger will be the best $170 for boondocking. Will come close to cutting your generator time in half and AGMs like more amps.
This post is my opinion (free advice). It is not intended to influence anyone's judgment nor do I advocate anyone do what I propose.
Sold 04 Dynasty to our son after 14 great years.
Upgraded with a 08 HR Navigator 45โ€™...

Sam_Spade
Explorer
Explorer
wa8yxm wrote:

There is truly no advantage to AGM over liquid filled Maintenance freer for RV use.


Sure.

IF....you disregard the fact that they will not sulfate or self discharge nearly as fast. And they are able to "withstand" really BAD deep discharges better. And that they tend to last 30 to 100% longer.

Yep, no real advantage. :R
'07 Damon Outlaw 3611
CanAm Spyder in the "trunk"

Sam_Spade
Explorer
Explorer
mark52 wrote:
The house batteries in our new motorhome need to power a 2000w inverter and allow us to boondock for several days at a time.


With no mention of a generator, this is NOT a practical goal.

And just because the residential fridge is THERE does not mean that it MUST be used while boondocking.

If you didn't WANT that kind of fridge, why DID you get a unit with one in it anyway ????

In general, I am a big fan of deep cycle AGM batteries for RVs.
I think they are well worth the extra expense.
'07 Damon Outlaw 3611
CanAm Spyder in the "trunk"

BFL13
Explorer II
Explorer II
wa8yxm wrote:
I agree the value and specs look find being GC (Golf Car) batteries they will be DEEP CYCLE which is good.. Now he said Sealed Valve Regulated Lead Acid (Maintenance free) DId he specifically say AGM?

There is truly no advantage to AGM over liquid filled Maintenance freer for RV use. For OFF ROAD use yes. and not just AGM but perhaps Optima (Physically way more rugged than any other battery) but for RV use I have yet to be convinced there is an advantage to AGM over other SVRLA batteries (liquid filled).

They are more expensive however.

But I think you will be very happy with these non the less.


Can you give an example of a sealed deep-cycle flooded battery?

I use AGMs to mount inside the RV where I can't with the fumes of unsealed flooded ones.
1. 1991 Oakland 28DB Class C
on Ford E350-460-7.5 Gas EFI
Photo in Profile
2. 1991 Bighorn 9.5ft Truck Camper on 2003 Chev 2500HD 6.0 Gas
See Profile for Electronic set-ups for 1. and 2.

wa8yxm
Explorer III
Explorer III
I agree the value and specs look find being GC (Golf Car) batteries they will be DEEP CYCLE which is good.. Now he said Sealed Valve Regulated Lead Acid (Maintenance free) DId he specifically say AGM?

There is truly no advantage to AGM over liquid filled Maintenance freer for RV use. For OFF ROAD use yes. and not just AGM but perhaps Optima (Physically way more rugged than any other battery) but for RV use I have yet to be convinced there is an advantage to AGM over other SVRLA batteries (liquid filled).

They are more expensive however.

But I think you will be very happy with these non the less.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times

BFL13
Explorer II
Explorer II
https://www.battsys.com/amfilerating/file/download/file_id/8/

Should work. Having four 6s at 77lbs each could be handy. I have a 250AH 12v AGM in 8D size which I needed help with to install it is so heavy.

The charging specs are unclear to me. Usually with AGMs you charge them at a minimum of 20% AH rate, so at least 50 amps for 250, and at some max rate, usually about 30% (except Lifeline you can do more %). This shows cyclical recharge at 0.15 to 0.1 as rate, but for equalizing (see Float maintenance guide at bottom) 0.3 is given. It also says 68 amps max or 27%. Some other AGMs also use 27%. (136 amps on the 500)

If mine, I would recharge the 500AH at minimum 100 amps or more to a max of 150 amps. To do that, you would need one of those inverter/chargers that have those amps. To power a power factor corrected charger such as in those inverter/chargers at 150amps you will need a 3000w generator.

Your typical RV converter will undercharge those batteries with its low amps and incorrect charging profile.

Be sure to fully recharge to 0.5 amps/100AH -- so taper down to 2.5 amps at 14.6v on the Trimetric (you must have an ammeter of some kind to see that figure --part of the AGM set-up) before dropping to 13.6 Float.

Important to wire the four in series/parallel with the load/charging with pos on one pair and neg on the other pair. DO NOT let the dealer wire them up with a "downstream" pair like he probably will.
1. 1991 Oakland 28DB Class C
on Ford E350-460-7.5 Gas EFI
Photo in Profile
2. 1991 Bighorn 9.5ft Truck Camper on 2003 Chev 2500HD 6.0 Gas
See Profile for Electronic set-ups for 1. and 2.

2oldman
Explorer II
Explorer II
Sounds like really robust jars. AGM is nice, had 8 lifeline.
"If I'm wearing long pants, I'm too far north" - 2oldman

hbillsmith
Explorer
Explorer
Check this out YOUTUBE INDEPTH ON BATTERY JAN2019
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time2roll
Nomad
Nomad
The value and specs look fine. I usually compare to Lifeline brand AGM. Not sure what your expectations are to camp off-grid. I suspect you will be running the generator a couple hours every day. If there is space I would be looking to go a bit more battery all things considered. Will depend on your usage.

No I have not used those batteries. My set of 4x GC2 are just wet cell.