yellowtop optima not holding charge?

[vanhack]

Okay folks, I am going to re-iterate. The fridge is set to shut off at 11.4V, this is the "medium" setting as per ARB manual. The Fridge will restart at 12.2V, which would be when alternator is supplying. The dual battery management system is voltage isolator design, where it senses if main battery has 13.4V, which would be yes. If this voltage drops below 12.7V on the main battery when alternator is running, it stops feed to the optima yellowtop and feeds to the main starter battery.

I have not reached 10.5V ever, but I have mentioned this voltage due to confusion over what is considered deep discharge, Optima themselves say that a 10.5V is deeply discharged, but as per the ARB fridge it would not let the yellowtop reach that due to the setting on the fridge.

Diplosat, that power bank system is phenomenal, but for me it is a no go, 600AH with 500W of solar. Reason is that we drive 90% on sandy desert terrain, where every extra kilo works against you. We also do not have the same retail expertise, for example, just yesterday I talked to the sales person for the Optima batteries, and he kept suggesting that I use a normal battery, I don't believe he knew that I needed a deep cycle to run my fridge, and don't need the FLA's mass current in bursts for the fridge.

The ARB fridge has a 0.87A/hr rating as per their own website.

As I limited in space and don't want to add more weight to the car, I am going to change the way that I use the fridge.

 

[Happykamper]

Optima= trouble.
I got on the " optima band wagon" early on. Putting twins in my rigs. Baaaad mistake $$$$$$$$$

Diehard agm's never fail. Well once but that was DEFINATLY user error ******** .

 

[DiploStrat]

I LUV Sand!

vanhack,

I grew up in Jordan and have driven the Sahara, Atacama, and the Kalahari. I love sand! My current truck actually does rather well in sand.

But to the point:

-- Assuming a steady 1Ah consumption, you need 24Ah for each day you are camped.

-- Applying the 50% rule, or even a 75% rule, that means that a weekend requires about 75Ah. That calls for a camper battery of 100 - 200Ah to assure cold beer. Real simple.

-- In a small vehicle, that probably means a shore charger unless you carry portable solar.

Notes:

-- This assumes that you keep the fridge off during the week and cool it down (on shore power) before you depart.

-- As dwh noted, your 70A alternator is probably fine. 14.7v is great. Just need to be sure that the wires are at least as large as the factory wiring to the starter battery.

Can you source a 100+ Ah deep cycle battery or would you have to use two 55Ah units?

N.B. As you may have noted, Optima has a mixed reputation.

Nothing you want to do is impossible.

 

[vanhack]

Diplostrat, sourcing the battries is not an issue. But fitting the batteries in the patrol engine bay is no go, I have mine mounted mine to the chassis rail.

 

[Ducky's Dad]

Diehard agm's never fail.

Mine did, right at the three year mark, and Odyssey replaced it because Sears would not. Note that the new DieHard AGMs are no longer coming from Odyssey. Supposed to be coming from Northstar.

 

[vanhack]

We dont have much choice in automotive deep cycles...just optima and even poorly represented odyssey. Optimas here are sold to military and a few offroaders.

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[dwh]

I have not reached 10.5V ever, but I have mentioned this voltage due to confusion over what is considered deep discharged

Right. And I only mentioned it to clear up the confusion. Obviously, Optima's marketing droids have been programmed to avoid the use of the word dead. 11.4v is deeply discharged. 10.5v is dead.

As I limited in space and don't want to add more weight to the car, I am going to change the way that I use the fridge.

Another option would be to replace the split charge relay with a multistage DC->DC charger. Though I don't think it would make all that much difference with short daily drive times.

Another option would be a regular overnight session on the shore power charger. Say mid-week, like Wednesday nights.

 

[vanhack]

Just a newbie question...shore charge is AC battery charger?

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[dstock]

Optima= trouble.
I got on the " optima band wagon" early on. Putting twins in my rigs. Baaaad mistake $$$$$$$$$

Diehard agm's never fail. Well once but that was DEFINATLY user error ******** .

Wrong x2 both Diehard Platinums failed. And based on the pallet full I saw at Sears, I will happily take my chances with Optima.

 

[dstock]

Not sure if you park in the sun, but some on-board solar might mitigate the short commute, and keep your batteries topped off.

 

[dwh]

Just a newbie question...shore charge is AC battery charger?

Sent from my LG-H818 using Tapatalk

Aye. Dock a boat and plug into "shore power". The term is also commonly used in the RV world. Old habit...