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Discussion Starter · #1 ·
I have a 2500 with the 220amp alternator. I'd like to add a house battery (probably AGM) run through a battery isolator. I initially wanted to get a Battery Doctor 150 amp but it's only rated to 165 amps at peak. Have any of you dealt with this issue?
 

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Ooops, when you said Battery Doctor, I thought you meant a plug in charger... But you meant their isolator. Get a higher rated isolator, I have a Stinger SGP35 500-AMP Relay/Isolator for my 3000 watt inverter system.
 

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Should not be an issue unless you have a HUGE battery bank. I have (2) 100Ah AGM batteries connected to a 150A Battery Doctor with an 85A breaker in line. The breaker has never popped. I think the most my alternator has ever fed to the BD is about 40A.

Your 220A battery has the CAPACITY to provide 220A, but it only provides what is required, much less in this case.
 

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2014, 138WB, High Roof, Gas, SW MT
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Hi,
I agree with proeddie.
I have 220 amp-hrs of FLA house batteries and have never seen more than 38 amps charging current, and that only briefly. Have a 50 amp breaker in this line and it has never opened.

Decide on which house batteries you are going to get, then find out what the maximum charging rate the battery manufacturer recommends and put a breaker in the line that is a bit over the max charging rate. The breaker will likely end up being much less than 150 amps.

Gary
 

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Discussion Starter · #6 ·
thanks everyone. I'll go ahead with the Battery Doctor 150 and an 80 inline fuse. The house battery I get won't be too gib, maybe a 100 amp hour AGM or so
 

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My DIY has the 220 amp alternator and I am using the 150 amp Battery Doctor “isolator”with no problems. Although my AGM Battery is only 75 Ahr


Sent from my iPad using Tapatalk
 

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How many amp hrs do you think you can charge with the battery doctor 150?

Anyone care to share photos of their install please?
 

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If it is attached to a 220 amp alternator running long enough ........ all the batteries in the World but very slowly as that alternator will be putting out about 150 amps once the vehicle load is taken into consideration.
As a practical charging scheme about 300 A-H and expect it to take about 4 hours to charge them fully as the internal resistance of the batteries rises and Ohm’s law rules so increased internal resistance reduces the current.
This is really about how long you have matching the battery size you can charge in that time.
 

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I use a 60A breaker in line with the isolator. It never tripped.
2 x 120Amps Deep cycle marine batteries.
My isolator is rated 80Amps.

You will never see a too high current, that will fry the batteries.
The internal impedance of the batteries will not allow for a higher current.
 
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