Setting Amp Hours In Battery Monitor
I have a shunted battery monitor. It gives you alot of information. In setup one of the parameters is to input the amp hours of your battery bank. I have four deep cycle lead acid batteries with ...
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Assuming your battery monitor STOPS going down (percentage-wise) when it gets to 0% on the monitor (regardless of what the true state of charge is) and STOPS going up when it hits 100%, you MUST program your controller with the full amount of AH of your battery bank.
Reason: If you only put 170AH as your battery bank (when you really have 340AH) you could easily have a problem knowing your actual state of charge. Consider the following situation.... Let's say you program your battery monitor telling it your battery bank is 170AH. Now lets assume you start with fully charged batteries and you start using/draining your battery while camping. Let's assume you actually use 340AH worth of battery power over a couple of days. As soon as you use 170AH your monitor will say "0% full" on your battery monitor. BUT, let's say you don't notice and you actually use 170AH more. Your battery monitor will still just say "0% full". You will incorrectly think that means your batteries are "actually at 50% state of charge". But in reality they are closer to 0% true state of charge (almost dead). Now assume you start charging and you charge your batteries 170AH worth of charge. Your batteries will ONLY be half charged (50% state of charge), but your battery monitor will now say they are fully charged up to 100% (when in fact they are not). Understand?
So program your monitor to 340AH and simply realize that when it is at 170AH (50%) you should think about getting them charged.
Note: It's been debated for years, but (my opinion) if ONCE IN A WHILE your batteries discharge 60, 70, 80% they will be just fine as long as you don't let them sit there for days/weeks/months at a time. Perhaps you will only get 400 "cycles" of your batteries instead of 500 (...or choose whatever numbers you want...). But ask yourself this: Will you be dry camping enough so that you will EVER cycle your batteries 300, 400, 500 times? For most casual RV users, they will never cycle their batteries this many times.
Hope that all helps!
Chris
PS: If you don't have solar yet, throw up 200-500w of cheap solar and you will have yet another power source. There are some cheap ways to do it. Feel free to send me a PM
Reason: If you only put 170AH as your battery bank (when you really have 340AH) you could easily have a problem knowing your actual state of charge. Consider the following situation.... Let's say you program your battery monitor telling it your battery bank is 170AH. Now lets assume you start with fully charged batteries and you start using/draining your battery while camping. Let's assume you actually use 340AH worth of battery power over a couple of days. As soon as you use 170AH your monitor will say "0% full" on your battery monitor. BUT, let's say you don't notice and you actually use 170AH more. Your battery monitor will still just say "0% full". You will incorrectly think that means your batteries are "actually at 50% state of charge". But in reality they are closer to 0% true state of charge (almost dead). Now assume you start charging and you charge your batteries 170AH worth of charge. Your batteries will ONLY be half charged (50% state of charge), but your battery monitor will now say they are fully charged up to 100% (when in fact they are not). Understand?
So program your monitor to 340AH and simply realize that when it is at 170AH (50%) you should think about getting them charged.
Note: It's been debated for years, but (my opinion) if ONCE IN A WHILE your batteries discharge 60, 70, 80% they will be just fine as long as you don't let them sit there for days/weeks/months at a time. Perhaps you will only get 400 "cycles" of your batteries instead of 500 (...or choose whatever numbers you want...). But ask yourself this: Will you be dry camping enough so that you will EVER cycle your batteries 300, 400, 500 times? For most casual RV users, they will never cycle their batteries this many times.
Hope that all helps!
Chris
PS: If you don't have solar yet, throw up 200-500w of cheap solar and you will have yet another power source. There are some cheap ways to do it. Feel free to send me a PM
