Stone said:My flashlight batteries don't receive any charge when they're hooked up in series in my flashlight.
I think the issue started way back when people tapped off of their low side battery to draw their 12V power. This caused the low side battery to draw down, resulting in sulphation. I have heard that the high side battery can become overcharged in a system where there is a bad low side battery, causing the high side battery to boil over.
This is how I have hooked up my system, drawing from the low side battery so that I can draw large transient 12V loads when I need it. I have my Solar Converter shunting current in load balance mode, and it keeps my batteries fairly equal to each other. I then flip my switch to turn it into strict convert mode when I need to leave my vehicle for days at a time, to avoid drawing down my batteries. My system has been very happy for almost two years this way, using two Interstate Workaholic batteries.
As I've stated in my post, mine is more a gut instinct type feeling. I have read on one website that concurs with your theory that batteries hooked up in a bank, whether in series or parallel, act as one battery, and that in series, a bad cell does not necessarily cause any problems with current flow. I'm going to be doing a bit more reading.
I think it should added that it might not only be connections but general battery health that could contribute to the difference. Starting at manufacture a difference could start.Greg_B said:, and there will be anywhere from a .05 to .50V difference in a standard set-up. Trucks run for years with minor differences. Over time it will shorten battery life.
Old salts would recommend swapping the batteries at each oil change to try and minimize this difference, and extend battery life as long as possible...in the shaky 4 banger diesel environment.
Thanks Stone, One thing to mention, my anology is not taking into account your draining of 12 from a low side battery. Also to note, As I have heard of certain cruisers using 12 for headlights......etc, I am not taking that into account.
Any time an imbalance is present, you rotating the battery theory does sound ok. Althought it sounds like a flawed system from the get go.
I still concur that anytime the batterys are hooked together they act as one tho.
your flashlight(lets therorize) is rechargeable. the individuall batterys are 1.5 volts, together you have 3 volts, your load is a bulb of 3 volts. You use the flash light and later recharge, later to do this over and over. This is my point, unless you are stealing from one battery more than the other(in your truck for 12v) then in my theory you have batterys that are doing the same thing, acting as a 3v(or 24v) battery. positioning either battery in the flashlight will not give any other results. being on the top or the bottom.
Now duracell or energizer could manufacture a battery that is not as good as the other, so could motormaster, or delco. But that is beyond your control.
As I said before, if your a 24v system only drawing 24volts, I see no reason why you could not just charge with 24v. If the batterys are of the same age, the over charging and undercharging should not occur. One thing that could hinder the equal charge when doing both batteries with 24v is dirty connections, which act as resistors and lower the voltage being applied to the battery.
Or source out 24v batterys for your truck. They run around 5-6 hundred. 1700 if you want one as big as I buy for the aircraft I maintain. And its lead acid too.