battery question.

[bottom-bouncer]

Here is my question or what I want to do. If I run two 12 volt batteries in series so as to still be 12 volts not 24 and if I do this with 4 batteries two in each set can I still use a 2 bank on board charger to charge all 4 batteries? also by running 2 batteries together will I see change in how long they will last? This is for my wheel house so I am looking for the best way to get the most time out of my batteries and still be able tp use the 2 bank charger and not have to bring the generator with on a 3 or 4 day trip. thanks chris

[Macgyver55]

First off you want to run them in "parallel" not series to remain twelve volts.

Yes, they will last longer but will also take longer to charge, but you should be able to use the same charger.

[bottom-bouncer]

Thanks mac

[delcecchi]

First off you want to run them in "parallel" not series to remain twelve volts.

Yes, they will last longer but will also take longer to charge, but you should be able to use the same charger.

You can use the same charger if they are the same type battery.

[BobT]

When you say same type of battery, what are you referring to? Do you have to use different chargers for gel-cell batteries than for wet-cell for example?

[delcecchi]

I don't think you have to use different chargers but I don't think having them in parallel while charging will work. I notice many battery chargers have different settings for battery type. Or they figure it out on the fly.

[Macgyver55]

If the batteries are the same, charging in parallel is not a problem, I guess I just assumed that they were.

[BobT]

Applying 12v to one 12v battery or 10 in parallel doesn't matter. They will all be recharged. The difference might be in how the charger is designed to recharge battery types. For example, my charger has two settings. One for regular 12v batteries and one for deep cycle 12v batteries. I haven't been able to tell a difference in how the two settings react except maybe in how the charger senses the battery's charge state.

Edit:

I decided that I would be better off to dig into this a little more so I did a little research into the difference between recharging regular starting batteries and deep cycle batteries and I might have to eat a little crow. While I am correct that both types of batteries will get recharged connected in parallel, it seems that battery manufacturers generally do not recommend mixing battery types, i.e., deep cycle and regular starting batteries.

I have sent an email to Schumacher to ask how the battery type selection on my charger affects the charger’s operation. I asked for a technical explanation. It seems this kind of information is hard to find from a technical perspective. Lots of sites with people’s opinions but we all have those, including me.

I will post back if I learn something.

[BobT]

I have received some information from Schumacher.

One of the questions I asked was about the possibility of damaging a battery by choosing the wrong battery type option, i.e., regular vs. deep cycle. The reply was, “You will not harm the battery by choosing the wrong setting, but the battery may not reach full charge.”

Another question I asked was which setting to use for a dual-purpose battery. The reply was, “Use the deep-cycle setting for a dual-purpose battery.”

I have also asked for a more technical explanation about the different settings but am still waiting for a reply.

There was something else I learned while browsing their HSOforum that explained an experience I have had. My charger has four different voltage/ampere settings to choose from.

* 6v/15A manual

* 12v/2A automatic

* 12v/15A automatic

* 12v/100A engine start

I have noticed that if I use the 12v/2A setting for my deep-cycle battery I have to watch my electrolyte level more closely because it will evaporate. I also noticed that when using this setting I never see the battery charger’s green LED light up to indicate a full charge. For this reason I suspected that a deep-cycle battery might not have a high enough resistance at full charge to reduce the current draw below 2A and the charger is therefore unable to detect a full charge.

The HSOforum basically confirmed my suspicions. They DO NOT recommend using the 2A setting to maintain a battery for extended periods of time. They recommend using the 15A setting because this setting will operate in a maintenance mode. In this mode it will monitor the battery voltage and when it drops below a certain level the charger turns on and brings it back up and then turns off again. I thought this was good information to share. You can buy special maintenance chargers that work at lower current levels.

I have also reconfirmed what I already believed.

From most of the battery OEM sites I visited, the general consensus seems to be that the best way to maintain our deep-cycle wet cell batteries is to employ the following.

* Avoid cycling deeper than 50%

* Recharge them as soon as possible after each use

* Recharge them quickly. Exception: for batteries cycled below 50% use a trickle charger to bring up to at least 50% first The reason is that a very low battery is basically a short-circuit and the charger may try to recharge the battery too fast, which may damage the battery.

* The best charger to use is a fully automatic charger that incorporates three-stage technology; Bulk, Absorption, & Maintenance

[daylate]

Thanks for the research Bob! Your info is very usefull.

[bottom-bouncer]

A big thanks bob that is very usefull info.