Upgrading your battery system....

[Ron in BC]

Originally Posted by Jim Bennett

Maybe I need to learn more on these multibank battery chargers, and how they work, as it sure seems like they are dealing with either separate batteries, or or ones in parallel.

Gotta agree, to me, two 6 volt batteries permanently connected in series isn't a multibank situation.

Ron

[cpaharley2008]

Back to my original post. today I received my Zamp Solar Battery Check kit. See here for details for the Battery Check info http://www.zampsolar.com/solar-acces...ry-management/
I'll be posting the dual battery and Battery Check install right after the holidays. I need to find some old battery cores to turn in between now and then. If anyone else is interested in the Battery Check, Zamp Solar- is offering their kit which sell for $299 retail a special $265 price for forum members, both here and over FGRV. If interested, please p/m me and I'll provide the person to call. Happy Holidays until then.

[Brian B-P]

Originally Posted by thoer

So, I guess I should start putting my little INNOVA 3721 Battery and Charging System Monitor into the Tacoma while driving and notice what its delivering.

Yes, that's informative. I have a similar socket-mounted voltmeter, and have used it to understand how the charging system is behaving in a couple of cars. These devices have green/yellow/red lights to indicate "battery charge status", but it's just another indication of the same voltage, compared to some set levels.

Just one note: you are measuring voltage at an accessory socket, which will be very close to battery voltage. Your trailer is getting something lower, depending on how much resistance is in the wiring from your tug battery to trailer, and the current flowing in that circuit.

[Brian B-P]

Originally Posted by thoer

Latest reply from NOCO about their charger:

You can use the G7200 to charge the two 6V batteries its just not ideal. Even though they are the same size, condition and age, when your batteries are in use one battery is going to discharge faster than the other...

It still looks to me like they're describing a parallel set of banks instead of a series set of cells in one bank; however, I have seen wiring recommendations from a charger manufacturer which shows separate charging of batteries in series.

Originally Posted by thoer

I don't see why one would discharge faster than the other as they contend, when they are wired in series.

There is some logic to this, because the current passed through a battery is not exactly the same as the change in state of charge. Each cell has some internal inefficiency, and if the cells of one battery are not in exactly the same condition as those in the other battery, delivering exactly the same current from each battery will cause slightly different changes in the state of charge. The same thing happens, of course, between the cells of one battery, which is why batteries routinely die due to the weakest cell becoming unacceptable, even though the others are still usable.

I think most people - and most battery manufacturers - are okay with charging any number of cells in series with one charger, and just treating the whole series as a set which will need to be replaced together.

[Brian B-P]

Originally Posted by thoer

Not sure on your differentiation, other than the amount of time it takes to charge?

Yes, I'm thinking mostly of time. If I'm going for a weekend trip and will make the entire trip on stored energy, then have a week (or weeks) to charge before the next trip, then charging speed doesn't matter. If I have an overnight stop with outside power to get the batteries back up, then it does matter.

Originally Posted by thoer

From what I have read, Interstate talks about charging volts not watts, and when I take multimeter readings, this one is reaching the 14.7v it is rated at during the absorption phase.

This means that 5 amps is enough to complete the absorption phase. I wouldn't have been certain of that, since the target current for the end of the bulk charge phase (as shown in Trojan Users Guide as an example) is ramping down from 10 to 13% of the C20 capacity (so, 23 to 31 amps for a 232 Ah battery bank) to 1 to 3% (so, 2.3 to 6.9 amps for a 232 Ah battery bank; the 3% or 6.9 amp value preferred) as the voltage is held in at the terminal voltage of that phase (14.1 to 14.7 V).

In other words, the 5 amp charger doesn't really get a chance to go through bulk and absorption states - it does its best, and is current-limited for the whole time until it essentially reaches the state (14.7V and almost 3% of rated capacity per hour flowing) that a faster charger would reach in bulk plus absorption stages. If that is good for the battery, then fine.

[thoer]

Originally Posted by Brian B-P

Just one note: you are measuring voltage at an accessory socket, which will be very close to battery voltage. Your trailer is getting something lower, depending on how much resistance is in the wiring from your tug battery to trailer, and the current flowing in that circuit.

I was thinking that too. I suppose the easiest way might be to get a same time reading at the socket and at the battery and calculate the % voltage loss between them.

[thoer]

Originally Posted by Brian B-P

Trojan Users Guide as an example) is ramping down from 10 to 13% of the C20 capacity (so, 23 to 31 amps for a 232 Ah battery bank) to 1 to 3% (so, 2.3 to 6.9 amps for a 232 Ah battery bank; the 3% or 6.9 amp value preferred) as the voltage is held in at the terminal voltage of that phase (14.1 to 14.7 V).

In other words, the 5 amp charger doesn't really get a chance to go through bulk and absorption states - it does its best, and is current-limited for the whole time until it essentially reaches the state (14.7V and almost 3% of rated capacity per hour flowing) that a faster charger would reach in bulk plus absorption stages. If that is good for the battery, then fine.

The NOCO would not meet those current requirement either, so I might as well just save my money for more homebrew ingredients!

[Brian B-P]

Originally Posted by thoer

The NOCO would not meet those current requirement either, so I might as well just save my money for more homebrew ingredients!

I agree that the NOCO G7200 is marginal by this measure, which may be why NOCO is reluctant to recommend it. The NOCO G26000 would have suitable boost and absorption stage output; I don't know why they don't recommend it as a maintainer in the application chart, but it is still listed as "usable".

[thoer]

Originally Posted by Brian B-P

I agree that the NOCO G7200 is marginal by this measure, which may be why NOCO is reluctant to recommend it. The NOCO G26000 would have suitable boost and absorption stage output; I don't know why they don't recommend it as a maintainer in the application chart, but it is still listed as "usable".

Now I see NOCO has a 15A model the NOCO Genius G15000 My BatteryTender may have gone bad on me, so now I'm once again thinking of a maintainer for storage use that would do a better job than the built in model. Anybody tried the G1500? I'm considering it vs the BatteryMinder people have recommended.