Mysterious battery drain... where to begin?

[ranger58sb]

Originally Posted by OrangeCrush

Thanks, Chris, but after a lot of thinking I decided against AGMs because my boat is kept at a mooring and will rarely be connected to shore power so won't be brought up to 100% charge frequently enough. My solar array is not huge, and I think the GC2s will tolerate my less-than-ideal charging conditions better than AGMs.

Yep, sounds like a good reason for going FLA.

FWIW, NOCO and Bonar make some interesting looking boxes...

-Chris

[OrangeCrush]

As usual, I've gotten to the next step and realized it's not nearly as straightforward as I'd hoped...

I'm wiring up my bank of 6 series-then-parallel GC2s and I'm trying to avoid reinventing the wheel as far as the electrical system goes since it was recently and professionally redone. But I did come across one thing that I think is a mistake that I need to fix.

In the old bank, both negative and positive house leads were attached to the same battery. The rest of the batteries were wired up in parallel "down the line" using 2/0 interconnect cables. I've learned that this is not ideal, since the draw will not come evenly from all batteries, and that I need to connect either the positive or negative lead to the "far end" of the battery bank.

So I'm going to get a 4 foot long 2/0 gauge cable to run from the battery monitor shunt (where the old negative lead was connected) to reach the negative post on the farthest series-pair of batteries. It seems that this cable run will introduce some voltage drop into the system, but it will have the advantage of utilizing the battery bank as "one-big-battery".

Does it sounds like I have this right?

Lastly, where do people get their battery cables? There aren't a ton of pre-made options online, so I'd probably end up with slightly longer cables than necessary. If I made my own I could get the lengths perfect, but then again I'm really not eager to buy more tools I won't use anytime soon, and I'm thinking I won't crimp/solder as well as pros anyway.

[fallingeggs]

You plan sounds sound.

genuinedealz.com is the bees knees for cables. You can order them with the connectors installed. Get the heavy wall lugs. Free shipping.

I ordered 60' of 0/2 cable and an assortment of lugs from them. As I didn't know the lengths I'd want, I'm crimping on the boat with a nice lug crimped, followed by a heat shrink. A long process, but having the right lengths is nice and tidy.

[skipgundlach]

Yes, you're on the right track.

Same interconnect distances, too (series and parallel jumpers).

Genuinedealz has great service and prices if you don't want to have to make them up yourself (and will sell you the bits, too). Highly recommended.

[ErikFinn]

Originally Posted by OrangeCrush

As usual, I've gotten to the next step and realized it's not nearly as straightforward as I'd hoped...

I'm wiring up my bank of 6 series-then-parallel GC2s and I'm trying to avoid reinventing the wheel as far as the electrical system goes since it was recently and professionally redone. But I did come across one thing that I think is a mistake that I need to fix.

In the old bank, both negative and positive house leads were attached to the same battery. The rest of the batteries were wired up in parallel "down the line" using 2/0 interconnect cables. I've learned that this is not ideal, since the draw will not come evenly from all batteries, and that I need to connect either the positive or negative lead to the "far end" of the battery bank.

So I'm going to get a 4 foot long 2/0 gauge cable to run from the battery monitor shunt (where the old negative lead was connected) to reach the negative post on the farthest series-pair of batteries. It seems that this cable run will introduce some voltage drop into the system, but it will have the advantage of utilizing the battery bank as "one-big-battery".
Does it sounds like I have this right?

Having the same project on my to-do-list these three links from my bookmarks are the best info I've found so far:

http://www.smartgauge.co.uk/batt_con.html

http://www.cruisersforum.com/forums/f14/eight-golf-cart-batteries-in-one-bank-46662.html#post519050

http://www.cruisersforum.com/forums/f14/multiple-cables-on-battery-terminal-52947.html

Hope this is helpful

[skipgundlach]

Great links, but unfortunately oriented to 12V batteries.

The wiring is a bit more complex with series/parallel banks, but the same concept would apply.

Trojan has a nice diagram illustrating how to do that, and an optional cabling which goes beyond the in one end/out the other for balancing, for big banks...

[OrangeCrush]

Originally Posted by ErikFinn

SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank

Glad to know I'm on the right track, and thanks to all for the help. This smartgauge article is particularly useful. Method 1 is what the previous owner had. Method 2 is what I had in mind. Method 3 is not impossible but would cost more and maybe is unnecessary for what is essentially only a 3 battery bank (3 6v pairs). Method 4 is clever, but I'm getting quite the headache trying to translate it to my 3-pair plan. Unless anyone disagrees, I think Method 2 will suit me fine.

Just to be extremely clear, the series-pair connections will be shorter than the parallel connectors (about 6" each versus 18"). This is balanced as long as all connectors of the same type are the same length, correct?

[skipgundlach]

I'm not an electrical engineer, but I think you have to make them all the same length.

In my case, the series did a u-turn to accommodate how I had my cells positioned, whereas the parallels merely had a small s-turn at the ends to miss the auto-type lug on the way to the bolt.

Trojan Battery Company

https://www.survivalmonkey.com/threa...arallel.37039/

Check the pic at the bottom: https://www.wholesalesolar.com/18985...8-battery-bank

[OrangeCrush]

Originally Posted by skipgundlach

I'm not an electrical engineer, but I think you have to make them all the same length.

Hmm I'm obviously not an expert either but that doesn't sound right to me... as long as the series connectors are the same in each battery pair, each will have the same overall resistance. The diagrams I'm seeing don't generally show the series connectors equal to the parallel connectors anyway.

But the labeling on this diagram (my exact setup) also confuses me. What do they mean by "Equal length cables To +12v and To Ground"? Measured from where, the positive bus bar and negative shunt? Since I'm going extend the negative house connection to the far side of the battery bank, it will not be equal unless I add 5ish feet of extra coiled up cable on the + side of the house connection. Seems irrelevant anyway since it is outside the overall "cell" of the battery bank.

I'm definitely going to make the 3 short series-pair connectors all the same length as each other, and the 4 parallel battery connectors all the same length as each other. Can anyone confirm if I need to do more than that?

[skipgundlach]

Here's the one I'd been thinking of with the interconnects:

[OrangeCrush]

Originally Posted by skipgundlach

Here's the one I'd been thinking of with the interconnects:

That's a lot of batteries in series, and I don't know why those dotted lines would be making parallel and series connections on the same terminal.

I have three pairs and they're all in a straight line. I think you can think of the series-pair connector as simply part of the internal resistance of each battery (pair). As long this is the same in each series-pair, their length has no bearing on the length of the parallel connections, which should also be the same as each other so the load draws equally on each battery pair. Making all connectors the same length in my case would mean a foot of 2/0 gauge slack awkwardly twisted up on each pair of batteries for reasons that still escape me.

I'd love to hear an engineer/expert chime in on this one.

[mrm]

Originally Posted by OrangeCrush

[...]I'm definitely going to make the 3 short series-pair connectors all the same length as each other, and the 4 parallel battery connectors all the same length as each other. Can anyone confirm if I need to do more than that?

You don't. The uppermost 'equal length' remark on the diagram you posted seems superfluous, unless there is another bank paralleled with the one pictured.

You are building one large battery out of smaller ones. Keeping internal (inside this large battery) connections equal is important. Load connecting wires can be arbitrary length (within acceptable voltage drop for a given load and cross-section).

[Cadence]

Originally Posted by OrangeCrush

That's a lot of batteries in series, and I don't know why those dotted lines would be making parallel and series connections on the same terminal.

I have three pairs and they're all in a straight line. I think you can think of the series-pair connector as simply part of the internal resistance of each battery (pair). As long this is the same in each series-pair, their length has no bearing on the length of the parallel connections, which should also be the same as each other so the load draws equally on each battery pair. Making all connectors the same length in my case would mean a foot of 2/0 gauge slack awkwardly twisted up on each pair of batteries for reasons that still escape me.

I'd love to hear an engineer/expert chime in on this one.

I'm with you. I can't ever follow some of the nonsense about equal wire length. Maybe if paralleling one battery aft and one forward.

[skipgundlach]

Originally Posted by OrangeCrush

That's a lot of batteries in series, and I don't know why those dotted lines would be making parallel and series connections on the same terminal.

I have three pairs and they're all in a straight line. I think you can think of the series-pair connector as simply part of the internal resistance of each battery (pair). As long this is the same in each series-pair, their length has no bearing on the length of the parallel connections, which should also be the same as each other so the load draws equally on each battery pair. Making all connectors the same length in my case would mean a foot of 2/0 gauge slack awkwardly twisted up on each pair of batteries for reasons that still escape me.

I'd love to hear an engineer/expert chime in on this one.

Ping Rod Collins/MaineSail...

[OrangeCrush]

Originally Posted by Stu Jackson

Simple.

Freedom 20: you'll need to change the dip switch settings on your remote panel, if you have one. Your Link 10 doesn't control the F20, IIRC. My Link 2000 controls my F15.

Balmar Max Charge Regulator (most likely an MC-612, or maybe a newer MC-614) You'll need to reprogram to FLA voltages. There are the presets in the manual.

If you don't have the manuals, they are available online for the Freedom (Xantrex's discontinued models), and at www.balmar.net

Stu (or anyone),
I'm still having trouble with this step, maybe you can help me... My Freedom 20 Combi Inverter/Charger is stuck on the Gel 1 setting. I've got all the manuals: it says to hold "Invert" for 5 seconds and the lights will turn off and I can change the setting. But it also says if I have a remote then refer to the remote manual to change the setting that way. The manual for the Freedom remote gives instructions to change battery type for 485 Series only, not the simpler one that I have (even though mine is pictured on the manual.) As you pointed out, my Link 10 doesn't have that setting. I can seem to change charge voltage through the remote by holding down "setup", as well as inverter amps or power share modes, but I can't seem to change battery type. Lasty, unplugging the remote and doing it on the charger only doesn't seem to work either. Even resetting to factory settings would probably work...

Any familiarity with these units or different buttons combinations I could try? I'll try calling Xantrex on Monday but that leaves me a bit stuck for the weekend...

Alternatively, how bad is it to charge golf cart batteries on "gel" settings for a day or two while I get this worked out?

Pictures to follow... Huge thanks in advance for any help


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