Trojan v. West Marine 8D AGM batteries

[Happ]

When I was building an electrical system from scratch I came across company called batterystuff.com. Great resource and you can’t beat there pricing! Their customer service is outstanding. I’m not affiliated with them.

[Mardagan]

Pacific Yacht Systems based out of Canada has some amazing articles and videos about batteries worth looking into.

Check out this article they have on the topic:

https://www.pysystems.ca/resources/t...for-your-boat/

[john61ct]

Originally Posted by Exile

I thought that when you had 2 separate alts charging the same bank of batts, the one with the lower output gets effectively cancelled out by the higher output one.

No.

In theory there is no difference between theory and practice.

In practice there is, no problem, just connect as many disparate charge sources as you like concurrently to any battery bank.

As long as each's setpoint will not harm that chemistry, neither will the combination, no coordination, central control, no "confusion" or "fighting" each other, all works out fine in the end.

Even if it doesn't actually charge much faster, no more energy is "wasted" than with dedicating an alt to a Starter that is never depleted.

[Medic 4 U]

The company I work for uses Trojan batteries in our APUs. I know many people who use Penn Decca batteries in their trucks, and have many problems with them. The Trojan batteries are not perfect, but give a good bang for the buck. Penn Decca not so much with all the quality problems. I have gone onsite to train technicians on installing our product, and have often come across brand new trucks with 3 of 4 brand new Penn Decca batteries defective from new. I would steer clear of them personally. IF you can afford them, Oddesey brand batteries are fantastic. Expensive, but worth every penny. Be advised, DO NOT MISTAKE Oddesey batteries with the gel cel Optima battery, which is mediocre in it's performance. I use a bank of 4 Group 31 Oddesey batteries instead of my 6.5 Onan gen set to run my Cruise Air AC for 8+ hours. Then, the next day my 2 5.7 Crusader engines each charge 2 of the Oddesey batteries back up in roughly 5 hours cruising time. Good luck.

[john61ct]

The EPM brand is spelled Deka.

The Enersys one is spelled Odyssey.

East Penn makes great FLA batteries, IMO as good as Trojan.

But, this thread is about AGM.

Neither of those two makes great AGM, sure better than some pseudo "marine deep cycle" from big box, but not in the top say five makers list.

Odyssey makes great AGM, along with Lifeline.

[Exile]

Originally Posted by john61ct

No.

In theory there is no difference between theory and practice.

In practice there is, no problem, just connect as many disparate charge sources as you like concurrently to any battery bank.

As long as each's setpoint will not harm that chemistry, neither will the combination, no coordination, central control, no "confusion" or "fighting" each other, all works out fine in the end.

Even if it doesn't actually charge much faster, no more energy is "wasted" than with dedicating an alt to a Starter that is never depleted.

Understood, and thank you. My only real concern is overworking/overheating the larger of the two alts (80A) by having it do most if not all of the work charging a larger bank of 3 Lifeline 8Ds, i.e. 765ah. Right now that same alt is only charging two of the 8Ds, i.e. 510ah. I realize that also having the smaller 50A alt spinning won't hurt anything, but my question was whether it would take any of the load off the larger alt as is the case now (with smaller alt charging eng start 8D only).

[Pete7]

Originally Posted by CaptRory

Buy them straight from Trojan even if you have to drive a few miles and you will get batteries that have been recently manufactured

Had this problem during the winter when I ordered a pair of rolls 12v batteries. Delivered on a pallet the date of manufacture was Jun 2107, easily seen because Rolls stamp the date on the battery case. They went straight back.

Next came a set of Trojan TMX dated July 2108, slightly more complicated because they use a date code which needs deciphering but details are on their website. Sadly the TMXs come with a really odd battery terminal so extra work required to covert from the UK SAE engine battery clamp to crimp type.

So, what ever battery is chosen, check the date of manufacture.

Pete

[john61ct]

Originally Posted by Exile

Understood, and thank you. My only real concern is overworking/overheating the larger of the two alts (80A) by having it do most if not all of the work charging a larger bank of 3 Lifeline 8Ds, i.e. 765ah. Right now that same alt is only charging two of the 8Ds, i.e. 510ah. I realize that also having the smaller 50A alt spinning won't hurt anything, but my question was whether it would take any of the load off the larger alt as is the case now (with smaller alt charging eng start 8D only).

Yes, both will contribute. There are many variables involved in exactly to what extent how the work gets "shared", but in any case better than now.

A solid VR like Balmar MC-614 will help you "tune" the handling of an overtemp situation - if any - but that is an expensive step to take prior to just "try it and see".

You could put in 1-2-B switches to direct each alt output (also cranking input) if you wanted max flexibility, but again as above,

plus "expensive" in adding points of failure / complexity.

Could put them in for a period of testing then hard-wire once satisfied.

But really, I am 100% sure this is overthinking, IMO Just Do It

[Exile]

Originally Posted by john61ct

Yes, both will contribute. There are many variables involved in exactly to what extent how the work gets "shared", but in any case better than now.

A solid VR like Balmar MC-614 will help you "tune" the handling of an overtemp situation - if any - but that is an expensive step to take prior to just "try it and see".

You could put in 1-2-B switches to direct each alt output (also cranking input) if you wanted max flexibility, but again as above,

plus "expensive" in adding points of failure / complexity.

Could put them in for a period of testing then hard-wire once satisfied.

But really, I am 100% sure this is overthinking, IMO Just Do It

Certainly could be some overthinking at play here, which can lead to some paralysis. But then it may be better than under-thinking which can lead to an expensive invoice from a marine electrician! Some complexities inherited from the PO include 3 separate switches for house, eng start, and gen start banks; 1-2-ALL switch for two 8Ds comprising house bank; two house batts parallel at switch rather than at batts; two solenoid relays which can bring in house bank for eng & gen starting if needed. I've been told it's a good system but one that's somewhat customized so not directly comparable to what we often read about.

It's also been a well performing system over the years, with the only possible fault I see is dedicating an 8D for eng starting only. Seems like overkill, but I don't want to presume being smarter than the designers by making what I see could be improvements without having them fully thought through (and probably diagrammed out). I'm learning a lot though, so either way a fun project. Thanks again for the help.

[john61ct]

Yes many setups are not negatively affected by carrying too much "dead lead" around, that and a bit of cost are the only downsides.

Reworking an in-place design that already works OK would usually not be worth the time and hassle.

But when a boat's electrickery needs an overhaul anyway, best for the owner to understand the various options and their trade-offs so they can make the right choices in line with their setup and preferences.