Questions

[Gunny]

With my new 3 stage charger, will it be charging from the alternator at a different voltage than the normal alternator voltage?

I have looked at the TriMetric battery meters. Are they needed? Is there a cheaper alternative? I don't want junk, if I have to pay that much ($178) so be it, but I would rather not. Something mounted where a doofus like me could tell what's going on.

During the summer I will be using a generator often, I hope that will take care of charging, I want to start small with solar but want to be able to expand in the fall when generator is not used as much.

Solar may have to wait a bit until I find out how much the repairs to my truck are. It's always something. 

Any help will be appreciated.

Rob

 

[SternWake]

Your PD9245 only works when it is plugged into a 115vac source, like the grid, or a generator. The alternator is a completely different charging source, and it is controlled by the vehicle's voltage regulator, which migh thave the VR internal to alternator, external, or inside the engine computer, if one exists. if you are towing a trailer then the 7 pin or 4 pin connector will not pass much charging current to the house batteries in trailer. A dedicated charge path for the house batteries would help a lot.

https://www.amazon.com/Keeper-KTA14...sim_263_1?ie=UTF8&refRID=147ND97WNXYBJX94R5M6

https://www.amazon.com/Keeper-KTA14...rd_wg=b1VmZ&psc=1&refRID=M8H9BK0K6M0RZ2Y48XST

After driving just separate connector. Hook the ring terminals right to alternator (+) output stud and a mounting bolt(-) for best results. If you hook the top link to the engine battery a fuse must be employed at the engine battery or very close to it

You do not really need a battery monitor, Nobody needs a battery monitor. they are a great tool for learning how much electricuty one is using. they enable one to say, well I have used 45 amp hours and my batteries read 12.43v while still under a 3.2 amps load.

After many observations one could see 12.45 volts, a 3.4 amp load and guess that they have used around 45 amp hours. One could use just an Ammeter and a voltmeter and skip the more expensive amp hour counting battery monitor.

In general when you see 12.2v under light loads, it is about time to apply a charging source, but in an emergency or if one just wants one more day, the occasional dip to the mid to low 11's is not an instant battery killer. The battery killer is never getting the batteries back to a much higher state of charge, and preferably a true 100% state of charge.

The solar is nice as it has the time to complete the full charge. A battery that was depleted to 50% can, with a high amp charging source, be recharged to 80% pretty quickly, but 80% to 100% takes no less than 3.5 more hours and that is with a charging source seeking mid to high 14 volts, and that is not what most vehicle's voltage regulators will allow for very long.

It is great when the solar can take over for that 3.5 hours. Top off the batteries silently. You can add it later. 200 watts for that 220aH battery bank would suffice for that 3.5 hour 80 to 100% duty, but more is better. Add as much solar wattage as your roof and chosen solar charge controller will allow, when you can.

Sometime you just gotta hammer the batteries. thats what they are there for. not to be coddled. Use em, charge em, and occassionally charge them fully, and this might take a long time no matter how powerful the charging source.

No one needs to achieve the perfect recharge regiman, unless they are trying to achieve the maximum possible cycle life from the batteries. it is usually easier to just accept lesser lifespan than to obsess over the perfect recharge. Your batteries Plus East penn/Deka GC-2s are going to handle abuse better than most any other battery you could have bought, and at 89$ a piece are a great bang for the buck

 

[Gunny]

Thanks Sternwake. I appreciate the time you take to answer my less than novice questions.

Rob

 

[John61CT]

Yes, sensible and very well put.

With flooded batteries, you could still monitor them very closely with an accurate voltage reading, cross-referenced with SG from a cheap hydrometer, logged to a notebook.

This will allow you to adjust your charging/usage patterns and get a nice long life even out of your cheap GCs.

$200 on a BM just automates the process, less work logging and a convenient display.

 

[makenmend]

This is an inexpensive monitor, may not be as accurate as the one you mentioned, but I find it comforting to know at a glance where my battery voltage is. https://www.amazon.com/gp/product/B013PKYILS/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

MM

 

[Weight]

I have a Victron from Maine Sail. Yes, $180, but at a glance it tells me the % charge on my batteries. With a push button I can see voltage, amps being used, charge being done. I would probably like a Trimetric TM2030, as it can be linked to their SC2030 to control solar charging. My Victron needs to be reset sometimes, I do it about every 6 months, during heavy duty battery maintenance day. http://www.pbase.com/mainecruising/programming_a_battery_monitor

 

[DuneElliot]

If you go with the Trimetric 2030 (which is what everyone on here recommended to me) I can confirm that the install was pretty darned simple for someone who had never done anything like it before. The toughest part was deciding where to mount it and then drilling the holes for the wire!!!

 

[Weight]

the trimetric will also need calibration on some schedule. So far only Belmar Smart Gauge is automatic.

 

[SternWake]

Resetting the battery monitors needs to be done occassionally when the batteries are known to be full, and this can only be determined with a hydrometer, or an ammeter with voltmeter on AGM. Assuming the monitor to be accurate without verification is unwise.

Battery monitors do not know how much capacity the batteries have lost, so if programmed for 100Ah capacity and the battery is at 90AH remaining, well 50% displayed is actually 45% state of charge, perhaps less, perhaps much less.

I use the AH from full screen and ignore the % remaining screen. Also When AH from full does not jibe with amps accepted at absorption voltage I know it is time for a reset.

It seems large amperage charging sources can make the 'AH from full' appear to be higher than it actually is, at least on my IPN pro remote monitor. I know when my battery is full as at absorption voltage, when it can only accept 0.4 or less amps, it is full, and often I will see the monitor at 0.8 amps at 14.7v and read 100% and ) from full, when i know the battery still needs another hour for amps to taper to 0.4.

Other times It will read 8Ah from full when it can only accept 0.2a at 14.7, and I know the monitor needs to be reset. I reset mine by removing power to solar controller. i only do this at night when the solar panels are making nothing.

Most battery monitors do not acount for the peukert effect. A healthy fully charged 100Ah battery can deliver 5 amps for 20 hours before 10.5v and 100% discharge is accomplished, but load that battery with a 10 amp load and it is no longer a 100Ah battery but a much smaller capacity battery and most battery monitors do not take this into account. So running huge loads for a while on a microwave or something could have the readings well out of true.

The battery monitors are not the end all be all of determining state of charge, That is stil the hydrometer on flooded batteries or an accurate Ammeter used on an AGM battery held at the proper temperature compensated absorption voltage. Do not have blind faith in a battery monitor to be accurate. that is extremely unwise.

They are however useful learning tools, and should be considered well less than 100% accurate, and the percentage remaining screen is misleading, as it does not account for declining battery capacity, and is usually not starting counting down from a true full charge anyway, but it is so much better than using voltage alone on a loaded battery as a state of charge indicator.

If the inexactness of an expensive battery monitor is irritating to the reader, welcome to the club. For those uninterested in keeping batteries healthy for long periods, all they really need to know is to recharge somewhere around 12.2 volts when under a light load. Heavier loads can pull this lower but when removed voltage should rebound to the 12.2 range and the battery will be in the 50% range.

A good voltmeter can be substituted, no one NEEDs a battery monitor, but they are a good learning tool and can have periods and conditions where they are indeed accurate, but the user needs to know when that is, rather than simply relying on an electronic gizmo to do what its marketers claim it can, when it really can't.

https://www.amazon.com/DROK-Voltmet...rd_wg=ry03S&psc=1&refRID=JWGCCFHXY2T89J5B97H7

Install the above, turn on loads, watch voltage drop. Around 12.2v, time to recharge. Here is another voltage based indicator of dubious accuracy as voltage alone is never truly representative of state of charge on a battery in actual use.

https://www.amazon.com/DROK-Black-l...rd_wg=bfP05&psc=1&refRID=4HQM4ASVW8E50WAEQQRB

Here is a low dollar battery monitor. I have no Idea how accurate it is, and there are a lot of complaints about the instructions, and few reviews where the results are compared to known accurate tools.

https://www.amazon.com/DROK-Multime...e=UTF8&qid=1493405538&sr=8-1&keywords=monitor

I own none of the above linked products, have not tested them, and am not endorsing them, merely presenting them as available options.

I'd like to test the drok, but have no desire to shell out for it and have other projects I care more about completing.

 

[John61CT]

Merlin SmartGauge (Balmar in NA) is not shunt-based, does not count amps in & out, just shows State of Charge for one bank, voltage for two.

More accurate than even the most expensive coulomb-counters while the bank is at rest, usually within 2% under gentle loads, 4% while charging or heavily discharging.

Never needs resetting or calibrating, and **does** automatically take declining AH capacity into account as the bank ages.

 

[Weight]

I'm happy with my Victron. It takes account for the peukert effect. It is simple enough to maintain. I follow instructions to compensate for declining battery life. I would not own a cheap device. There are better ways to save money. No more to say.

 

[John61CT]

Yes, I will use coulomb counters as well for watching and logging AH in and out, and SG is no good for LFP anyway.

The Victron BMV-70x has an excellent rep, and the relay control can help protect the bank.