Re: Odyssey batteries - confusion with solar charging

[jen1722terry]

Hello Cruisers,

We have some issues with charging our Odyssey AGM batteries on our Cape Dory 31. We live aboard all summer at a mooring on mid-coast Maine.

We have two Odyssey group 31s (92 ah each) for a house bank and one Odyssey group 24 (62 ah) for a starter (all installed new in 2015). We also have a 130 watt solar panel and a new 65 amp engine alternator. We originally had a Morningstar Duo-Saver solar controller charging the house bank and the starter battery on separate circuits controlled by the standard battery selector switch.

On the advice of some kind folks on this and other forums, we learned that the Duo-Saver was not providing sufficient voltage to fully charge and maintain the three AGM batteries. So, we recently had a local solar electrician here in coastal Maine install a new Morningstar ProStar MPPT 25M controller.

A couple of problems occurred with the new controller installation:

The electrician informed us that we no longer have a separate charging circuit for our starter battery. All three batteries are now on one circuit (the battery selector switch now stays on "All"). Thus, if a malfunction (like a bilge pump switch) should run down the batteries, we have no separate starter battery to rely on.

2. We just heard from Odyssey that, even with the new solar controller, we do not have sufficient solar charging power on board to get the full absorption charge on all three batteries. Thus, we may be slowly killing the batteries by not bringing them up to the full float charge at fairly frequent intervals. Sulfation of the batteries will eventually kill them.

3. Also, we’re not sure how long we have to run the engine and at what speed to have a chance of getting the three AGM batteries to a full charge on a sunny day or on a cloudy day.

So, we feel we may have gained little by spending $800 to have the Morningstar ProStar controller installed.

So, what to do?

1. We own an Odyssey portable charger. We can bring the boat into a slip for shore power once a month or so and run the full “recondition” program on each battery individually to remove sulfation (we would turn off the controller, disconnect the ground from each battery and run the portable charger on the "recondition" program).

2. Disconnect the 62 ah starter battery completely (remove ground cable from battery) from the charging circuit (after reconditioning). It will just sit on board disconnected for the rare time we may need an emergency starter battery: it would then be used to start the engine with jumper cables or, if possible, by reconnecting it to the other two batteries via the solar controller for the engine start (this may not work if the other two batteries are really under charged). We’re not sure how to start our engine with jumper cables only now that the batteries are all on the same charging circuit (“in parallel” according to the Morningstar rep).


3. Doing the above would leave us with two, 92 ah Odyssey AGM batteries on the one solar charging circuit. We’re not sure that, even with this lower total amperage, we can fully charge these two batteries using our Prostar MPPT 25M controller and 130 watt solar panel, with or without our 65amp engine alternator. We’re also not sure how long it might take to fully charge the batteries with the solar and engine alternator.

Any advice any of you can give would be most appreciated. If worse comes to worse and we’re slow killing our AGM batteries, we can start planning for new batteries that will work better with our on-board charging capabilities.

Pasted in below is the most recent message from Odyssey technical support.

Any comments or advice any of you can offer would be deeply appreciated. Also, if any of you can recommend a good marine electrician in the Mt. Desert Island, ME area, we would love to hear.

Jenn and Terry
CD 31 “Glissade”

From Odyssey Battery customer support:

Equalization (exceeding 15.0V at 77°F or 25°C) is not recommended for any ODYSSEY battery as it can lead to overheating due to overcharging resulting in loss of critical moisture and premature failure. The charger is temperature compensated and that is good. You may see voltages exceed 15.0V when the temperature drops below a certain point which is acceptable when required. When paralleling batteries, the battery bank becomes the total Ah rating of all of the batteries in the bank. In this case 92 + 92 + 62 = 246Ah at the 10 hour Ah rate. At 40% of that rating, we would recommend a minimum charge current for the entire bank of about 100A. I would suggest doing a custom setting with Absorption at 14.7V for 180 min or longer if available, Float at 13.5V, and Equalize OFF. If the equalize mode can be set at 14.7V as well, then I would suggest turning that ON with maximum length available as well to prolong the Absorption time on charge if that is how it works (ask Morningstar to verify). That said, if the batteries are at 50% depth of discharge (12.2V with no electrical load), at 125Ah to recover it would take 5 hours (300 min.) at an optimum charge current of 25A at 14.7V to get to a 85-90% state of charge. Hence the recommendation to charge at 14.7V in both Equalize and Absorption modes for a combined charge time of about 420 minutes if that is how it works.

Note that a higher current charger would be recommended for the entire bank. At 25A (optimum) the charging system will eventually get the batteries fully charged however, I would not recommend discharging them below 50% depth of discharge on a regular basis. Most solar charging systems are about 85-90% efficient and can be less efficient and are dependent on the sun availability. A 130W solar panel can provide 8.8A at 14.7V optimum. I’m not sure but I believe that even if the controller can work at 25A max, a single 130W solar panel will never provide that type of current. It would take 3 panels that size to max out the system. I would contact Morningstar to confirm. If I am correct, then at optimum of 8.8A (100% efficiency), it would take almost 30 hours constant voltage at max current at 14.7V to get the batteries to 100% state of charge from 0%. Again, low current “trickle” charging is not recommended as it will contribute to the premature sulfation of the batteries over time. Solar charging tends to be that way. It will eventually get the batteries fully charged but will not de-sulfate the batteries as well as with higher current charging (100A for the battery pack).


_________________
Jennifer & Terry McAdams
Kearsarge, New Hampshire
Mahone Bay, Nova Scotia
CD 31 #33 "Glissade"
Way too many other small boats

[ranger58sb]

Can't help, but FWIW usually folks use the 20-hour rate. So your Group 31s (PC-2150s) would be 100 Ah each, and the Group 34 (PC-1500) would be 68 Ah.

Extreme Series Battery Specifications – ODYSSEY battery

Just caught my eye because we have a bank of PC-2150s and our genset starter is a PC-1500 (latter charged only by the generator alternator).

-Chris

[rgleason]

I'm very interested in your experience and how you work out the use of these batteries. I have some ideas how you can possibly top them off when needed:

1. What external regulator and alternator do you have on the boat?
2. What is the Crank Pulley dia / Alt Pulley dia ratio? This determines how fast the alternator will turn and consequently the output. Roughly what rmp do you motor at into and out of the harbor? Make sure your alternator output is sufficient for bulk mode (ie: 40% x 230ah = 92 ah) minimum. If you add the other start battery it is more. IMHO it would be better if your alternator was 100a or even better 120a. This would get your wonderful expensive batteries up to at least 80%-90% State of Charge simply by motoring an hour or so.
3. How is your alternator AO positive output wired? Direct to thee house battery?
4. How is your external regulator wired? Direct to the house battery?
5. How are your external regular + and - sensing wires wired? Direct to the house battery?
6. Once the Alternator/Regulator charging system is confirmed adequate, charge the system up past bulk and to above 80%SOC to 85% or 90%. Leave the boat for several days for the Solar PV to fill the batteries up past 99%, possibly with all the batteries combined, provided the solar controller is providing adequate voltage.
7. With these adjustments and changes, your 130ah of SolarPV would have half a chance of bringing the charge up towards 100% over multiple days.
8. My reading of Ocean Planet's website about Firefly batteries "SOC 100% every 20-30 days, for best life, cycle them from 10% to 90% SOC. No need to charge 100SOC each cycle."
9. Then every 20-30 days, after several days away from the boat, power up the alternator again and finish charging the batteries so the trailing amps are below the manufacturer specification for 100%SOC (usually 1% of 20C= 230ah x 0.01 = 2.30 amps, but you should probably get it below 2 amps). Now you are 100%SOC without shore power.
10. According to the Ocean Planet website the advantage of these batteries is that they can be undercharged for a number of cycles which reduces capacity, and then they can be charged back up several times to get to full capacity again.
11. IMHO talk with Bruce Schwaub of Ocean Planet, or Brad about this.

[smac999]

don't put your switch to all. there is no need to charge the start battery. if wired right an agm battery will stay charged for 6 months without running the engine. nothing should be draining it. every time you run the engine it will be quickly recharged. it will always be full. run the engine every month and it will be fine.

the solar amount needed is 100% dependent on how much power you use and weather in your area. some boats could live off 130w and some boats need 1000w.

it needs to be able to put back the power that is used each day.

a battery monitor like a victron 702 will help you figure out how many AH you use each day. and how much the solar is putting back in.

for a live aboard 130w is likly way too small. 130w wouldn't even run an avg boat frige for 24h on a sunny day, let alone a cloudy one. now add everything else you're using.

[HankOnthewater]

I am with Smac999: not to have all batteries in one bank. Indeed one starter battery separated from the others will provide power to start the engine, even after 12 months!

Maybe a setup as below might be suitable for your boat.
In my campervan (RV) I have x3 PC2150 batteries:
- one battery is used only for starting engine, and absolutely for nothing else
- the other 2 batteries are in parallel, and I call them 'house' batteries
- all the charging, about 200 W in solarpanels, and large alternator charge the house batteries only
- the single engine starter battery is charged via a Sterling combiner that connects it to the house batteries if the battery voltage exceeds 13.7 volt
- the solar controller is a cheap and simple unit, that I had planned to replace with a "better" unit....... but after 6 years, it is still working perfectly, never had the occasion that I could not start engine. Yes, on two occasions I ran the two house batteries flat because of the fridge, but the engine alternator took care of the charging on my next drive.

On my boat I have a similar setup, and BTW, planning to replace my genset and engine starter battery (currently Optima), with Odyssee ones. Yes, the boat has lots more power requirements, but also has more solar, more batteries etc, but the same principle applied.

As said in a previous post, your 130 watt of solar is likely not enough for staying on board and running a fridge etc, more more than a couple of days, unless you are prepared to run the engine for a few hours each day.

Instead of using a Sterling (or other) combiner there are now even better DC to DC chargers available. In your (or my) case, only a 2 amp charger might be sufficient, to keep the starter battery 100% charged.

[Suijin]

The electrician said everything is now on the same charging circuit but that does not mean that the starter battery is now part of the house bank. Did he specifically tell you that it is now part of the house bank? That would be a weird thing to do. If he did put them all in one bank you now face batteries of different condition mixed in the bank and the problems that go with it.

The general rule is that you need at least more solar in watts than you have amp hours in your bank at a minimum to get to float but of course that depends on your energy usage. And you’re in Maine so could need considerably more on all but sunny days in June.

I don’t think anyone can tell you for sure whether you can get to float with solar and engine with your specific set up. Will depend on your alternator output, how long you run it, condition of your batteries etc.

[barnakiel]

Imho:


1) Take the start battery OFF the solar charging circuit.


Why do you solar charge the start battery anyway? Do you have anything but the starter (and the alternator) connected to it?



2) Get more solar panels.


If you have insufficient solar juice, no MPPT nor anything else will help you. Start with plenty of solar Watts in the first place. Then even a cheapo PWM charger will do the work fine.


If space is the ultimate problem, replace regular panels with the newer black ones. Our old technology panels are 75W each but now you can see +100W panels in the same footprint.



Our 150W array charges our 120Ah bank any given day back to 100%. Mind we are in very very sunny spots (Canary Islands and West Indies + the passages). I would go for at least 4 / 1 (solar Watts/Ah battery) if we had a fridge, an AP or any other such power hungry toy.



Cheers,
b.

[barnakiel]

You are a 130/180 (solar W/Ah battery) set up. Way way too little solar power available.


If you use the alternator to fill up, make sure you have a 3 stage proper regulator on it too. Car ones are good for jokes (in a boat, they are OK in cars).



How much insolation is Maine?


We have 150/120 in a most eco-friendly boat, in full tropical sun. Our morning deficit is 10 to 15 Ah. Batts full up long before noon each day.



What is you morning status then? What % is your house battery, say at sunrise?



b.

[john61ct]

Did not read all.

Get rid of the 1-2-B switch.

Starter should only be combined during charging, via a small ACR or EchoCharge.

You need more solar panels.

Meantime run alt / genny for 1-2 hours before solar charging starts, will give a boost of Bulk high-amp charging.

Get a SmartGauge, maybe also Victron BMV-712.

[rgleason]

OP boat has an acceptance rate of 92ah with a 65a Alternator and we don't know how much it is really charging, if it has external regulation with temp sensors, or if it has gotten fried from overheating. They charge monthly with an Odyssey charger to recondition, which seems ok to me.

...I don't understand what the problem really is. It seems like Odyssey customer support is a little too anxious about their claims about the batteries!!! Maybe that is the real problem?

[john61ct]

Originally Posted by rgleason

OP boat has an acceptance rate of 92ah

Acceptance rate is amps, not AH which is a unit for capacity or usage per time only.

> It seems like Odyssey customer support is a little too anxious about their claims about the batteries

No idea what you mean by that.

They stated the problem is insufficient energy inputs to keep up with load demands, which really has nothing to do with the batt storage.

[rgleason]

My comments are interleaved between paraphrased- I've learned something in this exercise, about Solar PV requirements for Odyssey batts.

Summary

House: 2 Odyssey group 31 (92 ah each) 2015
Starter: 1 Odyssey group 24 (62 ah) 2015
Alternator: New 65 amp
Solar PV: 130 watt solar panel
Controller: Morningstar ProStar MPPT 25M controller. (Duo-Saver not providing sufficient voltage to fully maintain 3 AGM batteries.)
House & Starter Batteries Joined: "All", thus malfunction, bilge switch stuck, runs down batteries. No backup battery.
Odyssey support: Not sufficient solar power to provide a full absorption charge on all 3 batteries which will slowly kill the batteries by not putting full float charge at fairly frequent intervals. Sulfation of the batteries will eventually kill them.
State of Charge: Not sure how long to run the engine and what speed to recharge to full charge.

What to do?
1. Shore power charging once a month and run the full “recondition” program on each battery individually to remove sulfation (we would turn off the controller, disconnect the ground from each battery and run the portable charger on the "recondition" program).
2. Starter Battery --> Reserve Battery -Disconnect completely (after reconditioning).
* Comment: Leave Reserve Battery Connected. Turn 3way Switch to Bank 1 House, leave it there, until there is an emergency.
* Comment: To charge the Reserve Battery when under power, if your alternator is wired direct to the house bank, turn the 3way switch to "Both", not going through "Off" (just to be safe) to charge your reserve battery up to full too.

3. This would leave (2)92 ah Odyssey AGM batteries on the one solar charging circuit. Not sure solar PV with fully charge, with or without Alt. Not sure how long it might take to fully charge the batteries with the solar and engine alternator.
* Comment: It is pretty clear you will not be able to charge from 50% to 100% with this solar setup on a regular basis.
* Comment: Often will want to leave your house batteries at at least 85% SOC so solar has a chance to reach 100%. This will require 184ah x .35 = 64.4 amps from the alternator (1-1.5 hr).
* Comment: Solar PV charging - 184ah x .15 = 27.5 amps
* Comment: 27.5 amps / 8.8A (100% eff) at absorption 14.7v x Efficiency 80% = 27.5 amps / 7.4 amps = 3.7 Hrs
* Comment: So in 1-2 days it should fully charge.
* Comment: When back on the boat, run the engine again for .5-1 hour, to be sure it is fully charged.

Support:
When paralleling the batteries, 92 + 92 + 62 = 246Ah at the 10 hour Ah rate. At 40% of that rating, we would recommend a minimum charge current for the entire bank of about 100A.
* That is one of the reasons we suggested a bigger Alternator. (with External regulation and temp sensors)
* 92+92=184ah and at 40% the alternator should still be 75 amps. (However a 65 amp Alternator will just take longer to charge.)

Support re Morningstar Controller:
Custom setting - Absorption 14.7V for 180 min or longer, Float 13.5V, Equalize OFF.
If Equalize can be 14.7V turning that ON with maximum length available to prolong the Absorption time if that is how it works (verify).
At 50% SOC (12.2V resting), at 125Ah to recover it would take
5 hours at optimium current 25A at 14.7V to get to a 85-90% Soc.
Thus suggest charge at 14.7V in both Equalize and Absorption modes (combined time of 420 minutes.)
* Comment: Perhaps there is an easy way to restart the Morningstar so the Absorption timer goes back to 0?

Note a higher current charger is recommended for the entire bank. At 25a (optimum) charging system will eventually fully charge however,
discharging them below 50% depth of discharge on a regular basis [is not recommended].

* Use higher current charge sources like Alt and Shorepower Charger to counter this problem, as appropriate. (It appears that they want a couple of more solar panels too.)


Solar charging systems 85-90% efficient and less and are dependent on the sun availability.
130W solar panel can provide 8.8a at 14.7V optimum.

Even if the Solar controller can work at 25A max, a single 130W solar panel will never provide that type of current.
(requires 3 -130 watt panels to max out the system)(verify).

At 8.8A (100% efficiency) x 30 hrs constant voltage at max current 14.7V to reach 100% SOC from 0%.

Low current “trickle” charging not recommended, contribute to premature sulfation. Solar charging will eventually fully charge but will not de-sulfate as well as higher current charging (100A).
* Comment: You will be using a combination of higher current Shore power and Alternator charging sources at appropriate times.


-----
Note John: This support person has totally negated some of the advantages of Firefly used in marketing the batteries. See this on Bruce Schwab's Ocean Planet Energy website

• Unparalleled Resistance to Sulfation – Sulfation is what usually kills AGM batteries. The Oasis carbon foam AGM can operate or be stored at a partial state of charge for long periods of time without a loss in capacity. Check out this article by Professional Boatbuilder Magazine to learn more about sulfation.
• Depths of Discharge to 80%-100% of rated capacity without any loss of performance
• Superior Life Cycle – capable of 3X the number of deep discharge cycles than that of other lead acid batteries
• Strong Performance in Extreme Cold and Heat– performance range is -20° C to 50° C
• Fast Bulk Charging and topping up is seldom required
• Greater Usable Capacity– you can replace your existing bank with a smaller Oasis bank due to its deep discharge capability

"This grid prevents large sulfate crystals from forming, thus the sulfate will easily dissolve back into the electrolyte with a full charge. For a full capacity recovery, no “equalization” is required with Oasis. Only do a full recharge as needed to “open up” the full capacity once again. There is no permanent damage or capacity loss from extended PSOC operation, or from deep discharging to a low SOC."
----
"Depth of Discharge 80-100% of capacity without loss of performance"


John
Get rid of the 1-2-B switch. - Why?
Starter should only be combined during charging, via a small ACR or EchoCharge. - Won't the ACR also combine when solar charging gets up to 14.7 volts, thus increasing the size of the bank? It seems like we don't want that to happen to allow the solar to charge the house bank more effectively?


I agree with the other points.


A bigger Alt would also be helpful.

[ranger58sb]

I'm not really able to follow the discussion very well, with all the twists and turns and Fireflies and so forth...

But for OP -- Jen, I'd guess the easiest thing to do is like this:

Separate the G34/PC-1500 starting battery from the house bank and the solar. (If it's not already really separate anyway.) Keep the starting battery connected to the engine. Start the engine with the starting battery, charge the starting battery with the engine. Period.

Make the engine alternator also charge the two G31/PC2150s that make up your 200-Ah house bank.... and only do all that solar stuff to that house bank. Maybe add more solar, if you need to and if you can.

Come to shore and use your Odyssey charger when you can.

Keep some jumper cables on the boat, so if for some reason your starter battery won't start the engine -- shouldn't happen for maybe 10-12 years, they don't self-discharge much -- you'd be able to temporarily jump from the house bank to that starter battery, to get the engine running.

Worry about battery options for eventual replacement later, using what you learn from all this to evaluate options.

Something like that.

-Chris

[john61ct]

And run high-amp dino juice charging early in the day maybe 1-3 hours, say to 85-90%, and keep loading light, so solar can more likely get to 100% in the afternoon.

2-3 times a week will really help with longevity

[mitiempo]

Originally Posted by rgleason

Get rid of the 1-2-B switch. - Why?
Starter should only be combined during charging, via a small ACR or EchoCharge. - Won't the ACR also combine when solar charging gets up to 14.7 volts, thus increasing the size of the bank? It seems like we don't want that to happen to allow the solar to charge the house bank more effectively?


A bigger Alt would also be helpful.

Why get rid of the 1-2-B switch?

Batteries should never be combined for use. They are commonly combined for charging on boats that are wired that way from the factory. This is not the best way by a long shot.

What would I do?

Wire all charge sources - alternator, solar, and shore power charger to the house bank - this is the bank most in need of charging and always will be.

Install an Echo Charge between house bank and start battery. This will charge the start battery whenever the house bank is being charged from any source.

I would buy 3 On/Off switches like the Blue Seas 6006. One for start only, one for house only, and a third for emergency starting from the house bank. Wiring is shown below. You never should combine a dead battery with a charged or partially charged battery or bank.

I agree you probably do not have enough solar - but it depends on your daily usage. Do you know what it is? Buy a battery monitor like the Victron BMV series - 700,702, or 712. Then you will know where you stand.