Solar and AGM'S

[peterwilliam]

I have 6 210AH lifeline AGM's with 400 watts of solar controlled by a BlueSky Solar Boost 3024iL MPPT Controller on a 12 volt system. when I am down about 100Ah I only get about 8A charging and have never seen more than 15A. when charged off the 80A engine alternator I get about 10-15A. When charged of shore power / generator the twin Cristec 40a battery chargers only give about 10A. does this sound normal???

[gunnado]

Peter your charging current sounds low for 100 used amps, your equipment should be charging close to there maximums for a short time at the beginning of the cycle?

1. Pull the manual up on your batteries and read the charging voltages and check that your systems are charging at manufacturer recommendations. maybe your system was programmed for gel batteries (lower voltages) and never changed?

2.Check your voltages before charging begins at 100 used amps 12.6-12.7? for battery condition?

3. shut down or disconnect you batteries and make sure your amps are being counted are 0, as instruments can get out of sync and your battery bank may not be as depleted as you think, not needing as much amps as indicated.

when you batteries are close to fully charged then the measurement you have stated sound normal.

i have 400w of solar, in the tropics at the best time of day with no shading i have seen 32amps charging on my battery monitor. i have 3 lifeline agm 210amp each. at 100 amps discharged on my battery bank, my 80 amp alternator would charge at around 60amps for a short time.

[gunnado]

ted, if your batteries are deformed and or leaking you may have an overcharging issue or your batteries are defective, this sounds dangerous and you should have it looked at ASAP to prevent fire. (not sure if i read it right due to you stating that it works a treat??)

Try to have the same types of batteries for optimum charging, but you can have different types with poorer performance, just make sure charging voltages do not exceed either types. yes im sure there are lot of people with agm house and flooded led acid for start with no problems like i do.

[2Wind]

Originally Posted by peterwilliam

I have 6 210AH lifeline AGM's with 400 watts of solar controlled by a BlueSky Solar Boost 3024iL MPPT Controller on a 12 volt system. when I am down about 100Ah I only get about 8A charging and have never seen more than 15A. when charged off the 80A engine alternator I get about 10-15A. When charged of shore power / generator the twin Cristec 40a battery chargers only give about 10A. does this sound normal???

6 X 210AH = 1260AH total.
Lets say on a power hungry day you use 300AH.
Each battery will be down only 50AH
That equates to 76%.

The Solar Boost therefore will not charge at the "bulk" rate i.e only when discharge <70%, rather it charges at the "acceptance" rate, until near full (95%) and then at "float" charge. You can check this by looking at the voltage during the charge. Bulk charge, where your current will be high takes it up to 14.4V. If you are sitting there at 13.2V or there about charging at 8AH, then you will be in acceptance stage with near full batteries.

So, having so much energy stored means your batteries never deplete to the point where rapid charge is possible (i.e when <70% where bulk stage charging is achievable).

http://www.blueskyenergyinc.com/uplo...E_SB3024iL.pdf

[gunnado]

norwestr,
my tips for a liveaboard installing solar
1.install a battery monitor like a zantrex or victron that counts the total amps used. get an idea of what sort of renewable energy your after.
2. measure the space you have availible for solar panels and use it. (you may only get .6 x hours of sun of your panel watts).
3.match a quality solar controller 25% larger than all your panels max added together.

[leftbrainstuff]

Originally Posted by sailinglegend

My Lifeline AGMs are now in their 10th year.
Not all AGMs are the same, many are not designed to be discharged to 50%, they are for Solar or Telecom standby use.
Their main advantage is that they charge FASTER than FLAs, even with modest Solar Arrays, you don't need a 200 amp charger to get the best out of them, but that will also help.
There are NO disadvantages except the price - mine can and should be equalized regularly.

Why so many negative posts when the OP was asking for help with the AGMs he already has?

If you ask someone the time you don't want a long lecture on why haven't you got a watch, and which is the best watch to buy.

Please everyone offer useful feedback, not feedback based on ignorance.

--------------------
Ignorance isn't what you don't know, it's what you think you know that is incorrect.

+1. Nicely put.

Sent from my GT-I9300 using Cruisers Sailing Forum mobile app

[Stumble]

Originally Posted by gunnado

norwestr,
my tips for a liveaboard installing solar
1.install a battery monitor like a zantrex or victron that counts the total amps used. get an idea of what sort of renewable energy your after.
2. measure the space you have availible for solar panels and use it. (you may only get .6 x hours of sun of your panel watts).
3.match a quality solar controller 25% larger than all your panels max added together.

I would add a 0 step to this.

First do everything possible to reduce consumption. LED lights, lower screen brightness on instruments, DC-DC charging for laptops, iPads, ect...

Then go on to 1.

It is almost always easier and cheaper to reduce consumption than to increase production. And making an energy budget based on old usage numbers will result in a more costly system than needed. Of course if you have the money to burn having excess capacity is never a bad thing.

[exMaggieDrum]

There are so many learned opinions on this I hesitate to put in my two cents but I have never claimed to be oversmart. I was a good IMHO marine electrician and I have installed more batteries than I can ever remember and have seen the goods and the bads of both batteries and the TLC, or lack thereof, of all kinds.

Basically - AGMs are great if you manage them right. Ditto for wets. AGMs are fundamentally different than wet cells though and any opinions to the contrary are suspect. Again IMHO. All batteries like to be charged to 100% and often. Do they need to be charged to 100% daily - no way.

I'll get to the solar issue next, but AGMs charge faster and will take stronger charges than wets. They are MUCH lower maintenance. All batteries should be monitored 100% of the time though. You need to know where your batteries are and act accordingly. Charge at 12.3-12.4v and not at 12.1v. Lots of other do's and don't's. AGMs can take far more abuse than wets. They can last longer (and do). The people who hate them have either not used them or have not maintained them right or got some bad batts to start with (it happens with all makes, models, types unfortunately). Wets are a true pain in comparison. They have to be mounted upright. They not only have to be monitored by meter but also by water level. They produce nasty gas when charging and most always get corrosive liquids outside at some point (they need liquid tight enclosures). They are very good batts though - if sized right and maintained right and high quality to start with. They won't have as many duty cycles. They are not as efficient charging. They take longer and more amps to charge than the equivalent wets. Good wets are way better than bad wets though. Quality matters.

Re solar, or other partial charges: We had lots of solar with a Morningstar charge controller and AGMs'. We cruised extensively and used our batteries and the solar was a BIG help. The solars may not top off the batts but they put in amp-hours that you don't have to add with your alternator or genset. They are a plus in any situation but the charge must be regulated to the battery type. More the better as far as watts but there is always a limit (space and $$). Even small helps. They will only 100% charge a battery if they give out more amps than you use - math. If the batteries are not being used they will top off and maintain the 100% charge. They can even equalize the batts if you have enough sun and watts (and the regulator supports that mode). They will overcharge without a controller - huge voltage will fry any type of batt.

Our latest (5 weeks new) cruiser came with AGMs of unknown age. Also solar with an Outback solar controller. The controller is not set and/or working right though as it is charging to too high a voltage. I am sorting out the boat just now and that is a priority on my list. Massive solar and three 8D's (more than we need actually). Also a 275A alternator/genset. And a 100A alternator on the auxillary. You need a high output alternator for a large amp-hour bank, especially AGMs otherwise you will never keep them charged and you will likely burn out the small alternator. Wets aren't as destructive since they don't charge as fast but it is then harder to get them to 100%.

So absolutely solar is a good investment - the more the merrier. Good regulator, set right,is essential. Alternator sized to the batt bank with a good regulator set right. Monitor the heck out of the batts when using a lot. Keep them charged whatever type. AGMs are expensive but best IMHO for cruising - more use cycles and easier to charge. Wets are great too - just a bit more work and they charge slower for same output of alternator and/or solar. AGMs are more tolerant of low charges but no batt likes that. If I had good wets I would keep them and love them. It's a trade off as are most things. I can't afford the best of most but I splurge on batteries and battery systems. If you go from marina to marina and use AC to charge, it doesn't matter so long as it is well regulated. Ditto for short cruises between marinas.

[gunnado]

Step 0 is makes the most sense to keep cost down.

Even just a Led anchor light can be a game changer

Love the knowledgeable people on this forum I have been away for a wile and missed it




Sent from my iPhone using Cruisers Sailing Forum

[zboss]

Originally Posted by exMaggieDrum

Wets are great too - just a bit more work and they charge slower for same output of alternator and/or solar.

Question:

Only if the solar is capable of putting out more amps than the wet cells can accept -right? If the solar array is only able to put out 20 amps at peak output but the batts are able to accept 30 amps (wet made up number) or 130 amps (agm made up number)... won't they charge at the same rate?

However, in another scenario, if that same array can put out more than the 30 amps that the wet cells can accept, then the AGM's will be a better charging value since they will accept up to 130 amps from a larger solar array.

Am I off here?

[sailinglegend]

Originally Posted by zboss

Question:

Only if the solar is capable of putting out more amps than the wet cells can accept -right?.....

You are talking about the charge acceptance rate of AGMs being higher which means they can charge MUCH faster than FLAs - but you do need a higher current charging source to take advantage of this - but the OTHER reason AGMs charge faster is their charge efficiency.

Wet cells worse case scenario may be only 70% efficient which means about 140Ah must be put in to actually raise the capacity of a battery by 100Ah.(70% of 140Ah is 100Ah) AGMs may be up to 98% efficient so only 102 Ah needs to be put in. In this scenario that’s nearly 40% faster charging and it doesn’t take a large solar array to do it.

Even if you only get half this rate of charge AGMs will always charge faster at all stages of the charging process.

The problem with charging efficiency is it is difficult to measure. - it is highly non linear, so at 50% SoC it may be 95 %, even for FLAs, but at 85% SoC it may be down to 50%, and falls even lower as the SoC increases, so an overall figure is given which is used to programme your battery monitor. So if most of the time you only discharge to 85% SoC then lowering the Charge Efficiency in your BM may make it more accurate - it certainly worked for me.

[Rustic Charm]

Thanks everyone for your help.

I've decided and source four 120amp Fullriver AGM batteries which I can get for $330 each seeing I'm buying four. I'm also going to get two replacement 125 watt solar panels to replace the single 80amp I have.

Now someone suggested I also put a separate alternator regulator on as well? Not sure why. I have a 90amp Alternator that I had serviced only last year.

Why do I need a new alternator regulator?

[2Wind]

Originally Posted by tedsherrin

Thanks everyone for your help.

I've decided and source four 120amp Fullriver AGM batteries which I can get for $330 each seeing I'm buying four. I'm also going to get two replacement 125 watt solar panels to replace the single 80amp I have.

Now someone suggested I also put a separate alternator regulator on as well? Not sure why. I have a 90amp Alternator that I had serviced only last year.

Why do I need a new alternator regulator?

Here's a deal: 280AH 12V AGM Deep Cycle for $539

[Rustic Charm]

Originally Posted by 2Wind

Here's a deal: 280AH 12V AGM Deep Cycle for $539

That's 73kg! I don't think I want two of those in my boat, not to save just $200.

[Ex-Calif]

Originally Posted by tedsherrin

Thanks everyone for your help.

I've decided and source four 120amp Fullriver AGM batteries which I can get for $330 each seeing I'm buying four. I'm also going to get two replacement 125 watt solar panels to replace the single 80amp I have.

Now someone suggested I also put a separate alternator regulator on as well? Not sure why. I have a 90amp Alternator that I had serviced only last year.

Why do I need a new alternator regulator?

Ted - I've lost the plot a bit - what engine and alternator do you have?

Now that you re going to have a large battery bank there is some goodness in getting the maximum charge into them during the bulk stage.

A "normal" internally regulated alternator gets it's "sense" from the battery state - as the battery voltage comes up the charge rate goes down. These alternators are predominantly optimized to charge wet cells which can't take a charge as fast as an AGM. Even wet cell batteries (in large banks) can be more efficient with an optimized charge profile.

There are a couple of ways to do this - Modify your alternator to bypass the internal regulator and add an external regulator or there is a newer product made by sterling that accomplishes the same thing without needing to do the alternator mod.

The third option is to buy a new purpose built alternator with no internal regulator and add the external regulator. I presume you are happy with your "stock alternator so that option is not worth pursuing too much.

There is a recent and raucous thread about the two options that you might want to read through to see if this is a good step for you.

http://www.cruisersforum.com/forums/...er-124895.html

Basically what you are likely going to be doing is bulk charging when you can with the engine and absorption and float charging with the solar. Depending on how far down your batts go in a given period (based on your consumption and solar efficiency) a hopped up alternator regulator might help reduce engine running time.

If you haven't got a monitor for your batteries I would recommend getting a smartgauge monitor before getting a regulator. Get both if you can afford it.

This is getting a bit pricey for sure but with >$1200 for batts and a more than a few bob for new solar, you grit your teeth and make sure you can monitor what is going on with the batts and then keep them charged up the most effective way you can.

Cheers!