Solar and AGM'S

[2Wind]

Originally Posted by tedsherrin

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

Aren't your 120AH's 36.5KG EACH? ie DC120-12
4 X 120AH = 480AH at 146Kg

2 X 280AH = 560AH at 146Kg.......

[Ex-Calif]

Originally Posted by 2Wind

Aren't your 120AH's 36.5KG EACH? ie DC120-12
4 X 120AH = 480AH at 146Kg

2 X 280AH = 560AH at 146Kg.......

It's a compelling idea - Plus fewer battery connections to corrode.

Although I am not sure how you get 80 a/h with the same weight?

Does the case weight of 2 extra 120 batteries do it or are the plates somehow lighter/thinner in the 280s?

The other issue is that 73 kg is a heck of a lot to manhandle into place.

@Ted - Are you doing the install yourself or having someone do it? I presume you have fusing and switching all sorted as well?

[Rustic Charm]

Originally Posted by 2Wind

Aren't your 120AH's 36.5KG EACH? ie DC120-12
4 X 120AH = 480AH at 146Kg

2 X 280AH = 560AH at 146Kg.......

Yes, that's correct. But you try lifting 36.5kg.. it's damn difficult as it is, but it's manageable. 76kg i'd need a winch, which to get them into the confines of the battery box I have, then it's simply not practical.

I appreciate the recommendation just the same.

[Rustic Charm]

Originally Posted by Ex-Calif

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!

Yes, I intend getting a battery monitor as well. Lucky it's 'tax' time here in Australia and I pay extra tax so I can put aside to spend on my 'mistress' (boat) without the wife knowing what I'm spending.

I'll read the link you sent. I havn't got time just at the moment. Then I'll see what to do.

[sailinglegend]

Originally Posted by tedsherrin

.....Why do I need a new alternator regulator?

You need a good EXTERNAL alternator regulator with multi-stage control that can raise the alternator output voltage and will then charge the battery faster. It will also reduce the output voltage to a Float mode when the battery is fully charged to prolong the battery life. There are many other very good reasons why you should fit a good external regulator, even if your internal regulator is producing 14.4 volts.

1. It should have multi-stage voltage settings for different battery types.

2. It should also be custom programmable to match the alternator and battery bank sizes. There are so many ‘new’ batteries now that don’t fit the standard charging profiles. Balmar's regulators allow many parameters to be changed, for example they may set the Boost voltage to 14.6v, hold that for 45 minutes and then reduce it to 14.3v, just below the gassing voltage, and hold it there for the duration of the absorption stage . They can be programmed to stay longer in the absorption stage without dropping down to float too early.

It is worth noting that with sealed batteries most battery manufacturers recommend that you use a multi-stage regulator to drop the charge down to float mode at 13.2-13.8 volts to avoid gassing and overcharging. This is a condition of the warranty on some batteries.

3. It will delay the charge current for about a minute at start up until the engine oil is well distributed. A 100 amp alternator draws 4 HP which is a heavy load on an engine when starting with a weak battery.

4. It will also accept a sensor to measure the alternator temperature and control the charge rate. Even a 100 amp alternator could be providing 15 amps to the boat systems, another 25 amps to say a watermaker or an inverter, and then a heavily discharged bank may be demanding 50 or 60 amps. In this situation the batteries may not get charged and the alternator will overheat and burn out from continually trying to deliver its maximum output if not protected by a temperature sensor. It is too easy for the alternator on a boat to get too hot if used for long periods.

5. It will also accept a sensor to measure the battery temperature which will rise with a heavy charge current. At 25ºC batteries start to gas at 14.4v, at 40ºC they gas at 14v so the external regulator will reduce the charging voltage automatically to compensate for this. If batteries are fitted in an engine compartment it is very easy for them to get too hot and lose water. This is fatal for sealed batteries. Sailing in high temperature regions may mean the batteries are already at 30C before charging starts.

6. It will have a voltage sensor at the batteries not on the alternator. This will compensate for split diodes or losses on cable runs to the battery.

7. A Balmar regulator has a “small engine mode” that allows you to cut the output to 50% with a switch to reduce the alternator load on the engine when you suddenly need extra power in a big sea. It also has belt manager to reduce the load on the alternator. A 100 amp alternator set to 70% will run cooler and produce 70 amps at a lower speed

Enough reasons?

[Rustic Charm]

Originally Posted by sailinglegend

You need a good EXTERNAL alternator regulator with multi-stage control that can raise the alternator output voltage and will then charge the battery faster. It will also reduce the output voltage to a Float mode when the battery is fully charged to prolong the battery life. There are many other very good reasons why you should fit a good external regulator, even if your internal regulator is producing 14.4 volts.

1. It should have multi-stage voltage settings for different battery types.

2. It should also be custom programmable to match the alternator and battery bank sizes. There are so many ‘new’ batteries now that don’t fit the standard charging profiles. Balmar's regulators allow many parameters to be changed, for example they may set the Boost voltage to 14.6v, hold that for 45 minutes and then reduce it to 14.3v, just below the gassing voltage, and hold it there for the duration of the absorption stage . They can be programmed to stay longer in the absorption stage without dropping down to float too early.

It is worth noting that with sealed batteries most battery manufacturers recommend that you use a multi-stage regulator to drop the charge down to float mode at 13.2-13.8 volts to avoid gassing and overcharging. This is a condition of the warranty on some batteries.

3. It will delay the charge current for about a minute at start up until the engine oil is well distributed. A 100 amp alternator draws 4 HP which is a heavy load on an engine when starting with a weak battery.

4. It will also accept a sensor to measure the alternator temperature and control the charge rate. Even a 100 amp alternator could be providing 15 amps to the boat systems, another 25 amps to say a watermaker or an inverter, and then a heavily discharged bank may be demanding 50 or 60 amps. In this situation the batteries may not get charged and the alternator will overheat and burn out from continually trying to deliver its maximum output if not protected by a temperature sensor. It is too easy for the alternator on a boat to get too hot if used for long periods.

5. It will also accept a sensor to measure the battery temperature which will rise with a heavy charge current. At 25ºC batteries start to gas at 14.4v, at 40ºC they gas at 14v so the external regulator will reduce the charging voltage automatically to compensate for this. If batteries are fitted in an engine compartment it is very easy for them to get too hot and lose water. This is fatal for sealed batteries. Sailing in high temperature regions may mean the batteries are already at 30C before charging starts.

6. It will have a voltage sensor at the batteries not on the alternator. This will compensate for split diodes or losses on cable runs to the battery.

7. A Balmar regulator has a “small engine mode” that allows you to cut the output to 50% with a switch to reduce the alternator load on the engine when you suddenly need extra power in a big sea. It also has belt manager to reduce the load on the alternator. A 100 amp alternator set to 70% will run cooler and produce 70 amps at a lower speed

Enough reasons?

Thank you for your response. It seems that changing to AGM' is not as simple as I'd planned. I'll source a Balmar.

I'm presuming I need to disconnect the regulator on the alternator?

Is their a specific Balmar you would recommend?

[Ex-Calif]

Originally Posted by tedsherrin

Thank you for your response. It seems that changing to AGM' is not as simple as I'd planned. I'll source a Balmar.

I'm presuming I need to disconnect the regulator on the alternator?

Is their a specific Balmar you would recommend?

Ted at the risk of recreating the debate about Balmar vs. Sterling regulator please go have a read of the thread I linked.

The pros and cons of both ideas are weightily discussed.

The bottom line to the argument is this -

Balmar works great! You have to modify your alternator to make it work. You may not have the savvy to do so. It requires cracking the alternator open and modifying the connections inside. If the alternator ever fails you have to replace it with a modified or a specifically designed alternator.

Sterling does effectively the same thing with the same temperature protections. It is a plug and play device. All you do is plug the wires in. It will work with any internally regulated alternator.

[Rustic Charm]

Hell, these Balmar's are expensive. Very expensive.

[Snowpetrel]

Spend the money on more solar, LED's and better insulation on your fridge.

[Rustic Charm]

Originally Posted by Ex-Calif

Ted at the risk of recreating the debate about Balmar vs. Sterling regulator please go have a read of the thread I linked.

The pros and cons of both ideas are weightily discussed.

The bottom line to the argument is this -

Balmar works great! You have to modify your alternator to make it work. You may not have the savvy to do so. It requires cracking the alternator open and modifying the connections inside. If the alternator ever fails you have to replace it with a modified or a specifically designed alternator.

Sterling does effectively the same thing with the same temperature protections. It is a plug and play device. All you do is plug the wires in. It will work with any internally regulated alternator.

Thanks Ex-Cal, I'd forgotten. I'll go read through it now and get back to you. A plug and play device is much more up my ally.

[sailinglegend]

Originally Posted by 2Wind

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

Not all AGMs are the same!!!

These are 'dual purpose' and also designed for standby telecoms use, not discharged every day to 50% SoC and then have to fall off a 3 metre wave in a boat. Full River will be much better - which is what they are more expensive. Lifeline would be the best.

Originally Posted by tedsherrin

Hell, these Balmar's are expensive. Very expensive.

If you change to AGMs you are waiting your money if you don't charge them properly. You really need as a minimum a 100 amp 'hot rated' alternator, your automotive 90 amp may give you 60 amp if you are lucky when it gets hot. You should also up your shorepower charger to 120 amps as well.

If you do a lot of sailing all this investment is worth it - if you're a weekend sailor don't bother.

[Rustic Charm]

Well, having read the link I can see there is quite the stirling / Balmar camps.

But, even a stirling is $600 Aust.

Whilst I can understand that engine alternators are poor chargers, I have an 90amp alternator and if I replace my 80watt solar panel for two 125 watt or even bigger, would that not suffice to charge my four 120amp AGM and 120ah reserve?

[Maine Sail]

Originally Posted by Ex-Calif

Ted at the risk of recreating the debate about Balmar vs. Sterling regulator please go have a read of the thread I linked.

The pros and cons of both ideas are weightily discussed.

The bottom line to the argument is this -

Balmar works great! You have to modify your alternator to make it work. You may not have the savvy to do so. It requires cracking the alternator open and modifying the connections inside. If the alternator ever fails you have to replace it with a modified or a specifically designed alternator.

Sterling does effectively the same thing with the same temperature protections. It is a plug and play device. All you do is plug the wires in. It will work with any internally regulated alternator.

As I stated earlier the Sterling can not to a proper float voltage IF your factory regulator is set higher than you need to do a proper float. There are diodes in the output path that drop it about .3V - .4V but if your factory alt is set at 14.6V or 14.4V or even 14.2V then you will not get the 13.4V - 13.6V one may desire.. They really do not do the same thing IF you actually need a float voltage, and most sail boats won't need float for an alternator.....

[sailinglegend]

Originally Posted by tedsherrin

Well, having read the link I can see there is quite the stirling / Balmar camps. ?

I'm afraid it is usually always down to cost and/or simplicity.

Best practice is always expensive.

Originally Posted by tedsherrin

... Whilst I can understand that engine alternators are poor chargers,....

One of the key factors with AGMs is they need higher charge currents for a longer life. Lifeline recommend a MINIMUM charge current of 20% of the capacity - the more the better - whereas FLAs need a MAXIMUM of 20%, Trojan recommend 10% for a longer life.

Since we spend a lot of time motoring then it's best to maximise the charge we get from the engine. Running the engine JUST to charge the batteries on a regular basis is not the best idea. Why use a 50 HP engine when you only need 5 HP or less.

All the solar does is try and get the batteries full with a very small charge current.

[colemj]

The amount of current is irrelevant to charging or battery life regardless of type of LA battery - it is only relevant to the amount of time it takes to reach full charge.

No one type of LA battery needs higher charging current than any other type. Voltages are different among different types, of course, but the amount of current supplied at the correct voltage only controls the amount of time it takes to fully charge the battery.

If solar provides enough charging current to fully charge your batteries, then it is equal to any other charging source. In fact, one is better off charging with lower current than with higher current as long as a full charge is reached. This is true for all types of LA batteries - AGM/FLA/Gel.

The typical cruiser is better off adding more solar than replacing a decent internally-regulated alternator like your stock 90A. Use the stock alternator to quickly charge the initial part of bulk in the morning if needed and let the solar carry to full charge through the afternoon.

Mark