Alternator choices

[dcorbert]

I have an 80 amp Balmar model 70-80 that came with a used engine which I have installed in my boat.

I understand it needs an external regulator which I do not have. I have been told that it will work with a car regulator. I do not need a lot of amps( only charging 2 T-105s & engine start battery) & have adequate solar. And do not want the expense of getting a smart regulator and getting it shipped down. ( I live in Guatemala)
My question is: will it work with a car regulator?

[wsmurdoch]

Originally Posted by dcorbert

I have an 80 amp Balmar model 70-80 that came with a used engine which I have installed in my boat.

I understand it needs an external regulator which I do not have. I have been told that it will work with a car regulator. I do not need a lot of amps( only charging 2 T-105s & engine start battery) & have adequate solar. And do not want the expense of getting a smart regulator and getting it shipped down. ( I live in Guatemala)
My question is: will it work with a car regulator?

Yes, a Ford external regulator works well and will give you the first two stages of a three stage regulator for about $10.

See post 83 of http://www.cruisersforum.com/forums/...ml#post1134340 plus a little more in posts 85 and 86.

Saunter was in Mexico, and I was in the Bahamas.

Bill

[john61ct]

Transpo 911-02R

adjustable voltage 14 - 20V

maybe $90

[dcorbert]

thanks a lot guys

[evm1024]

Based on the good advise in this thread I've been looking at getting a Delco-Remy 28Si alternator. I'll need to set up a J-180 mount but I have the room etc.

Question:

There are a lot of inexpensive ($150 US) made in China 28Si style alts out there. There is the 28Si clone made by Transpo inthe $320 range and then there is the original Delco-Remy made 28Si in the $500 range.

Does anyone have experience with 28Si in any of these versions? How interchangable are the internal parts? How hard to convert to external regulation etc.

[Trawlerman]

Your extensive reply is accurate and good. It appears that it was a semantics issue. To me, the "charging voltage" is the voltage that the battery "feels". Apparently to the OP, the "charging voltage" is the voltage prior to the voltage regulator.

[kenbo]

Originally Posted by evm1024

Based on the good advise in this thread I've been looking at getting a Delco-Remy 28Si alternator. I'll need to set up a J-180 mount but I have the room etc.

Question:

There are a lot of inexpensive ($150 US) made in China 28Si style alts out there. There is the 28Si clone made by Transpo inthe $320 range and then there is the original Delco-Remy made 28Si in the $500 range.

Does anyone have experience with 28Si in any of these versions? How interchangable are the internal parts? How hard to convert to external regulation etc.

Pasco Battery Warehouse has the 160A Delco for $300 and 200A Delco for $365. I'd go with Delco.

[john61ct]

Voltage before the VR is irrelevant.

VR sets a V,

during Bulk, "striving for" that, but actual V depends on batt resistance, amps accepted.

Once V reached, VR limits to that as a maximum.

A good VR will keep that V setpoint even if overheating forces downrating current.

If there is a significant V drop between Alt output and Bank posts, fatter wiring is needed.

A good VR will have a dedicated V sensor wire separate from output current, will help charging accuracy.

[joezzz]

My conversation with Balmar,based solely on recharging of batteris indicated a larger alternator doesn't mean faster charging.
Why? As they told me, each series battery can only absorb a fixed amount of charging amps. So larger is not better. If your battery can only handle lets say 45 amps/hr. A 75 amp alternator will not charge it faster.

[wayne.b]

Originally Posted by joezzz

My conversation with Balmar,based solely on recharging of batteris indicated a larger alternator doesn't mean faster charging.
Why? As they told me, each series battery can only absorb a fixed amount of charging amps. So larger is not better. If your battery can only handle lets say 45 amps/hr. A 75 amp alternator will not charge it faster.

===


That's all true of course but some of us have fairly large house batteries. Ours is almost 1,000 amp-hours and it will easily accept charging currents of over 100 amps. When underway we charge it with a 320 amp Leece-Neville fire truck alternator driven by 3 belts. In addition to recharging, it eliminates the need for running the generator.

[darylat8750]

Originally Posted by joezzz

My conversation with Balmar,based solely on recharging of batteris indicated a larger alternator doesn't mean faster charging.
Why? As they told me, each series battery can only absorb a fixed amount of charging amps. So larger is not better. If your battery can only handle lets say 45 amps/hr. A 75 amp alternator will not charge it faster.

Yes.. But. As mentioned large battery banks can use a lot of amps. Especially if you use AGM or LiFe. Also what loads do you have underway? That will be on top of what ever the battery bank can accept. We can use the microwave or coffee pot without slowing down the charging of the battery bank.

[Stu Jackson]

Originally Posted by joezzz

My conversation with Balmar,based solely on recharging of batteris indicated a larger alternator doesn't mean faster charging.
Why? As they told me, each series battery can only absorb a fixed amount of charging amps. So larger is not better. If your battery can only handle lets say 45 amps/hr. A 75 amp alternator will not charge it faster.

joe,


Not to seem to be piling on, but...

You're right, as far as it goes.

However, the concept of a "larger" alternator is to reduce the heat and wear on the alternator and belt.

Regardless of battery types and generally sizes, the concept in this example may be scaled:


Example:

400 ah house bank, AO goes to house bank, reserve or start bank charged via VSR

Statistics and reality meet [from years of my own operation and reading Maine Sail!!!] and indicate that for a 50% SOC house bank, the battery acceptance CURRENT for this sized wet cell house bank will be in the range of 50A, perhaps higher at first startup, but rapidly tapering off to that as the bulk phase does its work as the voltage rises to the setpoint and amperage is maximized.

Given that, does one choose a 45A alternator or a larger one? The 45A will "work" just fine, right at its max. But small case alternators, which most of us have, don't work well for very long at rated max load.

So, we buy larger alternators, amperage not size, separate topic, and find that they last longer because even at PEAK required output (i.e., 50A) they are running at half their designed COLD rated output.

For the coastal sailor with a traditional engine setup, the max load that a usual 3/8" belt can deal with without heavy belt dust and disintegration is this load and wrap around a 100A alternator. If the battery acceptance is higher than 50A because of going lower than 50% SOC or other reasons (a high use load when running the engine) the 100A alternator can handle it for a short period. Any time longer the belt squeaks and/or dies prematurely.

Of course, there are more sophisticated electrical charging systems that many on this forum have employed, including all the other charging sources like wind, solar and generators [which serve to decrease the discharge and increase the SOC and reduce the battery acceptance load when the engine starts]. And different battery types that, if they can accept more amperage, completely favor the larger alternator.

But this response has been deliberately focused on alternator sizing in response to your post, and why, within reason, bigger actually is better. And once the choice to buy an alternator is made, there is only an incremental difference in price.

That's one of the Whys.

[Jasmynonblue]

I have a 4-236 and run a second 80 amp from a small shaft that is bolted to the front pulley. The 2 alternators are then controlled by a control box which charges the house bank first then it charges all the batteries. The 2 80 amp deliver 130 amps usually. If you go to big amp alternators you'll need big Serpentine belts as v belts won't hack the HP. I also run my watermaker from that front shaft as well.

[a64pilot]

Originally Posted by preventec47

I would like to ask if when the battery banks are full and there is no need

for any charge from the alternator, is the alternator still putting a load

on the engine and if it is a large alternator as discussed... is it approx a

3 hp load even when no charging is taking place ? I would hope that

the pulley on the alternator is spinning freely when it is not outputting

electricity..... and that the load on the engine progresses incrementally

as the charging goes up.

Your correct, an alternator is a variable load, load varies of course with output.

[evm1024]

Originally Posted by kenbo

Pasco Battery Warehouse has the 160A Delco for $300 and 200A Delco for $365. I'd go with Delco.

Thanks for the link. By far the best price (including shipping). I've ordered one. And when I get going on the conversion I'll start a thread on that.