Solar and the isolator

[admiralslater]

Our Outremer 45 is fitted with a 5 pole isolation block the has seprate port ,stbd alternator inputs and also seprtat post for both starting batteries and the house bank .
The block wrks fine but is starting to crack.
I can just replace like for like or i can use modern selection switches etc from blue sea .
The reduction of voltage loss is the big advantage of the upgrade .
Also the present installation does not have the solar running through it and I see no mention of this in Blue sea catalogs. The solar has its own breakers etc up stream of the house bank .
Any opinions appreciated( well not any but most )

[admiralslater]

Just bumping , I was hoping so of better electrical minds might help here

[CatNewBee]

I did not know, such thing exists (2 sources to 3 batteries).
Usualy it is a massive aluminum heat sink with molded connector poles, how can this thin break?


Anyway, it is not only the solar, but also the shore power charger that go a different path. I think, this separator is ok as-is for the alternators connection. Depending on your solar you can use a similar device to distribute the charge, but normaly it is sufficient to only charge the house battery.

There are also solar controller with a separate output for the start battery to trickle charge with low amps. If you have one of those, you could connect this output to the input of your battery separator in parallel to one of the alternators inputs.

I would not recommend to do so with the main output of the solar controller. This should go straight to the house bank.

[admiralslater]

Originally Posted by CatNewBee

I did not know, such thing exists (2 sources to 3 batteries).
Usualy it is a massive aluminum heat sink with molded connector poles, how can this thin break?


Anyway, it is not only the solar, but also the shore power charger that go a different path. I think, this separator is ok as-is for the alternators connection. Depending on your solar you can use a similar device to distribute the charge, but normaly it is sufficient to only charge the house battery.

There are also solar controller with a separate output for the start battery to trickle charge with low amps. If you have one of those, you could connect this output to the input of your battery separator in parallel to one of the alternators inputs
I would not recommend to do so with the main output of the solar controller. This should go straight to the house bank.

CarNewBee, thanks . I should have mentioned the E victron controllers. They go straight to the house now .
My question which you answered was should the solar go through the isolator.
What is the current thinking on isolation as opposed to the ACRs and modern switches for the engine side of charging

[CatNewBee]

On my Lagoon there are 2 isolators one per engine, they distribute power only to the one start battery and to the house bank.

I am completly fine with them. Alternators are not meant to charge house batteries, but to re-charge the start current and provide power for on-board electric by the engine.

so there is no multi-stage charging like bulk, absorption, float, trickle etc. they just provide bulk. Said that, it simply does not matter, if there is a smal voltage drop or not, they will never charge in absorption nor fill the battery to 100% SOC. If they are set to such high voltage, they would boil the batteries over time.

This tasks are best done by the other controller on board - solar, shore power...

Start batteries are kept always in bulk/float by the alternator so to say - no absorption phase with higher voltage. But start batteries are not deep discharged and oversized, so no problem for many years

If you want to use the alternators as sole source to charge the house battery, instead of playing around with relay / ACR, use a multi-stage programmable B2B charger.

[john61ct]

Originally Posted by admiralslater

should the solar go through the isolator.
What is the current thinking on isolation as opposed to the ACRs and modern switches for the engine side of charging

Isolators traditionally involve too much voltage drop.

One-way functionality is often unneeded.

But low-drop versions are available, usually MOSFET based and expensive.

VSR / ACRs otherwise.

Best design goal is **all** significant sources to House.

Then a little Echo Charger can handle Starter(s)

[john61ct]

Originally Posted by CatNewBee

Alternators are not meant to charge house batteries, but to re-charge the start current and provide power for on-board electric by the engine.

so there is no multi-stage charging like bulk, absorption, float, trickle etc. they just provide bulk. Said that, it simply does not matter, if there is a smal voltage drop or not, they will never charge in absorption nor fill the battery to 100% SOC. If they are set to such high voltage, they would boil the batteries over time.
…
If you want to use the alternators as sole source to charge the house battery, instead of playing around with relay / ACR, use a multi-stage programmable B2B charger.

For setups where large alternators can become very significant charge sources, it can be worth upfitting them to do so properly.

They can in some cases eliminate the need for a separate genset, or at least greatly reduce its runtime.

So,

"**Most** alternators are not meant to charge house batteries, but…

**Stock** alternators, without a proper VR like MC-614 provide no multi-stage charging like bulk, absorption, float, trickle etc. they just provide bulk…

I agree in most cases, B2B is the better, easier choice.

[smac999]

The solar can not go through the isolator. Leave it on the house bank.

Take a look at the victron fet isolators
https://www.victronenergy.com/batter...tery-isolators

Though it looks like they are only one alt. You'd need 2 of them. One for each alt

[admiralslater]

Originally Posted by smac999

The solar can not go through the isolator. Leave it on the house bank.

Take a look at the victron fet isolators
https://www.victronenergy.com/batter...tery-isolators

Though it looks like they are only one alt. You'd need 2 of them. One for each alt

Yes I would need two . Since I only have one cable to the house bank at the moment ,would I be able to feed the output line from each isolator to it sort of a y configuration.
If I can combine into the house bank I will use this system as most of the existing wiring would work .

[CatNewBee]

No problem, you can combine the outputs on a single cable, as long as the cable can take the amps.

[admiralslater]

Originally Posted by CatNewBee

No problem, you can combine the outputs on a single cable, as long as the cable can take the amps.

Thanks so much for your help . Some one ask how it was failing.The the plastic coating through which the studs protrude is cracking and lifting ,and since I don’t really know if it is a seal or somthing else I thought it was time.
Also if i reduce the voltage drop I believe I woud also increase my charging capabilities.
I s this last sentence true
David

[admiralslater]

Originally Posted by smac999

The solar can not go through the isolator. Leave it on the house bank.

Take a look at the victron fet isolators
https://www.victronenergy.com/batter...tery-isolators

Though it looks like they are only one alt. You'd need 2 of them. One for each alt

Smac999, thanks I just fired of a note requesting pricing . I like the Victron stuff and this seemst fit the bill
David

[fxykty]

We have a Sterling ProSplit-R PSRT134 2 in 4 out isolator/combiner for our cat, with the two engine alternators in and the two start batteries and house as 3 of the outs (4th is connected to 3 as it can’t be left empty). Our solar and wind are connected to 3 (house) as well.

Works OK but we’ll probably remove it when we upgrade to externally regulated alternators and more modern solar controllers, as it would be nice to properly control which battery gets charged when.

[john61ct]

The level of fine control the ProSplit-R claims to deliver is of marginal benefit.

Just combine with a simpler, cheaper device.

[john61ct]

Originally Posted by admiralslater

if i reduce the voltage drop I believe I woud also increase my charging capabilities.
I s this last sentence true

Yes.

To the extent the drop was bringing bank voltage below its mfg spec, then the more significant the impact.

Best to shoot for 1% drop, but with very fat cabling over long runs it can get so unwieldy or expensive, that a B2B becomes more practical.