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Old 15-05-2015, 15:23   #1
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Need to charge three banks but wants to get rid of the battery isolator

Hi,

Currently I have a Cristec MOSFET battery splitter (with three outputs) supplying my three banks: House bank with 6 x EXIDE EP900, bowthruster bank with 4xOPTIMA Red Top and a EXIDE EK900 for the starter.

I am about to upgrade my alternator with a Balmar AT-165 and a MC-614 regulator but need to consider how to handle the three banks going forward since the MOSFET battery splitter can handle 100A only.

Ideally I want to get rid of the battery splitter to improve charging of the bow truster batteries but can not really see what alternative I have. The Echo Charger and the Duo Charger are both designed to handle two banks only.

Are there a better alternative to improve charge of the bow truster batteries in the bow?

Thanks in advance
Steen
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Old 15-05-2015, 18:21   #2
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Re: Need to charge three banks but wants to get rid of the battery isolator

Yep, there is.

I'd use an EchoCharge for the start battery (it requires VERY LITTLE CHARGING, anyway, and the 15A capacity is more than enough to maintain it), then...

I'd use another EchoCharge for the thruster batteries or, better, a DuoCharge for these since it can supply 30A when needed. Alternatively, an ACR could be used.

I, too, have a separate battery bank up forward for my windlass batteries and have for many years charged them with a dedicated 120VAC battery charger....an Iota DLS-55/IQ4. This charger can be powered either from shorepower or my onboard 120VAC generator or, when necessary, by my Victron inverter.

Bill
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Old 16-05-2015, 01:24   #3
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Need to charge three banks but wants to get rid of the battery isolator

SmartBank Advanced ? 200 amps for 3 banks

Is it not best to combine the Service bank with the Windlass battery (with engine on) rather than relying on a low amp trickle charger between the two ? Never know when you need the amps ...


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Old 16-05-2015, 04:26   #4
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Re: Need to charge three banks but wants to get rid of the battery isolator

Quote:
Originally Posted by btrayfors View Post
Yep, there is.

I'd use an EchoCharge for the start battery (it requires VERY LITTLE CHARGING, anyway, and the 15A capacity is more than enough to maintain it), then...

I'd use another EchoCharge for the thruster batteries or, better, a DuoCharge for these since it can supply 30A when needed. Alternatively, an ACR could be used.

I, too, have a separate battery bank up forward for my windlass batteries and have for many years charged them with a dedicated 120VAC battery charger....an Iota DLS-55/IQ4. This charger can be powered either from shorepower or my onboard 120VAC generator or, when necessary, by my Victron inverter.

Bill
Thanks Bill.

Sounds like the way to go. Adding an independent 230VA charger to the bowtruster pack driven by 230VA shore and the 230VA genset will solve the low charge current issue.

I guess I would then install a local bowtruster charge bar with two inputs: From the local 230VA charger and another input from the Duo Charger.

Just one concern: Do I need to include some kind of protection on the Duo charger to protect it against "feedback charge current" from the dedicated truster bank 230V charger. I.e. if I am charging the truster bank and the house bank is at a lower voltage?

Regards
Steen
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Old 16-05-2015, 07:29   #5
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Re: Need to charge three banks but wants to get rid of the battery isolator

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Thanks Bill.

Sounds like the way to go. Adding an independent 230VA charger to the bowtruster pack driven by 230VA shore and the 230VA genset will solve the low charge current issue.

I guess I would then install a local bowtruster charge bar with two inputs: From the local 230VA charger and another input from the Duo Charger.

Just one concern: Do I need to include some kind of protection on the Duo charger to protect it against "feedback charge current" from the dedicated truster bank 230V charger. I.e. if I am charging the truster bank and the house bank is at a lower voltage?

Regards
Steen
No, I don't think so. The DuoCharge is a one-way device designed to pass current only in one direction, e.g, from the house bank to the thruster bank.

The #4 LED will probably blink twice intermittently to signify "start battery voltage too high", meaning that the DuoCharge is not passing any current from the house batteries because their voltage is lower than the start (in your case, the thruster) battery.

Bill
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Old 16-05-2015, 07:35   #6
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Re: Need to charge three banks but wants to get rid of the battery isolator

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Originally Posted by SFH View Post
............
Ideally I want to get rid of the battery splitter to improve charging of the bow truster batteries but can not really see what alternative I have.
Use a battery combiner (automatic changing relay) instead of a splitter. These have no voltage drop. You can use multiple combiner for more than two banks.
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Old 16-05-2015, 09:20   #7
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Re: Need to charge three banks but wants to get rid of the battery isolator

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Originally Posted by rwidman View Post
Use a battery combiner (automatic changing relay) instead of a splitter. These have no voltage drop. You can use multiple combiner for more than two banks.
Thanks Rom

I can see that the combiner solution might be a good solution if the banks are within a few feets from each other but in my case two banks are next to each other while the third on is more than 30FT from the two other.

My concern is the voltage drop in the 2x30FT of cable which results in under-charging of the third bank in the bow

Regards
Steen
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Old 16-05-2015, 09:54   #8
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Re: Need to charge three banks but wants to get rid of the battery isolator

I suggest two independent Blue Sea Arc control relays. Install two control SWITCHES on the ARC controllers. You can set each bank for its own voltage to connect or disconnect . Each bank can be isolated, each bank can be connected for two way power. They can be controlled automatically or manually. Control switch can be mounted almost anywhere you want. Simple to install.

Just a suggested method which is pretty trouble free. 30 ft is not an issue if you use 4 or 2 awg cable.

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Old 16-05-2015, 10:29   #9
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Re: Need to charge three banks but wants to get rid of the battery isolator

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.......... My concern is the voltage drop in the 2x30FT of cable which results in under-charging of the third bank in the bow

Regards
Steen
If the cable size is large enough the voltage drop will be insignificant. Regardless of the cable size as the remote battery charges, the current through the cable will be less and eventually nearly zero and the voltage drop will be insignificant.

How are you preventing the windlass from drawing current from all the batteries though the 30' cable?
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Old 16-05-2015, 16:00   #10
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Re: Need to charge three banks but wants to get rid of the battery isolator

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Originally Posted by btrayfors View Post
Yep, there is.

I'd use an EchoCharge for the start battery (it requires VERY LITTLE CHARGING, anyway, and the 15A capacity is more than enough to maintain it), then...

I'd use another EchoCharge for the thruster batteries or, better, a DuoCharge for these since it can supply 30A when needed. Alternatively, an ACR could be used.

Bill
This is pretty much what I'm currently installing:
- Alternator and controller charges the house back (T-105s 675Ahr).
- DuoCharge for the Engine Start Battery
- Another DuoCharge for the Thruster Battery (Mastervolt AGM 160Ah)

The only concern which Balmer had was that when using the thruster it's possible that more than 30A will be drawn through the AWG 10 wire (~70 round trip) to the thruster battery which will blow the fuse. In my discussions they though the risk was low because the wire will act as a spring and should eliminate this problem. I'll know the first time I use the thruster (next summer) If I do have a problem I'll need to change the set-up to include a relay as suggested in their documentation.
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Old 16-05-2015, 16:41   #11
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Re: Need to charge three banks but wants to get rid of the battery isolator

Yep, Balmar has had a problem with the DuoCharge in high-amp draw applications.

The "spring" might work as they suggest, but the relay would likely be a safer "bullet-proof" solution.

Although it won't work for everyone, I still like my completely separate charging setup, using an independent AC-powered battery charger to maintain the two T-105s I use for windlass batteries. No need to run wires all the way from the bow to the house batteries, no voltage drop issues, no relays, no automatic charge controllers, etc.

Bill
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Old 17-05-2015, 02:11   #12
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Re: Need to charge three banks but wants to get rid of the battery isolator

Guess I have pretty much made up my mind based on very good inputs

I like the approach Bill has taken and will install a AC Victron Blue Power Battery Charger IP67 in the bow to take care of the truster battery pack.

Adding a Balmar Duo charge to the house pack will keep the starter battery charged

I can then eliminate the Cristec MOSFET isolator which is insufficent to handle the high charge from the AT-165 alternator

Thanks for good advice

Cheers
Steen
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Old 17-05-2015, 10:45   #13
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Need to charge three banks but wants to get rid of the battery isolator

Well my windlass can draw 100 amps ish. I have a dedicated battery up front for thruster and windlass. I have a 240v power charger for all three banks when land connected or on genny.
But - I like the fact a can ship some significant amps to the windlass from the alternator and protect the battery up front from a battering - with a direct connection when needed. Don't they say you should really run the engine when you raise the anchor. 100m of 10mm can take some time to raise especially if you need to re-anchor a few times.

Just my personal thoughts - happy to be shot down ....


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Old 17-05-2015, 12:48   #14
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Re: Need to charge three banks but wants to get rid of the battery isolator

You raise a good point, i.e., shipping some "good amps" to the windlass and/or bow thruster from the engine/alternator when running. That, of course normally requires running a battery charger from shore power or an onboard generator unless there's a wired direct run from the house battery bank.

I have the same draw on my boat....upwards of 100 amps or more at times when raising the anchor. My windlass battery bank consists of two Trojan T-105s which, without supplement, are perfectly capable of lowering and raising the anchor multiple times (200ft of 3/8" HT chain with a 45lb anchor). I like this because I like often to come to anchor and leave from an anchorage under sail alone, without starting the engine.

Whenever I do need to supplement the power available from these batteries, I can run the generator to power the 55A Iota charger which is dedicated to the windlass batteries OR I can power this charger from the 2500 watt Victron inverter, preferably with the engine running.

Different strokes for different folks!!

Bill
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Old 18-05-2015, 00:54   #15
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Re: Need to charge three banks but wants to get rid of the battery isolator

Quote:
Originally Posted by btrayfors View Post
You raise a good point, i.e., shipping some "good amps" to the windlass and/or bow thruster from the engine/alternator when running. That, of course normally requires running a battery charger from shore power or an onboard generator unless there's a wired direct run from the house battery bank.

I have the same draw on my boat....upwards of 100 amps or more at times when raising the anchor. My windlass battery bank consists of two Trojan T-105s which, without supplement, are perfectly capable of lowering and raising the anchor multiple times (200ft of 3/8" HT chain with a 45lb anchor). I like this because I like often to come to anchor and leave from an anchorage under sail alone, without starting the engine.

Whenever I do need to supplement the power available from these batteries, I can run the generator to power the 55A Iota charger which is dedicated to the windlass batteries OR I can power this charger from the 2500 watt Victron inverter, preferably with the engine running.

Different strokes for different folks!!

Bill
Bill,

Out of curiosity I checked out the IOTA supply/charger. Why did you select this one?
What happens if you draw more than the 55A for e.g. a truster?

Steen
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