Correct Bowthruster Battery System

[Sulaire]

Hi,

Could someone give me a little assistance in figuring out a question regarding a battery set up that i inherited.?

I have 3 lifeline 210 batteries, split into 2 banks, (house banks), using 2 battery switches, a dedicated start battery 105ah, all these are aft ,and 1- 225 ah bowthruster battery up front. The only reason i can think for the split is that the ssb is connected to a single battery to isolate it from the other 2?

I am considering doing away with the splitting of the house batteries and making them into 1 larger bank, this will allow me to do away with 1 battery selection switch.

I would then wire the start battery to the other terminal on the remaing battery switch, this will simplify things i feel.(1-house bank , 2 - start , off , both).

At the moment i have a cable coming from the bowthruster battery, to a simple conection switch that links it into the house batteries for charging.

All that seems quite simple, my problem is that i have xantrex monitors for each of the 3 banks ( house 1 , house 2 and start). If i flick the switch to bring in the bowthruster battery to the house bank i can see a few problems, (i fitted the bowthruster after inheriting the set up).

1) it is in a different location and as such different ambient temp from house bank
2) when i flick this switch, there is always a run of current in one way or another, depending on which bank is higher charged, (house or bowthruster),could this cause damage?
3) the xantrex monitors are calibrated for the size of the house banks, flicking the switch to bring the bowthruster battery into this system, increase the battery bank size by 225ah, therefore the xantrex will never read correctly?
4) is there a danger of run away charging because of the differing locations of the batteries?.

Does anyone have any ideas of a better set up, i was thinking of a split diode, but which bank to share with the bowthruster through this diode, my initial thought was the start battery?

Any help would be gratefully received

Charlie.

[James S]

Hey Charlie, welcome to the forum.
I wont be able to be much help with your system...OK, no help at all. But I can bump this thread since no one has yet to reply and we have plenty of folks here who can certainly help.

[Sulaire]

Here is a diagram of things how they are now.

I plan to parallel aux1,2,3 and disconect red 1&2 and connect aux 1 +ve to black 1 then red switch becomes obsolete and I have 2 banks.

The problem is how to connect bow, as you can see it is simply plugged into aux bank. Is this ok?

[James S]

I'm going to try and lighten/enlarge the attachment.
Come on guys...cant someone give any thoughts?

[mitiempo]

Charlie

How are you charging the multiple banks - through the switches I assume?

I agree with combining the 2 house banks into one. This will make more sense to the Xantrex monitor.

If your charging is as I guessed above I would add an ACR for charging the start battery and remove any charge sources from the switches - all charging sources to the house bank. This makes the charging foolproof as it does not require switching.

I would link the thruster battery with the start battery. If the start battery is dedicated to engine starting it will seldom be down more than an AH or so. The thruster is in the same position really - thruster use is high draw like a starter but again for a very short period of time. I don't think there is a need for anything between the start and thruster batteries except fusing and a switch for isolation when it is not in use. The few AH used by the thruster battery will be replaced quickly and the engine will be running while the thruster is in any case.

I don't think there is any issue with thermal runaway.

Is the cable from start to thruster battery is a heavy cable? If so the above is what I would do. If the cable is smaller gauge you could install an Echo Charge between the start and thruster batteries for charging.

[Sulaire]

Hi

Thanks for the input.

I did not think of an ACR, that makes sense. The cable to the b/t battery is indeed a heavy one, so no worries there!

Charging is through switches. Previous owner spent a lot of time red-doing the wiring behind the dc panel and is a credit to him. Unfortunately he must have got bored by the time he got to the battery set up and did not include any fuses at the batteries and overcomplicated the switching system. I can only think he was trying to create a back up house bank or isolate the ssb by splitting the houe bank.

Anyway, i will redraw my proposed set up and ponder a while before commiting to it, so any other input on ways to improve the set up will be gratefully received, whilst i stroke my chin !! ;-)

Charlie.

[matauwhi]

G'day, Charlie. Mitiempo advice on also connecting your starting & bow thruster battery is good. I, essentially, have the same system and it has served me well over the years. My anchor windlass is also wired into the bow thruster battery, is yours?

The control relay doesn't have to necessarily be an automatic one. I just have a manual relay that I control when charging. If I am motoring for a long period of time, I can combine the house and starting/bow thruster/windlass bank to charge them through the engine alternator. I installed some 12vdc led indicating lights in the control switch circuit both at the engine and genset panels to highlight when the banks are combined.

If I am docking or lifting the anchor, I can keep the banks separate to put all the engine alternator amps into the starting/bow thruster/windlass bank.

BTW, depending upon your SSB, if you don't let your house bank get below 12.3 volts, you shouldn't experience any voltage related issues with your rig. Cheers.

[James S]

Some other info here http://www.cruisersforum.com/forums/...ing-71862.html

[CharlieJ]

Charlie-I typically do away with the traditional 1-2-both-off switches and install either simple on-off switches (Blue Sea 6006, 9003e or 3000) or remotely operated battery switches (Blue Sea ML7700) for battery isolation and to simplify the system.

Charging sources are generally connected to the house bank and the starting battery or batteries and the bow thruster and/or anchor windlass batteries are charged with either an ACR (Blue Sea 7610 or ML 7620) or a Balmar DuoCharge.

To continue with simplification of the system, the legacy split house bank system on older vessels is combined to become a single house bank. This philosophy, championed by Nigel Calder, has developed and matured over the last several years and is the generally accepted practice now.

I usually upgrade the connections to the batteries or their bus bars through a compact Blue Sea Marine Rated Battery Fuse (MRBF) that provides circuit protection as close to the source (the battery) as is physically possible. MRBF fuse holders are Blue Sea 5191 (single) or 2151 (double) and fuse are from 30A to 300A, have a 10,000A AIC are ignition protected and have an IP rating (susceptibility to water intrusion) that resists water jets.

(Most of this sound familiar JamesS?!)

Hope this helps.
Charlie

[Bill S]

I have a single house bank as influenced by Calder. However, I am having a problem with the thruster, windlass and refrigeration compresser affecting the elecytronics. I have a lot of electronics. The thruster will reboot the chart plotter due to a deep volatage drop. The compresser will cause the chart plotter to flash on & off due to voltage fluctuation from the smart alternator controller kicking in right after the compresser.

I am considering breaking the house bank into two in order to isolate the electronics from the high power devices. Before you combine you two banks, consider if your electronics could be affected by the thruster.

[James S]

Originally Posted by CharlieJ

Charlie-I typically do away with the traditional 1-2-both-off switches and install either simple on-off switches (Blue Sea 6006, 9003e or 3000) or remotely operated battery switches (Blue Sea ML7700) for battery isolation and to simplify the system.

Charging sources are generally connected to the house bank and the starting battery or batteries and the bow thruster and/or anchor windlass batteries are charged with either an ACR (Blue Sea 7610 or ML 7620) or a Balmar DuoCharge.

To continue with simplification of the system, the legacy split house bank system on older vessels is combined to become a single house bank. This philosophy, championed by Nigel Calder, has developed and matured over the last several years and is the generally accepted practice now.

I usually upgrade the connections to the batteries or their bus bars through a compact Blue Sea Marine Rated Battery Fuse (MRBF) that provides circuit protection as close to the source (the battery) as is physically possible. MRBF fuse holders are Blue Sea 5191 (single) or 2151 (double) and fuse are from 30A to 300A, have a 10,000A AIC are ignition protected and have an IP rating (susceptibility to water intrusion) that resists water jets.

(Most of this sound familiar JamesS?!)

Hope this helps.
Charlie

Absolutely Charlie, thanks again for the first class electrical system and the most excellent summer installing it, and general goofing off.

[Sulaire]

Thanks for all the advice guys.

I have a 230Ah battery up forward for the bowthruster, i am going to wire the windlass (lofrans falkon 1500w), into that too, rather than current system where the cables go all the way aft then all the way forward again.

The engine is always running when I use the thruster or windlass, so should not be too much of a strain, i will leave an emergency connection to the house bank incase of problems, but this will be disconnected as standard. ( should avoid the problem mentioned above)

The thruster battery will be connected to the engine battery with an ACR ( thanks to your advice). The engine battery is a high cranking version that only has a 27ah rating , but 700cca .This will go to one side of the battery switch (charliej- i am sticking with switches at the moment, but mybe in the future I will follow your sage advice; i like to take small steps!).

The house bank will be combined into 1 bank and attached to the other side of the switch.

Shunts with xantrex monitors will manage things with charge from a balmar 100 amp charger with smart controller when on the iron sail and when on shore power a victron isolation transformer will lead to a victron 100amp 3 ouput charger.

I think this system is simple but sofisticated enough to handle our needs while living onboard.

As an extra question, how would you connect up 3 batteries in parallel, i have seen an article where the standard daisy chaining is Shunned in favour of a more balanced mutiple connection system that shares the loads over all batteries more evenly? That was for 4 batteries, I have 3.

Cheers

Charlie.

[mitiempo]

Like this:

[Sulaire]

Hi

Thanks for the pic, that was how i was intending to do it until I read this

http://www.smartgauge.co.uk/batt_con.html

What do you think? The example is for 4 batteries, on 3 is it just a case of conecting 1 and 2 together then a link from 1 to 3 on + ve then start from battery 3 going the other way on the - ve side?

Or is this all just six and two threes !?

Something tells me i am missing a trick ?

Charlie.

[goboatingnow]

Charlie, the connection strategy put forward in this piece is technically and theoretically correct, but in practice the mismatch between cells and batteries is such that they outweigh any resistance issues between batteries ( unless your connections are bad), So in real life there is always lazy batteries , but not necessarily the ones as pointed out in the Smartguage article.

dave