Combiner with Battery Brain

[40Toes]

I purchased a Mac26x last year and over the winter I have been planning/working on some mods. My question deals with the batteries: House and Start. My 50hp Bigfoot calls for 465 MCA or 1000 MCA if below 0 degs C and I know there has been debate on whether a starting battery is actually required, regardless, my system is a start and house. My current config is thru (1, 2, both, off switch). I want to make the system sailor proof so what I am thinking of doing is putting a Yandina Combiner 100 on, and in addition putting a battery brain on the start battery. The battery switch always stays on 1 and the DC panel is feed from 2 (house battery). If I need more juice for the engine start I can switch to both or if I need more DC when not motoring I can switch to both and draw from the start battery without worrying about draining it below its abilitiy to start the engine. Does this make sense?

[Bobby T.-26X #4767]

i have that exact set-up minus the "battery brain".
several on this board profess to use 3-on/off switches rather than the Perko 1,2,both,off switch that i use.
i've got the WestMarine Combiner, now called the Yandina Combiner 100.
one battery is dedicated house, the other is dedicated start/motor.
with the combiner, they both charge w/out draining one over the other (did i say that right?).
anyway, it works great for me!



one suggestion...when you replace a battery, replace both to the same brand/size.
with the combiner, it's best to use equal batteries so that the max charges stay the same.

Bob T.
"DāBob"
'02X w/ '04 90-TLDI (14" x 11 pitch)
Dinghy Motor: '06 2.5-Suzuki

[Chip Hindes]

Not familiar with your Yandina system or exactly what is a "battery brain", but what it sounds like is the modern three switch system with isolator.

I have two identical deep cycle marine bateries, and two years ago replaced my off-1-2-both switch with a three switch system. Separate circuits and switches for the house and motor, both of which are normally left on. The third switch is normally off, used for paralleling both batteries only in the event of a starting battery failure.

With the paralleling switch open, the systems are isolated, with charging controlled by a voltage sensitive relay (VSR). This charges the starting battery first, then when the starting battery is full charged it automatically switches to charge the house battery.

As with many others, I don't believe in the need for a true starting battery for our puny 50HP outboards, thus two deep cycle batteries. In fact, in this setup the "starting" battery gets hardly any use at all, so each spring I physically switch the batteries from one location to the other to equalize the wear and tear.

My house circuit powers everything, including instruments and running lights. Only the motor itself is on the starter circuit. In most shore based situations I've would not hesitate to parallel the batteries if I needed additional power for house use because I have found that my Tohatsu 50 is incredibly easy to rope start.

I like this system so well in the Mac that I will replace the off-1-2-both switch with the three-switch VSR system on my second boat (Newport 30) this Spring.

[March]

I agree with the one above...

Our boat has a two battery system with a XANTREX Pathmaker in between. The electronics and light are connected to the house battery, and the engine battery is for the engine only. Three years ago the house battery shorted out: we were off St Marco's island, Florida, and found ourselves at night with no anchor light and no depthfinder. (No moon-light either to recharge the system through the solar panel.) However, we were able to start the engine with no problem the following morning, even though the gauge showed both batteries in the red (it's a weird little gauge that came with the boat and I am not sure if it shows the amps or the volts or what, but the red/green areas are pretty self-explanatory.

We were able to recharge the house battery by keeping the manual switch on the Pathmaker on "both." (it's under the sink and it gave me a crick in the neck) We did not have to keep it on "both" to start the engine though.

Eventually, the battery was changed and so was the Pathmaker that got screwed up in the process. Now everything is fine. I got a remote switch for the Pathmaker as a bonus when purchasing it on e-bay, change the pathmaker, but never needed to combine the batteries in order to start the motor. I am not 100% sure the Pathmaker does its full job though, since under heavy electrical load at night, the engine battery is no longer 100% full in the morning (more like 80%) I would expect the engine battery to be fully disconnected at night, no? Yet the engine always starts

Likewise, when the house battery is full due to the solar panel, the system clicks and cycles repeatedly, but eventually everything equalizes

[Chip Hindes]

Interesting. Yandina's website confirms they used to manufacture for the West marine Brand but in 2006 they started making their own branded stuff and selling through Defender.

They also state they will sell their stuff directly but actually recommend you buy it from Defender because it's cheaper. What a refreshing way to do business.

[40Toes]

Not familiar with your Yandina system or exactly what is a "battery brain", but what it sounds like is the modern three switch system with isolator.

If you do a search under Marine Battery Brain or Battery Guard you will find the units. Sorry I am not permitted to post links yet. They all basically do the same thing - mitigate my stupidness.

[Night Sailor]

After decades of disatisfaction and mistakes simply because of marine tradition, I finally installed two years ago what really makes me and my boat happiest:
three blue sea mini switches, one for the start batt, one for the two house batts, one for both.
West Marine 50 amp combiner transfers charge to house after start batt has been satisfied.
Charge to start comes from 111 watts of solar, and occasional running of Merc 50.

[rockman]

I also have the two battery setup with the Yandina combiner & a solar panel. I have it set up so that the motor starts off battery 1 & all house power from 100AHr battery 2. The two charging sources - alternator and solar panel, work through the combiner to ensure the batteries are charged.

1. The alternator charges the starter battery. When its fully charged it switchs over to charge the house battery.
2. The solar panel charges the house battery. When its fully charged it switchs over to charge the starter battery.

It all does this without the need to do any switching. I will take some pics of the system and post them on the modifications page.

Cheers

[RickJ]

I'm in the process of installing something very similar in the I bought last autumn (which I have yet to put into the water!).

It came with separate (and different) starter and house batteries, and an electrical system full of good ideas but needing a complete re-work. I've bought a Victron Cyrix 80 VSR, which looks pretty much the same as the Yandina mentioned here. I hope it works well in practice

A PO has fitted a control panel covered with switches and fuses, which basically allows different groups of equipment to be run from house or starter batteries by flicking a switch. I'm currently cleaning this up - several soldered joints have fallen apart etc. It also has both a solar panel and low-power wind charger, I'm going to configure these to primarily charge the house battery, and the VSR should switch in the starter battery when the house is full - we hope

I've decided I don't believe OBM numbers for cranking current. My 10 year old Suzuki 55 states in the manual the battery should be rated at 398 CCA (an oddly precise figure). However, the starter cable is 3m of twin 6 sq.mm cable, which cannot possible carry 400A and leave any voltage at the starter motor (a cable this size wouldn't take much more than 400A if short-circuited). I measured the actual voltage drop when cranking on a pretty cold day, and it worked out that the current was in fact about 50A.

If that rated CCA was real then it would need at least 25 sq.mm cable for the starter, that's probably thicker than in your car!

[Moe]

I measured the actual voltage drop when cranking on a pretty cold day, and it worked out that the current was in fact about 50A.

IIRC, the Mercury BigFoot Service Manual I owned specified the "Locked Rotor" amps at 70-something. Unless the crankshaft got bent and the engine wouldn't turn, the starter motor would never draw that. 50-60 amps seems about right. You could supply this with a pretty small lead-acid battery, like that used on a 800-1000cc motorcycle. Any deep cycle battery that powers a 500-600W inverter at rated power supplies that much without dropping voltage very low at all. Otherwise, the inverter would cut out.

[DaveB]

I bought a new 9.8 hp 4 cycle out board and put it on my Pottor 19 just to try it out and it started right up with my old motorcycle (650 CC) battery.
I run two Gell batteries in parrel on my Potter and lasts for 5 days without chargeing, this includes autopilot and small TV with CD, depth,vhf and cabin lights. Anchor lights are run on LED's AAA batteries and have other LED's in cabin.
I plan on putting 2 AG batteries on the Mac.X and haveing a little Motorcycle battery for backup for engine, this battery will not be connected until I need it, at 5 lbs and 6"x5"x2.75" it's easy to lift.
On my Compac 19 I had 2- 6 volt golf batteries and this also did well.
I don't like to use diodes as they take away from chargeing and by haveing twins in parrel the charger won't start falling as the battery gets up voltage.
I also used this system on my Alberg 35 with 4 banks of batteries and Wind Generator.
Dave

[RickJ]

A point about these battery combiners. The Cyrix and Yandina (and some others) do not use diodes, they are VSRs - Voltage Sensitive Relays.

They monitor the voltage of the batteries, and if either reaches around 13.5V - indicating either near-full charge or a generous charging current - the relay closes so that the second battery is connected directly. If the voltage drops to around 12.5 then the relay opens preventing both batteries being accidentally drained from a load connected to one of them. There is thus no voltage drop across diodes to mess up the charging characteristics.

They also have an override mode allowing the relay to be manually closed using a separate switch. This temporarily parallels the batteries to provide a starting boost if needed. I'm going to wire a push-button on the console which I can press while turning the starter key. I may never need it, but I may as well put it in just in case.

You can also get diode-based combiners, which have their advantages, but to work properly the voltage regulator on the alternator needs to be re-wired to sense the battery voltage directly. This is much more doable on an inboard than an outboard!

So far this is all theory from my point of view - time will tell if it all works out in practice

Cheers
Rick

[richandlori]

A better way....





Xantrex Echo Charge

The digital Echo Charge is a smart way to charge a starter or auxiliary battery without the complexity of isolators or combiners.

The Echo Charge detects when the house battery bank is being charged and directs a portion of the charge current to auxiliary or starting batteries. The maximum charger current passed by the Echo Charge is limited to 15 amps.

Product Features

* 15 A maximum charge current
* Automatically adjusts for 12 or 24 volt battery banks (both battery banks must be the same DC voltage and battery type)
* Automatically switches on when charge is applied to the house bank from any source
* Utilizes excess current from the primary charging source to charge the start battery
* Built-in thermal and over-current circuits
* Reverse polarity protection
* Easy three wire installation

Web Link

[DaveB]

Rick, My 50 Honda has a 10 amp charger but it really only puts out 8.5 volts when battery is at 11.5-12 volts. The more the battery is charged after reaching 12 volts the lower the amps charge. at 12.4 volts the amps may only be putting out 4 amps or less.
With a 2 bank parrel battery system it will take twice as long for chargeing but charger amps will be putting out max. amps when lower voltage.
Point is I want to charge the battery up at the higher chargeing amps as quickly as possible while running the outboard.
I don't think relays will allow it, but I may be mistaken.
On my 21 hp universal desil it had a 55 amp Alt. with built in regulator Diodes that I bypassed to a reastrate to regulate output and worked out well.
That was back in 1982 and systems are much improved over the years.
With the Mac. all I need is enough juice for 2 wks or less and may have to dig in deep for a 50- 75 watt solar panel.
Dave

A point about these battery combiners. The Cyrix and Yandina (and some others) do not use diodes, they are VSRs - Voltage Sensitive Relays.

They monitor the voltage of the batteries, and if either reaches around 13.5V - indicating either near-full charge or a generous charging current - the relay closes so that the second battery is connected directly. If the voltage drops to around 12.5 then the relay opens preventing both batteries being accidentally drained from a load connected to one of them. There is thus no voltage drop across diodes to mess up the charging characteristics.

They also have an override mode allowing the relay to be manually closed using a separate switch. This temporarily parallels the batteries to provide a starting boost if needed. I'm going to wire a push-button on the console which I can press while turning the starter key. I may never need it, but I may as well put it in just in case.

You can also get diode-based combiners, which have their advantages, but to work properly the voltage regulator on the alternator needs to be re-wired to sense the battery voltage directly. This is much more doable on an inboard than an outboard!

So far this is all theory from my point of view - time will tell if it all works out in practice

Cheers
Rick

[40Toes]

There is alot of good info on setting up for charging, back-up batteries etc. Has anyone actually used a battery brain type product with their set ups to protect against accidental drain?