> I think he meant it's not the *perfect* solution. Exactly.
> The perfect solution would be a separate voltage regulator for the starting >battery, > which probably would mean a second alternator/charger, which just doesn't >make sense on our boats. The DC - DC smart chargers provide most of that, by keeping a 13.4 V output alternator which is fine for charging / topping off the start battery and adding a smart three stage charger for the house bank. > The Sail Net link Certainly understand the problems with unclear documentation. I assumed that the echo charger had a diode in it to prevent reverse current, and that diode caused a slight voltage drop. The blurb states "limited voltage drop" which doesn't help much. I guess if the house bank ramps up to 14.4 V during the bulk charge stage, and the echo charger has a 0,2 V diode drop then the time the start battery is being possibly overcharged is limited. Not perfect but may not cause any damage. I see from the manual: > When it reaches 14.4/28.8 volts, the charge current will decrease, > maintaining a float condition. > The starter battery will be fully charged without overcharging. May effectively work that way, but it does contravene basic electrical theory. The battery has a rest voltage, as an example for a flooded lead acid at room temperature it might be 12.8 V. Most batteries will accept a long term trickle charge, lets say 13.2 V. This is overcharging the battery maybe a little bit, hard to know if any measurable loss of battery life will result. The marine alternator may be set to 13.4 V, a compromise to charge a discharged battery and not overcharge it during a longer run. The only way you could get 14.4 V on a flooded lead acid would be to pump some current into it, or alternatively if you forced the voltage to 14.4 V there would be current flow. You cannot arbitrarily set a voltage and a current across a load at the same time, laws of electricity derive current from voltage and load resistance, or voltage from current and load resistance. The Sail Net rant follows logic fairly well, but concludes incorrectly. The part that the writer missed is that the echo charger is designed to follow a smart charger. There may be a period of time when the source bank is ramping up in voltage and the start battery is being overcharged, but at some point the smart charger will drop back to float voltage and so will the start battery. Further, if the start battery is discharged a bit and there is a diode based voltage drop in the echo charger it may not cause a problem. So the issue of the echo charger not disconnecting may not be an issue. Michael Brown Windburn C&C 30-1 Date: Thu, 8 May 2014 15:17:11 -0300 From: Rich Knowles via CnC-List <cnc-list@cnc-list.com> To: "Della Barba, Joe" <joe.della.ba...@ssa.gov>, "cnc-list@cnc-list.com" <cnc-list@cnc-list.com> Subject: Re: Stus-List Charging with engine, was mixed batteries Message-ID: <a879cbc6-2da8-4e32-9693-57466ef4f...@sailpower.ca> Content-Type: text/plain; charset=us-ascii That's the sail net item I'm not sure about. I'm going to do some tests just to satisfy my curiosity. Anyway, they do an excellent job of whatever they do:) Rich > On May 8, 2014, at 14:38, "Della Barba, Joe via CnC-List" > <cnc-list@cnc-list.com> wrote: > > Not exactly. It has an upper limit and a low voltage disconnect, but it does > not regulate between these too. > See > http://www.sailnet.com/forums/electrical-systems/72295-xantrex-echo-charger-rant.html > for details. > > Joe Della Barba > Coquina > -----Original Message----- > From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Rich > Knowles via CnC-List > Sent: Thursday, May 08, 2014 1:12 PM > To: w...@wbryant.com; cnc-list@cnc-list.com > Subject: Re: Stus-List Charging with engine, was mixed batteries > > Is. Not the EC a voltage regulator? > > Rich > >> On May 8, 2014, at 13:00, Wally Bryant via CnC-List <cnc-list@cnc-list.com> >> wrote: >> >> I think he meant it's not the *perfect* solution. The perfect solution >> would be a separate voltage regulator for the starting battery, which >> probably would mean a second alternator/charger, which just doesn't make >> sense on our boats. >> >> I worried for a few years when I watched a fully charged starting battery >> getting 14-plus volts while the house bank was still in acceptance mode. >> However, the fully starting battery wasn't accepting any amps, so it doesn't >> seem to matter. I've never had a problem with it. >> >> Wal >> >> you wrote: >>> Can you please explain why you say the Echo Charge is not a solution? >> >> ------------------------------ Message: 11 Date: Thu, 8 May 2014 14:33:11 -0400 From: Michael Brown via CnC-List <cnc-list@cnc-list.com> To: Rich Knowles <r...@sailpower.ca>, cnc-list Cnc-List <cnc-list@cnc-list.com> Subject: Re: Stus-List Charging with engine, was mixed batteries Message-ID: <3706695285-26...@mail.tkg.ca> Content-Type: text/plain; charset="utf-8" Hopefully wasn't being too concise. I am technical by nature and by profession ( Electrical Engineer ) so do tend to cover more detail than necessary sometimes. ?The overview of the post was for someone with an older C&C, original wiring and alternator considering a newer AGM large house bank. It was to point out that the design has some significant challenges if part of the upgrade was to have optimal bulk charging. ? The section that you refer to was in the context of optimal bulk charging, which is usually done in three stages. Given a barely discharged smaller starting battery and a moderate or fully discharged larger house bank the optimal charging profiles are very different. The start battery will need a small top off. maybe of 2 - 5 AH and a voltage of around 13.4 V for a flooded battery. Depending of the type of house bank, flooded - AGM - Gel, the voltage may ramp up to 14.4 V for bulk charging. ? An echo charger has no control over the input side voltage, though the smarter units will choose when to operate and charge the battery on it's output, and may also protect a charged battery from over current. The better units do help, and are worth the price. They do not, in the context of charging profiles, create different profiles for two different batteries. If properly installed ( yes, they can be install wrong ) in normal use they will do exactly what you say - no flat or overcharged starting battery. ? My term "solution" was in reference to providing a fast bulk charge to the house bank, which as earlier commented on was not what the original C&Cs were designed for. Charging rates up to 30 amps might be possible, but above that wiring, alternator, belt and temperature concerns need to be considered. ? I see some boats that have upgraded to a high output marine alternator, serpentine belt kit, external three stage regulator and upgraded wiring. That is definitely a solution, albeit may be costly. With that setup an echo charger for the starting battery is pretty much required to get the best life out of it. ? My post pointed out that the DC - DC chargers are also worth a look at, particularly if the boat does minimal longer trips and bulk charges a year. Less money, possibly less rewiring. ? I like the echo chargers, do a great job for the money. I was on one boat "for a beer" and "take a quick look" at the charging setup. Nice high end alternator with a three stage external regulator. Never got the batteries fully charged. Took a while to figure out but the starter battery was connected to the house bank when the engine was running. Took a few beers to trace everything. I asked the owner if he has to add water to the starter battery much. He said no, maybe a few cups every week. Effectively the flooded lead acid starting battery was absorbing a lot of the charging current and boiling away. Fixed everything with some slight re-wiring and telling the owner to add an echo charger. Rich - what brand do you use? Michael Brown Windburn C&C 30-1 Rich Knowles <r...@sailpower.ca> , 5/8/2014 10:23 AM: Michael: Can you please explain why you say the Echo Charge is not a solution? I have had one on my boat for 11 years now with never a flat battery and no overcharging problems. Ditto all the boats I have installed them on. Rich On May 7, 2014, at 12:11, Michael Brown via CnC-List <cnc-list@cnc-list.com> wrote: There is no single charging profile that works when you are trying to charge a barely discharged smaller starting battery and a large fully discharged house battery in parallel. Workaround - see solutions below. Note that a Voltage Sensitive Relay or Echo Charger can help a bit but is not a solution. -------------- next part -------------- An HTML attachment was scrubbed... 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