recharging while driving

[pianotuna]

I'm winding my way south and boondocking.

Last power was in Regina, SK

I used a heating pad and lots of computer time last night, powering them from a 400 watt MSW inverter.

Batteries were at 12.3 in the morning.

I drove for about 8 hours in total.

The first two hours, very little in the way of charging happened as I was using the head lights, running the heater fan on high and running the laptop with Microsoft Streets and trips. In fact, at first I was concerned that the alternator was not sending any energy to the house bank.

I stopped about 5 p.m. in Fargo, ND and voltage was back up to 12.9 (under load from the fridge and attempting to recharge a tablet, using a 12 volt adapter.)

I will be using the heating pad and perhaps the tablet tonight. The Tablet is supposed to be able to tether--but it won't. Nor will it do a hotspot. I'm too exhausted to deal with this tonight.

I may or may not have power tomorrow night.

[MrWizard]

, everything else makes sense , except this part

If I turn the alternator charging solenoids off the alternator ammeter shows 0.00. When I do this, in cold weather, the volts go up on the house side (as the bank charges). The volts on the engine side also appear to rise.

If the alternator meter is on the main wire from the alternator
It should be showing all loads , heater, headlights ignition etc..

Is that meter after chassis feed and only shows charging loads?

[pianotuna]

Here is what I have "in place"

1 field effect ammeter for the alternator circuit
1 field effect ammeter for the house loads (except the inverter)
1 volt meter on the dash (plug in type)
2 manually controlled solenoids (one for each battery bank)
2 switches for solar (ofebb)
2 Napa battery disconnect switches 1000 amps contacting 100 amps continuous (ofebb)
1 Trik-L-Start from OEM battery bank to starter battery.
Blue sky Solar 3024 MPPT controller temperature compensated harvesting from 256 watts of Unisolar panels (now 11 years old)
556 amp-hours of AGM Telecom batteries (nominally 13 volts)
125 amp-hour Marine starter battery from Walmart (7 years old)
1 ignition key that interrupts the solenoids
1 PD 40 amp with wizard (default is disconnect on 120 volt side)
1 Magnum 3012 Hybrid inverter charger (temperature compensation)

If the solar is producing and I start the engine the voltage measured by the Blue Sky drops, and the amps from the output of the Blue Sky also drop.

Once the house batteries exceed the voltage of the starter battery some but not all amps go from the house to the engine.

If I turn the alternator charging solenoids off the alternator ammeter shows 0.00. When I do this, in cold weather, the volts go up on the house side (as the bank charges). The volts on the engine side also appear to rise. If there is a differential of 0.7 volts then even though the solenoids have disconnected the ammeter starts showing a low number of amps going to the engine.

I am not sure where the trickle-l-start is wired to on the house--but it believe it to be on the house side of the after market add on solenoid. That would explain the small number of amps (it is limited to 5 by the TLS) and why it shows up one house voltage is 0.7 above the engine.

[pianotuna]

Hi landyacht,

That is what the solenoids are supposed to do.

landyacht318 wrote:
Keep house battery out of alternator loop for testing

In cold weather, I've seen 14.4

landyacht318 wrote:


What is engine battery voltage with engine running?

Perhaps your alternator's Voltage Regulator is only allowing 13.2v.

I do have a Black and Decker that can check the alternator. I've not used it for 5 years so it is in storage near Saskatoon, SK

landyacht318 wrote:


Perhaps it fried a diode or 2 and is only working on 1/3 or 2/3rd capacity.

Can't one check for AC voltage to determine a failed alternator diode?

I would regularly see back feeding when the house bank was full and the solar was producing power.

landyacht318 wrote:


If the Alternators voltage regulator is allowing more voltage than either battery, there will be no backfeeding going on when driving regardless of resting voltage differences between engine and house battery.

Short lived I suspect. I've arrived at my destination, Altamonte Springs.

landyacht318 wrote:


Thanks for bringing the cooler weather to florida, even Temporarily.

[Gulfcoast]

.

[MEXICOWANDERER]

Then again a meter can lie it's bezel off. Do not discount it.

[MrWizard]

Try turning off your charge combine relays and marinco switches
Then look for feed back from house to chassis_engine battery
It won't feed back thru common ground unless there is a poor ground issue someplace
You have something that is not breaking connection

If you are talking about feed back while driving and charging
Then you have an alternator with reduced output, and solar with a higher voltage than the alternator

[landyacht318]

Keep house battery out of alternator loop for testing

What is engine battery voltage with engine running?

Perhaps your alternator's Voltage Regulator is only allowing 13.2v.

Perhaps it fried a diode or 2 and is only working on 1/3 or 2/3rd capacity.

Can't one check for AC voltage to determine a failed alternator diode?

If the Alternators voltage regulator is allowing more voltage than either battery, there will be no backfeeding going on when driving regardless of resting voltage differences between engine and house battery.

Thanks for bringing the cooler weather to florida, even Temporarily.

[pianotuna]

Hi Mr. Wizard,

There is no Aux start relay. I wish everything were as easy to eliminate.

[MrWizard]

pianotuna wrote:
Hi Phil,

No. The back feed is happening before dawn. I think it is a simple voltage issue. The AGM's are higher voltage than the starter jar.

Can't be any feed back unless they are some how connected
Given your system layout wth relays from the batteries to the alternator

Your relays are failing, (is it relays or marinco switches)
Possibly pitted, current is flowing from house thru relay to common alternator terminal to engine battery

Your charge circuits are an add-on
Could also be the aux start relay (if that is a separate relay)

[MEXICOWANDERER]

You might want to do a quiescent bleed check of the chassis battery and have a drawdown number. Same for the house batteries. Playing possum may entail more than you would believe. Just a thought. The handheld meter 10.0 ampere scale resolves fine enough.

[pianotuna]

Hi Phil,

No. The back feed is happening before dawn. I think it is a simple voltage issue. The AGM's are higher voltage than the starter jar.

[pnichols]

Don,

This is probably scratching the bottom of the barrel for a cause ... but from reading your post above it sounds like your solar controller feeds both the coach batteries and the engine battery?

If so, I wonder if - when the coach batteries come up to about 14.2 volts - the solar controller naturally (or because it's defective) starts to backfeed current from the higher voltage coach batteries into the lower voltage engine battery?

Maybe the solar controller is causing what you saw ... just a thought. :h

[Huntindog]

pianatuna wrote:
I may or may not have power tomorrow night.

Carry on.

[pianotuna]

Hi all,

Today I isolated the house batteries by switching off both solenoids. Voltage gradually climbed from solar charging to 14.2 and about 9 amps were flowing in.

Voltage also climbed on the engine.

Then something odd happened. At 14.2 on the house jars--the ammeter that measures flow between the house and alternator charging circuits started showing energy transferring to the engine. I don't understand how the power was being transmitted with the solenoids on the off position.

There is a Trik-l-start but that doesn't get measured by the Hall effect ammeter, so far as I am aware. I could be wrong about that.

At lunch time I had a hankering for Kraft Dinner. So I boiled 6 quarts of water and then cooked the pasta for 8 minutes. Total run time was about 15 minutes and demand was 68 amps.

When I went back to traveling I switch the charger circuit back in. About 4 amps flowed to the house batteries and after 2 hours that had dropped to 1 amp.

When I stopped voltage was 12.9 on the house jars. Of course that was with the parasitic load of the gas valve on the fridge.

One more night of boondocking. I'm at Lake City Walmart which is open 24 hours. Tomorrow just a 3 hour drive. After that, the solar will be maintaining the house and starter batteries.