telecom batteries and boondocking

[pianotuna]

Hi all,

First night boondocking on the new batteries.

I ran a computer for 5 hours (100 watts) via my large inverter, and a 7 amp 12 volt heating blanket for 7 hours.

Battery voltage started at 13.1 but quickly settled down to 12.8

The usual parasitic loads were active.

In the morning batteries were at 12.5 volts.

I turned off the inverter, then drove for about 1 hour at city speeds. Initial charging was at 40 amps. By the end of the drive 7.4 amps were coming from the alternator and 2.5 from solar. End of drive placing my foot on the brake at stop lights caused current to flow from the house jars to the engine. (about 1.5 amps). With transmission in neutral that went back to the 7.4.

At my destination, after turning off the engine, and turning off the solar voltage was displayed as 13.1. I used the fridge on 120 volts ac (30 amp load) for 1 minute to "knock down" surface charge. Battery voltage displayed at 12.9.

It is a grey day. Blue Sky 3024di controller is sending 2.2 amps to the battery bank at 13.1 volts. Normal parastic loads are running.

Ambient temperature is 11.3 C (52.3 f)

[MEXICOWANDERER]

I am blasting the fan of one of the Megawatts right up onto the bridge of a shunt on the ceiling of the BORG. Yeah I am going to push 70 amps through a 50 amp 75mv shunt - and it won't play toaster iron. Yeah the 50-amp analog meter needle will be laying over at 3:00 O'clock.

[Big_Katuna]

In my youth I installed telephony equipment for Stromberg Carlson including battery rooms with 1,2 or 3 1600A 48VDC three phase charger. 32 runs of 750 MCM Copper to the main distribution cabinet. All current was monitored with shunts and (then) Analog voltmeters, later, DVM.

I never saw a shunt failure but it was indeed climate controlled and well designed with proper breakers, fusible links, etc.

I agree if you run 500A thru a 100A shunt something has to give. So don't do it.

[MEXICOWANDERER]

pianotuna wrote:
There is another thread on this.

Shunt's can burn out.

Big Katuna wrote:
So why a Hall Effect and not a shunt and meter?

Lessee,

A 500-amp rated shunt will get very warm at 700-amperes. But the circuit breaker entered into a conspiracy with the T-rated fuses in the inverter so they could malfunction and not open. Meanwhile the wiring insulation is blazing about one feet in height never mind the temper of the system owner when he found out the shunt is not invincible.

With a Q-tip smear an oil coat over the shunt metallics. Silicone grease spread oil thin, does wonders for protection. And when launching your rig into salt water, be sure to not immerse the shunt.

Aww Jeez fellas I couldn't resist! An opportunity to make Pianotuna smile was irresistible.

[pianotuna]

Hi Gjac,

I paid $120 each and purchased 4. My expectation is that they will outlast the Marine Wallyworld batteries I had before. They lasted between 6 and 10 years.

However, they are used and not new.


Ten year life span is possible.

Six volt cells vs twelve volt cells, I really think it depends on the loading. I push my bank HARD drawing up to 276 amps, so my gut feeling is that 12 volt may be better for me.

[Gjac]

pianotuna wrote:
They are Dynasty UPS12-490MR

The chemistry is Lead Calcium AGM with a SG of 1.300

Amp-hour capacity 139.2 when new.

They are a non starved acid AGM.

I think they are pretty much the same as yours Niner.

I have four in two balanced banks.

Don, how much did you pay for these batteries? How long do you expect these to last compared to your wet cells? Do these 12 v AGM batteries last as long as the 6 v AGM batteries?

[full_mosey]

MrWizard wrote:

full_mosey wrote:
Here is another UPS battery on CL Powerware 12 Volt 135 AH Deep Cycle Reserve Batteries

and a mfgrs pdf link

.

HTH;
John

Fantastic
if i was in Okie city, i would snap up eight of those
ok ok i'm a battery nut
....

I did buy two! 🙂

HTH;
John

[pianotuna]

There is another thread on this.

Shunt's can burn out.

Big Katuna wrote:
So why a Hall Effect and not a shunt and meter?

[Big_Katuna]

So why a Hall Effect and not a shunt and meter?

[pianotuna]

Hi Mex,

In my previous RV which had a scant 30 watts of solar (from 1989) I did urban dock using a Kipor 2800 watt generator and survived six days on the streets of Calgary. The daily high was -27C and snow was more or less constant. I was at a convention during the day, so I used the stove top as a blue flame heater partly to help 'fool' the main thermostat, and partly to provide heat that required no power. I had two Walmart Marine batteries, and an old fashioned Magnetec converter.

As you, and others are probably aware, I will NOT run a generator while sleeping.

The daily routine was to wake up, climb into clothing, start the generator, turn up the furnace, turn on as much electric heat as I could and make breakfast. At 8:30 I left for the convention, after setting the furnace as low as it was safe to do so and lighting off the four stove burners--as low as I could get them to be.

In the evening, I'd get back about 8 p.m., start the generator, plug in the block heater, turn up the furnace and run electric heaters. (the old unit was a diesel from 1987, no block heater, no start!!!).

After an hour, I'd start the diesel and drive to the nearest gas station to top up the generator fuel tank. I restarted the generator and at about 10 p.m. I'd shut it down.

I do believe that, in my new RV, if I were willing to forgo electric cooking, and water heating, that with 1400 watts of solar I would be able to survive for six days--provided I was not in the RV during the day time.

I am set up to heat 100% electrically--but in the worst of the winter that requires 7100 watts peak load with an average of about 5000 watts. My Yamaha can't do even 50% of that, so I'd be burning propane. I do have three shore power cords so I can just barely squeak through on three 15 amp circuits provided I use the load support feature of the Magnum inverter. I do have a 'break out box' for a 50 amp pedestal which gives me 30 amps on one leg and two 20 amp circuits on the other leg, each with their own breaker.

I would still have the engine alternator as an 'emergency' charging device. If it were a trailer, or other unit that has no engine, I'd agree that a generator would be a requirement.

MEXICOWANDERER wrote:
Geemanize PT haven't you been through a plains blizzard yet? -25C 80 kph wind and horizontal snow? Four, five, six days.

Solar can't save you. So you need the generator or risk a "permanent" blackout.

[pianotuna]

Hi niner,

Day 4

Day 3 I ran the generator for an additional 30 minutes at supper time. It was showing 10 amps at the end of the time period.

I purposely let the heat build in in the RV so last night I did not run the electric heating blanket.

I often fall asleep to streaming BBC radio plays and for that I power the laptop with a small msw 300 watt inverter via a cigarette plug. The laptop eventually goes into sleep mode. I woke up early and turned on a 50 watt 120 volt heating pad to keep me cozy.

In the morning, since I knew I would be moving after breakfast, I chose to do sausage, egg, toast and coffee from the main inverter. It was a bit chilly so I ran the electrical heating rug under the dinette table. I had slept in until 9:30 am, so the solar panels had already replaced some of the energy I used during the night.

When I started the engine, about 14 amps was flowing from the house bank to the engine. After it started the flow reversed and 20 amps flowed into the jars. After a short time, when I stopped for a red light current flowed to the engine battery. If I put the RV in neutral, about 8 amps would flow to the house bank. Engine run time was about 30 minutes.

It is mostly cloudy, but I'm harvesting 5.9 amps @ 13.1 volts and using 4.1 amps, so I'm not going to do a generator run this morning.

[MEXICOWANDERER]

Geemanize PT haven't you been through a plains blizzard yet? -25C 80 kph wind and horizontal snow? Four, five, six days.

Solar can't save you. So you need the generator or risk a "permanent" blackout.

[JiminDenver]

pianotuna wrote:
Hi Mr Wizard,

I paid 2700 for the generator. If I had invested that in solar, I'd have had about 1400 watts of panels installed. I'd rarely use the generator.

I do snow bird in Florida--but I purchased a Condo there. That seems to have been a mistake--because now it is cheaper to fly than to drive down.

Don

I did go the opposite route as you have probably seen me post that I spent our money on solar and battery rather than the big expensive generator. It has worked out well for us in the situations we use it but as you found out, situations change. When the time does come that the solar can't keep up, I hope to goodness we are not in a dry campground where I will have to run that 3500/4000 around others.

[NinerBikes]

What will day 4 bring...

[pianotuna]

Day 3 and finally decent solar harvest.

My small inverter and parasitic loads amount to about 3.5 amps. So today the solar is running my laptop--and putting energy into the battery bank.

I did run the generator for .75 hours as it was 1 C this morning at 6 a.m. During the generator run of .25 hours for breakfast the Magnum was in float at 13.8 with 20 amps showing. That means 16.5 going into the battery bank, plus what ever the panels are 'doing'.

See day 4 for the rest of day 3.