Datel round digital voltmeter install

UroGator

Saw this round Datel DMR20-10-DCM round digital voltmeter on the Yamaha section and decided to install in place of my generic rectangular cheapo I got off eBay. This meter is accurate to one hundredth of a volt (ie. 38.xx etc) and is nice and small. Here's my custom made aluminum backing plate I made to fit all the switches and meter. I like it much better than my old rectangular meter and the superb accuracy is icing on the cake. With this new meter, I found that my old SOC meter was actually 0.3 volts off (too low).

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BGW

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UroGator

Another pic (can't figure out how to attach more than one photo at a time from my phone)

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JohnnieB

I may be picking nits, but the Accuracy is +/- 0.06V in the LO range while the Resolution is 0.01V,

Nice installation.

Hopefully, you put the batteries on charge after taking the pictures, they are down to 84.7% SoC.

Do you have it connected directly to the battery, or tapped into the keyswitch?

UroGator

Thanks!

Just bought the cart and it has 3 year old Trojan T-605s that I can only get to charge up to 90% max capacity. Going to pick up 6 new Trojan T-105s this Friday so I can get up to 38.20 .

I have this wired straight to battery. I love walking by the cart seeing the actual state of charge of the batteries. I have them on a float charger, so the minimal draw the meter has makes no difference.

JohnnieB

I'm probably preaching to the choir, but for the benefit of those not aware of how to break in new batteries.

As received by the customer, new batteries only have about 75% of their maximum storage capacity, and have to be broken in properly to reach their full potential.

Be sure to charge the new batteries before you use them the first time. It's okay to test the cart to make sure the batteries are wired correctly, but don't take it out for a drive until the batteries receive a full charge after being installed in cart.

The first charge often takes a long time. Six to ten hours isn't unusual and some new battery packs have taken upwards of twenty hours, so the back-up timer (typically 16 hours) may shut-off the charger before the pack is fully charged and the charger may have to be re-started to reach a full charge.

Everybody's cart usage is different, but for the first dozen or two charge cycles avoid discharging below about 75% SoC. If your cart usage is light, try to discharge to 90% SoC or lower on your daily trips and intentionally take some longer trips to get them below 80% SoC.
Basically, use the batteries at least a bit, but not too much for the first two to four weeks of daily use, then use them like you normally would.

For maximum lifespan, recharge after each use.

BTW: Being directly connected to the battery pack will give you the most accurate voltage readings.

UroGator

Thanks johnnieB for the advice. That's what I intend to do.

However, the story is a bit more complicated than just buying new batteries. I actually already bought one new T105 to replace a shorted out battery last month when I initially bought the cart. This was before I found this great site and wealth of info and learned that running the new battery with the old is a bad idea. So I am actually buying 5 new T105s to complete the new pack. My questions is, how should I equalize the battery I bought last month with the 5 new batteries? Should I bring that one battery down to 75% SOC before I charge all the other 5 up with this single newish 6v?

JohnnieB

It gets a little confusing because batteries have the same voltage regardless of what their Storage Capacity (AH) is. A new battery (and an old battery) have less storage capacity, but the will read about the same voltage when the are at 100% SoC (State of Charge) and when they are at 50% SoC, or anywhere else between 0% SoC and 100% SoC.

A new T-105 may only have about 170AH of storage capacity when you get it from the vendor, but will read about 6.37V (Typically a bit higher)when fully charged (100% SoC). After it is broken in, it will have about 225AH of storage capacity, but will still read about 6.37V when fully charged.

Putting a new T-105 in an old pack did age it some, but probably not very much in a single month and some, if not all, of that aging is reversible.

If you can lay your hands on a 6V charger, charge that battery until the On-Charge voltage stops climbing. Then add it to the five new ones and charge with your 36V charger.

Then check the On-Charge voltage of the individual batteries while charging. They should all six be about the same (within 0.1V of each other)

If not, initiate another charge cycle and measure again. Repeat until the On-Charge voltage is close as you can get it.

If you don't have access to a 6V charger, connect the the old battery with the highest On-Charge voltage in series with the new one and use a 12V charger.

Worst case, charge the new battery as fully as possible in the old pack and the repeatedly charge the new pack after that battery is installed until the On-Charge voltage evens out.

This is called equalization charging.

Mancebo

UroGator,
Do you have any pics on the install? How easy was it to wire it up? Does yours turn off on key switch. I ordered my DVM from Scottyb, and I always like to research prior to receiving parts so I know if it is a 6 pack job, or a case. Any information you provide would be greatly appreciated.

UroGator

Can you see the picture on the first post? Was very easy to install. Ran wire from positive and negative terminals from battery to gauge. Took about 15 minutes to install. It never turns off but the battery drain is so minimal that it doesn't matter. The benefit of never turning off is that I always know what the pack voltage is also.

mattadata

I agree! I used to have it connected at the key switch. I used to think that having it on all the time would bug me.....kinda like leaving the house with a light on.

But after I changed it to direct attach to the pack, I can easily glance at it while walking past it. I like it much better this way.